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1
Sitters, Humphrey P. "The role of night-feeding in shorebirds in an estuarine environment with specific reference to mussel-feeding oystercatchers." Thesis, University of Oxford, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.342740.
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Zharikov, Yuri. "Feeding ecology of shorebirds (Charadrii) spending the non-breeding season on an Australian subtropical estuarine flat /." St. Lucia, Qld, 2002. http://www.library.uq.edu.au/pdfserve.php?image=thesisabs/absthe16734.pdf.
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Kalejta, Bozena. "Aspects of the ecology of migrant shorebirds (Aves: Charadrii) at the Berg River estuary, South Africa." Doctoral thesis, University of Cape Town, 1992. http://hdl.handle.net/11427/14287.
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Includes bibliographies.The waterbird populations of the Berg River estuary, South Africa, were studied from September 1987 to April 1989. The main objectives of the study were to assess the importance of the estuary for Palearctic-breeding migratory waders and to identify the factors affecting their distribution, abundance and behavioural patterns. The findings were related to the dispersion patterns of waders on the east Atlantic seaboard, and their significance was evaluated in the light of predictions of current models for the migratory behaviour of shorebirds. Controversy over the Winter competition model is discussed. The intertidal mudflats (144 ha) at the Berg River estuary support an exceptionally high density of migratory shorebirds during the austral summer. The high density of birds results in a high predation pressure. Although the rate of prey removal by birds is one of the highest recorded in the east Atlantic, it represents only 17% of the annual production of invertebrates. A bird-exclusion experiment confirmed that birds have little impact on their prey populations. Although the energy balance for the majority of species was apparently negative for much of the austral summer, the energy deficits measured in the field were less than those recorded in north temperate estuaries. The highest predation pressure by birds coincided with the period of highest production of the most important invertebrate prey. Because of low prey diversity in the estuary, there was considerable overlap in the prey species taken by different bird species. The preferred prey of most species were nereid worms. Within this prey class there were clear differences in the size classes of worms eaten by different birds. The distribution of birds on the estuary was related to both biotic and abiotic factors. The observed patterns of partitioning of both food and space resources was attributed to the superabundance of prey and to interspecific differences in foraging techniques unrelated to competition. The spatial redistribution of birds within the estuary during the first four months after their arrival from the breeding grounds was related to changes in feeding conditions on their preferred foraging sites, rather than density-dependent factors mediated by competition. I propose that a combination of high prey abundance and production, coupled with an apparently low level of competition, makes the Berg River an attractive nonbreeding site for migrant waders. Their relatively sound energy budgets and the benign climate may enhance nonbreeding survivorship sufficiently to offset any additional risks incurred in long-distance migration.
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Scott, Ian Alexander. "Studies on seasonal variation in metabolic rate related to changes in body composition with particular reference to shorebirds (Charadrii)." Thesis, Durham University, 1992. http://etheses.dur.ac.uk/6207/.
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The basal metabolic rate of three species of shorebird was measured throughout the non-breeding season. These measurements were related to change in body mass and body composition. No seasonal pattern in BMR was apparent after variation related to changes in body mass and body composition had been accounted for. Seasonal variation in body mass of captive Grey Plover and Redshank was found to resemble that of the same species in the wild. This was not so for Sanderling. Body composition changes were either inferred from destructive analysis, or measured using a technique known as total body electrical conductance (TOBEC). The intraspecific relationship between TLM (Total lean mass) and TOBEC index was found to be best described by a linear equation. Separate intraspecific allometric equations were derived relating BMR to body mass for two shorebird and one wildfowl species. The mass exponents in these equations were found to be 1.03, 0.62 and 0.61 for Redshank, Grey Plover and Wigeon respectively. The results were related to the current interpretations of the BMR/body mass exponent. The within-individual BMR/body mass relationship was investigated for Redshank and Grey Plover. The mean mass exponent was found to be 1.23 and 0.92 respectively. No significant relationship was found for any individual Sanderling. Variation in BMR within an individual was related to variation in body composition. In most cases variation in body fat was found to be the most important predictor of within-individual variation in metabolic rate. In Vitro determinations of the oxygen uptake of avian fat, liver and muscle tissues indicated that the energy consumption of fat was less than one tenth that of liver and muscle. This indicates that within-individual increases in BMR with increased levels of fat are probably associated with increased metabolic output of the lean tissues.
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Turpie, Jane. "Comparative foraging ecology of two broad-ranging migrants, grey plover Pluvialis Squatarola and whimbrel Numenius Phaeopus (Aves: Charadrii), in tropical and temperate latitudes of the Western Indian Ocean." Doctoral thesis, University of Cape Town, 1994. http://hdl.handle.net/11427/8494.
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Bibliography: leaves 186-205.A seasonal study of the nonbreeding foraging ecology of Grey Plovers and Whimbrels was undertaken at the Zwartkops estuary, South Africa, and additional data were collected from a variety of sites in tropical and south temperate latitudes during the premigratory period. The main objective of the study was to provide comparative data on shorebird foraging ecology in the southern hemisphere, in order to contribute to the general understanding of shorebird foraging behaviour and migration patterns.
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Elias-Gerken, Susan P. "Piping plover habitat suitability on central Long Island, New York barrier islands." Thesis, This resource online, 1994. http://scholar.lib.vt.edu/theses/available/etd-12052009-020325/.
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Kupper, Clemens. "Molecular ecology of the Kentish plover Charadrius alexandrinus." Thesis, University of Bath, 2008. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.492099.
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Molecular ecology has already provided profound insights into behaviour, ecology and systematics of organisms improving our understanding of the relationship between genetic variation and biodiversity. The objectives of my PhD were to develop new genetic markers and use these markers to address fundamental issues in evolutionary biology using shorebirds as model organisms. Shorebirds are part of the ancient avian Charadriiformes order and are characterised by extraordinary ecological and behavioural diversity. However, due to the lack of appropriate genetic markers the molecular ecology of many shorebirds has not been investigated previously. Therefore, first, I developed polymorphic microsatellite markers from genomic libraries for a behaviourally diverse shorebird, the Kentish plover Charadrius alexandrinus (Chapter II). Second, using the genomic data-bases I expended this work to develop further markers that cannot only be used in the Kentish plover, but also a large number of other shorebird species (Chapter III). Third, I investigated population differentiation and genetic diversity of Eurasian and American Kentish plover populations using the newly developed microsatellite markers and further mitochondrial markers (Chapter IV). The genetic differences between Eurasian and American populations that are mirrored by phenotypic differences call for a reconsideration of the current taxonomic status of the species; Eurasian and American populations should be recognised as belonging to two separate species. Finally, I asked how genetic diversity influences the fitness of precocial Kentish plover young (Chapter V). I found that survival of chicks until fledging was associated with genetic diversity (measured as heterozygosity) at three of eleven marker loci. Genetic diversity at one marker locus had a positive effect on survival whilst it had negative effects at two loci. The results of my PhD have brought up many new questions and I propose promising lines that need to be explored in the future (Chapter VI).
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Burns, Fiona E. "Conservation biology of the endangered St. Helena Plover Charadrius sanctaehelenae." Thesis, University of Bath, 2011. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.544502.
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Oceanic islands contribute significantly to global biodiversity due to the high levels of endemism they exhibit. Many island species have, however, become extinct following the arrival of humans, and many others remain threatened. This thesis focuses on one of these threatened island species; the St. Helena Plover, Charadrius sanctaehelenae. The objectives of my PhD were threefold: to understand the current status of the St. Helena Plover, to investigate aspects of its environment that may threaten its persistence, and to compare conservation options. Observational data were used to understand how variation in the environment influences the plover’s distribution and demography. This information was used to inform a controlled trial investigating the use of nest exclosures as a way to improve productivity. New understanding of the species’ population ecology was brought together to create a stochastic meta-population model. This model was used to understand the influence of demographic and life history parameters on the population growth rate and to compare alternative conservation options. Indicators of the future status of the St. Helena Plover population appear mixed; with numbers predicted to decline slowly, but with a high chance of species persistence over the timeframe simulated, 50 years. Nest predation by introduced species, predominately cats, was predicted to suppress nest survival and bring productivity at some sites below that required for population stability. The use of nest exclosures did not increase nest survival and led to a decrease in adult survival. Habitat characteristics were more important in determining the species distribution than influencing its demography. The plovers appeared to select breeding habitat to maximise the visibility from the nest and the accessibility of invertebrate prey. Simulations suggested that predator control would have a large beneficial effect on the population growth rate and that concurrent habitat improvement would have greater than additive benefits. Targets for conservation management include Deadwood Plain; predator control as this key site was predicted to lead to the largest increase in the overall population growth rate, and Man and Horse; there may be potential at this site to increase adult survival, which was found to be the most influential demographic parameter.
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Le, Fer Danielle. "Piping plover (Charadrius melodus) foraging ecology in the Great Plains." Diss., Virginia Tech, 2006. http://hdl.handle.net/10919/28695.
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The Great Plains piping plover (Charadrius melodus) population was listed as threatened under the Endangered Species Act in 1986. The challenge for managers of this population is to increase the fledging rate and to ensure that there is sufficient habitat to support an increasing population. According to the revised recovery plan, there are insufficient quantitative data that relate habitat characteristics to reproductive success in riverine habitat. In particular, additional data are needed to determine if piping plover reproduction is limited by food abundance at breeding sites. The goal of this research was to determine whether piping plover chick survival was limited by foraging site quality on the Missouri River. Productivity has historically varied among river reaches. The alkali wetlands, reported to be very productive, serve as an index to the upper limit of reproductive potential. We compared indices of foraging site quality, chick growth and survival among a reservoir, two river reaches and alkali wetland sites from 2001-2003. We compared piping plover use of protected shoreline and exposed shoreline to availability along two reaches of the Missouri River (Gavins and Garrison). We also examined piping plover chick diet. Chick weight gains were higher at alkali wetlands than Gavins and Garrison. Invertebrate numbers were higher at the alkali wetlands than the three river sites and lowest downstream of the cold water release dam. Invertebrate biomass was highest at the alkali wetlands and downstream of the warm water release dam and lowest downstream of the cold water release dam. Invertebrate biomass downstream of the cold water release dam was the lowest of all 4 sites. There was no relationship between chick daily survival rates and invertebrate biomass or predator presence. Although Diptera occurred more frequently (23% - 64%) at all sites (sticky traps), Coleoptera occurred most frequently in the fecal samples (fecal analysis; 69% to 89%). On the Missouri River, protected shorelines were important foraging sites for piping plovers during the breeding season. We also found that sandbars with low-lying moist habitat are important to foraging chicks. Results are consistent with the prediction that foraging conditions downriver from cold water release dams are inferior to conditions in other habitats in the region. Differences in prey availability are reflected in chick growth rates, but not in survival rates. These results underscore the variability in different indices of habitat quality (invertebrate indices, predation, growth rates, survival rates) among the four sites, and the need for monitoring and management strategies that address each site individually. When managing or creating sandbars, ensuring the availability of protected shoreline will benefit piping plovers on the Missouri River.Ph. D.
10
Badzinski, Debra S. "Population dynamics of semipalmated plovers (Charadrius semipalmatus) breeding at Churchill, Manitoba." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2001. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp04/MQ57977.pdf.
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Skrade, Paul Daniel Blom. "Incubation behavior and dispersal patterns in the Mountain Plover (Charadrius montanus)." [Ames, Iowa : Iowa State University], 2008.
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12
Dos, Remedios Natalie. "The evolutionary history of plovers, genus Charadrius : phylogeography and breeding systems." Thesis, University of Bath, 2014. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.619154.
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Identifying the mechanisms driving the evolution of breeding systems is one of the central goals in behavioural and evolutionary ecology. Understanding the evolutionary history of species of interest is fundamental to this goal. The objectives of this PhD were, firstly, to investigate the role of sex biases in breeding system evolution among closely-related populations and, secondly, to explore the phylogeographic origins of the plovers, genus Charadrius. The plovers are characterised by extraordinary ecological and behavioural diversity and are therefore ideal study species for this work. Firstly, I investigated the role of sex biases among offspring in breeding system evolution at the population level across four populations of Kentish and snowy plover exhibiting differing levels of male and female care. Theoretical hypotheses link male-biased offspring sex ratios, mating opportunities and male parental care. I present modest support for this hypothesis: male offspring had higher survival levels than female offspring under particular conditions (Chapter 3), and also a tendency for faster growth (Chapter 4) in two populations with predominantly male parental care in contrast to two populations with more balanced parental care roles. Without a phylogenetic framework for the genus Charadrius, evolutionary studies on these diverse shorebirds have been limited in scope. Therefore, secondly, I present the first global, species-level molecular phylogeny of the genus Charadrius and outline their phylogeographic origins. I identified the Northern hemisphere (North America, Europe and Siberia) as the origin of the ancestral Charadrius species between 19.2 and 36.6 million years ago (Chapter 5). I suggest that early evolutionary diversification occurred due to shifts in the range of ancestral Northern hemisphere species in response to global cooling during the Miocene period, leading to colonisation of the Southern hemisphere (Chapter 5). Thirdly, I present the results of a more in-depth phylogeographic study on the Charadrius plovers of Africa. I identified the widespread Kittlitz’s plover (C. pecuarius) as the closest sister species to the ‘critically endangered’ St Helena plover (C. sanctaehelenae) and ‘vulnerable’ Madagascar plover (C. thoracicus; Chapter 6). Additionally, I identified genetic structure consistent with subspecies status among African populations of the white-fronted plover (C. marginatus), three-banded plover (C. tricollaris) and chestnut-banded plover (C. pallidus), but not the Kittlitz’s plover (Chapter 6), with implications for the influence of breeding systems on population-level genetic differentiation. Overall, this thesis both highlights and facilitates several promising new lines of investigation for future research, with the Charadrius plovers as ideal study species (Chapter 7).
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Owens, Ian Peter Farrar. "Sexual selection in the sex-role reversed Eurasian dotterel, Charadrius morinellus." Thesis, University of Leicester, 1991. http://hdl.handle.net/2381/34187.
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Current theory concerning the evolution of parental care posits that one or both of the sexes may reduce parental care when the fitness gained from alternative reproductive opportunities exceeds that from continuing with parental care. If this situation leads to a difference between the sexes in potential rate of reproduction, intra-sexual competition for mates will occur in the sex with the higher potential reproductive rate, and the other sex will display mate choice (called inter-sexual selection). In the majority of avian species biparental care is the most common form of parental care. Polygyny is the most common consequence of polygamy; males compete for access to females and females exercise mate choice. Sex-role reversal is rare (ca. 3% of species in the world) but presents an opportunity to test the basis of theories of the evolution of parental care and sexual selection. This thesis presents the results of a three-year study of sexual selection and sex-role reversal in a breeding population of the Eurasian dotterel, Charadrius morinellus, in the Cairngorm region of Scotland. In this species, the female is the competitive sex and the male usually provides all of the parental care; females are sequentially polyandrous. Dotterel are dependent on a widely dispersed breeding habitat. Rather than defending territories, females compete for access to males on mating arenas (Chapter 2). After producing a clutch, females return to the arenas in order to compete for further males, this leads to a female-biased skew in the operational sex ratio (Chapter 3). The proximate factors which produces the skew in the sex ratio predict the temporal variation in the potential for sexual selection (Chapter 3). There is considerable intra-sexual plumage variation which is correlated with behavioural variability (Chapter 4). Bright females are more aggressive than dull females and thus initiate and win more fights (Chapter 4). Bright females also perform more courtship than do dull females and therefore get mates earlier in the season, as, via assortative mating, do bright males (Chapter 4). Females are, however, also the more choosy sex; females prefer to court bright males which are, in turn, likely to be in better physical condition than duller males (Chapter 4). Bright males are less likely to desert the clutch in bad weather conditions (Chapter 5). Females therefore appear to choose males on the basis of their ability to incubate their clutch. Male dotterel, because of their high level of parental care and relatively low potential rate of reproduction, are expected to exhibit behaviour which has been selected to protect their paternity. This prediction is upheld; male dotterel assure paternity of the brood for which they care through a combined strategy of prolonged, close mate-guarding and strategically timing copulations to the few days immediately before egg-laying (Chapter 6). Active female choice for male quality related to phenotypic traits which are also influenced by the environment is contrary to the predictions of the conventional theory of mate choice. In sex-role reversed species, because the potential reproductive rate of the male is lower, male choice is expected. A new model of mate choice is introduced and used to study the effects of differences between the sexes in both the relative potential reproductive rate and relative variation in mate quality (Chapter 7). This model is successful in predicting the form of mate choice observed for all permutations of variation in potential reproductive rate and mate quality. Finally, sex-role reversed mating arenas are compared with polygynous lekking (Chapters 3,4,7). Constraints on the potential reproductive rate of females determine that the direction of mate choice will only rarely be reversed in non-territorial sex-role reversed species (Chapter 7). Therefore, although the mating arenas of dotterel resemble leks, an important component of true lekking, active mate choice by the non-competitive sex, is absent.
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Catlin, Daniel H. "Population Dynamics of Piping Plovers (Charadrius melodus) on the Missouri River." Diss., Virginia Tech, 2009. http://hdl.handle.net/10919/27442.
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Habitat loss and predation are threatening many shorebird populations worldwide. While habitat preservation often is preferable, sometimes habitat needs to be restored or created in order to stave off immediate declines. The Great Plains population of piping plovers (Charadrius melodus) was listed as threatened in 1986, and habitat loss and predation appear to be limiting the growth of this population. On the Missouri River, piping plovers nest on sandbars, but the damming of the mainstem of the Missouri in the mid-twentieth century reduced the natural capacity of the Missouri River to create sandbar habitat. In 2004, the United States Army Corps of Engineers (USACE) implemented a habitat creation project on the Gavins Point Reach of the Missouri River (stretch of river immediately downriver from the Gavins Point Dam) in an effort to promote recovery of piping plovers and the endangered least tern (Sternula antillarum). The USACE built 3 sandbars in 2004 â 2005 and built another sandbar on Lewis and Clark Lake in 2007. We studied the population dynamics of piping plovers in relationship to this newly engineered habitat. We monitored 623 nests on 16 sandbar complexes, to evaluate habitat selection, determine the factors affecting nesting success, and compare nesting success between natural and engineered habitat. From these 623 nests, we banded 357 adults and 685 chicks to investigate the factors affecting adult and juvenile survival. We used a logistic-exposure model to calculate nest survival. Adult and juvenile survival was calculated using Cormack-Jolly-Seber based models in Program MARK. We used the estimates from these studies to create a matrix population model for piping plovers nesting on the Gavins Point Reach. We used this model to predict the effects of engineered habitat on the population growth rate.
Piping plovers selected for engineered sandbars and against natural and natural/modified habitats. Daily survival rate (DSR) on engineered habitats was significantly higher than on natural or natural modified habitats (log odds: 2.71, 95% CI: 1.20 â 6.08). Predator exclosures around nests did not affect DSR after controlling for the effects of date, nest age, and clutch size. Piping plover juvenile survival to recruitment was negatively related to nesting density on the relatively densely populated engineered sandbars. On the less dense natural sandbars, survival to recruitment was positively correlated with density. Adult survival did not appear to be related to density within our study. Movement within the study area was related also to density. Juveniles from densely populated engineered sandbars were more likely to leave engineered habitat to nest on natural sandbars than were juveniles hatched on less densely populated engineered sandbars. Movements among sandbars by breeding adults suggested that adults preferred engineered habitat. It is possible that juveniles moved to natural habitats because they were unable to compete with adults for the more desirable engineered habitats. Adults and juveniles emigrated from the study area at a higher rate after the 2006 breeding season, a year when water discharge was higher, nesting densities were higher, and reproductive success was lower (as a result of predation) than in the other years. Deterministic modeling suggested that engineered habitat significantly increased population growth. Decreased productivity over time and associated predicted negative population growth suggest that the amount of engineered habitat created was inadequate to sustain population growth, and/or that relatively high water discharge and nesting densities coupled with low reproductive rates and high emigration rates could lead to rapid declines in the plover population. Continued research is needed to determine the effects of these factors on long-term population growth. Our results suggest that habitat creation could be a viable short-term solution to population declines in shorebird populations limited by habitat loss, but high densities and increased predation associated with habitat creation indicate that other, long-term solutions may be required.Ph. D.
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Catlin, Daniel Herbert. "Population Dynamics of Piping Plovers (Charadrius melodus) on the Missouri River." Diss., Virginia Tech, 2003. http://hdl.handle.net/10919/27442.
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Habitat loss and predation are threatening many shorebird populations worldwide. While habitat preservation often is preferable, sometimes habitat needs to be restored or created in order to stave off immediate declines. The Great Plains population of piping plovers (Charadrius melodus) was listed as threatened in 1986, and habitat loss and predation appear to be limiting the growth of this population. On the Missouri River, piping plovers nest on sandbars, but the damming of the mainstem of the Missouri in the mid-twentieth century reduced the natural capacity of the Missouri River to create sandbar habitat. In 2004, the United States Army Corps of Engineers (USACE) implemented a habitat creation project on the Gavins Point Reach of the Missouri River (stretch of river immediately downriver from the Gavins Point Dam) in an effort to promote recovery of piping plovers and the endangered least tern (Sternula antillarum). The USACE built 3 sandbars in 2004 â 2005 and built another sandbar on Lewis and Clark Lake in 2007. We studied the population dynamics of piping plovers in relationship to this newly engineered habitat. We monitored 623 nests on 16 sandbar complexes, to evaluate habitat selection, determine the factors affecting nesting success, and compare nesting success between natural and engineered habitat. From these 623 nests, we banded 357 adults and 685 chicks to investigate the factors affecting adult and juvenile survival. We used a logistic-exposure model to calculate nest survival. Adult and juvenile survival was calculated using Cormack-Jolly-Seber based models in Program MARK. We used the estimates from these studies to create a matrix population model for piping plovers nesting on the Gavins Point Reach. We used this model to predict the effects of engineered habitat on the population growth rate.
Piping plovers selected for engineered sandbars and against natural and natural/modified habitats. Daily survival rate (DSR) on engineered habitats was significantly higher than on natural or natural modified habitats (log odds: 2.71, 95% CI: 1.20 â 6.08). Predator exclosures around nests did not affect DSR after controlling for the effects of date, nest age, and clutch size. Piping plover juvenile survival to recruitment was negatively related to nesting density on the relatively densely populated engineered sandbars. On the less dense natural sandbars, survival to recruitment was positively correlated with density. Adult survival did not appear to be related to density within our study. Movement within the study area was related also to density. Juveniles from densely populated engineered sandbars were more likely to leave engineered habitat to nest on natural sandbars than were juveniles hatched on less densely populated engineered sandbars. Movements among sandbars by breeding adults suggested that adults preferred engineered habitat. It is possible that juveniles moved to natural habitats because they were unable to compete with adults for the more desirable engineered habitats. Adults and juveniles emigrated from the study area at a higher rate after the 2006 breeding season, a year when water discharge was higher, nesting densities were higher, and reproductive success was lower (as a result of predation) than in the other years. Deterministic modeling suggested that engineered habitat significantly increased population growth. Decreased productivity over time and associated predicted negative population growth suggest that the amount of engineered habitat created was inadequate to sustain population growth, and/or that relatively high water discharge and nesting densities coupled with low reproductive rates and high emigration rates could lead to rapid declines in the plover population. Continued research is needed to determine the effects of these factors on long-term population growth. Our results suggest that habitat creation could be a viable short-term solution to population declines in shorebird populations limited by habitat loss, but high densities and increased predation associated with habitat creation indicate that other, long-term solutions may be required.Ph. D.
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Noel, Brandon Lennon. "The winter ecology of the piping plover (Charadrius melodus) in coastal Georgia." Connect to this title online (Georgia Southern site) Connect to this title online (U.S. Fish & Wildlife Service site), 2006. http://www.fws.gov/nc-es/birds/Noel_2006_MSThesis.pdf.
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Hoffmann, Alexandra. "Incubation behavior of female western snowy plovers (Charadrius alexandrinus nivosus) on sandy beaches /." California : Humboldt State University, 2005. http://hdl.handle.net/2148/19.
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Argüelles-Ticó, Araceli. "Sexual selection, breeding systems and melanin-based plumage colouration in plovers Charadrius spp." Thesis, University of Bath, 2011. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.582832.
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Documenting behavioural and morphological differences across populations reflecting local adaption is of large interest to biologists. Yet, natural, geographic variation in targets and intensity of selection within species has been vastly underexplored. Here I focus on how the extraordinary diversity of breeding systems exhibited across multiple populations of plovers may influence ornamentation. Using data from nine geographically distinct populations of Kentish (Charadrius alexandrinus) and snowy plovers (C nivosus) I explore the variation in brood care and found extensive differences across populations in the duration of care and timing of brood desertion. Biogeographical parameters seem to partly explain the observed diversity of care patterns. I subsequently show that the differences in melanin-based plumage ornamentation across populations were predicted by the breeding system and geographic and climatic factors. I argue that geographic variation in intensity of sexual selection as associated with the diversity in breeding systems may shape individual phenotypes. To corroborate that proposition, I investigate whether the signalling function of the ornaments varies across populations. I show that melanin-based plumage traits are honest signals of parental care in two distinct populations, despite differences between both populations in the extent and direction to which both sexes adjust parental care in response to ornamentation. In my final chapter I aim to explore a potential mechanistic basis of the diversity in ornamentation by investigating correlations between melanic plumage traits. The correlations between plumage traits are highly variable across populations. Such apparent phenotypic plasticity suggests that local selection pressures influence the expression of melanisation. In sum, in my thesis I show that the behavioural and morphological outcomes of local adaptive regimes provide a wealth of diversity in natural history between populations. Exploring this natural variation at a behavioural, physiological and genetic level is likely to substantially advance our understanding of what constitutes a wild animal's phenotype.
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Zonick, Curtis A. "The winter ecology of piping plovers (Charadrius melodus) along the Texas Gulf Coast /." free to MU campus, to others for purchase, 2000. http://wwwlib.umi.com/cr/mo/fullcit?p9988713.
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Keane, Shannon E. "Effects of Herring Gulls and Great Black-backed Gulls on Breeding Piping Plovers, South Monomoy Island, Massachusetts." Thesis, Virginia Tech, 2002. http://hdl.handle.net/10919/35908.
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The large population of breeding Herring Gulls and Great Black-backed Gulls on South Monomoy Island, Cape Cod, Massachusetts has been thought to negatively affect the breeding success of the threatened Piping Plover. Following the Piping Plover Recovery Plan s call for gull colonies to be removed from Piping Plover breeding sites, in 1996, the USFWS conducted gull removal on part of South Monomoy Island. We determined relative gull abundance on South Monomoy Island from 1998-2000 by counting gulls within 100-m radius plots located on the shoreline. We quantified Piping Plover behavior and habitat use by conducting instantaneous and 5-minute behavioral observations. We quantified characteristics of Piping Plover nesting habitat by measuring characteristics along random transects. We measured gull abundance, beach width, and prey abundance, and then used logistic regression to determine what habitat characteristics influenced Piping Plover nesting area selection. We monitored Piping Plover reproductive success and population fluctuations on South Monomoy Island.
Gull abundance in the gull-removal area was lower than gull abundance in the reference area throughout the Piping Plover breeding season. The difference in gull abundance between the areas did not affect Piping Plover behavior, nest success, chick survival, or productivity. We found that gull removal did not result in an increased Piping Plover population on the island. In both management areas, prenesting plovers preferred to forage in moist substrate habitats. Wide backshore and open vegetation habitats characterized nesting areas. Broods spent most of their time foraging and preferred moist substrate habitats when available. Plovers were not prevented from occupying more suitable habitat by large gulls.
Fewer large gulls were observed near prenesting plovers, plover nests, and plover broods than near random plots. Fewer large gulls were observed in plover nesting areas than in unused areas when the nesting areas were defined by all area within 100-m or 500-m of a plover nest. We argue that this apparent spatial separation between Piping Plovers and large gulls is due to different habitat preferences among the species. We found that gull removal on South Monomoy Island did not result in increased Piping Plover reproductive success, and large gulls did not affect breeding Piping Plovers on South Monomoy Island from 1998-2000.Master of Science
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Sung, Ha-Cheol. "Vocal communication and individuality of piping plovers (Charadrius melodus), description, quantification, and applications for management." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape7/PQDD_0033/MQ62432.pdf.
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Weithman, Chelsea E. "Piping Plover (Charadrius melodus) demography, behavior, and movement on the Outer Banks of North Carolina." Thesis, Virginia Tech, 2019. http://hdl.handle.net/10919/89915.
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The Piping Plover (Charadrius melodus) is an imperiled shorebird that inhabits sandy beaches along the North American Atlantic Coast. The species' decline has been attributed to habitat loss, disturbance, and predation throughout its range, although most conservation efforts have focused on increasing reproductive output during the breeding season. On the coast of North Carolina, Piping Plovers breed in areas with large amounts of recreational and tourism use. Beach recreation is known to reduce nest success, chick survival, and potentially fitness in other parts of the species' range. To reduce potential negative effects from human activities on breeding Piping Plovers, managers close areas to pedestrian and vehicle access using exclusion buffers delineated by symbolic fencing. However, the reproductive success and population size of Piping Plovers in parts of North Carolina has not appeared to increase as a result of these management strategies, despite the importance of the park and its protections to these birds on their southward migration in the fall.
To understand how disturbance and attempts to mitigate it affected plover demography, we examined Piping Plover population dynamics, brood movement, and migration in North Carolina from 2015–2017. We monitored 46 nests and 19 broods, and we used a logistic exposure nest survival model and Cormack-Jolly-Seber model to estimate reproductive success. We uniquely banded 77 adults and 49 chicks to understand annual survival and fidelity rates using a live encounter mark-recapture model. During the pre-fledge period, we observed movements of Piping Plover broods, and we gathered information on their environment that may affect their behavior. We recorded 191 brood locations, collected 132 focal chick behavior samples, and 113 potential disturbance environmental samples. We used multiple linear regression to evaluate several hypotheses regarding daily and hourly brood movement rates. We also conducted 22 migratory surveys after the breeding season in 2016 at an area in Cape Hatteras National Seashore thought to be used by large numbers of south-bound migrating Piping Plovers. We used integrated Jolly-Seber and binomial count models on resighting and count data to estimate stopover superpopulation and stopover duration of migrating birds based on their breeding region of origin.
Annual survival of adults from North Carolina (x ̅ = 0.69, SE = 0.07) was not different from another population on Fire Island, New York (x ̅ = 0.73, SE = 0.04), but the North Carolina population annually had low reproductive success, primarily due to low rates of chick survival. As a result, the North Carolina population was predicted to decline during the study period (λ<1 each year). Historically this population has not met the estimated rate of reproductive output needed for a stationary population (1.07 chicks per pair, SE = 0.69); therefore, it is likely the population is sustained by immigration from an unknown source. Daily (x ̅ = 71.5m/24hr) and hourly (x ̅ = 183.3m/hr) brood movements each had considerable variation (Daily: SD = 70.6, range = 0.0–327.2m; Hourly: SD = 262.3, range = 0.2–1450.9m). Chicks did not appear to move in response to the environmental factors we examined. The rate of brood movement suggests regular daylight monitoring is necessary to adequately protect unfledged broods from anthropogenic disturbance under current management methods. We found that 569 Piping Plovers (95% CI: 502–651), nearly 15% of the estimated Atlantic Coast population, stopped at a single area in Cape Hatteras National Seashore, North Carolina during fall migration. Birds stayed an average 4–7 weeks, depending on the breeding region from which they migrated, and they primarily used a relatively new protected area. These findings suggest that North Carolina is an important area for Piping Plover ecology during multiple stages of their annual cycle.Master of Science
A federally threatened species, the Piping Plover (Charadrius melodus) lives on sandy beaches along the North American Atlantic Coast. On the coast of North Carolina, Piping Plovers breed in areas with large amounts of recreational and tourism use. To reduce potential negative effects on breeding Piping Plovers from human activities, land managers close areas to pedestrian and vehicle access. However, the plover population there has not appeared to grow as a result of these management strategies, but large numbers of migrant Piping Plovers have capitalized on this management. Recent work that hypothesized population dynamics in North Carolina may function differently than other Piping Plover populations, and this study was designed to test that hypothesis. To understand how disturbance, and attempts to mitigate it, affected plover demography, we studied Piping Plover population dynamics, chick movement, and migration in North Carolina from 2015–2017. We monitored breeding efforts of Piping Plovers and used banding techniques to understand survival of chicks and adults. We observed behavior and movements of Piping Plover chicks before they fledged and gathered information on habitat they selected and potential risks that may alter their behavior. We also conducted migratory surveys after the breeding season at an area thought to be used by large numbers of Piping Plovers. Survival of adult plovers from North Carolina was not substantially different from that of plovers from other areas, but the North Carolina population had low reproductive success caused by low chick survival, and we estimated the population was declining. However, historically this population has not had enough breeding success to maintain itself; therefore, it is likely the population relies on plovers that immigrate to North Carolina from elsewhere. Plover brood movement was variable, and did not move in response to several environmental factors. The rate of brood movements we observed suggest regular daylight monitoring is necessary to adequately protect unfledged broods from anthropogenic disturbance and mortality using current management methods. We found that nearly 15% of Atlantic Coast plovers stopped at a single area in Cape Hatteras National Seashore, North Carolina, during fall migration, staying an average 4–7 weeks. These findings suggest that North Carolina is a unique area to Piping Plover ecology during multiple stages of their annual cycle.
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Flynn, Laura. "Philopatry, nest site tenacity, and mate fidelity in semipalmated plovers, Charadrius semipalmatus, breeding at Churchill, Manitoba." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp04/mq21686.pdf.
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Zharikov, Yuri. "Mating behaviour and paternity of socially monogamous semipalmated plovers Charadrius semipalmatus breeding in the sub-Arctic." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp01/MQ30240.pdf.
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Schulz, Jessica L. "Factors Affecting Prey Availability and Habitat Usage of Wintering Piping Plovers (Charadrius melodus) in Coastal Louisiana." Thesis, University of Louisiana at Lafayette, 2016. http://pqdtopen.proquest.com/#viewpdf?dispub=10002450.
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The Gulf of Mexico is home to a large proportion of the wintering population of the threatened piping plover, but little is known about the bird’s ecology in this region. In Louisiana, the majority of wintering piping plovers are found on the state’s rapidly eroding barrier islands. Between August 2013 and May 2014, we conducted shorebird surveys to assess the abundance and habitat use patterns of piping plovers on a barrier island refuge in south central Louisiana. Seventy-five percent of piping plovers observed were foraging, mostly (92%) in the intertidal zone; 20% were roosting in more diverse microhabitats. To characterize the prey base for piping plovers on the islands, we collected core samples in the intertidal zone of two islands on the refuge. The invertebrate community was dominated by haustoriid amphipods, which comprised 87.5% of individuals collected. Bivalves and polychaetes accounted for 9.3%, and 2.7%, respectively. We used generalized linear models to evaluate the effects of environmental predictors on amphipod abundance and odds of bivalve and polychaete presence at the sample site scale, and also on piping plover densities at the transect scale. Moisture had a positive effect on amphipod abundance and polychaete presence. Seasonal patterns and between-island differences were observed in all three taxa, but these effects differed between main beach habitat and the gulf- and bay-sides of prominent sand spits. Amphipod densities and piping plover densities were correlated on Trinity Island and during spring 2014, but prey abundance did not differ between sample sites where piping plovers were foraging versus random sites. Uncertainty in the degree to which piping plover distributions in Louisiana are driven by prey abundance is of concern because the extensive beach nourishment programs being implemented to stave off coastal land loss may have potentially substantial impacts to benthic invertebrates and their predators.
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Gómez-Serrano, Miguel Ángel. "Ecología y conservación del Chorlitejo Patinegro (Charadrius alexandrinus) en ecosistemas dunares mediterráneos sometidos a perturbaciones humanas." Doctoral thesis, Universidad de Alicante, 2016. http://hdl.handle.net/10045/54306.
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En esta tesis doctoral se estudia la biología reproductora de una especie de ave limícola, el Chorlitejo patinegro, en ecosistemas dunares de playas del mediterráneo español. Se estudian diferentes aspectos de la reproducción de esta especie, como la selección del hábitat, supervivencia de los nidos o el comportamiento de las aves durante la incubación, en relación al nivel de perturbación humana de las playas. Se analizan diversos compromisos ecológicos que deben afrontar las aves en lo que respecta a la supervivencia de las puestas y el riesgo de depredación, como la relación entre el camuflaje de los nidos y la detección temprana de los depredadores (a través de la visibilidad desde el nido), o la contribución relativa de la defensa de los nidos (y los riesgos asumidos frente a la depredación) sobre el éxito reproductor. Se evalúan diferentes métodos de seguimiento de los nidos de varias especies de aves limícolas en relación a su uso como evidencias de existencia de actividad en las puestas, así como para la estimación del éxito o fracaso de los nidos. Finalmente, se presenta una revisión bibliográfica del impacto de las actividades humanas en playas sobre los procesos biológicos de las aves litorales. Se presentan numerosas propuestas de gestión para compatibilizar los usos turísticos de las playas con la conservación de las aves litorales.
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Richardson, Isabelle M. G. "Predator exclosures, a management technique to increase piping plover (charadrius melodus) reproductive success in the Canadian prairies." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp01/MQ40100.pdf.
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Bellman, Henrietta A. "Hurricane and human-induced habitat changes on Fire Island and Westhampton Island, New York, and the effects on breeding piping plovers (Charadrius melodus)." Thesis, Virginia Tech, 2019. http://hdl.handle.net/10919/87402.
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Barrier islands are dynamic environments facing increasing vulnerability to climate changes, sea level rises, and anthropogenic activities. Hurricane Sandy (October 2012) modified the Atlantic coast of the United States. On Fire Island and Westhampton Island, New York, multiple overwashes and three breaches occurred. The U.S. Army Corps of Engineers filled two breaches, increased dune elevation and stabilized dunes by planting American beachgrass (Ammophila breviligulata). They built two restoration areas to mitigate the impact of an island stabilization project to federally listed breeding piping plovers (Charadrius melodus). The goal of this thesis was to quantify habitat changes after Hurricane Sandy, and assess habitat use of piping plovers specifically in human-created restoration areas. We created land cover maps using an object-based classification method (overall accuracy 85%), and field-collected data from four post-hurricane habitat types. Vegetation cover increased across all habitat types, especially in manipulated (30.1% increase) and natural overwashes (37.9% increase), while dry sand for nesting declined by 8%. Vegetation density indices were higher in natural overwashes than planted engineered dunes, likely a reflection of plant age and establishment. We monitored 83 nests (67 pairs) of piping plovers from 2015�"2017. Restoration areas were successful in attracting breeding piping plovers, although pair densities were lowest in this habitat in 2016, and in 2017 plovers selected against the restoration areas (�2 = 29.47, df = 3, p<0.0001). There was no effect of habitat type on reproductive parameters. We suggest vegetation removal may be necessary to maintain early successional habitats for piping plover management.Master of Science
Barrier islands are thin strips of land, which generally lie parallel to the mainland. They are dynamic environments subject to change from weather conditions and ocean currents. They are vulnerable to future climate changes, sea level rise, and increased human activity. Hurricane Sandy, October 2012, caused major landscape changes to the Atlantic coast. On two barrier islands, Fire Island and Westhampton Island, south of Long Island, the U.S. Army Corps of Engineers (USACE) further modified the post-hurricane habitats. They created two restoration sites designed to offset the impact of an island stabilization project to a federally protected breeding shorebird, the piping plover. Piping plovers nest on unvegetated or sparsely vegetated sand. We created land cover maps from aerial images and collected field data to describe habitat changes after Hurricane Sandy (2013, 2015–2017) in four habitat types creating during or after the hurricane. The vegetation cover and density increased across these four habitats, but especially in the manipulated overwashes and natural overwashes. This is likely due to the age of the plants in each habitat type. As vegetation grew back, areas of sand in each habitat type declined. Human-created restoration sites were used by plovers but in 2017 plovers used them less than expected. We monitored piping plover nests and chicks (April to August 2015–2017), and there were no differences in these measurements among habitat types. The findings from this thesis will assist in piping plover conservation on Fire Island and Westhampton Island.
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Cross, Robert Richard. "Breeding Ecology, Success, and Population Management of the Piping Plover (Charadrius melodus) at Chincoteague National Wildlife Refuge, Virginia." W&M ScholarWorks, 1996. https://scholarworks.wm.edu/etd/1539626042.
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Wells, Michael John. "Aspects of the year-round ecology and behaviour of ringed Plovers Charadrius hiaticula on South Uist, Outer Hebrides." Thesis, Cardiff University, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.606100.
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Ringed Plovers Charadrius hiaticula L. were studied on South Uist, Outer Hebrides, from 1.11.83 to 30.12.86. Internationally important numbers were present throughout the year. Winter to summer residency was approximately 68%. The winter population was male-biased, and concentrated on 'feeding beaches' near rocky features of the coast. Site fidelity was high. The feeding beach invertebrate fauna was of low diversity, but exceptionally high density and biomass. Ringed Plover weights showed a variable midwinter peak. Individuals which disappeared between winters were lighter per unit body size than those which did not. Spacing behaviour varied from non-aggressive 'free-feeding' to the sharing of territories by individuals which then bred together inland. The probabilities of individuals holding territories varied with sex, age, size and environmental conditions. Fewer long-term to intermittently territorial males disappeared between winters than would have been expected from their proportion in the population.
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Robinson, Samantha G. "Piping plover habitat and demography following storm-induced and engineered landscape change." Diss., Virginia Tech, 2020. http://hdl.handle.net/10919/97725.
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Understanding the effects of large-scale disturbances and associated management actions on imperiled species can increase conservation value of future management. Piping plovers (Charadrius melodus) are federally threatened and endangered, disturbance-dependent shorebirds, nesting on broad, sparsely vegetated beaches, sandbars, and lakeshores. In October 2012, Hurricane Sandy storm surges cleared vegetation and opened old and new inlets through Fire Island and Westhampton Island, New York, creating plover habitat. Storm effects prompted an island-wide stabilization project, and certain sections of Fire Island were designed to create and/or improve plover habitat (hereafter, restoration areas) to mitigate possible habitat loss or degradation. Many plover populations range-wide appear to be habitat-limited, and we anticipated positive population growth following habitat creation.
To help predict what might happen to the plover population following Hurricane Sandy, we evaluated the effects of habitat-creating events at several other locations in the range, evaluating the hypothesis that plover population sizes are habitat limited. We estimated the amount of habitat available before and after four significant storm and flooding events by classifying pre- and post-disturbance aerial imagery and evaluated the population changes that occurred after disturbance-related habitat alterations. Following these habitat creating events, nesting habitat increased 27%–950%, and, subsequently, these plover populations increased overall 72%–622% (increase of 8–217 pairs in 3 to 8 years after the disturbance, average 12–116% increase annually). The demographic changes likely were driven by some combination of productivity and immigration occurring simultaneously with regional increases.
We then evaluated population and suitable habitat change on Fire Island and Westhampton Island following Hurricane Sandy. We developed an integrated population model to determine the primary contributors to population and assessed the effect of restoration areas on demographic processes during 2013–2018. We also recorded individual locations of adults and pre-fledge chicks to evaluate effects of post-Hurricane Sandy landscape features on resource selection of adults and chicks, and behavior and survival of plover broods. We evaluated whether breeding stage (pre-breeding, nesting, brooding, post-breeding), simple breeding stage (breeding, not-breeding), or instantaneous behavior class (parental, non-parental) best explained habitat selection during the 5-month plover breeding season. We also evaluated the effects of post-Hurricane Sandy landscape features on resource selection, behavior, and survival of plover broods during 2013–2019.
We observed positive population growth in three of five years and overall growth through the study (λ ̅=1.12). Immigration and reproductive output were correlated with population growth (r = 0.93 and 0.74, respectively). Compared to the rest of the study area, restoration areas had higher chick survival but lower nest survival and breeding fidelity, and population growth (λ ̅=1.09) in restoration areas was similar. For adult plovers, behavior class best explained habitat selection. Compared to non-parental plovers, plovers engaged in parental behavior (incubating, brooding, and accompanying chicks, hereafter 'parental') selected areas closer to bay intertidal habitats and with more dry sand. Non-parental plovers avoided areas with more dry sand and did not select for or against bay intertidal habitats. Additionally, non-parental plovers avoided development more than parental plovers and avoided areas of lower elevation more than parental plovers. In each year, there was more suitable habitat for parental plovers than non-parental plovers. Plover broods selected for flatter sites with less vegetation but selected for sites closer to development as time since Hurricane Sandy increased. Chick foraging rates were highest in moist substrates and were negatively influenced by nesting plover density. Chick survival was negatively influenced by nesting plover density and was greater for earlier hatched broods. Further, chick survival was higher following an outbreak of sarcoptic mange in the local red fox (Vulpes vulpes) population. If human interventions were reduced or modified in such a way as to create, maintain, and improve habitat, plover populations likely would reach higher numbers, and the potential for achieving recovery goals would be increased. Future restoration areas projects could use Great Gun as a model, although design criteria could be improved to increase access to moist, flat, low energy foraging sites. Efforts to increase immigration of novel breeding adults into the system, primarily by habitat creation or maintenance, are likely to have the greatest local effect on population growth but may not improve regional population persistence if habitat creation is only local. Management to improve reproductive output is likely to have a positive effect on population growth if there is suitable habitat to support recruits and will improve regional population persistence by producing emigrants. When improving or creating plover habitat, managers should consider habitat needs both for plovers of all life stages. Habitat management should focus on maintaining vegetation-free sand and access to low-elevation foraging habitat. Allowing hurricanes such as Hurricane Sandy to alter the landscape naturally will create these landscape features.Doctor of Philosophy
Piping plovers (Charadrius melodus) are federally threatened and endangered shorebirds that nest on sandy beaches, sandbars, and lakeshores. In October 2012, Hurricane Sandy created substantial habitat on Fire Island and Westhampton Island, New York, which could have acted as plover habitat. However, concerns about mainland safety from future storms prompted an island-wide project, building dunes planted with beach grass, to improve ability of Fire Island to protect the mainland. However, planted dunes had the potential to negatively affect newly created habitat, and certain sections of Fire Island were designed to create plover nesting habitat. Because of the habitat creation, we predicted that the population would increase. To illustrate that habitat creating events lead to plover population increases, we used freely available aerial imagery and identified all areas of dry and moist sand in study areas. We then used local plover monitoring data to relate habitat change to plover population change, and found that for several hurricanes and floods in the piping plover range, habitat increases led to population increase. We then evaluated population change on Fire Island and Westhampton Island, and found that the population increased 90% following Hurricane Sandy, and the increase was primarily due to new immigrant adults, and local reproductive success. The created restoration areas had similar reproductive output and population growth to the rest of the study area. To determine the areas on Fire Island and Westhampton Island that were adequate habitat for piping plover adults, we compared habitat used by plovers to what was available on the island and determined that habitat use differed between adults exhibiting parental behaviors and adults exhibiting all other behaviors. Non-parental plovers avoided dry sand. Both parental and non-parental plovers avoided development and high elevation sites. Overall, more sand was suitable for parental plovers than non-parental plovers. Because reproductive output also was influential to the population increase on Fire Island, we evaluated effects of landscape features on plover chick habitat, foraging, and survival. Plover chicks avoided vegetation, and selected flatter areas, but selected sites closer to development as time since Hurricane Sandy increased. Chicks spent more time foraging in moist substrates, and less time foraging when there were more plovers nesting in a management unit. Chick survival also was lower when more plovers were nesting in a management unit and was greater for earlier hatched broods. Further, chick survival was higher following a sharp decline in the local red fox (Vulpes vulpes) population. Overall, Hurricane Sandy was a positive force for this local plover population and local efforts to allow hurricane storm surges to modify the island in the future will improve long-term population persistence. Efforts to increase immigration of novel adults into Fire Island and Westhampton Island, primarily by habitat creation or maintenance, are likely to have the greatest local effect on positive population growth. Improving reproductive output is likely to have a positive effect on local and regional population growth, particularly by maintaining a low red fox population, if there is suitable habitat to support recruits. When improving or creating plover habitat, managers should consider habitat needs for plovers across the whole breeding season rather than just nesting. Habitat management should focus on maintaining vegetation-free sand, and access to low-elevation, flat foraging habitat. Habitat creation also may increase habitat amount and therefore local population growth.
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Stewart, Jaclyn Grace. "Matrix Model Analysis of a Coastal Northern California Subpopulation of the Western Snowy Plover (Charadrius alexandrinus nivosus)." Scholarship @ Claremont, 2017. http://scholarship.claremont.edu/cmc_theses/1513.
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Shorebirds are increasingly threatened by introduced predators, invasive grasses, and human disturbance. Matrix models can be used to predict population growth and assess management options. The Pacific coast population of the western snowy plover, Charadrius alexandrinus nivosus, is listed as threatened under the Endangered Species Act, largely due to high rates of nest predation. A matrix model for the entire Pacific coast metapopulation of western snowy plovers was published in 1999 by Nur et al., but population growth has not been comprehensively reassessed since, even after development of a recovery plan (USFWS 2007) and extensive management intervention. I built and analyzed a matrix model for one subpopulation of western snowy plovers previously considered a sink habitat—Recovery Unit 2 in northern California, comprising Humboldt, Mendocino, and Del Norte counties. Based on my model, growth rate (lambda) is 1.05—countering a previous finding that Recovery Unit 2 is a sink—compared to 1.036 for the Nur et al. (1999) metapopulation model. I found that sensitivities and elasticities for each vital rate were similar between the two models; adult survival had the greatest effect on lambda, followed by juvenile survival, and fecundity had the least effect. Even though fecundity was lower for my model than Nur et al.’s (1999), adult survival was higher, which had a larger impact on population growth. In terms of management strategies, predator control, habitat restoration, and restriction of human activity should continue as outlined in the recovery plan, so as to continue the trend of positive growth for the coastal breeding population. Future directions involve performing population viability analyses for other recovery units to reassess the state of western snowy plovers compared to 1999.
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DeRose-Wilson, Audrey Laura. "Demography, Nest Site Selection, and Physiological and Behavioral Responses to Overflights and other Human Activities, of Wilson's Plover (Charadrius wilsonia) at Cape Lookout National Seashore, North Carolina." Thesis, Virginia Tech, 2012. http://hdl.handle.net/10919/44899.
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There is little information on demographic trends of, or threats to the Wilsonâ s Plover (Charadrius wilsonia), despite concerns that habitat degradation may be causing the species to decline. I studied Wilsonâ s Plover demography, nest site selection, and physiological and behavioral responses to overflights at Cape Lookout National Seashore, North Carolina, where the National Park Service and U.S. Marine Corps recently lowered the altitude for overflights at tactical speeds. I monitored the responses of incubating Wilsonâ s Plovers to overflights and other human activities and compared heart rate, incubation rate, and vigilance behaviors during time periods with and without these stimuli. I compared habitat use vs. availability at the island-scale, and nest placement relative to geomorphic features and vegetative cover, both on a local and island-wide scale. Wilsonâ s Plovers increased vigilance during military rotary-wing and civilian fixed-wing overflights, but not during military fixed-wing overflights. Plovers were vigilant more and incubated less when researchers were present. Wilsonâ s Plovers selected for interdune areas, flats and isolated dunelets on flats, and against beach and dunes. At the local scale, nests were more likely to be near dense vegetation than random points. Mayfield nest survival was 25%, and predation caused most of the nest failure. Daily nest survival was negatively correlated with nest age and initiation date. Nests with cameras and heart rate monitors had lower survival, and nests with predator exclosures had higher survival. The mean number of chicks fledged per pair was 0.78.Master of Science
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Ray, Kacy Lyn. "Factors affecting Wilson's Plover (Charadrius wilsonia) demography and habitat use at Onslow Beach, Marine Corps Base Camp Lejeune, North Carolina." Thesis, Virginia Tech, 2011. http://hdl.handle.net/10919/30996.
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The Wilson’s Plover (Charadrius wilsonia) is a species of concern in most southeastern U.S. coastal states, where it breeds and winters. The U.S. Shorebird Conservation Plan listed this species as a Species of High Concern (Prioritization Category 4), and the U.S. Fish and Wildlife Service has designated it as a Bird of Conservation Concern (BCC). Despite its conservation status, Wilson’s Plover population trends are poorly understood and little research has been conducted examining habitat factors affecting this species’ breeding and foraging ecology. I collected Wilson’s Plover demographic data and explored which habitat characteristics influenced breeding success and foraging site selection among three coastal habitat types (i.e. fiddler crab (Uca spp.) mud flats, beach front, and interdune sand flats) at Onslow Beach, Marine Corps Base Camp Lejeune, North Carolina, 2008-2009. I observed little difference between years in nest success (≥ 1 egg hatched), failure, and overall nest survival. The majority of nest failures were caused by mammalian predators. For those nests that hatched successfully, greater proportions were located in clumped vegetation than on bare ground or sparsely vegetated areas. In-season chick survival for both years was higher for nests that hatched earlier in the season, and for nests farthest from the broods’ final foraging territory. Productivity estimates (chicks fledged per breeding pair) were not significantly different between years (0.88 ± 0.26 fledged/pair in 2008, 1.00 ± 0.25 fledged/pair in 2009) despite a shift in foraging behavior, possibly related to habitat alterations and availability in 2009. My findings indicate that Wilson’s Plover adults and broods were flexible in establishing final foraging territories; in 2008 all final brood foraging territories were on fiddler flats while in 2009, final foraging territories were sometimes split between fiddler flats, beach front, and interdune sand flats. For those Wilson’s Plovers establishing territories on fiddler flats, area of the flat was the most important feature explaining use versus non-use of a particular flat; area ≥ 1250 m² was preferred. Close proximity to water and vegetative cover were also important habitat features in foraging site selection on fiddler crab mud flats, and in all habitat types combined. My findings will directly contribute to population and habitat research goals outlined in the U.S. Shorebird Plan and will supplement limited data about foraging and habitat use related to Wilson’s Plover breeding ecology.Master of Science
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Walker, Katie M. "Piping Plover (Charadrius melodus) habitat selection, survival, and migration on New York barrier islands following natural and engineered habitat changes." Thesis, Virginia Tech, 2020. http://hdl.handle.net/10919/97889.
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The piping plover (Charadrius melodus) is an imperiled migratory shorebird that nests on mainland and barrier island beaches on the Atlantic coast of North America. Its population decline was attributed to habitat loss, predation, coastal development, and disturbance. Hurricane Sandy reached the Northeast United States in October, 2012. The storm breached and overwashed two barrier islands of New York that support breeding piping plovers, Fire Island and Westhampton Island. In response to geomorphic island changes, the U.S. Army Corps of Engineers stabilized the islands by filling breaches, building dunes, and nourishing beaches. In accordance with the U.S. Fish and Wildlife Service and the Endangered Species Act, the U.S. Army Corps of Engineers constructed piping plover nesting habitat to mitigate the loss of habitat from engineering. The objectives of this study were to assess habitat selection and quantify suitable habitat before and after Hurricane Sandy and to investigate survival and migration of fledgling piping plovers within their first year.
We studied piping plover nest-site selection, habitat, and abundance before (2010) and after (2015) Hurricane Sandy and engineered response. Before the storm, piping plovers selected nest sites (n=62) farther from the ocean (x̄ least-cost distance = 82.8 m) and bay (x̄ Euclidean distance = 697.7 m; x̄ least-cost distance = 24,160.6 m) than would be expected if they were selecting nest sites at random. Following the storm, piping plovers selected nest sites (n=45) that were close to, and had unobstructed walking access to, the ocean (x̄ least-cost distance = 123.4 m) and newly-created bayside foraging habitats (x̄ Euclidean distance = 468.0 m; x̄ least-cost distance = 728.9 m). Areas overwashed by the hurricane contained the most suitable piping plover habitat across all new habitat types. Piping plover abundance increased 93% by 2018 from pre-Hurricane Sandy abundances, with most pairs nesting in new habitats. However, only 58% of suitable piping plover habitat was protected from recreational use and only 4% of piping plovers used unprotected habitats for nesting during 2015–2017.
We assessed post-fledging survival with radio telemetry and mark-recapture methods. We banded and monitored 292 fledged chicks from 2013–2018. We affixed nanotags to 43 pre-fledged chicks and tracked them to document mortality on their natal grounds. We used a multi-state open robust design model to estimate post-fledging survival within the first year and migration and return probabilities. Daily survival rate as estimated with nanotags was the same as estimated with mark-recapture methods (0.997). Post-fledging survival did not vary in the six years following the storm, nor did it vary across stages within an individual's first year (0.36; 95% CI = 0.31–0.42). Fledgling migration occurred between July 1 and September 22 and reached its peak between August 15–23 (Ψ = 0.97, 95% CI: 0.92–0.98). Individuals with earlier fledge dates migrated earlier (β = ˗1.51, 95% CI: ˗1.11–˗1.91). Second-year plovers returned to the breeding grounds between February 20 and May 8, with a peak occurring in late April and early May (Ψ = 0.55, 95% CI: 0.41–0.70). Given that newly-created storm and engineered habitats benefitted nesting and brooding plovers, ensuring protection of these and other suitable habitats would likely safeguard fledglings that persist on Fire Island for more than a month before departure.Master of Science
The federally threatened piping plover (Charadrius melodus) is a migratory shorebird that breeds on sandy beaches along the Atlantic coast of North America. Coastal development, recreational use, and habitat loss are major factors that contributed to its listing under the Endangered Species Act in 1986. Hurricane Sandy reached the Northeast United States in October, 2012. The storm breached and overwashed Fire Island and Westhampton Island, prompting the U.S. Army Corps of Engineers to stabilize the islands by filling breaches, building dunes, and nourishing beaches. Because the islands support a breeding population of piping plovers, the U.S. Army Corps of Engineers also constructed piping plover habitat to mitigate the loss of habitat due to engineering. The objectives of this study were to assess habitat selection of plovers before and after Hurricane Sandy and to investigate survival and migration of fledgling piping plovers within their first year. We studied piping plover nest-site selection, suitable habitat, and abundance before (2010) and after (2015) Hurricane Sandy and engineered response. Before the storm, piping plovers selected nest sites farther from the ocean and bay than would be expected if they were selecting nest sites at random. Following the storm, piping plovers selected nest sites that were close to, and had unobstructed walking access to, the ocean and newly-created bayside foraging habitats. Areas overwashed by the hurricane contained the most suitable piping plover habitat across all new habitat types. Piping plover abundance increased 93% by 2018 from pre-Hurricane Sandy abundances, with most pairs nesting in new habitats. However, only 58% of suitable piping plover habitat was protected from recreational use and few piping plovers used unprotected habitats for nesting. From 2013–2019, we monitored post-fledging piping plovers through their first year. We estimated post-fledging survival and estimated fall and spring migration timing. Post-fledging survival was constant across their first year of life. Fledgling migration occurred between July 1 and September 22 and reached its peak between August 15–23. Individuals with earlier fledge dates migrated earlier. Plovers returned to the breeding grounds between February 20 and May 8 of their second year, with a peak occurring in late April and early May. Given that post-Hurricane Sandy habitats were suitable for plover nests and broods, ensuring protection of suitable habitats would also benefit fledglings that persist on Fire Island for more than a month before departure.
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Black, Kathleen Miles. "Red fox ecology and interactions with piping plovers on Fire Island, New York." Diss., Virginia Tech, 2021. http://hdl.handle.net/10919/102663.
Full textAbstract:
Red foxes (Vulpes vulpes) have been identified as a key predator of the threatened piping plover (Charadrius melodus) along the U.S. Atlantic coast. However, little is known about coastal red fox ecology, making it difficult to create effective red fox management strategies in these settings. Here, we quantify aspects of red fox population, spatial, and dietary ecology and interactions with threatened piping plovers on Fire Island, New York.
We conducted remote camera surveys, scat and sign surveys, den monitoring, and GPS tracking of red foxes on the island in 2015–2018. We used these data to estimate red fox occupancy, reproduction, survival, and population density. We used GPS data to investigate red fox space use, habitat selection, and responses to piping plover nest exclosure setup, pre-hatch pipping, and hatching. We used fecal dietary analyses and data from den prey item surveys to quantify the frequency of piping plover predation and to identify major prey items of red foxes on the island.
Red fox occupancy remained high even after substantial decreases in abundance, population density, annual reproduction, and seasonal survival following 2 sarcoptic mange outbreaks. Within their home ranges, red foxes selected areas that were closer to vegetation during the daytime and twilight hours, but farther from vegetation at night. We did not find clear evidence that red foxes in our study area keyed in on piping plover nest exclosure setup, pipping, or hatching at the spatial scales considered in our comparisons, although fox penetration of and digging at exclosures was an issue in 2015 at Smith Point County Park. Items from Orders Rodentia (rodents, 43% of scats), Coleoptera (beetles, 38%), and Decapoda (crabs and other crustaceans, 29%) were most frequently found in 293 red fox scats examined. Skates (Family Rajidae, 89% of dens with food items) and Atlantic surf clams (Spisula solidissima, 67%) were found most frequently outside of dens. We did not find any identifiable piping plover remains in red fox scats or outside of dens.
Our results suggest that direct interactions between red foxes and piping plovers during our study period and in our study area were less frequent than expected, but concurrent work by collaborators documented that the trap success of red foxes was negatively related to piping plover reproductive output during our study period. Lethal removal of red foxes is unlikely to eliminate them from shorebird nesting areas unless complete eradication of foxes from the island can be achieved. We recommend strategic vegetation management in and around piping plover nesting areas to reduce daytime resting areas and hunting cover for red foxes, and continued use of nest exclosures. We also recommend further investigation into indirect impacts of red foxes on piping plover populations, and into the possibility that anthropogenic food resources could be subsidizing the island's red fox population.Doctor of Philosophy
Red foxes have been identified as a key predator of the piping plover, a small migratory shorebird that breeds along the U.S. Atlantic coast and is considered 'threatened' (at risk of becoming endangered and eventually disappearing) within the United States. The lack of information about red fox ecology in coastal settings has been a challenge for wildlife biologists tasked with reducing predation on piping plovers. We investigated red fox ecology, behavior, and interactions with piping plovers on Fire Island, New York. We used trail cameras, collected scat (feces), monitored dens, and tracked red foxes on the island with global positioning system (GPS) collars in 2015–2018. We used these data to estimate red fox distribution, litter sizes, survival rates, and population sizes. We used GPS data to estimate red fox territory sizes, describe habitat selection, and investigate responses to piping plover nest exclosure setup, pipping (a period before hatching during which chicks vocalize inside the eggs), and hatching. We dissected red fox scats and recorded prey items found outside of dens to determine what red foxes on the island were eating. The proportion of each study area used by red foxes remained high even after substantial decreases in abundance, population density, annual reproduction, and seasonal survival following 2 parasitic disease (sarcoptic mange) outbreaks. Within their territories, red foxes selected areas that were closer to vegetation during the daytime and twilight hours but farther from vegetation at night. We did not find clear evidence that red foxes in our study area keyed in on piping plover nest exclosure setup, pipping, or hatching, although fox penetration of and digging at exclosures was an issue in some years at a site not included in those comparisons. Rodents, beetles, and crustacean remains were found most frequently in red fox scats. Skates and surf clams were found most frequently outside of dens. We did not find any identifiable piping plover remains in red fox scats or outside of dens. Our results suggest that that direct interactions between red foxes and piping plovers may be less frequent than previously believed, but concurrent work by collaborators documented that the trap success of red foxes was negatively related to piping plover reproductive output during our study period. Lethal removal of red foxes is unlikely to eliminate red foxes from shorebird nesting areas unless all foxes on the island are removed. We recommend strategic vegetation removal in and around piping plover nesting areas to reduce daytime resting spots and hunting cover for red foxes, and continued use of nest exclosures. We also recommend further investigation into indirect impacts of red foxes on piping plover populations, and into the possibility that anthropogenic food resources could be subsidizing the island's red fox population.
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Friedrich, Meryl J. "Population Dynamics of Threatened Piping Plovers on the Niobrara River, Nebraska." Thesis, Virginia Tech, 2018. http://hdl.handle.net/10919/83930.
Full textAbstract:
Prairie rivers of the Great Plains, USA, provide important habitat for the federally threatened piping plover (“plover”, Charadrius melodus). Plovers nest on open to sparsely vegetated river sandbars, and their demographic rates are closely linked to habitat availability and quality, as well as river flow. The Niobrara River in northern Nebraska has supported 22–41% of the state’s plovers since species listing in 1986, but the population and habitat are relatively understudied, and both have declined since 2010. The objectives of this study were to understand plover demography, habitat, and the role of the Niobrara in the regional plover population.
Periods of high river flow promote creation and maintenance of suitable sandbar nesting habitat, but increased river flow during the plover breeding season can decrease nest and chick survival. We estimated the effect of daily peak river flow on survival rates of 115 nests and 66 chicks on the Niobrara River, 2010–2016, using logistic exposure and Cormack-Jolly-Seber models, respectively. We monitored 1,874 banded hatch-year and adult birds across the regional population (Niobrara River, Lewis and Clark Lake, Gavins Point Reach segment of the Missouri River), and used multi-state mark-recapture models to estimate survival and inter-annual dispersal probabilities among sites relative to habitat availability. We developed land cover datasets from high-resolution aerial imagery to quantify suitable habitat and compare the relative effects of habitat characteristics on nest-site selection and nest success for a subset of years (2010, 2012, 2014, and 2016) using logistic regression models. We included data from a sympatric nester with similar nesting habitat needs, the interior least tern (“tern”, Sternula antillarum athalassos), to improve precision of our models. We compared 63 plover and 92 tern nests to 292 random unused points, and 73 successful (hatched ≥1 egg) to 79 failed nests.
Low nest and chick survival and high emigration from the Niobrara appear to be important factors contributing to population decline. Daily nest and chick survival were negatively related to river flow. Nest-site selection was based primarily on distance to the river bank (i.e., the nearest potential source of predators), yet flooding (eggs submerged or washed out of the nest bowl during increased river flow) caused at least as many nest failures as predation. Nests predominantly were surrounded by dry sand habitat, indicating some degree of flood avoidance, but were no farther from water than random, and drier nest sites were no less likely to fail. Dispersal occurred throughout the regional population, but plovers were more likely to leave the Niobrara than to enter it. Expansive flood-created sandbars on the Missouri River, concurrent with a trend towards more vegetated and saturated habitat on the Niobrara, may have drawn birds from the Niobrara population, especially those that dispersed to the Niobrara during sustained Missouri River flooding 2010–2011.
The outsized negative effect of flooding on nest success, the lack of protection afforded by dry sand nest sites, and selection for nesting habitat based more strongly on predator avoidance than flood avoidance suggest that plovers may have face more frequent and intense levels of breeding season flooding than is typical. Identifying and promoting the processes that contribute to creation and maintenance of high-elevation sandbars on the Niobrara is an important next step towards effective management of nesting birds.Master of Science
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Hunt, Kelsi L. "Management and Mother Nature: piping plover demography and condition in response to flooding on the Missouri River." Thesis, Virginia Tech, 2016. http://hdl.handle.net/10919/73480.
Full textAbstract:
Globally, riparian ecosystems are in decline due to anthropogenic modifications including damming, channelization and the conversion of the floodplain for human use.
These changes can profoundly affect riparian species as many have adapted to the historical dynamism of these ecosystems. On the managed Missouri River, an imperiled shorebird, the piping plover (Charadrius melodus) uses riverine sandbars to breed. From 2004 to 2009, due to limited breeding habitat and low population numbers, the U.S. Army Corps of Engineers constructed 255 ha of sandbar habitat to benefit piping plovers and least terns (Sternula antillarum). During the breeding seasons of 2010 and 2011, historically high flows resulted in the creation of 1,887 ha of suitable sandbar habitat. Our study compared the demographic response and the condition of piping plovers to these anthropogenic and natural habitat creation events.
From 2005–2014 we monitored 1,071 nests, and from those nests we uniquely banded 968 adults and 2,021 piping plover chicks. We obtained 405 egg (clutch) mass measurements, 1,285 mass measurements from 633 adults, and 7,093 mass measurements from 1,996 plover chicks resulting in 3,175 mass measurements from 654 broods of chicks. We also collected 3,347 invertebrate prey samples. We used a random effects logistic exposure model to estimate nest success, a random effects Cormack-Jolly-Seber model in RMARK to estimate pre-fledge chick survival and the
Barker model in RMARK to estimate hatch-year (HY) and after hatch-year (AHY) survival and fidelity to our study area. We then used estimates from these analyses to calculate reproductive output, reproductive output necessary for a stationary population, and population growth (λ). For adult condition and egg (clutch) mass we used generalized linear mixed regression, and for pre-fledge chick growth rates we used a modified Richard's model to estimate the effects of habitat type (pre- vs. post-flood). We also tested for differences in invertebrate prey abundance between habitat types using negative binomial regression.
Our results indicated that AHY survival varied throughout our study and was lowest during the flood (2010 and 2011). We found that nest success, pre-fledge chick survival, reproductive output, and HY survival and fidelity were consistently higher on the flood-created habitat than engineered habitat, leading to sustained population growth after the flooding, as compared to just one year of population growth prior to the flood. Unlike pre-flood engineered habitat, the demographic parameters we measured did not decrease as the post-flood habitat aged. These differences were related to increased sandbar habitat, low nesting densities, and decreased nest and chick predation on the post-flood habitat. Although we hypothesized that increased demographic rates would be reflected by increased piping plover condition following the flood, we found that our measured condition variables (adult mass, clutch mass, and pre-fledge chick growth rates) remained unchanged following the flood. We also found evidence that clutch mass, chick growth rates and invertebrate prey abundance decreased as the post-flood sandbar habitat aged. As the condition of individuals did not appear to contribute directly to the increased demographic rates following the flood, we suggest that the change in density-dependent predation pressure may explain the discrepancy. As many ecosystems have previously been altered, it's rare that ecologists have the opportunity to compare management practices with natural ecosystem processes. Results from this study suggest that management intervention may not be an equivalent substitute for natural ecosystem processes and provide insight on future management of riparian ecosystem.Master of Science
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Gieder, Katherina Dominique. "Assessing the Effects of Sea-Level Rise on Piping Plover (Charadrius Melodus) Nesting Habitat, and the Ecology of a Key Mammalian Shorebird Predator, on Assateague Island." Diss., Virginia Tech, 2015. http://hdl.handle.net/10919/56573.
Full textAbstract:
The piping plover (Charadrius melodus) is a federally-listed shorebird that nests on barrier islands along the U.S. Atlantic Coast and is highly vulnerable to habitat change and predation. We have addressed these two threats by 1) developing and implementing a linked model system that predicts future change to piping plover habitat resulting from sea-level rise and beach management efforts by joining dynamic models of sea-level rise, shoreline change, island geomorphology and piping plover nest habitat suitability, and 2) quantifying occupancy and movement of the red fox (Vulpes vulpes), a key shorebird predator at Assateague Island, Maryland and Virginia. We constructed and tested a model that links changes in geomorphological characteristics to piping plover nesting habitat suitability. We then linked this model to larger scale shoreline change resulting from sea level rise and storms. Using this linked model to forecast future sea-level rise and beach management efforts, we found that modest sea-level rise rates (3 mm and 4.1 mm/yr; similar to current rates) may increase suitable piping plover nesting habitat area in 50-100 years and some beach management strategies (beach nourishment and artificial dune modifications) also influence habitat availability. Our development and implementation of this tool to predict change in piping plover habitat suitability provides a vital starting point for predicting how plover nesting habitat will change in a context of planned human modifications intended to address climate change-related threats. Our findings regarding red fox occupancy and movement complement the use of this model for planning future management actions by providing vital information on the effects of certain predator management activities and habitat use of a key mammalian predator, the red fox, for shorebirds along the U.S. Atlantic Coast. Overall, we found that 1) red fox occupancy was strongly tied to eastern cottontail (Sylvilagus floridanus) trap success, increasing sharply with increased eastern cottontail trap success, 2) red fox occupancy did not change in response to an intensive eradication program, and 3) red foxes in our study area generally moved little between camera stations spaced 300 m from each other, but may move large distances (> 6km) at times, likely to occupy new territory available after lethal control efforts. Our findings have important ramifications for the sustainability of long-term predator removal programs and our understanding of future habitat change on the red fox. For example how vegetation changes affect eastern cottontails, how resulting fluctuations in eastern cottontails affect red fox occupancy, and how consequential changes in red fox occupancy affect plover breeding productivity. Our predictive model combined with these predator findings will allow wildlife managers to better plan and implement effective management actions for piping plovers in response to the multiple stressors of SLR-induced habitat change and predation.Ph. D.
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Brito, Patrícia Daniel Montenegro. "Estudo dos hábitos alimentares, comportamento e teste da hipótese de competição entre limícolas invernantes na ria de Aveiro : o caso do borrelho-grande-de-coleira (Charadrius hiaticula L.)." Master's thesis, Universidade de Aveiro, 2003. http://hdl.handle.net/10773/21603.
Full textAbstract:
Mestrado em Ciências das Zonas CosteirasEncontrando-se entre os ecossistemas mais produtivos do globo, as zonas húmidas são actualmente alvo de profunda intervenção humana, pelo que a superfície por elas ocupada tem vindo a diminuir. A Ria de Aveiro não é uma excepção, encontrando-se já profundamente artificializada. Desde o início da sua formação, por volta do século X, esta laguna começou a ser usada (e modificada) pelos habitantes da região. A maioria das espécies de aves limícolas utiliza as zonas costeiras, e em particular os ecossistemas estuarinos, como áreas de invernada. A Ria de Aveiro assume importância ornitológica internacional, uma vez que alberga mais de 1% de algumas populações invernantes da Europa, como o Borrelhogrande- de-coleira, Charadrius hiaticula, espécie ainda pouco estudada neste local. No presente trabalho propõe-se, então, investigar alguns aspectos relativos à biologia desta espécie, nomeadamente a fenologia da população invernante, os seus hábitos alimentares e ainda o comportamento nas zonas de alimentação. O trabalho de campo foi realizado no Canal de Mira, teve início em Setembro de 2000 e findou em Março de 2002. Foram efectuados censos de baixa-mar e determinada a distribuição geográfica dos indivíduos nos vários sectores da área de estudo, utilizados já em trabalhos anteriores. Verificou-se um padrão de variação do número de indivíduos bastante semelhante nas duas épocas de invernada. Durante a alimentação, os indivíduos apresentam preferência por quatro dos sectores considerados, provavelmente pelas suas características ao nível da disponibilidade de alimento e propriedades do sedimento. A perturbação humana foi também considerada, tendo sido determinado o número de mariscadores presentes em cada sector do Canal de Mira. Para a investigação dos hábitos alimentares foram colhidos e analisados dejectos produzidos nos locais de alimentação. Foi também feita a colheita de sedimento nos mesmos locais. Poliquetas e Gasterópodes (Hydrobia ulvae) constituem as principais presas do Borrelho-grande-de-coleira. Através de observações individuais e aleatórias, foi possível quantificar o tempo dispendido pelas aves nas diversas actividades. Assim, durante o período de baixa-mar, grande percentagem do tempo (cerca de 90%) é dedicado à alimentação enquanto que, durante a enchente, as aves se aplicam também nos cuidados com as penas (actividades de conforto). No que respeita a vasante, a alimentação é também a actividade predominante. Esta espécie apresenta algum gregarismo e, aparentemente, ocorrem fenómenos de competição intra-específica. Partilha muitas vezes os locais de alimentação com Charadrius alexandrinus e Calidris alpina; foram observados comportamentos agressivos para com os primeiros, não tendo ocorrido quaisquer situações reveladoras de competição inter-específica com C. alpina. A necessidade de investigação, visando a obtenção de técnicas e processos de recuperação e gestão urge nas zonas húmidas. Nesta linha de pensamento fica sublinhado o interesse que teria, em trabalhos futuros, a investigação do uso das restantes áreas da Ria de Aveiro por parte do Borrelho-grande-decoleira, principalmente as salinas, locais onde também ocorre, não só para a alimentação como para refúgios de preia-mar.
Being one of the globe’s most productive ecosystems, the wetlands have suffered profound human intervention, thus reducing their surface occupation ratio. The Ria de Aveiro is no exception, as it has been deeply artificialized. Since the beginning of its formation, around the 10th century, the inhabitants of this region have used (and modified) this lagoon. The majority of the wader species exploit the coastal zones, and in particular, the estuarine ecosystems as wintering areas. The Ria de Aveiro withholds an international ornithological importance as it holds more than 1% of some of the wintering populations of Europe, such as the Ringed Plover, Charadrius hiaticula, a relatively understudied specie in this region. The present dissertation investigates some of this species’ biological relative aspects, namely its wintering population distribution and variation, its feeding habits and its behaviour in the feeding areas. The field work, performed in the Mira Channel, commenced in September, 2000, concluded in March, 2002. Low-tide censuses were carried out and the geographic distribution of the birds in the various study areas sectors, analysed in previous work, was determined. A pattern in the variation of the number of birds was detected, being quite simillar in the two winter seasons studied. During feeding, the Ringed Plover individuals present a preference for four of the proposed sectors, probably because of their characteristics regarding food availability and sediment properties. The shellfish gatherers’ distribution was determined and therefore the human disturbance factor was weighed into the analysis. Excrement recovered from feeding spots were analysed for feeding habits investigation. Sediment samples were also gathered from the same sites. Ringed plover feasts mainly on polychaetes and gastropods (Hydrobia ulvae). The average time used by birds in different activities was quantified through individual and random observations. Thus, during low-tide periods a high time is spent feeding, while during flood the birds apply themselves in feather tending (comfort activities). Feeding is also predominant as the tides rush out. The species present some gregarism and, apparently, exhibit intra-specific competition phenomena. These birds share the feeding sites with Charadrius alexandrinus and Calidris alpina; aggressive behaviour towards the first was observed whilst no inter-specific competition was detected toward the latter. Wetland investigation is urgent for defining techniques, recuperation processes and management. Moreover the interest, here underlined, in future work, other areas of the Ria de Aveiro, namely of the salt-pans, which Ringed plovers also seek, not only for feeding but also for high-tide refuge.
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Ellis, Kristen Sue. "Habitat Selection and Nesting Ecology of Snowy Plover in the Great Basin." BYU ScholarsArchive, 2013. https://scholarsarchive.byu.edu/etd/3868.
Full textAbstract:
Snowy plovers (Charadrius nivosus) are small, ground-nesting shorebirds that are a species of conservation concern throughout North America. Despite increased efforts to understand factors contributing to the decline of snowy plover, little is known about habitat selection and breeding ecology of snowy plover for the large population found in the Great Basin. We tested hypotheses concerning the occupancy and nesting success of snowy plover. First, we identified factors influencing snowy plover nest survival at Great Salt Lake, Utah. We hypothesized that snowy plover would demonstrate differences in nest survival rates across years due to differences in habitat characteristics, predator abundance, human influence, resource availability, and fluctuating water levels. We conducted nest surveys at five sites along the Great Salt Lake to locate new nests or monitor known nests until nest fate was determined. We found 608 nests between 2003, 2005-2010, and 2012. The most common cause of nest failure was predation, followed by weather, abandonment, and trampling. Nest survival estimates ranged from 4.6 -- 46.4% with considerable yearly variation. There was no correlation between researcher activity (visits to nests and trapping of adults) and nest survival. Nests in close proximity to roads had lower survival than nests far from roads. Nests located on barren mudflats also had lower survival than nests in vegetated areas or near debris. We found that nests had a higher probability of survival as they increased in incubation stage. Because nesting areas around the Great Salt Lake host some of the largest concentrations of breeding snowy plover in North America, we suggest that managers consider measures to maintain suitable nesting habitat for snowy plover. Second, we determined factors affecting snowy plover occupancy and detection probabilities in western Utah between 2011 and 2012. We hypothesized that snowy plover would be associated with spring water flows and sparsely vegetated salt flats. We made repeated visits to randomly selected survey plots recording the number of snowy plover adults and habitat characteristics within each plot. We modeled the relationship between snowy plover detection probability and habitat and environmental characteristics. The detection probability was 77% (95% CI = 64 -- 86%) and did not vary by year. There was a positive relationship between ambient temperature and detection probability. Next, we modeled the relationship between snowy plover occupancy and individual habitat characteristics including distance to water, distance to roads, land cover types, and vegetative characteristics. Snowy plover occupancy did not vary by year and was estimated at 12% (95% CI = 7 -- 21%). Occupancy was best predicted by close proximity to water, playa land cover, and minimal shrub cover. We used habitat characteristics that best predicted snowy plover occupancy to generate a predictive habitat model that can help prioritize future snowy plover surveys and guide conservation efforts.
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Santos, Tiago Múrias dos. "Effects of habitat loss on waders (Aves, Charadrii) in the Mondego estuary (Portugal)." Doctoral thesis, 1998. http://hdl.handle.net/10316/2140.
Full textAbstract:
Tese de doutoramento em Biologia (Ecologia) apresentada à Faculdade de Ciências e Tecnologia da Universidade de CoimbraA perda de habitat é uma das principais causas que podem afectar a sobrevivência das limícolas (Aves: Charadrii) em muitos estuários da Europa. O principal objectivo deste estudo foi investigar os efeitos de alterações nos habitats das limícolas decorrentes da acção humana directa - a destruição de habitats supra-mareais (as salinas) - e indirecta - as exuberâncias ("blooms") periódicas de macroalgas nas vaseiras inter-mareais, consequência do processo de eutrofização em curso - num estuário submetido a intenso "stress ambiental", o estuário do Mondego.Desde 1984 que as salinas têm vindo a ser progressivamente abandonadas ou destruídas. Este estudo sugere que o desaparecimento deste habitat poderá representar uma sobrecarga de até 45% no número de horas de alimentação.aves-1 nas zonas de alimentação inter-mareais, que poderão revelar-se incapazes de albergar as aves para aí deslocados, especialmente se os níveis actuais de competição intra-específica forem já elevados. Esse efeito será amplificado se a alimentação nas áreas intermareais for afectada pelos "blooms" algais. O presente estudo não evidenciou níveis de competição intra-específicos suficientemente elevados para conduzir a um decréscimo das densidades de aves na zona inter-mareal; por outro lado não ficou demonstrado que as algas repelissem de alguma forma a alimentação das limícolas nas zonas por elas colonizadas. Como principal conclusão, pode inferir-se que, apesar da intensa pressão humana, a sobrevivência das populações de limícolas do estuário do Mondego não parece estar em risco imediato. Porém, a médio prazo, a destruição das salinas pode vir a afectar muitas espécies, devido à perda efectiva de tempo de alimentação, e a situação pode piorar ainda mais se for acompanhada por uma deterioração das condições alimentares nas vaseiras inter-mareais em virtude do crescimento incontrolável das áreas periodicamente afectadas pelos "blooms" algais, como consequência do processo de eutrofização acelerado que actualmente se verifica.
Habitat loss is a major factor that can potentially affect the survival of wader populations (Aves: Charadrii) in many estuaries of Europe. A number of studies have been made on this subject in northern Europe, in the last two decades, but there is a lack of data regarding the southern half of the continent. The main objective of this thesis was to investigate what could be the short to medium–term effects on waders of changes in the estuarine habitats as a consequence of two important factors directly or indirectly attributable to human action in the Mondego estuary (west Portugal): the loss of supra–tidal habitats (mainly salinas) and the increase of eutrophication in the mudflats, expressed as periodic ‘blooms’ of green macroalgae. The salinas are being abandoned and converted into fish-farms, which can not be used as feeding grounds by waders, at an alarming rate (5.2 ha.year -1in the the period 1984–94). Of about 305 ha of salinas in the estuary, 35% have been deserted or drained, 23% have been converted into fish-farms and only 42% were still producing during the course of this study. The Mondego estuary still hold a numerous and diversified wader assemblage, which was particularly important in winter and during the spring and autumn migratory passages. It includes one species (Avocet, Recurvirostra avosetta) of international importance, according to the criterion of the Ramsar Convention (>1% of the flyway population in winter) and at least 8 species of national importance (>1% of the national winter numbers). Part of the birds that used the estuary throughout the year remained in the salinas both at low-tide (30%) and at high-tide (58%), and most of them feed there. The active salinas were clearly more used for feeding than the inactive ones, but these could still hold a number of birds for a long time (up to 20 years) after they have been abandoned, depending on the particular environmental conditions of each salina. An hypothetical destruction of the salinas would mean that the feeding would subsequently be restricted to the mudflats. According to the calculations developed in this study, such increase could reach up to 45% of the birds–feeding hours that presently occur in the mudflats. However, not all species were likely to be affected in the same way by the loss of feeding opportunities in case the salinas were lost. Little Stint, Calidris minuta, Redshank Tringa totanus and Common Sandpiper Actitis hipoleucos would be the species more affected by the loss of space, while Turnstone Arenaria interpres and Dunlin Calidris alpina would be those more affected by the loss of feeding time at high–water. The predicted increase in the birds feeding–hours that would occur in the mudflats, if the salinas were to be destroyed, could be potentially detrimental for the survival of the estuarine populations of many species if the levels of inter-specific competition in the flats (which ultimately determine the carrying capacity of an area) were already high. The two tests used to assess the occurrence of interspecific competition (feeding interference among birds and depletion of the prey resources) suggested that the phenomenon was probably too weak to be perceived in the Mondego, at least with the methodology used. Thus, at present, the mudflats are probably still able to buffer the potential effects of the loss of space if the salinas were lost. However, the displaced birds would also lose feeding time, and this could not be recovered in the mudflats. The increasing process of eutrophication in the area may represent a direct threat to the mudflats, while feeding grounds for waders, through changes in the composition of the invertebrate communities and in the abundances of the main prey species. The present study did not present any evidence that the algae repelled the birds. Indeed, some species (e.g. Dunlin) may even have benefited of a surplus of food provided by the mats when they first appear, in early spring, but not in autumn, after the algal crash. This suggests that, at present, the occurrence of the algae on the flats do not represent an immediate threat to the waders’ feeding in the Mondego. Nevertheless, the situation can change in the long-term if the eutrophication process can not be reduced. The main conclusion of this study is that, in spite of the heavy human pressure in the estuary, the survival of the wader populations seems not to be threatened in the short–term. However, in the medium–term, the destruction of the salinas could seriously affect the survival of some species, and the situation could still become worse if it was accompanied by a global change in the composition of the prey communities caused by an increase of the eutrophication process in the estuary. Nevertheless, both these drastic alterations can still be prevented. Possible ways of achieving that in the salinas could be to find sustainable ways of keeping them actively producing, tomanage inactive ones in order tomake them suitable for waders, to carefully control the establishment of new fish-farms in old salinas, and to improve the design of the fish–ponds in order to provide waders with alternative feeding places to the destroyed salinas. As to the eutrophication process, any action to reduce it would have to be taken at a regional level, and would take more time. In any case, a long–term monitoring of the process at all levels of the trophic chain would be greatly welcome.
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Luís, António Manuel da Silva. "Influências de factores naturais e humanos nas limícolas (Aves, Charadrii) invernantes na Ria de Aveiro, com especial referência ao Pilrito-comum (Calidris alpina L.)." Doctoral thesis, 1998. http://hdl.handle.net/10773/24371.
Full textAbstract:
A evolução das zonas estuarinas tem sido condicionada, na actualidade como
no passado recente, por intervenções humanas, de tal forma que, um pouco por todo o
mundo, muitas podem considerar-se ameaçadas.
No caso da Ria de Aveiro esta intervenção tem tido, desde as fases iniciais de
formação da laguna, uma influência marcante e a Ria, tal como hoje se conhece, é
uma zona húmida profundamente artificializada.
Não obstante, a avifauna limícola invernante é bastante diversificada e
abundante e inclui duas espécies (Recuwirostra avosetta e Charadrius hiaticula) para
as quais, de acordo com os critérios da Convenção de Ramsar (mais de 1% da
população correspondente, pelo menos, a 100 aves), a Ria deve ser considerada de
importância internacional, além de outras nove que, usando os mesmos critérios,
conferem à laguna importância nacional.
Pretende-se, portanto, com este trabalho, investigar a forma como as aves
limícolas invernantes se organizam e distribuem no espaço, os processos pelos quais
exploram a Ria de Aveiro e se adaptam às condições existentes e, ainda, os
fenómenos envolvidos na regulação dos números de aves presentes, durante o
inverno.
O trabalho de campo iniciou-se no inverno de 1990191, com a realização de
alguns censos e visitas preliminares, e terminou em 1995196.
Ainda que se incluam informações relativas a outras espécies, faz-se especial
referência a Calidris alpina, por ser a espécie mais abundante e permitir, à partida,
boas perspectivas de sucesso na investigação proposta.
O estudo da organização espacial foi realizado no Canal de Mira e no salgado,
recorrendo, fundamentalmente, a métodos de recenseamento, captura e marcação de
aves e teledetecção.
A grande dificuldade experimentada na captura de aves, durante o inverno,
obrigou à utilização de várias técnicas e armadilhas, tendo mesmo sido concebida e
construída uma rede, semelhante às vulgarmente designadas por "redes-canhão",
disparada electronicamente, à distância.
As aves foram marcadas com ácido pícrico (no Canal de Mira) e com
rodamina (no salgado), de acordo com um código de coloração que permitisse
distinguir adultos e juvenis.
Durante o processo de capturaímarcação, observaram-se diferenças
significativas entre o número de aves marcadas e o número de aves marcadas
observadas, sugerindo-se, como explicação, a existência de um efeito perturbador
associado aos procedimentos de captura elou de marcação.
Foram efectuados censos de aves em preia-mar e baixa-mar e, ainda,
observações de movimentos nos limites das duas zonas de estudo.
Verificar-se-ia, em resultado deste trabalho, que os indivíduos das espécies
estudadas parecem restringir as suas actividades a alguns sectores da laguna,
delimitáveis geograficamente, adoptando um comportamento que mantêm ao longo
do inverno.
A área da Ria pode, assim, dividir-se em "unidades funcionais" (cujo número
total se desconhece), sendo uma "unidade funcional" definida como um conjunto de
zonas de alimentação e refúgios de preia-mar, utilizado por um grupo de aves, durante
um determinado período de tempo, correspondente, neste caso, ao inverno.
Este tipo de organização espacial, já investigado em anatídeos, não tinha
ainda, ao que se crê, sido objecto de um estudo específico realizado com limícolas.
O estudo comparativo do Canal de Mira e do salgado incidiu em C. alpina e
incluiu, essencialmente, a determinação da qualidade dos refúgios de preia-mar, a
investigação do efeito perturbador da actividade de captura de bivalves (e, no salgado,
da actividade cinegética), o estudo dos hábitos e comportamento alimentares das aves
e a caracterização dos grupos de indivíduos invernantes.
A qualidade dos refúgios foi determinada utilizando uma metodologia
desenvolvida neste trabalho. O método considera os refúgios descritos por nove
características principais (ou atributos), que se agruparam em três categorias:
perturbação, risco de predação e balanço energético. Os refúgios foram, então,
classificados, no que respeita a cada característica, numa escala de zero a três, sendo
depois a qualidade global determinada pela soma da pontuação atribuída a cada uma,
de forma que a pontuação máxima atribuível é de 27 pontos [...]The evolution of estuarine areas has been conditioned, nowadays as in the recent past, by hurnan interventions, in such a way that, a11 over the world, many of those areas may be considered as endangered. In the case of the Ria of Aveiro, this intervention has had, since the first stages of the formation of the lagoon, a strong influence, and the Ria, as it is known today, may be considered a deeply artificialized wetland. Nevertheless, the wintering waders are abundant and very varied and include two species (Recurvirostra avosetta and Charadrius hiaticula) for which, according to the criteria of the Ramsar Convention (over 1% of the population corresponding, at least, to 100 birds), the Ria should be considered of international irnportance, besides nine other which, using the same criteria, give the lagoon a national importance. The goal of this work is, therefore, to study the way in which the wintering waders organise and distribute themselves in the area, the processes through which they exploit the Ria of Aveiro and adapt to the existing conditions and, also, the phenomena involved in the regulation of the number of birds present, during winter. The field work began in the winter of 1990191, with some censuses and preliminary visits, and was concluded in 1995196. Even though information concerning other species is included, there is a special mention of Calidris alpina, because it is the most abundant species and indicates the success in the proposed research. A study of the spatial organisation was carried out in the Mira Canal and in the salt pan area, utilising, mostly, counting, bird capture and marking and radio-tracking. The great difficulty experienced in catching the birds, during winter, forced us to use severa1 techniques and traps, including a new kind of net, similar to those usually described as "cannon-nets", fired electronically, at a distance. xxi The birds were marked with picric acid (in the Mira Canal) and rodhamin (in the salt pan area), according to a marking code which allowed a distinction between adults and juveniles to be made. During capture and marking, significant differences were observed between the number of birds that were dye-marked and the number observed later, suggesting the existente of a distress effect associated to the capture andlor marking procedures. Censuses of birds were performed at high-tide and low-tide and observations of movements at the boundaries of the two study areas were, also, made. It would be seem, as a result of this work, that the individuals of the 'studied species' restricted their activities to limited sectors of the lagoon, adopting a behaviour which they maintained throughout winter. The area of the Ria may, therefore, be divided into "hctional units" (of an unknown total number), a "functional unit" being defined as a group of feeding areas and high-tide roosts, used by a group. of birds, during a certain period of time, corresponding, in this case, to winter [...]
Programa Doutoral em Biologia
44
Gorman, Leah R. "Population differentiation among Snowy Plovers (Charadrius alexandrinus) in North America /." 2000. http://hdl.handle.net/1957/9443.
Full text
45
Miller, Alexandra. "Manitoba Piping Plover Stewardship Program: a provincial strategy for the management of the endangered piping plover (Charadrius melodus circumcinctus)." Thesis, 2006. http://hdl.handle.net/1993/271.
Full textAbstract:
The Manitoba Piping Plover Stewardship Project was initiated in 2002 to determine the status of Piping Plovers (Charadrius melodus) in Manitoba and to develop a provincial management strategy that outlined provincial management goals and necessary stewardship actions. In 2002 and 2003, intensive surveys of historical and potential sites across Manitoba were conducted and measures taken to protect eggs and chicks from predation and human disturbance. With the use of fencing, signs, predator exclosures and guardian volunteers, predation and recreational disturbance were minimized sufficiently at most sites to allow for increased nest success and fledging rates. An overall apparent nest success rate of 62% and an apparent fledge rate of 1.16 fledglings/pair was achieved during this study. The study concluded that Piping Plover nest success and productivity at the majority of historical nesting sites in Manitoba is being limited by habitat availability, medium to high predation rates and recreational pressures.October 2006
46
Chen, I.-Ling, and 陳宜玲. "Prey choice of Kentish Plover Charadrius alexandrinus in winter at Tatu Estuary,Taiwan." Thesis, 1999. http://ndltd.ncl.edu.tw/handle/42365850893378412186.
Full textAbstract:
碩士東海大學
環境科學系
88
Kentish Plover (Charadrius alexandrinus) is one of the most common shorebirds on the western coast of Taiwan but few works have been done on its feeding ecology. The aim of this study is to explain the diet choice, foraging behaviour, and net energy intake of Kentish Plover based on principle of optimal diet theory. There are two parts in this study：(1) Laboratory study：Investigated the role of prey species (Mictyris brevidactylus, Scopimera longidactyla, Uca lactea ) and size (each species divided into three classes) in affecting prey choice of captive Kentish Plover from November 1997 to January 1998. (2) Field study：Foraging behavior observations of Kentish Plover were carried out in October and November 1998 at Tatu Estuary. Results of the laboratory study showed that Scopimera longidactyla and small classes of Mictyris brevidactylus and Uca lactea were preferred (p<0.05). The difference between field observations that Kentish Plover rarely forage Uca lactea and the results of laboratory study was attributed to the escape capability of Uca lactea . Low profitable Mictyris brevidactylu is also the main prey as high profitable Scopimera longidactyla because it''s profitability is higher than the energy intake rate of Kentish Plover to specialize on Scopimera longidactyla. It appears that Kentish Plover hunting for Mictyris brevidactylus search at a slower speed and make less aggression than do birds hunting for Scopimera longidactyla. Calculating the energy cost and benefit of foraging behavior of Kentish Plover showed that the net energy intake of birds specialize on either of the two crabs is equal, and maximizes while foraging both.
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Maslo, Brooke. "Evidence-based recommendations for Atlantic Coast piping plover (Charadrius melodus) conservation and habitat restoration." 2010. http://hdl.rutgers.edu/1782.2/rucore10001600001.ETD.000052135.
Full text
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Ku, Gordon, and 辜國展. "The activity patterns and home range of breeding Kentish Plovers (Charadruis akexandrinus) at the Tatu Estuary." Thesis, 2005. http://ndltd.ncl.edu.tw/handle/62325296282107196694.
Full textAbstract:
碩士東海大學
環境科學系
93
Field investigation and radio-telemetry was conducted to study the activity pattern, including nest-care time budgets and home range, of breeding Kentish Plover at the Tatu Estuary in Central West Taiwan. Data of nest-care time budgets by 18 pairs of parents were collected and analyzed from April, 2003 to August, 2004 were collected and analyzed. The results demonstrate that females mainly incubate during 09:00~13:00, where as males do so during 06:00~09:00 and 13:00~18:00. There is no significant correlation between wind velocity and the proportion of parent nest-care time budgets (P＞0.05), while significant correlation was found between sand temperature and the proportion of parent nest-care time budgets (P＜0.01). The results from 24hr tracking of 5 radio-tagged birds by minimum convex polygon method show that the home range of male is 123.5±31.3 hectares (n=3), and that of female is 189.3±7.9 hectares (n=2). The primary area of activity for both male and female is within 5 hectares. The results also reveal that the home range in daytime is larger than that in nighttime. According to the habitat investigation of its home range, there appears that to be a high utilization rate of breeding individuals in the inland fresh-water area, which is an important feeding habitat. Therefore, to recuperate the breeding habitat of Kentish Plover, establishment of suitable water environment in the core area of the parenting home range should be a priority to satisfy the demand for breeding and to increase the breeding success and nest density.
49
杜明林. "Nest site selection and hatching success of eastern kentish plover (Charadrius alexandrinus dealbatus) on changhua coast, Taiwan." Thesis, 1991. http://ndltd.ncl.edu.tw/handle/91840714536752455418.
Full text
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Yasue, Mai. "Breeding ecology and potential impacts of habitat change on the Malaysian plover, Charadrius peronii, in the Gulf of Thailand." Thesis, 2006. http://hdl.handle.net/1828/2349.
Full textAbstract:
Anthropogenic habitat change is the most important factor contributing to global losses in biodiversity. Ecological research can help identify the mechanisms that cause these declines by relating environmental characteristics to wildlife habitat use and productivity. Such studies can contribute to the design of land-use practices that enhance wildlife populations in conservation areas and promote efficient compromises between human use and conservation.
The conflicts between human-use and conservation are particularly evident in coastal areas, which have enormous economic value and are thus coveted areas for development. Human-use can alter the habitat quality and affect coastal taxa, such as shorebirds.
iv
In this study I examine the breeding ecology and conservation biology of a beach-nesting, near-threatened shorebird, the Malaysian plover Charadrius peronii, which breeds on coastal areas throughout Southeast Asia. Although nearly half of the threatened shorebird species breed in tropical areas, little research has been conducted on the conservation and ecology of these species. My study is the first detailed research conducted on the Malaysian plover. It contributes to a better understanding of the environmental factors constraining breeding strategies in the tropics and identifies key mechanisms linking anthropogenic habitat change and wildlife populations.
I used behavioural approaches to collect a wide range of data over a short-time period in order to describe the breeding ecology of Malaysian plovers, evaluate different types of constraints, identify anthropogenic impacts and provide recommendations on management approaches to mitigate the impacts of habitat change.
Malaysian plovers have long breeding seasons, high site fidelity, complete biparental care and can nest multiple times in a single year. In contrast to shorebirds in Arctic environments, where fecundity is limited by the brief pulses of high seasonal productivity, Malaysian plover fecundity appeared to be constrained more by habitat availability rather than time. Malaysian plovers began defending territories several months prior to the breeding seasons and nested in the same habitats even if there were significant reductions in habitat quality throughout the course of the breeding season.
In the Gulf of Thailand tourism-related habitat change that narrows beaches, alters vegetation structure and enhances human disturbance levels reduce habitat availability and breeding success. Enhanced vulnerability of clutches to tidal flooding, chicks to predation, exposure of eggs to heat and chicks to predation may be key mechanisms leading to these effects. Moreover Malaysian plovers had a density-dependent decline in breeding success. Consequently, if birds are displaced from preferred beaches due to habitat change, then breeding success may be reduced in otherwise high quality habitat as plovers crowd into remaining beaches.
When people approach nesting or chick-rearing plovers, one or both of the adults will leave the clutch or chicks to conduct distraction displays. Compared to holarctic species, tropical shorebirds may be more vulnerable to the fitness impacts of human disturbance because even short periods of exposure to direct sunlight can cause clutch failure, whereas eggs are resistant to chilling. These results suggest that the environmental and ecological conditions in tropical regions may affect the susceptibility of breeding shorebirds to fitness impacts of anthropogenic disturbance and habitat change.
Future research should assess cumulative impacts of habitat change by conducting multispecies studies and include wintering or stopover shorebirds. As my research was conducted in the best Malaysian plover breeding habitat in Thailand, it is important to assess the generality of my results by comparisons to other regions or across several years in which there may be a different range of predators or prey. Finally, it is important to note that these types of ecological conservation studies are only a first step towards
successful protection of threatened species. The greater challenge is to tackle the ultimate socio-economic and institutional factors that limit the effectiveness of protected areas and contribute to the number of environmentally destructive coastal development projects.