Дисертації з теми "Amphibiens – Habitat"
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1
Perret, Nadège. "Dynamique de population en habitat fragmenté chez deux espèces d'amphibiens urodèles (Triturus alpestris et T cristatus)." Lyon 1, 2000. http://www.theses.fr/2000LYO10283.
Повний текст джерелаАнотація:
La dispersion est un processus clé en écologie en raison de ses implications multiples tant au niveau de la dynamique des populations fragmentées, des variations des stratégies d'occupations de l'espace que de la viabilité des populations. Nous avons cherché dans ce travail à mettre en évidence les modalités de dispersion chez deux espèces d'amphibiens urogèles : les tritons alpestres et les tritons crêtés (espèce patrimoniale). Ces deux espèces, par leur mode de reproduction qui généère une agrégation des adultes dans des mares, représentent typiquement le schéma structurel d'espèces se reproduisant dans des patches d'habitats framgentés (les mares). L'habitat est caractérisé par une hétérogénéité spatio-temporelle de la capacité d'accueil qui est à l'origine de processus de dispersion. Les méthodes utilisées pour appréhender les processus dispersifs seront tour à tour l'analyse démographique par capture-marquage-recapture (CMR) dans différentes populations framgentées, la modélisation mathématique et l'expérimentation. Nous avons tout d'abord caractérisé l'impact des méthodes de marquage (tatouage et transpondeur) sur la survie des tritons alpestres. [. . . ] Les mécanismes comportementaux qui influencent la sélection de l'habitat lors de la dispersion sont étudiés. [. . . ] L'ensemble de ces résultats sont ensuite discutés en regard avec les théories actuelles concernant l'évolution de la dispersion, la variabilité spatio-temporelle de la distribution des individus dans les populations fragmentées liées à la dispersion, et enfin, en rapport avec la sélection de l'habitat par le comportement d'attraction par les congénères comme vecteur d'agrégation lors de la reproduction de ces amphibiens
2
Rejaud, Alexandre. "Origine et diversité des Amphibiens d'Amazonie." Thesis, Toulouse 3, 2021. http://www.theses.fr/2021TOU30161.
Повний текст джерелаАнотація:
Avec une surface de plus de six millions de kilomètres carrés, l'Amazonie abrite la plus grande forêt tropicale humide au monde, ainsi qu'une grande partie de la diversité terrestre. Cependant, les origines spatiales et temporelles de cette diversité demeurent mal comprises et nécessitent d'être plus étudiées pour identifier les causes de cette impressionnante diversification. Les amphibiens sont un groupe taxonomique particulièrement adapté à l'étude de la biogéographie historique en Amazonie car ils ont diversifié de manière importante dans la région et présentent d'importante variations d'utilisation de l'habitat ainsi que de capacités de dispersion entre groupes. Nous avons d'abord reconstruit l'histoire biogéographique du genre Allobates qui se rencontre principalement dans des forêts de terra-firme et pour lequel l'Amazonie de l'Ouest a joué un rôle important de source de diversification il y a entre 14 et 10 Millions d'années. Ce patron spatio-temporel coïncide avec une période marquée par la présence d'un système de méga-marécage qui recouvrait la plupart de l'Amazonie de l'Ouest il y a entre 23 et 10 Millions d'années. La décharge progressive de ce système marécageux a été suivie par une expansion des forêts de terra-firme en Amazonie de l'Ouest, une disponibilité en habitat favorable qui a probablement contribué à la diversification d'Allobates. Nos résultats suggèrent également que les rivières de l'Ouest Amazonien ont pu promouvoir la diversification au cours des 10 derniers Millions d'années en agissant comme une barrière semi-perméable à la dispersion, permettant la spéciation par dispersion suivie d'isolation géographique. Dans un second temps, nous avons reconstruit l'histoire biogéographique du groupe Pristimantis conspicillatus qui a diversifié de manière continue au cours du temps. Ce groupe présente un patron spatial de diversification particulier, avec quatre clades anciens ayant diversifié dans différentes aires simultanément, avec relativement peu d'évènements de dispersion comparé à Allobates. Ces importantes différences suggèrent que les espèces d'amphibiens ont des capacités de dispersion très variables qui sont probablement liées à leurs traits d'histoire de vie. Pour finir, nous avons comparé les histoires biogéographiques de six clades d'amphibiens partageant des temps d'origines comparables et qui sont représentatifs de la diversité Amazonienne en termes de taxonomie, de traits d'histoire de vie, d'utilisation de l'habitat et de type de reproduction. L'Amazonie de l'Ouest a été identifiée comme la principale source de diversification pour les amphibiens Amazonien, bien qu'elle ne se soit comportée comme tel qu'à partir d'il y a 10 Millions d'années pour les groupes présentant de l'adaptabilité dans la disponibilité de l'habitat ; et seulement entre il y a 10 et 5 Millions d'années pour les groupes conservatifs dans la disponibilité de l'habitat. Cela suggère que les groupes conservatifs dans la disponibilité de l'habitat remplissent la niche écologique plus rapidement que les espèces présentant de l'adaptativité, ce qui se traduit par des phases de diversification plus courtes. Nos résultats suggèrent également que les rivières agissent comme des barrières à la dispersion uniquement pour les groupes conservatifs dans l'utilisation de l'habitat. Nous tenons à souligner que ces résultats doivent être considérés avec prudence car ils ont été obtenus en étudiant une petite fraction de la diversité Amazonienne, ils apportent néanmoins de nouveaux éléments l'influence du conservatisme de niche sur les trajectoires évolutives en Amazonie, ce qui permettra peut-être d'inciter un plus grand effort de recherche sur cette thématiqueWith more than six million square kilometers, Amazonia hosts the largest tract of lowland tropical rainforest in the world and a large portion of the global terrestrial diversity. However, the temporal and spatial origins of this diversity remain poorly understood and need to be better comprehended to identify the processes responsible for this tremendous diversification. Amphibians are a particularly adequate group for investigating patterns of biogeographical history within Amazonia because they extensively diversified within the region and present important disparities in habitat use and dispersal abilities across groups. We first investigated the historical biogeography of the terra-firme genus Allobates and identified western Amazonia as an important source of diversification between 14 and 10 million years ago (Mya). This spatio-temporal pattern was coinciding with the existence of the Pebas system, a mega-wetland system that occupied most of western Amazonia during this period, that was unsuitable for terra-firme species. The Pebas system discharge was likely followed by an extension of terra-firme forests that likely fostered Allobates diversification. Our results also suggested that western Amazonia rivers might have subsequently (after 10 Mya) promoted diversification, by acting as semi-permeable barriers allowing speciation by dispersal and isolation. Secondly, we investigated the biogeographical history of the Pristimantis conspicillatus group which, instead, presented a continuous diversification throughout Neogene. This group displays a striking spatial pattern of diversification with four ancient clades that have diversified concomitantly in distinct areas in Amazonia and the Atlantic Forest, with much fewer dispersal events between areas than in Allobates. These differences suggest that amphibian species display differences in dispersal abilities that can be related to their life history traits. Finally, we compared the biogeographic histories of six frog clades, including the two aforementioned ones, that share comparable crown ages and span the Amazonian frog diversity in terms of life history traits, taxonomy, habitat use and reproduction modes. We identified western Amazonia as the principal source of diversification for Amazonian amphibians, although it acted as such only after 10 Mya for the groups that have adapted to various types of habitats; and only between 10 and 5 Mya for the ecologically conservative groups. This suggest that species with lower habitat availability reach niche filling more rapidly than ecologically adaptive species, resulting in shorter diversification phases. Our results also suggest that riverine barrier effect seems to have affected solely conservative groups particularly when the river course is stable over time. While these results were obtained by considering only a fraction of Amazonian diversity, they provide interesting insights on the influence of niche conservatism upon Amazonian evolutive trajectories, which will hopefully foster further and more ample research in this direction
3
Mazerolle, Marc J. "Mouvements et reproduction des amphibiens en tourbières perturbées." Thesis, Université Laval, 2004. http://www.theses.ulaval.ca/2004/21842/21842.pdf.
Повний текст джерелаАнотація:
Les déclins de populations d’amphibiens ont généré de nombreux travaux sur les effets de la perte d’habitats variés, mais peu en milieux naturellement acides. Néanmoins, plusieurs tourbières du sud-est canadien sont perturbées par l’extraction de la tourbe. Dans le premier chapitre, j’ai comparé l’utilisation des milieux tourbeux par les amphibiens à celle des milieux non tourbeux. Dans les quatre chapitres subséquents, j’ai quantifié les effets de l’extraction de la tourbe sur l’utilisation des étangs de tourbières par les amphibiens et mesuré les contraintes liées à leurs déplacements sur des surfaces exploitées. Les résultats indiquent que les amphibiens utilisent les tourbières surtout comme sites d’estivage. De plus, l’intensité de l’exploitation influence la fréquentation des étangs, mais la quantité et la proximité d’habitats complémentaires (i.e., étangs adjacents, forêt) semblent réduire ces effets. Finalement, les surfaces arides associées à certaines activités anthropiques telles que l’exploitation des tourbières ou l’agriculture, entravent les déplacements des grenouilles, bien que ces effets puissent être atténués par la présence de canaux de drainage.Global amphibian population declines have generated numerous studies on the effects of habitat loss, but few have been conducted in naturally-acidic environments. Nevertheless, many peatlands are undergoing peat extraction in southeastern Canada. Through five chapters, I have studied the use of bog habitats by amphibians, quantified the effects of peat extraction on amphibian occurrence at bog ponds, and measured the constraints associated with movements over mined surfaces. Bogs were less productive breeding sites than less acidic upland sites, but were used by adults and juveniles following breeding outside bogs. Bog ponds on surfaces actively mined for peat offered suboptimal habitats to green frogs (Rana clamitans), whereas bog ponds on surfaces drained for future peat mining, characterized by the presence of drainage ditches and vegetation, provided supplementary frog habitat. However, this positive effect was only temporary, as these surfaces were to be eventually mined. In a study conducted at a larger scale and focusing on bog ponds on unmined surfaces, I showed the importance of the amount and proximity of complementary habitats (i.e., adjacent ponds, forest) on the spatial distribution of amphibian presence at ponds. Moreover, frog movement experiments revealed that frogs translocated on barren peat surfaces had a lower probability of homing successfully than those translocated at a similar distance on an undisturbed surface, and that dehydration risks were the lowest on natural surfaces with vegetation cover. No reproduction occurred in drainage ditches, although frog survival in these structures was high. In addition, ditches did not impede the movements of individuals. Globally, results indicate that amphibians use bogs mostly as summering sites. Furthermore, peat mining intensity influences the occurrence of amphibians at ponds, but the proximity and amount of complementary habitats could mitigate these effects. Finally, barren surfaces associated with certain human disturbances such as peat mining and agriculture impede frog movements, although drainage ditches, particularly those containing water, may facilitate movements across these hostile environments.
4
Janin, Agnès. "Évaluer la connectivité en paysage fragmenté : de l'écologie comportementale à la biologie de la conservation." Phd thesis, Université Claude Bernard - Lyon I, 2011. http://tel.archives-ouvertes.fr/tel-00937294.
Повний текст джерелаАнотація:
Dans les paysages fragmentés, les mouvements entre les patchs d'habitats jouent un rôle primordial dans la persistance des populations en assurant les flux génétiques, la possibilité de recolonisation après extinction locale, la liaison entre différents habitats pour la reproduction ou l'acquisition des ressources, ... Malgré l'importance de ces mouvements, la structure du paysage entre ces patchs (i.e. la matrice) est le plus souvent considérée comme un ensemble homogène de non-habitat d'intérêt mineur et les adaptations comportementales en réponse à la fragmentation du paysage sont rarement prises en compte. Pour étudier l'importance de l'influence du paysage sur les mouvements, trois approches complémentaires sont pratiquées. 1) Des études expérimentales sont menées pour évaluer les réponses comportementales et physiologiques du crapaud commun (Bufo bufo) juvénile et adulte soumis aux différents types d'occupation du sol. Ainsi, les types d'occupation du sol sont caractérisés par le coût que leur traversée représente pour l'espèce étudiée. 2) Ce travail s'attache également à décrypter les règles régissant les déplacements en paysage hétérogène et à mettre en évidence des différences comportementales selon le paysage d'origine (adaptations). 3) Basé sur la modélisation, le troisième volet doit permettre d'effectuer des prédictions à l'échelle des paysages
5
Renoirt, Matthias. "Influence de l’habitat sur l’écologie et la physiologie du crapaud épineux (Bufo spinosus)." Electronic Thesis or Diss., La Rochelle, 2022. http://www.theses.fr/2022LAROS041.
Повний текст джерелаАнотація:
Un grand nombre d’études ont mis en avant les effets négatifs des pressions anthropiques dans le temps et dans l’espace sur la biodiversité. Parmi ces pressions anthropiques, les activités et l’expansion agricole jouent un rôle principal dans la modification des milieux et dans la perte de biodiversité. De fait, la question de la persistance des espèces animales dans ce type de milieux se pose. C’est dans ce contexte que ma thèse s’axe. Afin d’étudier les réponses des organismes à un milieu dégradé et les contraintes du paysage sur différents traits d’histoire de vie et l’écologie, je travaille spécifiquement sur une espèce d’amphibien occupant des milieux allant de fortement conservés à fortement dégradés. Afin de comparer les populations de crapauds épineux (Bufo spinosus) forestières et les populations agricoles, j’utilise un vaste panel de marqueurs pour examiner (1) la structure génétique des populations (marqueurs microsatellites), (2) l’écologie alimentaire (isotopes stables), (3) la qualité individuelle (télomères, morphologie, traits de développement) et son impact sur la reproduction. De ce fait et au cours de cette thèse, j’ai pu mettre en relation de nombreux facteurs associés aux paysages agricoles qui soulèvent de nombreuses questions quant au maintien des populations de crapauds épineux. Ainsi, nous avons pu montrer un effet significatif des fertilisants sur la signature isotopique en δ15N des populations de B.spinosus. Aussi, nous avons pu souligner que l’environnement agricole reste suffisamment perméable au maintien de la diversité génétique. Cependant, nous avons mis en évidence de nombreuses contraintes de ce milieu sur la reproduction des populations d’amphibiens, que ce soit par la faible (voir l’absence) abondance de femelles sur les sites de reproduction, et/ou directement sur le succès reproducteur et la qualité de la progéniture. Ces résultats suggèrent de possibles effets à long terme sur les populations d’amphibiens et nous suggérons d’approfondir les différentes voies de recherche que nous suggérons tout au long de cette thèse afin de mieux comprendre les mécanismes sous-jacents à ces résultats et de trouver des solutions quant à la pérennité des espèces sauvages qui n’ont d’autres choix que de s’adapterA large number of studies have highlighted the negative effects of anthropogenic pressures intime and space on biodiversity. Among these anthropogenic pressures, agricultural activities and expansion play a major role in the modification of environments and in the loss of biodiversity. Questions whether animal species persist in this type of environment arises. My thesis is based on this context. We aimed at study the responses of organism to a degraded environment and the landscape constraints on life history traits and ecology. My work is focused specifically on an amphibian species persisting in habitat ranging from highly conserved to highly degraded by agricultural activities. In order to compare forest and agricultural populations of model species (Spined toad, Bufo spinosus), I relied on a wide variety of markers to examine (1) population genetic structure (micro-satellite markers), (2) feeding ecology (stable isotope), (3) individual quality (telomeres, morphology, developmental traits) and the impact on reproduction. As a result, I was able to connect many factors associated with agricultural landscapes that raised many questions about the persistence of spined toad populations. We were able to show a significant effect of fertilizers on the δ15N isotopic signature of B.spinosus populations. Moreover, we highlighted that agricultural environment allows genetic diversity between populations. However, using correlative approaches, we pointed out various on strains of this environment on the reproduction of amphibians populations, either through low (or no) abundance of females on breeding sites, and/or directly on reproductive success and offspring quality. These results suggest possible long-term effects on amphibian populations, and we suggest that the various avenues of research we suggested throughout this thesis should be pursued in order to better understand the mechanisms underlying these results and to find solutions for the sustainability of wild species that have no choice but to adapt
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Schneider, Amy Elizabeth. "Continued study of the use of created ponds for amphibian breeding in fragmented forested areas." [Huntington, WV : Marshall University Libraries], 2008. http://www.marshall.edu/etd/descript.asp?ref=876.
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Morand, Alain. "Dynamique de la coexistence des espèces : de la théorie des perturbations à la théorie des traits d'histoire de vie : l'exemple du modèle amphibien dans l'espace alluvial du haut-Rhône." Lyon 1, 1996. http://www.theses.fr/1996LYO10182.
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8
Regosin, Jonathan V. "Terrestrial habitat use by pool-breeding amphibians in a suburban landscape /." Thesis, Connect to Dissertations & Theses @ Tufts University, 2003.
Знайти повний текст джерелаАнотація:
Thesis (Ph.D.)--Tufts University, 2003.Adviser: J. Michael Reed. Submitted to the Dept. of Biology. Includes bibliographical references (leaves 124-134). Access restricted to members of the Tufts University community. Also available via the World Wide Web;
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Hopkins, Samantha. "Chytridiomycosis in amphibian populations in the Western Cape, South Africa." Thesis, University of the Western Cape, 2002. http://etd.uwc.ac.za/index.php?module=etd&action=viewtitle&id=gen8Srv25Nme4_7137_1359702947.
Повний текст джерелаАнотація:
There have been many cases reported of amphibian populations declining. These are often due to anthropogenic factors such as habitat destruction and pollution. However, some eclines have not had an obvious cause and many of these have been investigated and found to be due to pathogenic disease. Batrachochytrium dendrobatidis is a recently described pathogen of frogs. The population declines that have been associated with chytridiomycosis have occurred in relatively undisturbed areas such as national parks. The declines tend to occur at higher altitudes or in colder climates. This is thought to be because of the frog immune system being slower at lower temperatures. This project gives an overview of chytrid infection in the Western Cape and at a small number of sites in the Northern Cape and Eastern Cape.
10
Greenwald, Katherine Rose. "Habitat fragmentation, functional landscape connectivity, and metapopulation processes in amphibians." The Ohio State University, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=osu1243366608.
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Greenwald, Katherine R. "Habitat fragmentation, functional landscape connectivity, and metapopulation processes in amphibians." Columbus, Ohio : Ohio State University, 2009. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1243366608.
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Purrenhage, Jennifer Lyn. "Importance of Habitat Structure for Pond-Breeding Amphibians in Multiple Life Stages." Miami University / OhioLINK, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=miami1240957514.
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Northrop, Robert John. "Development and assessment of a wildlife habitat relationship model for terrestrial vertebrates in the state of Maryland." Access to citation, abstract and download form provided by ProQuest Information and Learning Company; downloadable PDF file, 152 p, 2009. http://proquest.umi.com/pqdweb?did=1885544331&sid=2&Fmt=2&clientId=8331&RQT=309&VName=PQD.
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Simpkins, Clay Alan. "Abiotic and Biotic Factors Influencing the Assemblage of Tadpoles and Adult Anurans in Coastal Wallum Habitats of Eastern Australia." Thesis, Griffith University, 2013. http://hdl.handle.net/10072/367686.
Повний текст джерелаАнотація:
The emergence of the global amphibian crisis has seen the extinction of 122 species worldwide, with 18.8% of Australia’s 213 amphibian species being threatened. Despite these declines, little is known about the biology and ecology of certain Australian threatened species. Hence, successful conservation and management of threatened amphibian species cannot be fully realised.
Several environmental variables may influence amphibian adult or tadpole assemblages. These variables include, but are not limited to, water chemistry factors (i.e. pH, salinity, turbidity), predation, competition, hydroperiod and water flow. These variables will influence individual species differently, with each species displaying differences in tolerance to these specific variables.
The coastal wallum vegetation along the eastern coast of Australia is the primary habitat for four specialist frog species (Litoria olongburensis, Litoria freycineti, Litoria cooloolensis and Crinia tinnula) that are listed as Vulnerable under the IUCN Red List. All species are referred to as ‘acid’ frogs due to their association with low pH waters. ‘Acid’ frog populations within protected areas are believed to be stable. However, populations of ‘acid’ frogs occurring outside of protected areas are at risk from ongoing habitat loss and fragmentation. It is therefore vital that conservation managers know which environmental factors influence ‘acid’ frogs to ensure these environmental variables remain constant and populations remain stable. Furthermore, it is imperative to determine if these environmental variables are the same within anthropogenic waterbodies and if ‘acid’ frogs utilise anthropogenic waterbodies. This knowledge would assist in the future prioritisation of waterbodies for conservation. However, the factors influencing ‘acid’ frog species tadpole and adult relative abundance and occupancy within protected and non-protected wallum heathland waterbodies have not been reported.Thesis (Masters)
Master of Philosophy (MPhil)
Griffith School of Environment
Science, Environment, Engineering and Technology
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Callison, Catherine Mary. "Factors Influencing Oviposition Among Pond-Breeding Amphibians: Exotic Vegetation, Oviposition Braces, and Cover." PDXScholar, 2001. https://pdxscholar.library.pdx.edu/open_access_etds/4333.
Повний текст джерелаАнотація:
I examined oviposition in four pond-breeding amphibians (northwestern salamander [Ambystoma gracile], long-toed salamander [Ambystoma macrodactylum], Pacific treefrog [Hyla regilla], northern red-legged frog [Rana aurora aurora]), at Burlington Bottoms, a lowland riverine site in northwestern Oregon, to determine whether differential use of native versus exotic plant substrates occurs. I found differential use in all four species, but use was inconsistent with the hypothesis that selection for native plants (or selection against exotic plants) was occurring. If selection was occurring, the pattern implied that reed canarygrass (Phalaris arundinacea), a widespread exotic in this lowland system, was sometimes favored. However, inconsistent use of reed canarygrass led me to examine the alternative that substrate strength (measured as density, diameter, and mass), rather than plant status, might be the basis of selection. Species used for oviposition differed in strength, but eggs were not consistently laid on braces based on my strength measures. Failure to find support for this hypothesis led to examination of a third hypothesis for two species (red-legged frog and northwestern salamander), that cover characteristics of the oviposition brace or nearby vegetation might influence egg mass location. Analysis of structural complexity of species used as a brace (as percent cover within 15 em of the egg mass) did reveal a pattern consistent with complexity, but that was species-specific. Red-legged frogs selected braces with significantly more nearspace cover; northwestern salamanders selected braces with sparser cover. Comparison of marginal shrub and tree cover to the number of red-legged frog egg masses revealed that ponds with < 50% shrub/tree cover had few (< 5) masses. Ponds with ≥ 50% shrub/tree cover had many (≥ 10) masses. More complex vegetation may provide greater protection for egg masses or ovipositing red-legged frogs but further investigation is clearly warranted. Elucidating northwestern salamander cover requirements will require examining more occupied ponds. In particular, more refined examination, using experimental manipulation, is needed to verify the cover relationships revealed in this study. Meanwhile, managers should treat cover as important in red-legged frog oviposition life history, paying special attention to minimizing loss of marginal shrub and tree cover.
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Maxell, Bryce Alan. "State-wide assessment of status, predicted distribution, and landscape-level habitat suitability of amphibians and reptiles in Montana." Diss., [Missoula, Mont.] : The University of Montana, 2009. http://etd.lib.umt.edu/theses/available/etd-10122009-102104.
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Dietrich, Andrew Evans. "Stream-Associated Amphibian Habitat Assessment in the Portland-Vancouver Metropolitan Region." PDXScholar, 2012. https://pdxscholar.library.pdx.edu/open_access_etds/604.
Повний текст джерелаАнотація:
This study assessed the influence of landscape development on stream-associated amphibians in forested riparian areas within the Portland-Vancouver metropolitan region. Human alteration of landscapes may dramatically affect the ecology of neighboring aquatic systems. It was hypothesized that lotic amphibians would be negatively associated with greater amounts of landscape development and positively associated with forested area within the surrounding watershed. Thirty-seven 1st-3rd order streams were sampled between June 21st and September 21st in 2011. Streams potentially providing adequate habitat for stream-obligate amphibians were randomly selected. Amphibians were surveyed along 30-meter stream transects using an active-cover search (ACS). Environmental variables associated with development in surrounding landscapes were measured in situ. GIS delineation was conducted to define landscape-scale variables at stratified distances from riparian networks up-stream of each site via the utilization of the 2006 NLCD dataset and a finer-scale, regional dataset compiled by the Institute for Natural Resources (INR). Amphibians were detected at seventeen of the thirty-seven sampled streams. The most commonly detected species were Dicamptadon tenebrosus, Plethadon vehiculum and Plethadon dunni. Streams where amphibians were observed had lower average water temperature and conductivity, coarser stream substrate and were located on public property more often than streams where no amphibians were detected. Landscape variables were most significant to amphibians within 100 and 200 meters of the upstream stream network. Occupancy of a site by facultative species was best explained by the proportion of mixed forest in the surrounding watershed (R2=0.343, p<0.001). Occupancy of a stream by obligate species was best predicted by measurements of water quality and in-stream cover (Water Temperature: R2=0.275, p<0.001; Water Conductivity: R2=0.248, p<0.001; Cover: R2=0.323, p<0.001). Occupancy of stream refugia by all observed amphibians was positively influenced by higher percentages of forest cover and lower percentages of urban development and herbaceous vegetation in the surrounding watershed. Results of this study indicate that urban refugia must contain adequate riparian forest area, coarse stream substrate and clean, cool water to sustain stream-amphibian communities. Protection of remnant forested headwater stream networks is essential to the conservation of lotic amphibians in this urbanized region.
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Blomquist, Sean Michael. "Relative Fitness and Behavioral Compensation of Amphibians in a Managed Forest." Fogler Library, University of Maine, 2008. http://www.library.umaine.edu/theses/pdf/BlomquistSM2008.pdf.
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Blowers, Tracy. "Social Grouping Behaviors of Captive Female Hippopotamus Amphibius." Master's thesis, University of Central Florida, 2008. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/3492.
Повний текст джерелаАнотація:
Levels of sociality vary depending on the costs and benefits associated with grouping behavior. Grouping species form either ephemeral aggregations due to resource availability, or structured groups based on familiarity of individuals. Because there are different costs and benefits associated with different types of groups, it is important to understand more about group structure before making predictions about specific behaviors. Female Hippopotamus amphibius are known to aggregate in the wild but the true nature of their grouping behavior is still not understood. My objective was to determine if captive female hippos form either ephemeral aggregations or social groups. Behavioral data, using continuous focal animal sampling and scan sampling, were collected on a group of nine captive female hippos housed at Disney's Animal Kingdom Theme Park. The behavioral data were used to analyze interactions between hippos, association patterns for kin and non-kin as well as familiarity, dominance hierarchy, and habitat preferences. My results support the hypothesis that hippos are forming social groups due to the attraction to particular individuals. There were more associations between kin than non-kin and also between individuals that have been together longer. Captive female hippos were also found to exhibit dominance patterns within the group. The results from this study may aid in the general understanding of hippopotamus behavior and aid in the captive management of hippos. Using my results as a starting point, research can begin looking at grouping patterns and its costs and benefits of sociality in wild hippopotamus populations.M.S.
Department of Biology
Sciences
Biology MS
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Black, David Hills. "Landscape structure and distribution patterns of wetland herpetofauna in Southern New England." Thesis, University of Kent, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.314285.
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Puglis, Holly J. "Effects of Terrestrial Buffer Zones on Amphibians in Managed Green Spaces." Miami University / OhioLINK, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=miami1280773926.
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Dimitrie, David Anthony. "Effects of Habitat Characteristics on Amphibian Use of Aquatic and Terrestrial Environments." Case Western Reserve University School of Graduate Studies / OhioLINK, 2021. http://rave.ohiolink.edu/etdc/view?acc_num=case1623333871708777.
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FALASCHI, MATTIA. "INTERACTIVE EFFECTS OF HABITAT MODIFICATION AND INVASIVE ALIEN SPECIES ON AMPHIBIAN BIODIVERSITY." Doctoral thesis, Università degli Studi di Milano, 2021. http://hdl.handle.net/2434/822579.
Повний текст джерелаАнотація:
The biodiversity of our planet is facing a severe crisis. Habitat alteration, climate change, the spread of alien species, and overexploitation are major drivers of biodiversity loss. These global change drivers often act jointly or even synergistically on population declines. To identify priorities for conservation, it is thus essential to compare the relative impact of different threats on biodiversity. Amphibians are the vertebrates showing both the largest proportion of threatened species and the highest rate of decline. Out of the ~6,800 amphibian species assessed by the IUCN, more than 4,000 species are threatened by at least one stressor, and more than 2,000 by at least two stressors. Habitat modification (alteration and/or destruction) and alien species are the two factors threatening the largest number of amphibian species. For this reason, this thesis investigates the role of habitat modification and invasive alien species in determining the temporal dynamics of amphibian populations. The role of these stressors is examined at different spatial scales and jointly with other factors such as microhabitat, landscape, or climatic variables.
The first study (Chapter 2) is a continental-scale analysis, which evaluates the combined effects of alien species, habitat availability, habitat changes, and climate change in determining population trends of European amphibian (and some reptile) species over the last 45 years. The results showed that populations declined more often in areas with a high number of alien species and where climate change has caused a loss of climatic suitability. The effect of habitat availability was not relevant when averaged across species; however, when excluding the two commonest species, habitat loss was the main correlate of negative population trends for the remaining species. Furthermore, I observed a strong interaction between habitat availability and the richness of alien species, which indicated that the negative impact of alien species was particularly strong for populations living in landscapes with less suitable habitat
Then, the thesis focuses on a specific system: the invasion of the red swamp crayfish Procambarus clarkii in Italy, and its effect on the population dynamics of amphibians. The second study (Chapter 3) presents the updated distribution of the red swamp crayfish in Italy. Thirty years after its first record in Italy in 1989, the red swamp crayfish has invaded 80% of Italian provinces. The invasion is particularly extensive in central and northern Italy, where this invasive crayfish is present in 100% and 96% of provinces, respectively. Given the strong negative effects that the red swamp crayfish can exert on native amphibians, its widespread distribution raises concern about the future status of conservation of the Italian batrachofauna.
Chapter 4 analyses site occupancy data of newts in northern Italy, in an area suffering the introduction of the invasive crayfish, in order to investigate the role of microhabitat, landscape change, and invasive species in determining the decline of two newt species through time. Initial occupancy of newts was negatively affected by landscape alteration (i.e. urban and agricultural cover) and by the presence of fish. Both species suffered a strong decline, with a net loss of site occupancy of 25%‒36% along the study period. After the crayfish invasion, the main drivers of population dynamics sharply shifted, and occupancy changes were not determined by landscape or microhabitat alterations, as the strongest predictor of local extinctions was the colonization of wetlands by invasive crayfish.
The last study (Chapter 5) focuses on the effect of habitat characteristics and invasive crayfish in determining the temporal dynamics of the amphibian community in a large number of wetlands in northern Italy. Since connectivity among wetlands is fundamental for the dynamics of spatially structured populations, we considered two measures of connectivity acting on each focal wetland: incidence of the focal species, and incidence of invasive crayfish. Survival and colonization of local populations were jointly determined by factors acting at different scales. Survival probability was positively related to the area and the permanence of wetlands, while it showed a negative relationship with the occurrence of fish. Colonization probability was highest in semi-permanent wetlands and in sites with a high incidence of the focal species in nearby sites. Furthermore, the incidence of invasive crayfish emerged as one of the strongest drivers of colonization probability.
In this thesis, I showed that invasive alien species are a major driver of the decline of European amphibians. The negative effect of invasive alien species acted differently across species and spatial scales. While the site-level impact was evident only for a subset of species, the landscape-level effect of invasive crayfish was ubiquitous across the whole amphibian community. Habitat modification showed a less evident effect, but invasive alien species and habitat modification can strongly interact: the negative effect of alien species is exacerbated in highly modified landscapes. It is thus essential to directly prevent and manage the spread of alien species, while simultaneously preserving natural landscapes. This can help in mitigating the negative effects of invasives, even when habitat alteration is not the main threatening factor.
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Harper, Elizabeth B. "The role of terrrestrial habitat in the population dynamics and conservation of pond-breeding amphibians." Diss., Columbia, Mo. : University of Missouri-Columbia, 2007. http://hdl.handle.net/10355/4693.
Повний текст джерелаАнотація:
Thesis (Ph. D.)--University of Missouri-Columbia, 2007.The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from title screen of research.pdf file (viewed on September 25, 2007) Vita. Includes bibliographical references.
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von, May Rudolf. "Diversity Patterns of Amphibians in Lowland Amazonian Forests in Southeastern Peru." FIU Digital Commons, 2009. http://digitalcommons.fiu.edu/etd/85.
Повний текст джерелаАнотація:
Biological diversity is threatened worldwide and it is a priority to generate more information that can be used both for understanding ecological processes and determining conservation strategies. For my dissertation, I focused on amphibian diversity patterns in lowland rainforests of southwestern Amazonia to evaluate the importance of habitat heterogeneity in the region. My main purpose was to test the hypothesis that amphibian communities in different forest types differ in species richness, composition, and abundance. I used standardized visual encounter surveys to quantify the species composition and abundance of amphibians at four sites, each containing four forest types (floodplain, terra firme, bamboo, and palm swamp). I used leaf-litter plots to evaluate the effect of soil and leaf-litter characteristics on species richness and abundance of leaf-litter frogs. I intensively sampled at one site and then sampled three other sites (distance among sites varied 3.5-105 km) to evaluate whether the patterns observed at one site were similar elsewhere. I also updated the information on threatened and potentially threatened amphibians in Peru and my study region. I found that no species appears to have experienced population declines in southeastern Peru, suggesting that the region still contains the original species pool. My results support the hypothesis that amphibian communities differ across forest types and that patterns observed at the local scale (one site) are similar at the regional scale (four sites). My data also indicate that there is no correlation between species composition and geographic distance among sites. Instead, an important proportion of the gamma diversity is represented by habitat-related beta diversity. My leaf-litter plot data showed that part of the variation in the leaf-litter community structure is explained by soil and litter characteristics. I found that soil total phosphorus and, to a lesser extent, humidity, leaf-litter mass, and pH is linked to species presence/absence and abundance. My study provides the first standardized, quantitative comparison of amphibian community structure across four major forest types in southwestern Amazonia and highlights the fact that forest types are complementary and necessary for maintaining high species richness in the region.
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Préau, Clémentine. "Identification et modélisation des habitats d'espèces à enjeux et évolution de leur aire de répartition avec le changement climatique." Thesis, Poitiers, 2019. http://www.theses.fr/2019POIT2316.
Повний текст джерелаАнотація:
La chute de la biodiversité actuelle est le résultat des changements globaux et notamment du changement climatique. Elle contribue à amplifier les effets des changements globaux sur les écosystèmes. Bien que l’évaluation des impacts du changement climatique sur la distribution des espèces soit largement étudiée à de larges échelles, l’évaluation à l’échelle nationale, régionale ou même départementale est moins systématique bien qu’elle soit la plus appropriée pour être prise en compte dans les stratégies de conservation. Afin d’évaluer la vulnérabilité d’espèces emblématiques des zones humides au changement climatique, nous avons construit des scénarios de distribution en utilisant des approches basées sur la modélisation de niche écologique. Nous nous sommes intéressés aux amphibiens, organismes ectothermes présentant un mode de vie à la fois aquatique et terrestre et de faibles capacités de dispersion, qui sont fortement menacés par les activités humaines et le changement climatique. Nous avons évalué les impacts potentiels du changement climatique sur la distribution du sonneur à ventre jaune Bombina variegata, du triton crêté Triturus cristatus, de la rainette arboricole Hyla arborea, et de la rainette méridionale Hyla meridionalis, en estimant les interactions entre la présence des espèces et les facteurs environnementaux et en évaluant les effets des changements climatique et d’occupation du sol sur la distribution potentielle des espèces à l’échelle régionale. Puis, nous nous sommes intéressés aux effets de scénarios de changement climatique sur la distribution potentielle et la connectivité des habitats favorables chez le triton marbré Triturus marmoratus et T. cristatus à l’échelle du département de la Vienne. Enfin, nous avons évalué la capacité de T. marmoratus à suivre un potentiel déplacement des zones favorables dû au changement climatique, dans un contexte de changements d’occupation du sol à l’échelle nationale. Dans un second temps, nous nous sommes intéressés à une autre espèce emblématique des milieux humides et des cours d’eau, l’écrevisse à pattes blanches Austropotamobius pallipes. Ainsi, nous avons modélisé l’impact du changement climatique sur la distribution de l’espèce en prenant en compte explicitement la distribution d’une espèce invasive et compétitive, l’écrevisse signal Pacifastacus leniusculus. Les projections pour les conditions futures ont été réalisées à partir de scénarios de réchauffement climatique basés sur des grandes trajectoires de forçage radiatifs nommées RCP (Representative Concentration Pathways).Nos études ont permis de mettre en évidence que le changement climatique risque d’entrainer une contraction des aires de répartition ainsi qu’un potentiel déplacement des aires favorables de la plupart aux espèces étudiées, avec un impact plus ou moins important selon l’espèce et le scénario de changement climatique considéré. Par ailleurs, nous avons montré l’importance de l’occupation du sol pour l’atténuation des effets du changement climatique sur la distribution des espèces. Suite à la prise en compte des incertitudes et des limites relatives aux différentes études, les résultats des travaux présentés pourront être utiles à la conservation, à la gestion et à l’évaluation des espèces étudiées, et être reproduits pour d’autres espèces de zones humidesThe current decline in biodiversity is the result of global changes, including climate change. It contributes to amplifying the effects of global changes on ecosystems. Although the assessment of the impacts of climate change on species distribution is widely studied at large scales, assessment at the national, regional or even departmental scale is less systematic although it is the most appropriate to be accounted in conservation strategies. In order to assess the vulnerability of emblematic wetland species to climate change, we have constructed distribution scenarios using approaches based on ecological niche modelling. We focused on amphibians, ectothermic organisms with both aquatic and terrestrial stages and low dispersal abilities, which are highly threatened by human activities and climate change. We assessed the potential impacts of climate change on the distribution of the yellow-bellied toad Bombina variegata, the great crested newt Triturus cristatus, the tree frog Hyla arborea, and the Mediterranean tree frog Hyla meridionalis, by estimating the interactions between species presence and environmental factors and by assessing the effects of climate and land use changes on the potential distribution of species at the regional scale. Then, we focused on the effects of climate change scenarios on the potential distribution and connectivity of suitable habitats of the marbled newt Triturus marmoratus and of T. cristatus across the administrative department of Vienne. Finally, we assessed the ability of T. marmoratus to follow a potential shift of suitable areas due to climate change, in a context of land use change at the national scale. We then studied another emblematic species of wetlands and rivers, the white-clawed crayfish Austropotamobius pallipes. We modelled the impact of climate change on its distribution by explicitly accounting for the distribution of an invasive and competitive species, the signal crayfish Pacifastacus leniusculus. Projections for future conditions were forecasted using global warming scenarios based on radiative forcing trajectories called RCP (Representative Concentration Pathways).Our studies have shown that climate change is likely to lead to a contraction of ranges and a potential shift in the suitable areas for most of the studied species, with a more or less significant impact depending on the considered species and the climate change scenario. In addition, we have shown the importance of land use in mitigating the effects of climate change on species distribution. Following consideration of uncertainties and limitations, the results of the presented work may be useful for the conservation, management and assessment of the studied species, and may be replicated for other wetland species
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Zanini, Flavio. "Amphibian conservation in human shaped environments : landscape dynamics, habitat modeling and metapopulation analyses /." [S.l.] : [s.n.], 2006. http://library.epfl.ch/theses/?nr=3635.
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Fath, Natalie A. "AMPHIBIAN AND REPTILE SPECIES SURVEY AND HABITAT ASSESSMENT: INCORPORATING ENVIRONMENTAL EDUCATION AND OUTREACH." Miami University / OhioLINK, 2008. http://rave.ohiolink.edu/etdc/view?acc_num=miami1208884596.
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Thompson, Danielle Kaye. "Amphibian and Reptile Species Survey and Habitat Assessment: Incorporating Environmental Education and Outreach." Miami University / OhioLINK, 2008. http://rave.ohiolink.edu/etdc/view?acc_num=miami1208912407.
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Lucas, Amy P. "Amphibian Habitat Usage of Two Restored Bogs in Shady Valley, Johnson County, Tennessee." Digital Commons @ East Tennessee State University, 2009. https://dc.etsu.edu/etd/1785.
Повний текст джерелаАнотація:
Adjacent terrestrial habitat surrounding wetlands are critical for the survival and success of many species that use them. The primary purpose of this study was to determine amphibian movement from adjacent habitats into Orchard Bog, a restored bog located in Shady Valley, Johnson County, Tennessee. In addition, a secondary bog, Quarry Bog, was also studied determining baseline presence/absence data
A total of 16 species from six families were observed throughout the study sites. Seven species of anurans, Bufonidae, Hylidae, and Ranidae and nine species of caudates in the families Plethodontidae, Ambystomatidae and Salamandridae were identified. Fourteen of the 16 species were found within Orchard Bog.
Data collected can be used to help determine more beneficial land acquisitions and management strategies. Survey methods included pitfall traps, funnel traps, coverboard arrays, and opportunistic surveys.
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Bank, Michael S. "Mercury Bioaccumulation and Habitat Relations of Lotic and Lentic Amphibians from Acadia National Park, Maine, USA." Fogler Library, University of Maine, 2005. http://www.library.umaine.edu/theses/pdf/BankMS2005.pdf.
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Lau, Wai-neng Miguel, and 劉惠寧. "Habitat use by Hong Kong amphibians: with special reference to the ecology and conservation of Philautusromeri." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 1998. http://hub.hku.hk/bib/B31237216.
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Weyrauch, Shauna L. "Habitat fragmentation and woodland amphibians consequences for distribution, genetic diversity and fitness responses to UV-B radiation /." Connect to this title online, 2004. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1092668394.
Повний текст джерелаАнотація:
Thesis (Ph. D.)--Ohio State University, 2004.Title from first page of PDF file. Document formatted into pages; contains xiv, 138 p. : ill. Advisor: Thomas C. Grubb, Dept. of Evolution, Ecology, and Organismal Biology. Includes bibliographical references (p. 129-138).
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Lau, Wai-neng Miguel. "Habitat use by Hong Kong amphibians : with special reference to the ecology and conservation of Philautus romeri /." Hong Kong : University of Hong Kong, 1998. http://sunzi.lib.hku.hk/hkuto/record.jsp?B19736563.
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Hobbs, Michael T. "Amphibian mortality on roads| A case study in Santa Cruz long-toed salamander habitat." Thesis, San Jose State University, 2014. http://pqdtopen.proquest.com/#viewpdf?dispub=1552258.
Повний текст джерелаАнотація:
Amphibian populations have been declining at higher rates than bird and mammal populations. Agriculture, urbanization, including roads, and resource extraction continue to put pressure on all species. Roads in particular, are major sources of mortality. The Santa Cruz long-toed salamander ( Ambystoma macrodactylum croceum), one of the most critically endangered species in the US, is one amphibian that is declining as a result of anthropogenic impacts, especially habitat loss and fragmentation due to urban development. Migration across roads puts these salamanders at risk from road-related death. This thesis quantified the rate of road mortality to these salamanders and other common amphibians during two A. m. croceum breeding-migration seasons in 2011–13 in a portion of the subspecies' range. Vehicular traffic was a major source of mortality to the salamander. Through traffic doubled the overall vehicle load on roads where the A. m. croceum migrated to and from breeding ponds. The Pacific chorus frog was also killed on the roads. This common species can be used as an indicator of road mortality risk for rarer amphibians. This study indicated that measures to reduce road mortality to the Santa Cruz long-toed salamander could include restricting vehicular traffic on roads adjacent to salamander ponds by limiting traffic to residential use only during breeding migrations, installing structures to protect A. m. croceum while crossing roads, and potentially assisting animals crossing roads at nighttime during the breeding migrations.
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Gorman, Thomas Andrew. "Ecology of Two Rare Amphibians of the Gulf Coastal Plain." Diss., Virginia Tech, 2009. http://hdl.handle.net/10919/26780.
Повний текст джерелаАнотація:
Globally, amphibian species have been in decline and a wide range of factors have been purported to be driving the decline. The Gulf Coastal Plain of Florida has a high degree of endemism and rarity and the biodiversity in the region includes a diverse suite of amphibian species. Degradation of habitat has been considered by many to be a major part of amphibian declines, however amphibian declines are complex and in many cases multiple factors are occurring in concert. My dissertation research examined aspects of habitat ecology and occupancy for two rare amphibians, Florida Bog Frog (Rana okaloosae) (Chapter 1, 2, and 3) and Reticulated Flatwoods Salamander (Ambystoma bishopi) (Chapter 5), that are both restricted to the Northern Gulf Coastal Plain. Further, for R. okaloosae I examined the influence of a sympatric congener, Bronze Frog (R. clamitans clamitans), on microhabitat selection (Chapter 1) and growth of tadpoles (Chapter 4). My overall goal was to be able to elucidate factors that limit the geographic range of R. okaloosae and A. bishopi and to identify habitat characteristics that managers could maintain or create to conserve or increase populations of these species.
My first chapter examined the microhabitat relationships between R. okaloosae and R. c. clamitans. Rana okaloosae is endemic to northwestern Florida and is sympatric with R. c. clamitans, a more common and widely distributed congener. Further, the two species appeared to be syntopic, have overlapping breeding seasons, and are known to hybridize. The objectives of this chapter were to assess the microhabitat selection of both species and to assess differences in microhabitat use of males of both species during the breeding season. My modeling of habitat selection and comparison of variables used by each species suggests that males of these species select different resources when calling. Therefore, these sympatric ranids select for different resources at a fine scale, however there does appear to be some overlap among some selected habitat characteristics.
In Chapter 2, I assessed the habitat use of R. okaloosae at multiple spatial scales. I surveyed for R. okaloosae and evaluated habitat characteristics at used sites and sites where I had no detections to develop among- and within-stream habitat models for R. okaloosae. Rana okaloosae used habitats with high amounts of emergent vegetation at both the among-stream scale and the within-stream scale. Emergent vegetation appears frequently in models of anuran habitat selection, particularly those that occur in fire-dominated landscapes. Further understanding the habitat requirements of R. okaloosae will allow land managers to use appropriate management activities (e.g., prescribed fire) that will increase emergent vegetation and potentially restore habitat that may help increase populations of R. okaloosae.
In Chapter 3, I conducted aural surveys for R. okaloosae at two different spatial scales: range-wide and stream-level scales to understand how occupancy and colonization of R. okaloosae may be influenced by scale. My results suggest that at both spatial scales occupancy of R. okaloosae was best described by the presence of mixed forest wetlands at survey sites. At the range-wide scale, colonization and detection were constant across years, however, at the stream-level scale, colonization was predicted by the number of years since last fire and detection was best predicted by the additive combination of relative humidity and temperature. Occupancy of R. okaloosae was patchy at the range-wide and at the stream-level scales and colonization was low at both scales, while derived estimates of local extinction were moderately high. While R. okaloosae still occur in 3 watersheds where they were initially observed in the 1980â s, one of the three watersheds appears to be very isolated and detections there are becoming very infrequent.
In Chapter 4, I experimentally evaluated the effects of R. c. clamitans tadpoles on R. okaloosae tadpoles. My results suggest that there was limited influence of R. c. clamitans on R. okaloosae. Conversely, it appeared that Rana c. clamitans was more susceptible to intraspecific competition than interspecific competition. The lack of a strong competitive effect of Rana c. clamitans on Rana okaloosae suggests that competitive interactions among tadpoles may have a limited effect at the densities I examined.
In Chapter 5, our objectives were to evaluate a suite of within-pool factors (i.e., vegetation structure, water level, and an index to presence of fish) that could influence occupancy of breeding wetlands by larval flatwoods salamanders on Eglin Air Force Base in Florida, USA. Site occupancy over a 4 year period was best described by a model that incorporated high herbaceous vegetation cover and open canopy cover. Detection probability was assessed, but it varied among years and was not included in the model. Our study suggests that managing the breeding habitat of flatwoods salamander for open canopies and dense herbaceous vegetation may contribute to this speciesâ recovery.
In conclusion, Chapters 1-3 of my dissertation contribute to a growing understanding about the habitat ecology of R. okaloosae. I have evaluated habitat use of R. okaloosae at multiple spatial scales. At the finest spatial scale R. okaloosae selected for sites that had an abundance of cover probably decreasing their risk of predation (Chapter 1). Similarly, in Chapter 2 at two spatial scales, among and within-streams, R. okaloosae selected for emergent vegetation. Finally, at the broadest spatial scale, range-wide, R. okaloosae were found to be associated with mixed forest wetlands (Chapter 3). I did not find strong support for competition between R. okaloosae and R. c. clamitans tadpoles, although there was some evidence of asymmetric competition (Chapter 4). Further, adult males of each species did not select the same habitat characteristics for calling sites, so there appeared to be some resource partitioning (Chapter 1). Finally, the presence of A. bishopi larvae was found to be associated with herbaceous vegetation and moderate amounts of canopy cover (Chapter 5). Results from Chapter 2 and 5 suggest that both R. okaloosae and A. bishopi are associated with habitat conditions that are likely a result of fire penetrating wetland areas.Ph. D.
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Soares, Joana Ferreira de Paiva Morais. "Amphibian's distribution in caves of the Sicó Massif." Master's thesis, Universidade de Aveiro, 2018. http://hdl.handle.net/10773/22047.
Повний текст джерелаАнотація:
Mestrado em Biologia AplicadaAmphibians (salamanders, toads and frogs) are frequently found exploring karst environments, both at the surface and underground. This study aimed to approach both aspects through the evaluation of (a) the abundance and distribution of amphibians in caves of Sicó massif, central Portugal, and (b) the suitability of the water from Sicó massif sinkhole ponds and springs for amphibian’s early stages of development. Despite some studies reporting the presence of amphibians in European underground habitats, in Portugal there is a major lack of knowledge of these ecosystems, namely in the karst region. In order to provide further knowledge, several surveys were carried out in caves of the Sicó massif. Our main results document the observation of two species: Triturus marmoratus and Bufo bufo. Reports on these organisms are common in the underground habitats in Europe. However, in Portugal this is the first occurrence of both species in caves in central Portugal. Their presence might be due to searching for refuge and high humidity, escaping from predators, and accidental fall into cave entrances that might act as natural pitfalls. This research shows that the presence of amphibians in caves is underestimated and that more caves should be surveyed for the presence of amphibians in this particular massif, but also in other main karst areas in Portugal. Karst landscapes are threatened with pollution and contamination resultant from activities such as agriculture and industry, among others. Due to the scarcity of water on the surface, sinkhole ponds and springs are essential as breeding sites for these organisms. Considering these factors, we evaluated the effect of water collected from 6 different sites of Sicó massif in early stages of Hyla arborea. Through ecotoxicological essays, parameters such as survival, size, activity of antioxidant enzymes (GPx total, Se-dependent GPx, GRed and GST) and also lipidic peroxidation were evaluated. Complementarily, we determined several abiotic parameters and evaluated the presence of 6 pesticides. The results from both biomarkers evaluation and detection of pesticides show that in two sites conditions for larval development of amphibians may not be adequate. However, more studies are necessary to confirm these suspicions. Considering the relevance of these sites for conservation of various amphibian populations, further and complementary studies are necessary, namely for evaluating the effect of seasonality on water’s chemical parameters and the resulting effects of in situ exposure on larval stages.
Algumas espécies de anfíbios (salamandras, sapos e rãs) habitam ambientes cársicos, e são frequentemente encontrados tanto à superfície como em habitats subterrâneos. O presente trabalho aborda ambos através da avaliação da: (a) abundância e distribuição de anfíbios em cavidades do maciço de Sicó e da (b) adequabilidade da água presente em dolinas e exsurgências do maciço de Sicó para as fases iniciais de desenvolvimento de anfíbios. Apesar de existirem alguns registos de anfíbios em habitats subterrâneos na Europa, em Portugal existe uma grande lacuna no conhecimento acerca destes habitats, em particular nas regiões cársicas. Desta forma, foi feito um levantamento da presença de anfíbios em grutas do maciço de Sicó. Com base nos resultados, foram documentadas duas espécies: Triturus marmoratus and Bufo bufo. Ambas foram já documentadas em ambientes subterrâneos pela Europa. No entanto, este é o primeiro registo de observação destas espécies em cavidades no centro de Portugal. A presença neste tipo ambiente pode ser justificada pela procura de um local de refúgio com elevada humidade, para se defender de predadores ou ainda por quedas acidentais, uma vez que algumas entradas verticais atuam como armadilhas. Este trabalho demonstra ainda que a presença de anfíbios em cavidades cársicas é subestimada e serão necessários mais levantamentos para contemplar estas questões, tanto no maciço de Sicó como noutras áreas cársicas de Portugal. Relativamente à superfície e às massas de água das paisagens cársicas, sabe-se que estão ameaçadas pela poluição e contaminação resultantes de actividades como a agricultura e a indústria, entre outras. Devido à escassez de água à superfície, dolinas, lagos, nascentes e exsurgências são essenciais à reprodução de muitas espécies de anfíbios. Tendo em conta estes factores, avaliámos através de ensaios ecotoxicológicos, o efeito de água proveniente de 6 locais distintos do maciço de Sicó, em fases larvares de Hyla arborea. Os parâmetros avaliados foram a sobrevivência, o tamanho, a actividade de enzimas antioxidantes (GPx total, GPx Se-dependente, GRed e GST) e também a peroxidação lipídica. De forma complementar foi analisada a presença de 6 pesticidas e foram determinados vários parametros abióticos. Os resultados mostraram que, para dois locais, quer pela deteção de pesticidas, quer pelos resultados obtidos nos biomarcadores, poderão não existir as condições mais adequadas para o desenvolvimento de fases larvares de anfíbios. No entanto, são necessários mais estudos de forma a confirmar estas suspeitas. Considerando ainda a relevância destes locais para a conservação de algumas populações de anfíbios, é necessário realizar mais estudos complementares, nomeadamente avaliando o efeito da sazonalidade nos parâmetros químicos da água e avaliando em fases larvares os efeitos decorrentes de uma exposição in situ.
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Bonin, Joël. "Effect of forest age on woodland amphibians and the habitat and status of stream salamanders in southwestern Québec." Thesis, McGill University, 1991. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=22462.
Повний текст джерелаАнотація:
I studied two aspects of the ecology of amphibians in southwestern Quebec, an area characterized by a mosaic of small forests interspersed by cultivated land and by the presence of rare species at the northern limits of their distribution. One aim was to determine how forest age after clearcutting affected woodland amphibians. Path analysis was used to compare different causal effects of forest age on Plethodon cinereus density in 22 deciduous forests of 30, 60 and $>$90 years old. Repopulation of Plethodon followed forest litter recovery, 30 to 60 years after clearcutting. However, the effect of forest age was overridden by that of microtopography and soil texture. Rana sylvatica seemed also sensitive to clearcutting while Bufo americanus, Ambystoma maculatum and A. laterale seemed much less sensitive.A second aim was to determine the status and habitat of stream salamanders at the northern edge of the Adirondacks. Sixty stream sections were sampled. Eurycea bislineata was widespread (in 47 sites) and abundant, especially where rocks were numerous on the shore. The distributions of Gyrinophilus porphyriticus (8 sites) and, to a lesser extent, of Desmognathus fuscus (11 sites) were positively correlated with altitude and the presence of forest. It is proposed that these locations might offer the temperate and oxygenated waters needed by these species during winter and summer. (Abstract shortened by UMI.)
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Crawford, John A. "Beyond the edge : riparian habitat use and forest management effects on stream salamanders in the southern Appalachian mountains /." Diss., Columbia, Mo. : University of Missouri-Columbia, 2007. http://hdl.handle.net/10355/4758.
Повний текст джерелаАнотація:
Thesis (Ph. D.)--University of Missouri-Columbia, 2007.The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from title screen of research.pdf file (viewed on November 27, 2007) Vita. Includes bibliographical references.
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Arroyo, Lambaer Denise. "Conserving amphibian diversity: a species inventory and gene flow studies in fragmented montane forest, Mambilla Plateau, Nigeria." Thesis, University of Canterbury. School of Biological Sciences, 2015. http://hdl.handle.net/10092/10867.
Повний текст джерелаАнотація:
Nigeria is the most densely populated country in Africa and one of the most advanced economically in terms of both industry and soil and landscape utilization. This country is projected to have one of the largest urban growth rates by 2050. Thus, the demands of the rapidly increasing human population and its material consumption represent a severe threat to biodiversity. Nigeria has the highest deforestation rate of natural forest in the world, its original vegetation has largely been replaced by farming activities, urban development and other products of human activities. The principal causes of the decline and loss of biodiversity in Nigeria include human exploitation of natural resources, fragmentation of habitats and populations, conversion of wild areas to agriculture and other intensive human use and alterations in the structure and function of ecosystems. Amphibians are the vertebrate group with the highest number of species threatened with extinction and habitat loss and fragmentation are considered to be among the leading causes of their declines and extinctions. It has been recognized that one of the most severe problems in conservation biology is the scarcity of baseline data. Such lack prevents evaluation of the effect of the expanding anthropogenic impact and determination of potential population declines.
The mountains of eastern Nigeria, within Taraba State, are regionally important in terms of biodiversity and endemism, however, its herpetofaunal diversity has received little attention. Moreover, no studies have investigated how habitat loss and fragmentation may affect dispersal and gene flow among small and isolated amphibian populations, and in the absence of such studies attempts at amphibian conservation are compromised.
The aims of this project were threefold. Firstly, a comprehensive inventory of the amphibians and reptiles of Ngel Nyaki and Kurmin Danko Reserve on the Mambilla Plateau was compiled. The outcome, an annotated list of 21 amphibians and 11 reptiles, represent the most thorough inventory to date of the herpetofauna on the Mambilla Plateau. Based on this inventory four key anuran species were selected to conduct a population genetics study.
Secondly, molecular tools specifically AFLP markers were developed and used to analyze the genetic population structures of the four frog species Cardioglossa schioetzi, Leptodactylodon bicolor, Astylosternus sp. 1 and Astylosternus sp. 2. differing in geographic distribution and life history traits within the study area.
Thirdly, these species were assessed to understand dispersal and connectivity among fragmented and continuous populations on the Ngel Nyaki and Kurmin Danko Reserve. Genetic differentiation among the forest and the riparian fragment populations was observed for three of the target species, however, no significant genetic differentiation was detected among the populations located in continuous forest for any of the four frog species. In addition, geographic and genetic distances were not correlated significantly for any of the four target species, suggesting no isolation by distance at this fine geographic scale.
Results from both the inventory and the genetic population structure study revealed that the riparian forest fragments are of utmost importance for the persistence and migration of Cardioglossa schioetzi, and potentially for many other amphibian species. The new scientific findings are now part of the valuable baseline data on the diversity and genetic population structure of amphibian species in Ngel Nyaki and Kurmin Danko Forest Reserve. These results will better inform conservation managers who need to make decisions around management of montane habitat for amphibian species.
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Thompson, Michelle E. "Recovery of Amphibian and Reptile Communities During Tropical Secondary Forest Succession." FIU Digital Commons, 2018. https://digitalcommons.fiu.edu/etd/3701.
Повний текст джерелаАнотація:
The extensive clearing and modification of natural systems from anthropogenic activities is a pressing global concern. Forest habitats and animal communities within forests are among the most highly impacted, globally. Forest destruction has been repeatedly documented as a driver of biodiversity loss. However, little is known about how animal communities respond when altered landscapes are abandoned and left to regenerate into secondary forests. It is thought that the regrowth of secondary forests may help reverse biodiversity loss by restoring habitats to similar conditions as prior to land conversion. Of the forest cover that remains, over half is secondary forest, and in many countries secondary forest cover has been steadily increasing. Therefore, it is important to understand how and if faunal communities recover during secondary forest regeneration.
I combined meta-analytic, field-survey-based, and lab-based experimental techniques to determine how amphibians and reptiles respond to habitat change in general, and secondary forest regeneration on landscapes previously cleared for use as pasture. I addressed five specific questions: 1) what are the effects of habitat alteration on amphibians and reptiles?, 2) what are the effects of secondary forest succession on amphibians and reptiles?, 3) what is the relative importance of stochastic and deterministic effects on community assembly during secondary forest succession?, 4) how do amphibian and reptile species composition, probability of occurrence, and species richness change over the course of secondary forest succession?, and 5) is thermal quality of habitat an important mechanism of species response to secondary forest succession? I found that secondary forest has high conservation value for many amphibian and reptile species, environmental changes associated with secondary forest succession have a significant effect on shaping amphibian and reptile community composition, thermal quality is an important mechanism for species response and that strength of response is mediated by species-specific thermal biology. I also highlight the importance of riparian corridors in maintaining species diversity in modified habitats.
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Brom, Peta. "There might be a frog in McElligot's Pool: a study of the habitat characteristics and social factors associated with amphibian presence in urban residential gardens in a suburb in Cape Town." Master's thesis, University of Cape Town, 2017. http://hdl.handle.net/11427/27525.
Повний текст джерелаАнотація:
This thesis engages with urban ecology through the lens of garden amphibians within a community in Cape Town. The study explores habitat and maintenance features associated with amphibian presence and the social processes underpinning attitudes towards amphibians, with the aim of strengthening knowledge underpinning the "what" (knowledge of natural requirements), "Why" (social drivers for urban landscape form and management), and the "how" (working with people, for garden biodiversity initiatives. To explore the "Why" component, a social survey was conducted with 192 members of the community. One‐way anova and correspondence analysis were used to explore the relationship between values, culture, knowledge and memories of early childhood experiences against a general attitude towards frogs and toads. The findings are consistent with the theoretical framework of Connectedness To Nature where positive attitudes are supported by normative values, cultural beliefs, knowledge and positive experiences with care‐givers and role‐models. The garden habitat component of the study sought to explore the technical questions of the "What" requirement for amphibian presence in gardens. It was loosely based on the BIMBY tool with adaptations for context and targeted species. 50 gardens were visited and surveyed. They were divided into two groups for comparison: Those in which residents reported amphibian presence, and those which did not. Results indicate that the cape river frog (A. fuscigula) and clicking stream frog (S. grayii), are attracted to gardens with moderate to dense vegetation at groundcover level. Gardens with moderately planted beds were more likely to report frogs if they had additional resources, in particular, ponds and mulch. The "How" question brought together the two themes in a discussion on citizen mobilization and ways in which community groups are successfully implementing urban ecology conservation and reconciliation strategies. This work is important for urban nature conservation which seeks to engage private land‐owners (garden enthusiasts) and community and citizen groups in implementing urban biodiversity projects.
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Lūžaitė, Donata. "Varliagyvių tyrimai Krekenavos regioniniame parke." Master's thesis, Lithuanian Academic Libraries Network (LABT), 2007. http://vddb.library.lt/obj/LT-eLABa-0001:E.02~2007~D_20070816_153535-00190.
Повний текст джерелаАнотація:
Magistro darbe tiriamas varliagyvių vystymasis ir jų pasiskirstymas Krekenavos regioniniame parke. Darbo objektas – varliagyviai Krekenavos regioniniame parke Darbo tikslas – nustatyti Krekenavos regioninio parko varliagyvių rūšinę įvairovę ir jos pasiskirstymą. Darbo metodai – eksperimentas, natūralus stebėjimas, matavimas, maršrutinis metodas. Darbo rezultatai. Šiame darbe panaudota medžiaga buvo surinkta 2006.04.23, ir 2006.birželio – rugsėjo mėnesiais. Atlikus stebėjimus buvo pastebėti akivaizdūs skirtumai tarp namų ir lauko bandymo rezultatų. Kambario sąlygos, šiluma ir temperatūra nulėmė buožgalvių greitesnį vystymąsi, nei lauko sąlygomis. Namų sąlygomis buožgalvių metamorfozė nuo embriono iki buožgalvio trunka 4 dienas. Lauko sąlygomis buožgalviai vystosi panašiai, kaip ir natūraliomis sąlygomis , metamorfozė nuo embriono iki buožgalvio trunka 12 dienų. Smailiasnukės varlės ( Rana arvalis) gausiai sutinkamos pušyne. Paprastasis tritonas (Titrus vulgaris) aptinkamas tik sausuose pušynuose. Mišriame lapuočių miške – pievinės varlės (Rana temporaria). Glitėtų beržyne gausiai sutinkamos varlės ežerinė varlė (Rana ridisbunda) ir kūdrinė varlė (Rana esculenta). Senvagėje ir užtvankoje varlių pasiskirstymas nėra būdingas vienai ar kitai gyvenamajai aplinkai. Krekenavos regioniniame parke gausiausiai sutinkamos rudosios varlės, o iš jų – pievinė varlė (Rana temporaria); ji mažiausiai išranki savo gyvenamajai vietai.This master work analyses the development of amphibians and their distribution in Krekenava regional park. The object of this work – the amphibians in Krekenava regional park. The goal of this work – to determine the variety of amphibian species in Krekenava regional park, their abundance and distribution. The objectives of this work – experiment, natural observation, measurement, route method. The results of this work. The material used in this work was collected in 2006.04.23 and June ) September period of 2006. After observation there were noticed big differences between the results achieved in experiment within outside and inside conditions. Inside conditions, warmth and temperature have caused faster development of tadpoles than within outside conditions. The methamorphosis of tadpoles within inside conditions takes 4 days. The development of tadpoles within outside conditions in their natural habitat is very similar, only in takes 12 days to develop from embryo to tadpoles. Rana arvalis are very common in pine forest. Triturus vulgaris are found only in dry pine forest. Rana temporaria are very common in leaf – bearing forests. Rana esculenta and Rana ridibunda are very common in birch forest. The distribution of frogs in the old riverbed and the, pond isn’t common for one or the other natural habitat. The most common frog species in Krekenava regional park is the brown frog species - Rana temporaria , which is the least fastidious for its natural habitat.
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Larson, Lisa Irene. "Coeur d’Alene salamander abundance, distribution, and habitat use in Mount Revelstoke National Park of Canada." Thesis, University of British Columbia, 2009. http://hdl.handle.net/2429/4614.
Повний текст джерелаАнотація:
The Coeur d’Alene salamander (Plethodon idahoensis) is a species of special concern throughout its global range, which includes southeastern BC (COSEWIC, Nov 2007), Idaho, and Montana, due to disjunct populations and sensitivity to human disturbance. Within the Interior Cedar-Hemlock forest on Mount Revelstoke, BC, Coeur d’Alene salamanders occur at their highest abundance between 600 m and 800 m. Beyond the Mount Revelstoke National Park boundaries, the low-order stream habitat of this species is subject to disturbance from forestry, mining, road building, road maintenance, and watercourse diversions such as run-of-the-river hydro projects.
We conducted nocturnal salamander surveys and assessed habitat characteristics on 12 Sites (750 m² – 1000 m² stream transects) along three streams from June through September 2006. Coeur d’Alene salamanders were detected from 600 m - 1000 m on seven of the 12 study sites. Relative abundance of Coeur d’Alene salamanders ranged from 0.005 ± 0.001 per m² to 0.025 ± 0.005 per m² on six sites below 950 m. Coeur d’Alene salamanders occurred at an average of 0.001 ± 0.001 per m² at 972 m, the only site above 950 m where we detected salamanders. Our capture-mark-recapture efforts of three surveys per month in June and August yielded a very low recapture rate (3.95 %). Coeur d’Alene salamanders are challenging to enumerate due to their vertical distribution within the soil and underlying geological material.
Neonate, juvenile, and adult Coeur d’Alene salamanders were observed from June to September and the highest proportion of neonates occurred in June, soon after the salamanders emerged from winter hibernation. Results of a logistic regression analysis of 1-m² plots reflected the importance of fine scale habitat characteristics (quadrat gradient, boulder, cobble, moss, grass, and shrub) in addition to site-level habitat features (water volume and elevation) that in combination describe the association of Coeur d’Alene salamanders with cool and moist conditions. Coeur d’Alene salamanders appear to select streambed habitat during warm, dry periods, which may be a behavioural response to minimize dehydration during periods of activity at the surface of the forest floor.
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Neyland, Penelope Jane. "Habitat, home range, diet and demography of the water vole (Arvicola amphibious) : patch-use in a complex wetland landscape." Thesis, Swansea University, 2011. https://cronfa.swan.ac.uk/Record/cronfa42744.
Повний текст джерелаАнотація:
Water vole (Arvicola amphibius) ecology was studied at the National Wetland Centre Wales (NWCW), a National Key Site for water voles, consisting of a diversity of interconnected habitats, including ponds, ditches and reed-beds. A novel method of mapping the vegetation of the wetland landscape was devised, using patches of vegetation classified according to the dominant vegetation type (DVT). The richness and abundance of DVT patches was used as an index of diversity at the habitat level. This provided a basis for describing the matrix habitat, which underpins the study of water vole ecology at the patch-landscape scale. The practical application of the DVT mapping approach allows the stages of wetland succession to be monitored, identifies areas of high biodiversity and provides a baseline on which to monitor the distribution and movements of animal species. Implementation of this method reduces time and the need for specialist field surveyors, thereby facilitating efficient management practices if applied at a national level. An intensive four year study of a metapopulation of water voles on eight adjacent ponds in the NWCW wetland reserve revealed an important insight into the dynamics of wild populations in complex, non-linear habitats. Multi-annual fluctuations in population densities were observed, characterised by a peak density phase and a low density phase. Density dependent juvenile dispersal was characteristic of the water vole population. Female water voles in diverse pond habitats maintained intra-sexually overlapping home ranges, uncharacteristic of this species. During the breeding season, water voles selected the ponds with the highest habitat diversity (assemblage of DVTs) but were typically associated with the least diverse DVT patches within the vegetation mosaic. Temporal plasticity in niche partitioning was observed both between genders and between individual female water voles at NWCW. During the winter. Bramble (Rubus fruticosus) was the most important dominant vegetation type, providing a source of cover and protection from predation. Water voles selected 23 plant species (and 3 non-plant species) as food. Soft Rush (Juncus effusus) a species with high nitrogen and calorific content was favoured particularly. The physical effects of water vole grazing and burrowing, combined with the large amounts of nitrogen- containing faeces deposited in latrines and underground burrows, has implications for wetland nutrient cycles. The effects of large scale vegetation clearance are described and holistic management recommendations are presented.
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Ferreira, Mário Rui Mota. "Multi-species occupancy modeling of natural and anthropogenic habitats by mediterranean amphibians: grim prospects for conservation in irrigated farmland." Master's thesis, Universidade de Évora, 2012. http://hdl.handle.net/10174/10780.
Повний текст джерелаАнотація:
This study approaches the destruction of temporary ponds in an intensified agricultural landscape and the alternative breeding habitats for the amphibian community. We used several surveys to model the ponds survival since 1991 until 2009. Ponds inside the irrigation perimeter have a significant lower survival probability then those outside. Ponds, agricultural reservoirs, streams, irrigation channels and ditches were sampled for amphibian larvae in four different periods of a breeding season. We used a hierarchical dynamic occupation model that accounts for different detection probabilities to compare the occupation of aquatic habitats during the different periods. Ponds were the habitat with higher specific richness per site followed by streams and reservoirs. Ditches and irrigation channels, usually, only supports one species per site. All habitats, except for ponds, have high incidence of exotic predators (fish and crayfish), that explains, in part, the low specific richness of these sites. There’s no alternative habitat for the disappearing ponds. The conservation of the remaining ponds is essential for conserving the amphibian community. It should seriously be taken into consideration the construction of new clusters of ponds inside of the irrigation perimeter; Resumo:
Este estudo aborda a destruição de charcos temporários numa paisagem agrícola em crescente intensificação, bem como possíveis alternativas para habitats de reprodução da comunidade de anfíbios. Cruzámos a informação de vários levantamentos para modelar a sobrevivência dos charcos de 1991 a 2009. Os charcos dentro do perímetro de rega tem a probabilidade de sobrevivência significativamente mais baixa que os charcos fora do perímetro. Foram amostrados as larvas de anfíbios em charcos temporários, charcas de rega, ribeiras, canais de rega e valas de drenagem em quatro períodos distintos de uma época de reprodução. Usámos um modelo hierárquico de ocupação dinâmica, com correcção para a detectabilidade para comparar a ocupação entre os habitats ao longo dos diferentes períodos. Os charcos temporários foram os habitats com maior riqueza específica por local, seguido pelas ribeiras e charcas de rega. Os canais e valas são habitats mais pobres, raramente suportando mais que espécie por local. A elevada incidência de predadores introduzidos (peixe e lagostins) em todos os habitats menos nos charcos pode explicar em parte a diferença de riqueza específica. Esta comunidade de anfíbios não tem uma alternativa viável para os charcos que continuam a desaparecer e a sua conservação passa pela conservação dos charcos que restam. Deverá ser considerado a hipótese da construção de novos complexos de charcos dentro do perímetro de rega.
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Williams, Lori Ann. "Amphibian Population and Community Characteristics, Habitat Relationships, and First-Year Responses to Clearcutting in a Central Appalachian Industrial Forest." Thesis, Virginia Tech, 2003. http://hdl.handle.net/10919/10129.
Повний текст джерелаАнотація:
The overall goal of this project was to provide baseline data on amphibian species richness, relative abundance, and habitat use for a long-term landscape ecology study on MeadWestvaco industrial forest in the Allegheny Highlands of West Virginia. From results of area-constrained daytime searches (10 m x 10 m plots) across the landscape, I developed 9 regression models to predict amphibian relative abundance. I constructed models for each year for all plots on all habitat types, plots that were in a Stream Management Zone (SMZ), and plots that were in upland, or non-SMZ, habitat. Distance to perennial or ephemeral streams or perennial ponds (SMZ classification), the amount of available rocks along transects, and site index were the 3 most important habitat variables in models for all plots combined and were responsible for 24-32% of the inherent variation in population relative abundance. Other habitat variables that were significant in models were year, % canopy cover, the amount of available woody debris of decomposition classes 3-5 along transects, % woody stems (<7.5 cm DBH), soil pH, and % herbaceous vegetation. R2PRESS values for all 9 models ranged from 0.08 to 0.35. Amphibian relative abundance showed positive relationships with all significant habitat variables with the exception of year and % woody stems.
In natural cover object use/availability analyses, I discovered salamanders preferred rocks over woody debris, relative to the amount available of each. Salamanders preferred flat rocks to any other shape, flagstones to any other type of rock, and rock lengths in the 31-40 cm class. Preferred wood widths were in class 5-10 cm, while preferred wood lengths were in class <50 cm; salamanders exhibited strong preferences for wood in higher states of decomposition (class 3-5).
I provided baseline, preharvest data for 28-acre reference areas on 9 forest compartments scheduled for clearcuts. I sampled all 9 reference areas preharvest and sampled 3 during year 1 postharvest using coverboard and night plot surveys. On these 3 areas, species richness declined from preharvest to postharvest, but species diversity showed little change. Overall relative abundance declined significantly preharvest to postharvest with coverboard sampling (p=0.0172) and night plot sampling (p=0.0113). At coverboard stations, relative abundance declined significantly from preharvest to postharvest at a distance of 5-10 m (p=0.0163) and 40-50 m (p=0.0193) away from adjacent mature forest.
Finally, using Pianka's index, I compared the night plot and coverboard sampling techniques in terms of proportions of the 4 most common species captured. These sampling techniques on average were >80% similar for all reference areas.Master of Science
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Carrozzino, Amy Leigh. "Evaluating wildlife response to vegetation restoration on reclaimed mine lands in southwestern Virginia." Thesis, Virginia Tech, 2009. http://hdl.handle.net/10919/32190.
Повний текст джерелаАнотація:
Coal mining has had profound impacts in the Appalachian region, initiating a need to understand the implications of traditional and current reclamation practices on wildlife. I evaluated wildlife use of reclaimed sites of varying ages and cover types in southwestern Virginia. I compared reclaimed sites to another form of anthropogenic disturbance (clearcut) and relatively undisturbed mature forest. Birds were surveyed during early mornings throughout the breeding season in 2007 and 2008 using the point count method. Amphibians were surveyed using artificial cover, constrained-time night searches, and auditory pond surveys. Microhabitat data were collected at each sampling point and were combined with landscape-level GIS information to relate habitat characteristics and wildlife patterns.
I observed 80 bird species using reclaimed areas, clearcuts, and mature forest. Pre-regulation sites (prior to the Surface Mining Control and Reclamation Act of 1977) supported the highest number of species overall. Cluster analysis identified 4 bird associations based on habitat characteristics. I developed site-specific, landscape-level, and mixed-scale logistic regression models to identify habitat characteristics that best predicted the presence of 27 species. For 18 species, mixed-scale models performed best, suggesting the importance of a multi-scale approach to habitat analysis.
Salamanders were generally not detected on reclaimed areas, possibly due to the lack of soil moisture, leaf litter, and woody debris on young sites. Frogs were present in all water bodies surveyed, suggesting the importance of managing ponds and wetlands on reclaimed sites. Identifying and focusing on important habitat characteristics will help managers enhance post-mining land for wildlife.
Master of Science
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Castro, DÃborah Praciano de. "ComposiÃÃo, distribuiÃÃo estacional e uso de habitats em uma assemblÃia de anuros de afloramentos rochosos do semiÃrido brasileiro." Universidade Federal do CearÃ, 2012. http://www.teses.ufc.br/tde_busca/arquivo.php?codArquivo=7976.
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CoordenaÃÃo de AperfeiÃoamento de NÃvel SuperiorCompreender os nÃveis de abundÃncia e distribuiÃÃo espacial das espÃcies em seus habitats à um dos temas centrais em ecologia. PadrÃes de distribuiÃÃo espacial das espÃcies, aliados a fatores ambientais, tais como estacionalidade, fornecem informaÃÃes importantes para decifrar as forÃas que mantÃm e estruturam a diversidade biolÃgica. AnfÃbios anuros constituem Ãtimos pontos de partida para o estudo de assemblÃias ecolÃgicas, e o fato de serem altamente dependentes de variÃveis ambientais, torna o estudo destes animais ainda mais interessante. Partindo destes pressupostos, nÃs apresentamos como principal objetivo deste estudo fornecer informaÃÃes sobre riqueza, diversidade, modos reprodutivos e uso de microhabitats por uma assemblÃia de anuros de afloramentos rochosos do semiÃrido brasileiro. As pesquisas de campo foram realizadas de julho de 2010 a julho de 2011 em coletas mensais com duraÃÃo de trÃs dias, no municÃpio de Itapipoca-CearÃ, na Ãrea denominada de SÃtio PaleontolÃgico Lajinhas. Foram utilizadas as metodologias de busca ativa em sÃtios reprodutivos e encontros ocasionais para demonstrar a riqueza, frequÃncia e abundÃncia das espÃcies. Foram encontradas 19 espÃcies de anuros, distribuÃdas em 13 gÃneros de cinco diferentes famÃlias. A assemblÃia apresentou um maior nÃmero de espÃcies pertencentes à famÃlia Leptodactylidae e as espÃcies mais abundantes foram Pseudopaludicola mystacalis, Pleurodema diplolister, Physalaemus albifrons e Scinax xsignatus. Todas as espÃcies da assemblÃia fizeram uso diferencial de microhabitats como forma de resistir ao perÃodo seco do ano e apresentaram eventos reprodutivos restritos ao perÃodo chuvoso. A maioria dos padrÃes encontrados jà era esperado para o domÃnio das Caatingas, e demonstram que a anurofauna da Caatinga, independente da fitofisionomia abordada, tende a ser similar, utilizando estratÃgias comportamentais parecidas, apresentando flexibilidade comportamental acentuada e grande dependÃncia de chuvas.
Comprehending the levels of abundance and spatial distribution of species in their habitats is a central theme in ecology. Spatial patterns of species distribution, combined with environmental factors such as seasonality, provide important information to unravel the forces that maintain and structure biological diversity. Anuran amphibians are great starting points for studying ecological assemblages, and the fact that they are highly dependent on environmental variables makes the study of these animals even more interesting. Based on these assumptions, we present the main objective of this study to provide information on richness, diversity, reproductive modes and use of microhabitats by an assembly of anurans of rocky outcrops in Brazilian semi-arid region. The field work was conducted from July 2010 to July 2011 in monthly collections lasting three days in the city of Itapipoca, CearÃ, in the area called Paleontological Site Lajinha. Methodologies were used in an active search and occasional encounters at breeding sites to demonstrate the richness, frequency and abundance of species. We find 19 anuran species, distributed in 13 genera from five different families, most of them with broad occurrence in Brazil and Latin America. The assemblage had a greater number of species of the Leptodactylidae family, and the most abundant species were Pseudopaludicola mystacalis, Pleurodema diplolister, Physalaemus albifrons and Scinax xsignatus. All species of the assemblage made differential use of microhabitats as a way to resist the dry season, and showed reproductive events restricted to the rainy season. Most patterns found were already expected for the Caatinga domain, and we believe that this underscores that the Caatinga anuran fauna, in spite of the vegetation type considered, will generally be similar, using similar behavioral strategies, with sharp behavioral flexibility and heavy reliance on rains.
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Surdick, James A. "Amphibian and avian species composition of forested depressional wetlands and circumjacent habitat the influence of land use type and intensity /." [Gainesville, Fla.] : University of Florida, 2005. http://purl.fcla.edu/fcla/etd/UFE0010745.
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