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Artykuły w czasopismach na temat "Reptile populations"
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McInerny, C. J. "The study and conservation of adders in Scotland". Glasgow Naturalist 27, Supplement (2018): 67–71. http://dx.doi.org/10.37208/tgn27s10.
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This paper describes two projects that explored the study and conservation of European adders (Vipera berus) and other reptiles in Scotland. One involved the implementation of an environmental mitigation plan during the construction of a hydroelectric scheme through an area of high reptile densities. The other involved the monitoring of a population of adders in a highly managed environment on a golf course. In both cases the adder numbers persisted suggesting that the populations were not affected, and so they illustrate situations where this reptile species can co-exist with humans. Finally, more general observations about reptile habitat requirements and conservation in Scotland are inferred from these studies.
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Teixeira, Camila Palhares, Luiza Passos, Vinicius D. L. R. Goulart, Andre Hirsch, Marcos Rodrigues i Robert J. Young. "Evaluating patterns of human–reptile conflicts in an urban environment". Wildlife Research 42, nr 7 (2015): 570. http://dx.doi.org/10.1071/wr15143.
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Context Reptiles, especially snakes, can cause a fear reaction in the public and are, therefore, a good model to examine human–wildlife conflicts. Human city dwellers often respond to the presence of snakes or other reptiles by calling out the responsible agency for animal control, which has to mediate the situation. Aims To determine how the temporal and spatial occurrence of human–reptile conflicts were associated with environmental conditions and socio-economic factors in a large Brazilian city (Belo Horizonte). Methods The callout reports of the Environmental Police of Belo Horizonte, Brazil, over a 7-year period from 2002 to 2008 to mediate reptile conflicts were analysed. Densities of callouts were determined by kernel-density estimator and matched with the vegetation cover and land use, to determine how the environment affected reptile callout distribution. The study area was divided into nine regions with different socio-economic and demographic characteristics to evaluate the possible effects of human factors in the conflict. Key results Reptile callouts were almost exclusively about snakes or freshwater turtles, despite a large population of wild lizards. In general, the difference in callout distribution of snakes and freshwater turtles was the result of different attitudes from city dwellers on the basis of socio-economic characteristics. Snakes were less frequent as urbanisation increased, whereas freshwater turtles were associated with water or open areas. Significantly, more conflicts occurred during the rainy season. People in areas of high per capita income used the Environmental Police as mediators more often than did those in poorer areas, but callouts were not related to human population density. Conclusions Habitat type and climate were significantly predictive of human–reptile conflicts. Human populations with higher salaries and education levels tended to resolve their conflicts with reptiles using official mediators whether the reptile was venomous or not. Implications The environmental and climatic data show that it is possible to predict when and where human–reptile conflicts are most likely. Thus, official mediators can use this information for targeted education programs. Such education programs should emphasise, at all levels of society, how to deal with such conflicts sensibly, so as to ensure the best outcomes for people and reptiles.
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Slavenko, Alex, Erez Maza i Yuval Itescu. "Results of the First Herpetological Survey of Israel’s Mediterranean Coastal Islets". Russian Journal of Herpetology 28, nr 4 (1.09.2021): 231–36. http://dx.doi.org/10.30906/1026-2296-2021-28-4-231-236.
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Small islets in the Mediterranean Sea are often home to reptiles, typically representing an impoverished sample of the continental fauna, yet with high population densities and signs of rapid morphological and behavioral evolution. In this paper, we present the first herpetofaunal survey of several small islet clusters in close proximity to the Mediterranean coast of Israel, only recently geologically separated from the mainland. We performed surveys of five islets during March of 2017 – 2018 and recorded the presence of five different species of reptiles on four of the surveyed islets. Species richness varied between 1 and 4 species, and appeared to be correlated with island area, with a distinct nested structure. Reptile species may have colonized the islets by natural dispersal from nearby coastal populations, or by hitch-hiking on fishing boats and similar methods of human-assisted dispersal. Alternatively, the recorded reptiles may represent relictual populations from earlier geologic periods, when lower sea-levels supported continuous land-bridges between the islets and the mainland. These insular reptile populations require further study to establish the exact means of colonization and describe if and how they differ from mainland populations. We stress the importance of such small Mediterranean islets such as these as centers of unique biodiversity and encourage future study and conservation action aimed at them and similar islets.
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Maute, Kimberly, Kristine French, C. Michael Bull, Paul Story i Grant Hose. "Current insecticide treatments used in locust control have less of a short-term impact on Australian arid-zone reptile communities than does temporal variation". Wildlife Research 42, nr 1 (2015): 50. http://dx.doi.org/10.1071/wr14194.
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Context Despite the regular use of pesticides to control locusts, there is a lack of information on the effects of locust-control treatments on reptiles worldwide. Exposure to pesticides poses a significant potential hazard to small reptiles, both from the direct effects of exposure, and indirectly because of their largely insectivorous diet and small home ranges. Aims Our study aimed to monitor the effects of two insecticides applied operationally for locust control in Australia. A phenyl pyrazole pesticide, fipronil, and a fungal biopesticide, Metarhizium acridium (Green Guard®), were applied aerially in either a barrier or block treatment in the absence of dense locust populations, and effects on non-target arid-zone reptiles were measured. Methods We monitored reptile-abundance and community-composition responses to treatments using a large field-based pitfall-trapping experiment, with replicated control and spraying treatments, which approximated the scale of aerial-based locust-control operations in Australia. Key results Neither reptile abundance nor community composition was significantly affected by locust-control treatments. However, both abundance and community composition as detected by pitfall trapping changed over time, in both control and treatment plots, possibly as a result of a decrease in annual rainfall. Conclusions The absence of any significant short-term pesticide treatment effects in our study suggests that the two locust-control application methods studied present a relatively insignificant hazard to reptiles at our site, based on a single application. Similar to other areas of Australia, climate and other factors are likely to be stronger drivers of reptile abundance and community structure. Implications Monitoring over an area that approximates the scale of the current locust-control operations is an important step in understanding the possible effects of current pesticide exposure on reptile populations and will inform insecticide risk assessments in Australia. However, important information on the immediate response of individuals to insecticide application and long-term effects of exposure are missing. The preliminary research reported in the present paper should be complemented by future investigations on long-term and sublethal impacts of pesticide exposure on Australian native reptiles and the possible benefits provided to reptiles by the resource pulses represented in untreated high-density locust populations.
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Vasconcelos, Raquel, Eudald Pujol-Buxó, Gustavo A. Llorente, Ahmed Saeed i Salvador Carranza. "Micro-Hotspots for Conservation: An Umbrella Tree Species for the Unique Socotran Reptile Fauna". Forests 11, nr 3 (21.03.2020): 353. http://dx.doi.org/10.3390/f11030353.
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Umbrella species are defined as species that can be rare and sensitive to human disturbance, whose protection may confer the protection of other co-occurring species. The dragon’s blood tree Dracaena cinnabari Balf.f. was already considered an umbrella species on Socotra Island (Indic Ocean, Yemen) due to its ecological importance for some native biota. We studied the reptile community living on D. cinnabari from Socotra Island. We sampled reptiles on trees across most D. cinnabari populations and applied co-occurrence and network partition analyses to check if the presence of reptiles on D. cinnabari populations was random or structured. Regardless of its patched and scarce actual distribution, we report the use of this tree as a habitat by more than half of the reptile community (12 endemic reptiles). Co-occurrence and network partition analyses demonstrate that this community is structured across the distribution of dragon’s blood trees, reflecting complex allopatric, vicariant, and biotic interaction processes. Hence, these trees act as micro-hotspots for reptiles, that is, as areas where endemic and rare species that are under threat at the landscape scale co-occur. This Socotra endemic tree is currently threatened by overgrazing, overmaturity, and climate change. Its protection and declaration as an umbrella species are expected to benefit the reptile community and to protect evolutionary processes that are partially driven by the ecological links between reptiles and this tree. To our knowledge, no tree species has been proposed as an umbrella species for island vertebrate endemics so far, highlighting the ecological uniqueness of Socotra Island.
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Schlesinger, CA, JC Noble i T. Weir. "Fire Studies in Mallee (Eucalyptus Spp.) Communities of Western New South Wales: Reptile and Beetle Populations in Sites of Differing Fire History." Rangeland Journal 19, nr 2 (1997): 190. http://dx.doi.org/10.1071/rj9970190.
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Reptile and terrestrial beetle populations were sampled within adjoining mallee communities of similar botanical composition, but differing in fire history and vegetation structure. Studies were aimed at determining whether there were any major differences between faunal communities in sites with different fire histories. While the number of beetle species captured was significantly higher in the two most recently burnt sites, overall abundance of beetles did not differ significantly between various fire histories. Captures of Carenurn interiove were highest in a site burnt seven years prior to the study whereas captures of Tvichocarenum sp. were most common in the two most recently burnt areas. The number of reptile species captured did not differ significantly between sites but the relative abundance of nocturnal and diurnal reptiles was found to be significantly related to time since last fire. The number of geckos captured at the oldest fire site (burnt 18 years earlier) were significantly fewer than at the more recently burnt sites whereas captures of diurnal lizards did not differ. These patterns of reptile abundance are consistent with those found in other fire studies undertaken in similar habitats. This preliminary study confirms that both reptiles and beetles may be usefully incorporated in future management systems designed to monitor biological diversity in mallee ecosystems. Key words: fire, mallee, porcupine grass, nocturnal and diurnal reptiles and beetles
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Vera, David Gustavo, Diego Omar Di Pietro, Germán Tettamanti, Manuel Eirin, Clara Trofino Falasco, María Florencia Aranguren, Jorge Daniel Williams, Federico Pablo Kacoliris i Igor Berkunsky. "An annotated list of the reptiles of the highland grassland of Tandilia Mountains, Argentina". Neotropical Biology and Conservation 16, nr 1 (9.03.2021): 185–204. http://dx.doi.org/10.3897/neotropical.16.e60629.
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The study of biodiversity is a fundamental step to develop conservation strategies. Reptile populations are immersed in a global crisis, due to anthropic disturbances. Almost the entire Pampa ecoregion in Argentina was modified for agricultural and livestock activities, the only remnants of mountain native grasslands in Buenos Aires province being the Tandilia and Ventania mountain systems. Ventania reptiles have been exhaustively researched in last years, while Tandilia counts with fewer studies. We presented an actualized reptiles list of the Tandilia Mountain System. We used five data sources to collect presence records: literature, fieldwork, museum collection, citizen science, and a online database. The composition of reptiles from the Tandilia Mountain range includes 26 species in 12 families. Due to the presence of several endemic reptiles, and the representativeness of more than half of the reptiles of Pampa Ecoregion, Tandilia would be useful to determine conservation priority areas to conserve the native grassland and their reptile fauna.
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Hu, Yang, Graeme Gillespie i Tim S. Jessop. "Variable reptile responses to introduced predator control in southern Australia". Wildlife Research 46, nr 1 (2019): 64. http://dx.doi.org/10.1071/wr18047.
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Context Australia harbours an immense diversity of reptiles, which are generally expected to have frequent and diverse trophic interactions with introduced mammalian carnivores. Nevertheless, the potential for predatory or competitive interactions is likely to be contingent on multiple processes, including the importance of reptiles in the diet of introduced predators, alongside overlaps in their body sizes and ecological niches that would influence the strength of their interactions. In Australia’s temperate and relatively productive mesic environments there is little understanding of how introduced mammalian predators affect reptile assemblages. Aims The aim was to investigate the effects that a European red fox (Vulpes vulpes; 5–7kg) suppression program had on the abundance and species richness of a reptile community, with species ranging in size from the largest local ectothermic predator, the lace monitor (Varanus varius; 4–7kg), to small terrestrial reptiles (mostly 10–150g). Methods We utilised two sampling designs (baited camera monitoring stations and pitfall trapping) to evaluate the effects of fox suppression and other site-level ecological covariates (fire regime and habitat vegetation characteristics) on the lace monitor and small terrestrial reptiles. Reptile abundance and richness at site level were estimated from count-related abundance models. Key results For lace monitors, significantly higher abundances occurred in poison-baited areas relative to control areas. This suggests that fox suppression can affect the populations of the lace monitor via mesopredator release arising from reduced competition and, possibly, predation. For small terrestrial reptiles, neither abundance nor species richness were influenced by fox suppression. Individual abundances of the three most common small reptile species matched the overall pattern, as only responses to structural parameters of the habitat were detected. Conclusions Fox suppression can have different impacts for different reptile taxa, pending their ecological niche, as only the largest species was affected. Implications Increase in lace monitor abundance may change food web dynamics in fox-suppressed sites, such as by increasing predation pressure on arboreal marsupials.
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Kverková, Kristina, Alexandra Polonyiová, Lukáš Kubička i Pavel Němec. "Individual and age-related variation of cellular brain composition in a squamate reptile". Biology Letters 16, nr 9 (wrzesień 2020): 20200280. http://dx.doi.org/10.1098/rsbl.2020.0280.
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Within-species variation in the number of neurons, other brain cells and their allocation to different brain parts is poorly studied. Here, we assess these numbers in a squamate reptile, the Madagascar ground gecko ( Paroedura picta ). We examined adults from two captive populations and three age groups within one population. Even though reptiles exhibit extensive adult neurogenesis, intrapopulation variation in the number of neurons is similar to that in mice. However, the two populations differed significantly in most measures, highlighting the fact that using only one population can underestimate within-species variation. There is a substantial increase in the number of neurons and decrease in neuronal density in adult geckos relative to hatchlings and an increase in the number of neurons in the telencephalon in fully grown adults relative to sexually mature young adults. This finding implies that adult neurogenesis does not only replace worn out but also adds new telencephalic neurons in reptiles during adulthood. This markedly contrasts with the situation in mammals, where the number of cortical neurons declines with age.
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Triska, Maggie D., Michael D. Craig, Vicki L. Stokes, Roger P. Pech i Richard J. Hobbs. "Conserving reptiles within a multiple-use landscape: determining habitat affiliations of reptile communities in the northern jarrah forest of south-western Australia". Australian Journal of Zoology 65, nr 1 (2017): 21. http://dx.doi.org/10.1071/zo16074.
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Disturbed landscapes can provide habitat for a variety of species; however, for fauna, a strong understanding of their habitat affiliations is critical both to detect species and to develop management prescriptions to maintain their populations. We assessed habitat affiliations of common, uncommon and rare reptile species in a multiple-use landscape, the northern jarrah forest of south-western Australia. To identify predictors of reptile occurrence, we related reptile presence/absence, or relative abundance, to habitat, climatic and seasonal variables. Because the reptiles studied have cryptic behaviours and low numbers of detections, we used a combination of analyses including non-metric multi-dimensional scaling, occupancy and regression models. We identified specific habitat affiliations for the most common species and potential linkages with vegetation structure for most uncommon species. There were insufficient detections to determine habitat affiliations accurately for most rare species. Often species were detected too infrequently to determine specific habitat variables that influence occupancy and detection, and altering survey time and scale may increase detections so that habitat affiliations can be determined. However, in highly speciose landscapes, like our study area, we may not be able to wait until we have enough detections to define the habitat affiliations of all reptiles before we make management decisions. Therefore management activities that maintain habitat heterogeneity and complexity is likely to be the best strategy to conserve the most reptile species.
Rozprawy doktorskie na temat "Reptile populations"
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Baxter-Gilbert, James H. "The Long Road Ahead: Understanding Road-related Threats to Reptiles and Testing if Current Mitigation Measures are Effective at Minimizing Impacts". Thesis, Laurentian University of Sudbury, 2014. https://zone.biblio.laurentian.ca/dspace/handle/10219/2137.
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Reptile populations are suffering substantial global losses and roads are identified as one of the leading threats to their persistence. Currently, efforts to mitigate this threat are being implemented with various levels of success. I studied the effectiveness of exclusion structures (i.e., fencing) at preventing reptiles from gaining access to the road, and reducing road mortality. I also examined if population connectivity structures (i.e., ecopassages) were effective at reducing habitat and population fragmentation and allowing individuals to access habitats, resources, and mates on both sides of a major road (4 lane highway). I found that the fence was ineffective at preventing reptiles from gaining access to the road; however, reptiles were observed using the ecopassages to cross the road. Behavioural trials testing painted turtles’ (Chrysemys picta) willingness to use an ecopassage demonstrated that refusal was twice more likely than use of an ecopassage. I also examined the potential for roads to pose a physiological threat to roadside populations of reptiles by examining corticosterone (CORT), a stress hormone linked to negative health effects in cases of elevated levels over the long-term. To assess if individuals living near a major road had higher CORT levels than individuals from a less impacted population, I developed a novel means of measuring CORT from painted turtle claws in partnership with Dr. Gabriela Mastromonaco (Toronto Zoo). With long-term CORT levels considered as a proxy for chronic physiological stress, I did not find evidence that populations near roads had altered stress levels. However, this seminal study will provide the framework for further examination of more species, including species-at-risk, and a better understanding of effects of anthropogenic environments on wildlife health. As road ecologists strive to expand our understanding of the threats roads pose to reptiles, it is important that this field spans multiple disciplines, so that we can both understand the direct and indirect threats that roads cause and develop effective mitigation that preserves biodiversity within our anthropogenic landscape.
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Rodrigues, Murilo Guimarães 1978. "Estimating vital rates with imperfect detection in amphibian and reptile populations = Estimando taxas vitais com detecção imperfeita em populações de anfíbios e répteis". [s.n.], 2013. http://repositorio.unicamp.br/jspui/handle/REPOSIP/316218.
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Orientador: Ricardo Jannini SawayaTese (doutorado) - Universidade Estadual de Campinas, Instituto de Biologia
Made available in DSpace on 2018-08-23T04:29:37Z (GMT). No. of bitstreams: 1 Rodrigues_MuriloGuimaraes_D.pdf: 4926681 bytes, checksum: 057f2c8aa9c7d1baaa30995a12a9c858 (MD5) Previous issue date: 2013
Resumo: A ecologia de populações investiga os fatores que levam a variação das taxas vitais e, consequentemente, no número de indivíduos. Isso inclui testar hipóteses sobre aspectos da história de vida das espécies e entender os fatores que podem modular a dinâmica populacional. No entanto, a obtenção de dados para testar hipóteses pode ser difícil para populações que apresentam probabilidades de detecção < 1, como anfíbios e répteis. A marcação e recaptura é amplamente usada para estimar a detecção e inferir aspectos de dinâmica populacional e testar hipóteses ecológicas. Neste trabalho empregamos a teoria de marcação e recaptura para testar hipóteses relacionadas à ecologia e conservação de populações de anfíbios e répteis. Utilizamos o programa MARK para implementar modelos de populações abertas e fechadas incorporando a probabilidade de detecção dos indivíduos, para obter estimativas de sobrevivência, e outros parâmetros populacionais usando máxima verossimilhança. Organizamos esta tese em quatro capítulos. Iniciamos enfatizando a importância da probabilidade de detecção, além de simular cenários hipotéticos para demonstrar a relação entre esforço de campo, tamanho ótimo amostral e viés amostral. Em seguida comparamos o efeito de duas técnicas de marcação, o corte de artelhos e o implante de microchips, sobre a sobrevivência individual do sapo ferreiro, Hypsiboas faber. No terceiro capítulo estimamos a sobrevivência e o crescimento populacional da jararaca-ilhoa, Bothrops insularis incorporando emigração temporária aos modelos. Além do estudo de taxas vitais e de dinâmica nas populações, a alocação de energia e suas consequências na sobrevivência individual podem ser testadas com modelos de marcação e recaptura. Assim, no quarto e último capítulo consideramos dois caracteres sexuais presentes no sistema de acasalamento dos lagartos, o tamanho da mandíbula e a coloração chamativa, para comparar as estimativas de sobrevivência entre machos e fêmeas do lagarto cauda de chicote, Cnemidophorus cf. ocellifer. . De forma geral, observamos que a probabilidade de detecção individual nos sistemas estudados foi baixa e condizente com a detecção de vertebrados em ambientes tropicais. Além disso, a inclusão de covariáveis na investigação de parâmetros vitais e no processo de detecção é fundamental para o melhor entendimento dos fatores que explicam a dinâmica de uma população. Especificamente observamos que: (i) demonstramos que as taxas que não incorporam a detecção são enviesadas em relação às estimativas que consideram a detecção, (ii) as estimativas de sobrevivência foram similares em indivíduos de Hypsiboas faber marcados com ablação de artelhos e microchips , (iii) Bothrops insularis apresentou baixa probabilidade de sobrevivência anual e crescimento populacional anual negativo. Por fim, (iv) machos maiores do lagarto Cnemidophorus cf. ocellifer apresentaram sobrevivência mensal menor do que machos menores, mas o oposto foi observado para as fêmeas
Abstract: Population ecology aims to search for factors that lead to variation in vital rates and consequently, in the number of individuals. This includes testing hypotheses about natural history traits and threats to populations. However, obtaining data to test hypotheses is challenging because following individuals in the field can be difficult, especially for amphibians and reptiles, where detection probabilities are often < 1. Mark-recapture methods are widely used to estimate detection probabilities and to test ecological hypothesis. Here we used mark-recapture methods to test hypotheses related to ecology and conservation of amphibian and reptile populations. We implemented open- and closed-population models in Program MARK, to account for detection probabilities and to calculate survival estimates and other population parameters. We organized this dissertation into four chapters. In the first chapter we emphasize the importance of considering detection probabilities besides simulating hypothetical scenarios to show the relationship between field effort, sample size and precision. In the second chapter we used a Cormack-Jolly-Seber model to compare the effect of two amphibian marking techniques, toeclipping and PIT tagging, on survival in the blacksmith tree frog, Hypsiboas faber. In the third chapter our goal was to estimate survival and population growth of the golden lancehead, Bothrops insularis accounting for temporary emigration using Pollock's Robust Design. Besides the study of vital rates and population dynamics, energy allocation and its consequences for survival are testable with mark-recapture models. Thus, in the last chapter we used two traits from the lizard mating system, namely jaw size and courtship coloration, to compare survival estimates between males and females of the whiptail lizard, Cnemidophorus cf. ocellifer. In summary we observed that detection probability on the studied populations were low and similar to other vertebrate populations from the tropics. However, including covariates in estimation models of vital rates and detection is important to obtain more accurate results to explain population dynamics. Specifically we conclude that (i) return rates were biased low in relation to survival estimates that account for detectability, (ii) the estimates of survival were similar between toe-clipped and PIT tagged individuals of Hypsiboas faber, (iii) Bothrops insularis showed low survival probability and negative annual population growth. And (iv) larger Cnemidophorus cf. ocellifer males showed lower monthly survival probability than smaller males but the opposite was found for females
Doutorado
Ecologia
Doutor em Ecologia
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Lettink, Marieke, i n/a. "Adding to nature : can artificial retreats be used to monitor and restore lizard populations?" University of Otago. Department of Zoology, 2008. http://adt.otago.ac.nz./public/adt-NZDU20080715.091040.
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Artificial retreats are increasingly used to sample animal populations and in attempts to boost animal numbers in degraded habitats. Here, I test potential applications of artificial retreats for lizards inhabiting a coastal environment of high conservation value (Kaitorete Spit, New Zealand). I first conducted a pitfall-trapping survey examining the distribution and relative abundance of lizards in duneland, farmland and shrubland habitats, and tested the influence of trap placement on capture rates. Capture rates of the diurnal skinks Oligosoma maccanni (McCann�s skink) and O. nigriplantare polychroma (common skink) were highest in duneland and farmland, respectively, and were most sensitive to the distance separating traps from the nearest cover (the greater the distance, the lower the capture rate). Captures of O. lineoocellatum (spotted skink) and Hoplodactylus maculatus (common gecko) were rare.
Secondly, in separate chapters I test the utility of artificial retreats for monitoring: 1) a preference trial examining relative use of three types of artificial retreats by skinks (O. maccanni and O. n. polychroma) and geckos (H. maculatus); 2) a comparison of the effectiveness of artificial retreats relative to pitfall traps for detecting cryptic and primarily nocturnal geckos (H. maculatus) following translocation; and 3) capture-recapture estimation of population parameters (survival and abundance) of H. maculatus. I found that: 1) geckos strongly preferred retreats made of Onduline over corrugated iron and concrete tiles, whereas skinks exhibited no apparent preferences; 2) artificial retreats were more effective than pitfall traps for detecting geckos following translocation; and 3) monthly survival and recapture probabilities of geckos varied with age-class and over time. Estimated survival was unexpectedly low, possibly due to excessive trap spacing. I developed a new capture-recapture model specifically for population size estimation with data from artificial retreats, which gave estimates that were up to 50% greater than those predicted by conventional capture-recapture models. I caution that permanent placement of artificial retreats in long-term studies may be inappropriate for estimation of population parameters due to potential habitat-enhancement effects and/or altered predation risk.
Thirdly, I conducted a capture-recapture field experiment, using a replicated Before-After-Control-impact (BACI) design, to test the relative effects of habitat manipulation (artificial retreat addition) and partial predator removal (by fencing) on annual survival of duneland skink (O. maccanni) populations. Survival increased at sites with predator exclosures, but not at control sites or following the addition of artificial retreats, either alone or in combination with a predator exclosure. The magnitude of the increase in survival for the exclosure-only treatment was small, but sufficient to change the trajectory of an apparently stable population into an increasing one, suggesting that the population is limited by predators. Predator control, but not the addition of artificial retreats, is predicted to benefit O. maccanni.
To conclude, the Onduline design developed here appears to be particularly useful for sampling cryptic, terrestrial geckos; however, artificial retreats must be used appropriately to avoid bias arising from habitat-enhancing effects and/or altered predation risk. The restoration value of artificial retreats requires further testing on other species and in areas where natural retreat sites are limited.
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Guzinski, Jaro, i guzi0002@flinders edu au. "Investigating genetic population substructure of an Australian reptile tick, Bothriocroton hydrosauri, using highly polymorphic microsatellite markers". Flinders University. School of Biological Sciences, 2009. http://catalogue.flinders.edu.au./local/adt/public/adt-SFU20090324.125811.
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Despite long-term study, the mechanism explaining the parapatric distribution of two Australian reptile ticks species, Bothriocroton hydrosauri and Amblyomma limbatum, is not understood. This project aimed to use molecular genetic data to investigate aspects of the population biology of these two tick species, such as population structure and dispersal, to gain further insights into the cause and maintenance of this parapatric boundary. I developed and subsequently tested for Mendelian inheritance a suite of B. hydrosauri and A. limbatum species-specific microsatellites markers. Pedigree analysis showed one B. hydrosauri locus and all of the A. limbatum loci to be inherited in a non-Mendelian manner. Thus I could not investigate A. limbatum population structure and focused solely on B. hydrosauri.
The first part of this study tested predictions of a model formulated to explain B. hydrosauri transmission dynamics. The ripple model, based on detailed ecological and behavioural data on B. hydrosauri and Tiliqua rugosa, B. hydrosauris most common host, predicts higher relatedness among larvae than among nymphs or adults on a host, and significant spatial autocorrelation in larvae extending further than for the later life stages. The model also predicts that adult ticks are likely to encounter related partners and that this will generate inbreeding within the population. I tested those predictions using nine microsatellite loci on a sample of 848 ticks (464 larvae, 140 nymphs and 244 adults) collected from 98 T. rugosa hosts at the northern edge of B. hydrosauris distribution range. My data did support all of the predictions of the ripple model and indicated that the dynamics of transmission among hosts play an important role in parasite population structure.
The second part of this project focused on investigating the population genetic structure of B. hydrosauri at the edge of its geographic range and testing the predictions of a population model derived to explain B. hydrosauris parapatric boundary with A. limbatum. The ridge and trough model suggested the tick population was organised spatially into a series of ridges where tick density was high and troughs where it was low. Genetically, the expectation was to find clusters of more closely related individuals associated with the ridges. Cluster analysis of microsatellite allele frequencies and analysis of molecular variance of mitochondrial haplotype frequencies revealed the presence of four genetic clusters within a sample of 244 B. hydrosauri adults. As the highly genetically divergent clusters had overlapping distributions, and in some cases were syntopic, the genetic population structure predicted for these ticks by the ridge and trough model was not observed. Several explanations were considered for the observed B. hydrosauri genetic population structure, but syntopy of the clusters suggested that assortative mating is the most likely. I speculated that the clusters have formed in allopatry, when the environment was extremely heterogeneous, such that the ticks (and their hosts) were confined to isolated patches of high-quality habitat. Given sufficient time, this could have resulted in reproductive incompatibility between ticks occupying different patches. The population structure I uncovered indicates subsequent secondary recontact of divergent groups.
Although my study allowed for a better understanding of B. hydrosauri biology and population structure, the reasons for the parapatric distributions of B. hydrosauri and A. limbatum are still unclear. Further research should focus on investigating the population genetic structure of A. limbatum at the edge of its range, as well as on performing a larger-scale study of B. hydrosauri population genetic structure and a more detailed investigation of the applicability of the ridge and trough model to this tick species. Moreover, it will be useful to inspect the population structure of both these species within the centers of their ranges and compare these findings with population structure found at the edge of the range.
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Bissell, Ahrash N. "Population differences and behavior of lizards : on the road to speciation? /". view abstract or download file of text, 2001. http://wwwlib.umi.com/cr/uoregon/fullcit?p3024506.
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Thesis (Ph. D.)--University of Oregon, 2001.Typescript. Includes vita and abstract. Includes bibliographical references (leaves 121-147). Also available for download via the World Wide Web; free to University of Oregon users.
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Wasiolka, Bernd. "The impact of overgrazing on reptile diversity and population dynamics of Pedioplanis l. lineoocellata in the southern Kalahari". Phd thesis, Universität Potsdam, 2007. http://opus.kobv.de/ubp/volltexte/2008/1661/.
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Die Vegetationskomposition und –struktur, beispielsweise die unterschiedliche Architektur von Bäumen, Sträuchern, Gräsern und Kräutern, bietet ein großes Spektrum an Habitaten und Nischen, die wiederum eine hohe Tierdiversität in den Savannensystemen des südlichen Afrikas ermöglichen. Dieses Ökosystem wurde jedoch über Jahrzehnte weltweit durch intensive anthropogene Landnutzung (z.B. Viehwirtschaft) nachhaltig verändert. Dabei wurden die Zusammensetzung, Diversität und Struktur der Vegetation stark verändert. Überweidung in Savannensystemen führt zu einer Degradation des Habitates einhergehend mit dem Verlust von perennierenden Gräsern und krautiger Vegetation. Dies führt zu einem Anstieg an vegetationsfreien Bodenflächen. Beides, sowohl der Verlust an perennierenden Gräsern und krautiger Vegetation sowie der Anstieg an vegetationsfreien Flächen führt zu verbesserten Etablierungsbedingungen für Sträucher (z.B. Rhigozum trichotomum, Acacia mellifera) und auf lange Sicht zu stark verbuschten Flächen. Die Tierdiversität in Savannen ist hiervon entscheidend beeinflusst. Mit sinkender struktureller Diversität verringert sich auch die Tierdiversität.
Während der Einfluss von Überweidung auf die Vegetation relativ gut untersucht ist sind Informationen über den Einfluss von Überweidung auf die Tierdiversität, speziell für Reptilien, eher spärlich vorhanden. Zusätzlich ist sehr wenig bekannt zum Einfluss auf die Populationsdynamik (z.B. Verhaltensanpassungen, Raumnutzung, Überlebensrate, Sterberate) einzelner Reptilienarten.
Ziel meiner Doktorarbeit ist es den Einfluss von Überweidung durch kommerzielle Farmnutzung auf die Reptiliengemeinschaft und auf verschiedene Aspekte der Populationsdynamik der Echse Pedioplanis lineoocellata lineoocellata zu untersuchen. Hinsichtlich bestimmter Naturschutzmaßnahmen ist es einerseits wichtig zu verstehen welchen Auswirkungen Überweidung auf die gesamte Reptiliengemeinschaft hat. Und zum anderen wie entscheidende Faktoren der Populationsdynamik beeinflusst werden. Beides führt zu einem besseren Verständnis der Reaktion von Reptilien auf Habitatdegradation zu erlangen.
Die Ergebnisse meiner Doktorarbeit zeigen eindeutig einen negativen Einfluss der Überweidung und der daraus resultierende Habitatdegradation auf (1) die gesamte Reptiliengemeinschaft und (2) auf einzelne Aspekte der Populationsdynamik von P. lineoocellata.
Im Teil 1 wird die signifikante Reduzierung der Reptiliendiversität und Abundanz in degradierten Habitaten beschrieben. Im zweiten Teil wird gezeigt, dass P. lineoocellata das Verhalten an die verschlechterten Lebensbedingungen anpassen kann. Die Art bewegt sich sowohl häufiger als auch über einen längeren Zeitraum und legt dabei größere Distanzen zurück. Zusätzlich vergrößerte die Art ihr Revier (home range) (Teil 3). Im abschließenden Teil wird der negative Einfluss von Überweidung auf die Populationsdynamik von P. lineoocellata beschrieben: In degradierten Habitaten nimmt die Populationsgröße von adulten und juvenilen Echsen ab, die Überlebens- und Geburtenrate sinken, währen zusätzlich das Prädationsrisiko ansteigt. Verantwortlich hierfür ist zum einen die ebenfalls reduzierte Nahrungsverfügbarkeit (Arthropoden) auf degradierten Flächen. Dies hat zur Folge, dass die Populationsgröße abnimmt und die Fitness der Individuen verringert wird, welches sich durch eine Reduzierung der Überlebens- und Geburtenrate bemerkbar macht. Und zum anderen ist es die Reduzierung der Vegetationsbedeckung und der Rückgang an perennierenden Gräsern welche sich negativ auswirken. Als Konsequenz hiervon gehen Nischen und Mikrohabitate verloren und die Möglichkeiten der Reptilien zur Thermoregulation sind verringert. Des Weiteren hat dieser Verlust an perennierender Grasbedeckung auch ein erhöhtes Prädationsrisikos zur Folge. Zusammenfassend lässt sich sagen, dass nicht nur Bäume und Sträucher, wie in anderen Studien gezeigt, eine bedeutende Rolle für die Diversität spielen, sondern auch das perennierende Gras eine wichtige Rolle für die Faunendiversität spielt. Weiterhin zeigte sich, dass Habitatdegradation nicht nur die Population als gesamtes beeinflusst, sondern auch das Verhalten und Populationsparameter einzelner Arten. Des Weiteren ist es Reptilien möglich durch Verhaltensflexibilität auf verschlechterte Umweltbedingen zu reagieren.In semi-arid savannah ecosystems, the vegetation structure and composition, i.e. the architecture of trees, shrubs, grass tussocks and herbaceous plants, offer a great variety of habitats and niches to sustain animal diversity. In the last decades intensive human land use practises like livestock farming have altered the vegetation in savannah ecosystems worldwide. Extensive grazing leads to a reduction of the perennial and herbaceous vegetation cover, which results in an increased availability of bare soil. Both, the missing competition with perennial grasses and the increase of bare soils favour shrub on open ground and lead to area-wide shrub encroachment. As a consequence of the altered vegetation structure and composition, the structural diversity declines. It has been shown that with decreasing structural diversity animal diversity decline across a variety of taxa. Knowledge on the effects of overgrazing on reptiles, which are an important part of the ecosystem, are missing. Furthermore, the impact of habitat degradation on factors of a species population dynamic and life history, e.g., birth rate, survival rate, predation risk, space requirements or behavioural adaptations are poorly known. Therefore, I investigated the impact of overgrazing on the reptile community in the southern Kalahari. Secondly I analysed population dynamics and the behaviour of the Spotted Sand Lizard, Pedioplanis l. lineoocellata. All four chapters clearly demonstrate that habitat degradation caused by overgrazing had a severe negative impact upon (i) the reptile community as a whole and (ii) on population parameters of Pedioplanis l. lineoocellata. Chapter one showed a significant decline of regional reptile diversity and abundance in degraded habitats. In chapter two I demonstrated that P. lineoocellata moves more frequently, spends more time moving and covers larger distances in degraded than in non-degraded habitats. In addition, home range size of the lizard species increases in degraded habitats as shown by chapter three. Finally, chapter four showed the negative impacts of overgrazing on several population parameters of P. lineoocellata. Absolute population size of adult and juvenile lizards, survival rate and birth rate are significantly lower in degraded habitats. Furthermore, the predation risk was greatly increased in degraded habitats. A combination of a variety of aspects can explain the negative impact of habitat degradation on reptiles. First, reduced prey availability negatively affects survival rate, the birth rate and overall abundance. Second, the loss of perennial plant cover leads to a loss of niches and to a reduction of opportunities to thermoregulate. Furthermore, a loss of cover and is associated with increased predation risk. A major finding of my thesis is that the lizard P. lineoocellata can alter its foraging strategy. Species that are able to adapt and change behaviour, such as P. lineoocellata can effectively buffer against changes in their environment. Furthermore, perennial grass cover can be seen as a crucial ecological component of the vegetation in the semi-arid savannah system of the southern Kalahari. If perennial grass cover is reduced to a certain degree reptile diversity will decline and most other aspects of reptile life history will be negatively influenced. Savannah systems are characterised by a mixture of trees, shrubs and perennial grasses. These three vegetation components determine the composition and structure of the vegetation and accordingly influence the faunal diversity. Trees are viewed as keystone structures and focal points of animal activity for a variety of species. Trees supply animals with shelter, shade and food and act as safe sites, nesting sites, observation posts and foraging sites. Recent research demonstrates a positive influence of shrub patches on animal diversity. Moreover, it would seem that intermediate shrub cover can also sustain viable populations in savannah landscapes as has been demonstrated for small carnivores and rodent species. The influence of perennial grasses on faunal diversity did not receive the same attention as the influence of trees and shrubs. In my thesis I didn’t explicitly measure the direct effects of perennial grasses but my results strongly imply that it has an important role. If the perennial grass cover is significantly depleted my results suggest it will negatively influence reptile diversity and abundance and on several populations parameters of P. lineoocellata. Perennial grass cover is associated with the highest prey abundance, reptile diversity and reptile abundance. It provides reptiles both a refuge from predators and opportunities to optimise thermoregulation. The relevance of each of the three vegetation structural elements is different for each taxa and species. In conclusion, I can all three major vegetation structures in the savannah system are important for faunal diversity.
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Ineich, Ivan. "Recherches sur le peuplement et l'évolution des Reptiles terrestres de Polynésie française". Montpellier 2, 1987. http://www.theses.fr/1987MON20238.
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L'examen des statuts sytematiques a permis de distinguer deux especes de scincidae et dans les populations du gesco l. Lugubris, cinq clones parthenogenetiques diploides ou triploides, une lignee bisexuee et certains individus issus d'une hybridation entre ces deux groupes. Une analyse micro-evolutive de plus de 6000 individus montre que, malgre la repartition des iles sur une tres grande surface marine, les capacites de dispersion ne permettent pas l'isolement de populations. Les resultats obtenus sont confrontes aux donnees acquises sur deux groupes d'invertebres remarquables par leur radiations en polynesie francaise
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Bell, Kristen E. "Conservation ecology of amphibians and reptiles in Sarapiqui, Costa Rica : forest fragmentation and long term population change". FIU Digital Commons, 2005. http://digitalcommons.fiu.edu/etd/1481.
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In order to explore the conservation ecology of frogs and lizards in the Sarapiqui region of Costa Rica, I compared populations and communities among forest fragments and La Selva Biological Station, as well as across 35 years of sampling at La Selva. Species richness in nine fragments combined was 85% of that found in La Selva, and community composition varied among sites and by fragment size class. Although communities in fragments differed fundamentally from those in intact forest, the high diversity observed across all fragments indicates that preserving a network of small forest patches may be of great conservation value to the herpetofauna of this region. According to data from past studies at La Selva, most common species of leaf-litter frogs and lizards demonstrated significant decreases in density over the 35-year period. My findings may represent either natural population fluctuations or sweeping faunal declines at this site.
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Bissell, Kristin Marie. "Modeling habitat ecology and population viability of the Eastern Massasauga Rattlesnake in southwestern lower Michigan". Diss., Connect to online resource - MSU authorized users, 2006.
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Thesis (M.S.)--Michigan State University. Dept. of Fisheries and Wildlife, 2006.Title from PDF t.p. (viewed on Nov. 20, 2008) Includes bibliographical references (p. 118-124). Also issued in print.
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Sung, Yik-hei, i 宋亦希. "Impacts of illegal trapping and plantation forestry on herpetofaunal populations". Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2012. http://hub.hku.hk/bib/B48199308.
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Globally, as many as 30% of amphibians and 23% of reptile species are threatened and require urgent conservation action. The major threats are primarily caused by anthropogenic activities. This research aimed to investigate the impacts of two anthropogenic threats, over-exploitation and habitat changes on herpetofaunal populations in Hong Kong.
Platysternon megacephalum has been heavily depleted because of severe hunting pressure for the food and pet trades. Low densities of individuals and few remaining intact populations have limited our ability to study their ecology. I conducted mark-recapture and radio-telemetry studies on P.megacephalum populations in five streams in Hong Kong, one of which was free from trapping, over 34 months (2009–2011) to investigate the impacts of illegal trapping on populations of P.megacephalum and their spatial ecology and growth. Illegal trapping was associated with the absence of large adults, smaller body sizes of adults and skewed ratios of juveniles to adults. Home ranges were relatively small with a mean 100% minimum convex polygon 996m2. Males moved longer distances than females and both sexes moved longer distances in wet seasons. P.megacephalum was highly aquatic, preferring to stay in pools, and their microhabitat preferences were affected by stream width and depth, and substrate types. Juvenile P.megacephalum grew rapidly, with growth declining after attainment of sexual maturity. The average ages of sexual maturation were eight years for females. Illegal trapping remains the major threat to P.megacephalum populations and I recommend that regulatory personnel identify key streams and patrol regularly against illegal trapping to safeguard remaining populations.
In Hong Kong, large areas of primary forest have been replaced by secondary forests and plantations, and changes in tree species composition have often led to alteration of associated plant and animal communities. I examined the herpetofaunal assemblages in secondary forests and exotic Lophostemon confertus plantations. Amphibian abundances were higher in secondary forests while reptile abundance, species richness of amphibian and reptiles were similar. Secondary forests provided better habitats for amphibians and I recommend the planting of a mixture of native tree species and the thinning of exotic trees in future plantation management efforts in South China.
Our knowledge about the effectiveness of different herpetofaunal survey methods in Southeast Asia is limited. To fill the information gap, I examined the effectiveness of three survey methods, including transect surveys, pitfall traps and coverboards, for sampling terrestrial herpetofauna. Transect surveys were most effective at sampling species richness and pitfall traps were most efficient in capturing high numbers of reptiles. The results of this study will aid researchers in assessing the feasibility of and choosing herpetofaunal survey methods in Southeast Asia.
Despite the severe threats that herpetofauna are facing, our understanding of their ecology and conservation needs remains limited. More research and the initiation of monitoring programs for herpetofauna, strengthened enforcement of existing regulations, and proper habitat management are crucial for the conservation of herpetofauna in South China.published_or_final_version
Biological Sciences
Doctoral
Doctor of Philosophy
Książki na temat "Reptile populations"
1
Conservancy, The Nature, i California. Department of Fish and Game, red. Checklist of amphibians and reptiles: Carrizo Plain Natural Area. Bakersfield, Calif.?]: [U.S. Dept. of the Interior, Bureau of Land Management], 1996.
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Hallock, Lisa A. Herpetofauna inventory of Bureau of Land Management sites in Douglas, Franklin, Grant, Lincoln, Klickitat, Washington, 1998: Summary of work completed in 1998. Spokane, Wash: Bureau of Land Management, Spokane District Office, 1999.
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Daigle, Claude. Inventaires de la tortue des bois au Québec: Rapport d'étape, années 1994 et 1995. Québec: Ministère de l'environnement et de la faune, Direction de la faune et des habitats, Service de la faune terrestre, 1996.
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Maisonneuve, Charles. Inventaires aériens de sauvagine dans les bassins versants des rivières Boyer et Le Bras, 1992-1995. Québec: Ministère de l'environnement et de la faune, 1998.
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Shine, Richard. Diets and abundances of aquatic and semi-aquatic reptiles in the Alligator Rivers Region. Canberra: Australian Govt. Pub. Service, 1986.
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Reptile biodiversity: Standard methods for inventory and monitoring. Berkeley: University of California Press, 2012.
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D, Taylor R. Crocodile numbers on Lake Kariba, Zimbabwe and factors influencing them. Causeway, Harare, Zimbabwe: WWF Multispecies Project, 1993.
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James, Janice D. Short-horned lizard (Phrynosoma hernandesi hernandesi) populations in Alberta: 2002 survey results. [Edmonton]: Alberta Sustainable Resource Development, 2003.
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James, Janice D. A survey of short-horned lizard (Phrynosoma hernandesi hernandesi) populations in Alberta. [Edmonton]: Fish & Wildlife Division, Resource Status and Assessment Branch, Alberta Sustainable Resource Development, 2002.
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Harmata, Alan R. Nesting success and productivity of key raptor species and preliminary herptile survey, Kevin Rim raptor study area, Toole County, Montana, 2004: Challenge cost share progress report to: Bureau of Land Management, Great Falls District. Bozeman, Mont: Montana State University, Fish & Wildlife Program, Department of Ecology, 2004.
Znajdź pełny tekst źródłaCzęści książek na temat "Reptile populations"
1
Grant, Bruce W., Anton D. Tucker, Jeffrey E. Lovich, Anthony M. Mills, Philip M. Dixon i J. Whitfield Gibbons. "The Use of Coverboards in Estimating Patterns of Reptile and Amphibian Biodiversity". W Wildlife 2001: Populations, 379–403. Dordrecht: Springer Netherlands, 1992. http://dx.doi.org/10.1007/978-94-011-2868-1_31.
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Peterson, Charles R., i Michael E. Dorcas. "The Use of Automated Data-Acquisition Techniques in Monitoring Amphibian and Reptile Populations". W Wildlife 2001: Populations, 369–78. Dordrecht: Springer Netherlands, 1992. http://dx.doi.org/10.1007/978-94-011-2868-1_30.
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Scott, Norman J., i Richard A. Seigel. "The Management of Amphibian and Reptile Populations: Species Priorities and Methodological and Theoretical Constraints". W Wildlife 2001: Populations, 343–68. Dordrecht: Springer Netherlands, 1992. http://dx.doi.org/10.1007/978-94-011-2868-1_29.
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Joger, Ulrich, Uwe Fritz, Daniela Guicking, Svetlana Kalyabina-Hauf, Zoltan T. Nagy i Michael Wink. "Relict Populations and Endemic Clades in Palearctic Reptiles: Evolutionary History and Implications for Conservation". W Relict Species, 119–43. Berlin, Heidelberg: Springer Berlin Heidelberg, 2009. http://dx.doi.org/10.1007/978-3-540-92160-8_6.
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"Global Threats Affecting the Status of Reptile Populations". W Toxicology of Reptiles, 23–48. CRC Press, 2016. http://dx.doi.org/10.1201/9781420038361-6.
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Irwin, Lisa, i Kelly Irwin. "Global Threats Affecting the Status of Reptile Populations". W New Perspectives: Toxicology and the Environment, 9–34. CRC Press, 2005. http://dx.doi.org/10.1201/9781420038361.ch2.
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"Reptile Ecotoxicology: Studying the Effects of Contaminants on Populations". W Toxicology of Reptiles, 281–312. CRC Press, 2016. http://dx.doi.org/10.1201/9781420038361-14.
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Case, Ted J. "Reptiles: Ecology". W Island Biogeography in the Sea of Cortés II. Oxford University Press, 2002. http://dx.doi.org/10.1093/oso/9780195133462.003.0015.
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The reptiles of the islands of the Sea of Cortés have provided many opportunities to test ecological and biogeographical hypotheses because they support a diverse fauna with much insular endemism; are numerous and of varying ages and degrees of isolation; are relatively undisturbed by human activity and introduced species; and have a relatively well-understood geological history (see chap. 2). In particular, contrasts of mainland and island reptile populations in the region have resulted in significant progress in testing theories of island biogeography, principles of ecological character displacement, ecological release, density compensation, and vicariance biogeography (see chap. 8). The reptiles, being conspicuous in these arid habitats, have attracted relatively more research attention than other vertebrates, and today we have a reasonably complete picture of at least which species are on which islands. Since the first edition of this book, nearly 20 years ago, there have been only 15 new records for the major islands, of which all but one are of snakes. In this chapter I review the basic elements of reptilian island biogeography in the Sea of Cortés with an emphasis on ecological factors shaping distributions and evolutionary trajectories. I first examine the patterns of species diversity and association across islands. I then take a closer look at some particular island forms, reviewing features of their life history that seem divergent from mainland relatives. In this regard I present some new data from a long-term study of two insular species of chuckwallas. Finally, I review patterns of population density across islands and their possible determinants. A recurrent debate in island biogeography centers on the relative importance of contemporary and ongoing ecological factors relative to historical circumstances in accounting for the number and the identities of species on islands. Historical biogeographers typically view the number of species on an island as being determined by the availability of appropriate habitats. They see changes in species composition chiefly as a consequence of alteration of the mix of habitats due to climatic change (e.g., Pregill and Olson 1980; Olson and Hilgartner 1982); extinctions are posited to occur in waves, as old habitats disappear and new ones become available.
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"15. Population Size and Demographics". W Reptile Biodiversity, 283–322. University of California Press, 2019. http://dx.doi.org/10.1525/9780520952072-018.
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Thompson, William L., Gary C. White i Charles Gowan. "Amphibians and Reptiles". W Monitoring Vertebrate Populations, 233–60. Elsevier, 1998. http://dx.doi.org/10.1016/b978-012688960-4/50008-3.
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STANKEVIČIŪTĖ, Jolanta, Solveiga Marija BARKAUSKAITĖ i Gediminas BRAZAITIS. "DETECTION OF XENOBIOTIC SUBSTANCES IN MUTE SWANS’ (CYGNUS OLOR) BLOOD". W Rural Development 2015. Aleksandras Stulginskis University, 2015. http://dx.doi.org/10.15544/rd.2015.064.
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During recent years the attention towards the effects of xenobiotic substances on wild nature has been steadily increasing. Literature reviews have revealed that active hormone-disintegrating substances might affect the reproduction of some wild animal species. Research shows anomalies of reproduction and development in various animal groups such as birds, fish, invertebrates and reptiles. Species inhabiting water and its surroundings cause the highest concern. Due to insufficient baseline information it is difficult to determine the extent of the problem in these wild populations on an ecological scale. The research described in this article is the first attempt to analyse xenobiotic substances and evaluate possible accumulation of pharmaceuticals in animals higher up in the food chain in Lithuania. This research tests new methods for to analyse for xenobiotics substances, which might be used in the future. Blood samples of 7 swans were examined using liquid chromatography, however, no xenobiotics were detected. Negative results do not eliminate the necessity for further investigate of larger samples, other species or to search for non-pharmaceutical xenobiotics.
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Yoshida, N., S. Terukina, M. Matsuda, M. Moroi, M. Okuma i N. Aoki. "FIBRINOGENS KYOTO AND TOCHIGI, EACH WITH AN APPARENT ABNORMAL MOL. WT. γ CHAIN, ARE CHARACTERIZED BY REPLACEMENT OF γ ASN-308 BY LYS AND γ ARG-275 BY CYS, RESPECTIVELY". W XIth International Congress on Thrombosis and Haemostasis. Schattauer GmbH, 1987. http://dx.doi.org/10.1055/s-0038-1644702.
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Congenital inherited abnormal fibrinogens (Fbgs) Kyoto and Tochigi showed prolonged thrombin- and reptilase-time, normal release of fibrinopeptides A and B, normal cross linking ability and impaired polymerization of the fibrin monomer.Purified Fbg analyzed on SDS-PAGE under the reduced condition in the system of Laemmli contained 50 % of an apparent lower mol. wt. γ chain (γ Kyoto)(mol. wt.= 48,000 compared with 50,000 for the normal) in Fbg Kyoto and an apparent higher mol. wt. γ chain (γ Tochigi)(mol. wt.= 50,500) in Fbg Tochigi. Apparent mol. wt. differences were also detected in reduced and carboxymethyl ated Fbg, Fbg fragment D1, and D2, but not in D3. This suggested that the abnormality of γ chains in both Fbgs is in γ 303-356.Amino acid sequence analysis was performed for CNBr- or lysylendopeptidase-digested peptides of the γ chain or D1 peptides after fractionation on HPLC. In Fbg Kyoto, γ Asn-308 was substituted by Lys, and a deletion of short peptides corresponding to the mol. wt. difference of 2,000 could not be detected. In Fbg Tochigi, γ Arg-275 was substituted by Cys, and no abnormality of amino acid sequence was found in γ 303-356.These results suggest that some lesions or conformations containing γ 275 and γ 308 will directly or indirectly affect polymerization of fibrin monomers. Although the reason for apparent mol. wt. differences is not known yet, SDS-PAGE in the system of Laemmli will be useful for the analysis of abnormal Fbgs.Fbg Kyoto could not be separated into two or three populations and may contain hetero-dimer molecules, but Fbg Tochigi had unclottable Fbg with predominant γ Tochigi and may contain abnormal homo-dimer molecules and normal molecules.
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Gader, A. M. A., H. Bahakim, S. Malaika i F. A. Jabbar. "HAEMOSTATIC PARAMETERS IN VARIOUS ETHNIC GROUPS IN SAUDI ARABIA". W XIth International Congress on Thrombosis and Haemostasis. Schattauer GmbH, 1987. http://dx.doi.org/10.1055/s-0038-1644869.
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Geographical and racial differences in the incidence of thrcmbo-embolisn could be related to basic dissimilaritiesin the haemostatic system in different ethnic groups. However reliable comparative population studies in haemostatic parameters is lacking. The large expatriate ccmnunity in Saudi Arabia offers such a chance.Subjects tested were all healthy blood donors (aged 20-50 years) and were classified on the basis of ethnic origininto three categories (1) Arabs n=750, (2) Westerns (Americans and Europeans) n=400, and (3) S.E. Asians (Filipinos) n=570. The measurements done included PT, PTT, TT, Reptilase time, Plasma fibrinogen, AT III, Plasminogen, F.VIII:C, FX, α-2 Antiplasmin and Platelet aggregation in response to ADP (20.0, 2.0, 1.0, 0.5 & 0.25 uM), Collagen, Arachidonic acid, Adrenaline and Ristocetin (1.5, 1.2 & 1.0 mg/ml).There were no significant ethnic differences in the measured plasmatic clotting tests. This contrasts the finding of many smaller studies. Besides no significant ethnic differences were noted in platelet aggregation response to high doses of ADP (20 uM) or Ristocetin (1.5 mg/ml) and to Collagen. However, 45% of the S.E. Asians displayed abnormally inhibited responses to Adrenaline when compared to Arabs (34%) and Westerns (35.2%). Asians also displayed more inhibited responses to lower doses of ADP (2.0 & 1.0 uM) . On the other hand, S.E. Asians showed the lowest incidence of inhibited Arachidonic acid responses (9%) when compared to Arabs (24%) and Westerns (26%) . Similar racial differences were noted in response to low doses of Ristocetin (1.2 & 1.0 mg%) where Arabs and Asians showed high incidence of abnormally reduced responses (26-28%) when compared to Westerns (15%). No evidence of enhanced aggregation could be detected in Westerns. Changes of climate and/or dietary habits could be important factors influencing the haemostatic system in such a way that reduces ethnic dissimilarities.