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Determining habitat and biotic factors driving puma (<i>Puma concolor</i>) space use and underlying dynamic processes (colonization and extinction) over 20 years in protected and private areas throughout Belize, Central AmericaMcPhail, Darby K. 01 July 2024 (has links)
Despite being a top carnivore, there is relatively scant information on pumas (<i>Puma concolor</i>) in the neotropics especially compared to the more well-studied jaguar (<i>Panthera onca</i>). Understanding long-term puma distribution can affect land management decisions such as appropriate size of buffer zones around protected areas since pumas influence, and are influenced by, sympatric carnivore populations, lower trophic levels, and habitat. We used single-species, single-season and multi-season occupancy modeling to explore factors influencing distribution and persistence of pumas across the country of Belize. We used camera trapping data from 7 protected areas over 20 years with 2,198 camera stations covering ~5,000 km2. For both approaches, detection was mostly affected by distance to roads, enhanced vegetation index (EVI), and elevation, with variable directionality depending on site. In single season modeling, Occupancy increased at lower elevations and intermediate EVI in one site, and closer to water sources at another, while in multi-season modeling, intermediate EVI and canopy cover influenced occupancy. Biotic covariates were highly variable across sites and methods, but detection and occupancy were generally positively associated with prey, jaguar and ocelot trap rates, canopy cover, and elevation, while human trap rates negatively affected occupancy at one site. Colonization was positively affected by deer (<i>Odocoileus virginianus</i> and <i>Mazama americana</i>) trap rates while extinction had no supported covariates. Puma occupancy ranged from 0.41-0.96 in single season models and 0.55-0.90 in multi-season models across all site/years. Compared to other single-season studies, Belize generally had higher occupancy, even in areas of selective logging, however there are no other multi-season studies to compare. While sites with heavy human impacts had lowest occupancy, these areas are still used and likely serve as steppingstones between protected areas of higher occupancy. Such areas could be targets for protection to preserve landscape connectivity. Additionally, due to high occupancy and colonization across varying habitat and biotic factors the jaguar is likely an effective umbrella species for puma space use, however more analysis on other species is needed to ensure efficiency for more than just pumas. / Master of Science / The neotropics is an important global zone known for high biodiversity and carbon sequestration. Felids (wild cats) play an important role in maintaining biodiversity and structure in ecosystems, however, they are facing threats to their survival due to habitat loss and fragmentation, and negative human-wildlife conflict. To protect ecosystem health, managers often employ the umbrella species concept, meaning if they protect the jaguar with its large spatial requirements, other wildlife species that fall within that area will also be protected. However, there have been few studies on the effectiveness of this strategy, especially for species like the puma, that might be competitive with jaguars. Occupancy modeling is a powerful tool in wildlife management that uses presence absence analysis to determine where species occur on a landscape. We used camera trapping data across multiple protected areas over 20 years to determine what influences pumas across the landscape. We found pumas were affected by differing variables depending on habitat. Important variables were: thickness of vegetation, elevation, distance to roads and water, prey and there were positively associated with jaguars and ocelots. Additionally, pumas were more likely to move into a new site if the activity of their favored prey, deer, was high. Pumas occurred at 41-96% of camera stations depending on site, across all years, indicating they are widespread across Belize. Compared to 11 other occupancy studies from Latin America, Belize generally had higher occupancy, even in areas of selective logging, compared to the other available studies in the neotropics. While sites with heavy human impacts had lowest occupancy, these areas are still being used by pumas and likely serve as steppingstones between protected areas of higher occupancy. Such areas could be targets for protection to preserve landscape connectivity across Belize, which is rapidly developing in infrastructure. Overall, jaguars appear to be a suitable umbrella species for the puma, however, further analysis is needed for more specialized species such as threatened Baird's tapir, crested guan, black howler monkey, and smaller cat species, the margay and jaguarundi, to ensure that the jaguar is a suitable umbrella species that supports a wide variety of species within the community.
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Influência da paisagem sobre a persistência de mamíferos terrestres em fragmentos de Mata Atlântica / Landscape influence on the persistence of terrestrial mammals in Atlantic Forest fragmentsBeca, Gabrielle Cristina [UNESP] 29 January 2016 (has links)
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Previous issue date: 2016-01-29 / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / A crescente demanda por fontes alternativas de energia tem contribuído para o aumento da produção de biocombustíveis, levando a fragmentação dos habitats naturais. No entanto, paisagens naturais imersas em matrizes agrícolas podem reter uma diversidade de espécies considerável, mas os efeitos da mudança no uso do solo para a produção de biocombustíveis sobre a persistência das espécies nessas paisagens ainda permanecem incertos. A Mata Atlântica, ecossistema mais fragmentado do Brasil, tem apenas cerca de 12% de sua cobertura vegetal original. A maioria destes remanescentes estão distribuídos em fragmentos pequenos e isolados devido à expansão agrícola, especialmente pela monocultura de cana-de-açúcar. No presente estudo examinamos a riqueza e a composição de mamíferos de médio e grande porte, e quantificamos a contribuição da cobertura florestal, da área estrutural e da quantidade de borda sobre a persistência desses animais. Amostramos 20 paisagens fragmentadas, em um gradiente de cobertura florestal (3% a 96%), imersas em plantações de cana-de-açúcar. Registramos apenas 50% das espécies esperadas de mamíferos de médio e grande porte em todas as 20 paisagens, em comparação com o maior remanescente de floresta semidecídua, o "Parque Estadual Morro do Diabo". Isso nos mostra que esses remanescentes de Mata Atlântica estão altamente empobrecidos, restando apenas25% de espécies especialistas florestais, e a maioria dos mamíferos registrados são espécies generalistas, exóticas e típicas de cerrado. A cobertura florestal foi importante para explicar apenas a presença de alguns ungulados e um roedor de médio porte. As comunidades de mamíferos responderam à substituição de espécies entre as paisagens, que representou 94% da β-diversidade total. Nosso estudo é novo em mostrar que a riqueza de mamíferos não foi afetada pela quantidade de habitat. É importante implementar medidas eficazes de conservação das áreas naturais em paisagens agrícolas, a fim de desenvolver medidas de restauração da cobertura florestal dos fragmentos, pois estes são cruciais para manter populações viáveis de espécies que dependem da floresta e ainda persistem nesses ambientes modificados. / The growing demand for alternative energy sources has contributed to increased biofuel production, leading to fragmentation of natural habitats. However, natural landscapes immersed in agricultural matrices can retain a considerable diversity of species, but the effects of the change in land use for the production of biofuels on the persistence of the species in these landscapes remain unclear. The Atlantic Forest, the most fragmented ecosystems in Brazil, has only about 12% of its original vegetation cover. The most of these remnants are distributed in small and isolated fragments due to agricultural expansion, especially by the sugarcane monocultures. In the present study we examined the richness and composition of medium and large sized mammals, and quantify the contribution of the forest cover, the structural area and the edge amount over persistence of these animals. We sampled 20 fragmented landscapes on a forest cover gradient (3% to 96%), immersed in sugarcane plantations. We recorded only 50% of expected species of medium and large sized mammals in all the 20 landscapes, compared to the largest remnant of semideciduous forest, the "Morro do Diabo State Park". This shows that the Atlantic Forest remnants are highly depleted, with only 25% of forest-specialist species and most of the mammals registered are generalist species, exotic and typical from savana. Forest cover was important to explain only the presence of some ungulates and a medium sized rodent. The mammal communities responded to a high turnover of species between the landscapes, which represented 94% of the total β- diversity. Our study is novel in showing that mammal richness was not affected by the habitat amount. It is important to implement effective conservation measures in natural areas in agricultural landscapes in order to develop measures of restoration of forest cover of the fragments, because they are crucial to maintain viable populations of forest-dependent species and still persist in these modified environments. / FAPESP: 2013/21939-3
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Efeitos da fragmentação de habitat sobre a comunidade de mamíferos do médio Araguaia: aspectos teóricos, descritivos e conservacionistasLAGE, Alexandre Ramos Bastos 01 July 2011 (has links)
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Previous issue date: 2011-07-01 / Os efeitos da fragmentação de habitat vêm sendo cada
vez mais reconhecidos como a principal causa de perda de espécies da atualidade e, portanto, um grande número de
pesquisas tem buscado avaliar as respostas dos organismos
a este processo que é predominantemente resultado da ação antrópica sobre áreas de vegetação nativa. O processo de fragmentação de habitat ocorre em nível de paisagem, porém
a manipulação experimental de paisagens inteiras é bastante difícil e muitas vezes impossível. Desta forma, a geração de dados através de estudos observacionais em grandes escalas espaciais e temporais, tem se tornado cada vez mais importante para que sejam confrontadas as previsões de modelos teóricos, e para geração de dados que possam subsidiar ações conservacionistas em nível local, ou serem sintetizadas juntamente com estudos em outras regiões, para o estabelecimento de padrões aplicáveis a um grande número de paisagens fragmentadas. Devido à necessidade de grandes áreas de vida, o grupo dos mamíferos de médio e grande porte é um dos mais afetados pela perda de vegetação nativa de uma paisagem. Este trabalho buscou caracterizar a comunidade de mamíferos presente na paisagem fragmentada do município de São Miguel do Araguaia, Goiás. Utilizando exclusivamente o método de armadilhamento fotográfico, foram amostrados 12 fragmentos florestais com áreas
variando de 13 a 4.317 hectares. Foram obtidos 682 registros fotográficos de mamíferos silvestres de médio e grande porte e um total de 22 espécies foram detectadas na região. Espécies de grande porte e com grande área de vida foram
encontradas até nos menores fragmentos, indicando que estas espécies se deslocam pela paisagem e utilizam os fragmentos conjuntamente, o que demonstra a importância
da manutenção até dos menores fragmentos, que podem servir como fonte temporária de recursos e como elementos que ampliam a conectividade da paisagem. O armadilhamento fotográfico se mostrou um método bastante eficiente na
detecção de espécies de mamíferos em fragmentos florestais, onde transectos lineares ou a busca por vestígios podem ser bastante dificultadas pelo denso sub‐bosque existente no interior dos fragmentos, e pelo fato de o acúmulo da serrapilheira impedir a impressão e a visualização de rastros de espécies. OBS: A dissertação tem 2 capítulos c/ resumo. O texto acima é o resumo do capítulo 1.
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Introgression and the current status of the Scottish wildcat (Felis silvestris silvestris)Kilshaw, Kerry A. January 2015 (has links)
Baseline data on a species' distribution and abundance are essential for developing practical conservation management plans. Such data are difficult to obtain for many low density cryptic carnivores. The Scottish wildcat, Felis silvestris silvestris, is no exception with <400 individuals thought to remain. Its conservation has been further complicated by extensive hybridisation and introgression with the domestic cat (F.s.catus). Hybridisation has also resulted in difficulties in discriminating between wildcats, wildcat x domestic hybrids (hybrids) and tabby coloured feral domestic cats. This has inhibited survey efforts, leading to a lack of general ecological information. Using the most recent identification tools available, extensive surveys using various methods including camera trapping were carried out across Northern Scotland in order to examine the current status of the Scottish wildcat. Current distribution indicates a more restricted range than recent studies. Wildcats are at risk of hybridisation from feral domestic cats and in particular, hybrids, throughout their current probable range. The distribution of hybrids overlaps with both feral domestic cats and wildcats, pointing to a significant threat from hybrids acting as a bridge between wildcats and feral cats. Mean density estimates of 3.5 (SD=0.7) wildcats/100 km<sup>2</sup> were comparable with those from other studies in Scotland using different survey methods. Total population size estimates ranged between 115-314 individuals depending on local densities and home range size. Population viability analysis (PVA) indicated the current population is not viable unless management actions are undertaken in the near future (Mean time to extinction = 48.2 years (SD = 9.39), probability of extinction=1, SE = 0), and that reducing mortality rates and/or supplementing populations from captive bred cats are likely to be necessary to achieve viability. Based on these data, the Scottish wildcat may be more endangered than many other species classified as Endangered and the current status of the Scottish wildcat should be reviewed.
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Estimating Feral Swine Abundance and their Effects on Native Wildlife in the Mississippi Alluvial ValleyIvey, Matthew Ryan 04 May 2018 (has links)
Feral swine (Sus scrofa) are an invasive species in the Mississippi Alluvial Valley (MAV). They cause millions in damage annually to agriculture, and likely negatively affect native wildlife species. Using camera traps, I monitored 36 forest patches within the MAV to assess the effects of swine invasions on native wildlife species richness. I also modified the double-observer point count technique into a new method for estimating swine abundance with camera traps. Feral swine suppressed native vertebrate richness by 26% when compared to uninvaded patches. I validated the new double-observer technique by determining if it could detect an abundance-area relationship in wildlife populations and estimate a known decrease in abundance following swine removal. This technique was sensitive enough to detect the increase and decrease in abundance and estimated the number of individuals removed from the population relatively accurately. This technique may be useful in the future to manage feral swine populations.
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Distributions of Large Mammal Assemblages in Thailand with a Focus on Dhole (Cuon alpinus) ConservationJenks, Kate Elizabeth 01 May 2012 (has links)
Biodiversity monitoring and predictions of species occurrence are essential to develop outcome-oriented conservation management plans for endangered species and assess their success over time. To assess distribution and patterns of habitat use of large mammal assemblages in Thailand, with a focus on the endangered dhole (Cuon alpinus), I first implemented a long-term camera-trapping project carried out with park rangers from October 2003 through October 2007 in Khao Yai National Park. This project was extremely successful and may serve as a regional model for wildlife conservation. I found significantly lower relative abundance indices for carnivore species, and collectively for all mammals compared to data obtained in 1999-2000, suggesting population declines resulting from increased human activity. I integrated this data into maximum entropy modeling (Maxent) to further evaluate whether ranger stations reduced poaching activity and increased wildlife diversity and abundances. I then conducted a focused camera trap survey from January 2008 through February 2010 in Khao Ang Rue Nai Wildlife Sanctuary to gather critical baseline information on dholes, one of the predator species that seemed to have declined over time and that is exposed to continued pressure from humans. Additionally, I led a collaborative effort with other colleagues in the field to collate and integrate camera trap data from 15 protected areas to build a country-wide habitat suitability map for dholes, other predators, and their major prey species. The predicted presence probability for sambar (Rusa unicolor) and leopards (Panthera pardus) were the most important variables in predicting dhole presence countrywide. Based on my experience from these different field ecological surveys and endeavors, it became clear that local people's beliefs may have a strong influence on dhole management and conservation. Thus, I conducted villager interview surveys to identify local attitudes towards dholes, document the status of dholes in wildlife sanctuaries adjacent to Cambodia, and determine the best approach to improve local support for dhole conservation before proceeding with further field studies of the species in Thailand. A photograph of a dhole was correctly identified by only 20% of the respondents. My studies provide evidence that some protected areas in Thailand continue to support a diversity of carnivore speices of conservation concern, including clouded leopards (Neofelis nebulosa), dholes, and small felids. However, dholes' impact on prey populations may be increasing as tiger (Panthera tigris) and leopards are extripated from protected areas. The next step in dhole conservation is to estimate the size and stability of their fragmented populations and also focus on maintaining adequate prey bases that would support both large felids and dholes
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The influence of habitat features and co-occurring species on puma (Puma concolor) occupancy across eight sites in Belize, Central AmericaRowe, Christopher Brian 05 February 2018 (has links)
Large carnivores play many vital biological, economic, and conservation roles, however, their biological traits (low population densities, cryptic behavior) make them difficult to monitor. Pumas have been particularly difficult to study because the lack of distinctive markings on their coats prevents individual identification, precluding mark-recapture and other similar analyses. Further, compared to temperate areas, research on the interspecific interactions of Central American felids is particularly lacking. I used single- and multi-season, single-species occupancy models and two-species co-occurrence models to analyze camera trapping and habitat data collected at eight study sites across Belize. Puma occupancy was positively influenced by jaguar trap success, understory density, canopy cover, and human trap success, and negatively influenced by stream density. Jaguar trap success was the best predictor of where pumas occurred, while prey species were not found to influence puma occupancy. Mean occupancy was 0.740 (0.013) and ranged from 0.587 (0.042) to 0.924 (0.030). Over time, puma occupancy rates were generally high (> 0.90) and stable. Puma occupancy was higher in logged areas, suggesting that current levels of natural resource extraction at those sites were not detrimental to the species. Co-occurrence modeling showed little evidence for interactions between the carnivores, suggesting that jaguars may be acting as an umbrella species and that conservation efforts directed at jaguars are likely to benefit the other carnivores, including pumas. Overall, these findings are positive for puma conservation, but human-induced land use change is expanding and further monitoring will give us insight into how pumas respond to human encroachment. / Master of Science
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Effects of domestic megafauna and landscape on diversity of mammals in Atlantic Forest remnants /Rodrigues, Laís Lautenschlager. January 2019 (has links)
Orientador: Mauro Galetti Rodrigues / Resumo: A conversão de paisagens florestais para usos antrópicos é a principal causa do desmatamento das florestas tropicais em todo o mundo. Essas florestas são conhecidas por conter parte significativa da biodiversidade terrestre global, porém pouco se sabe sobre como as modificações na paisagem, como a perda de habitat para produção agropecuária e o principalmente o impacto do gado afetam a diversidade e ocupação de mamíferos resilientes nesses fragmentos. Sendo assim, nós examinamos como a riqueza de espécies e a composição de mamíferos são explicadas pela configuração da paisagem e como a presença do gado afeta a detecção de mamíferos de médio e grande porte. Foram amostradas 20 paisagens dominadas por pastagens ao longo de um gradiente de cobertura florestal (8% a 98%), no sudeste do Brasil. Nós registramos 75% das espécies de mamíferos esperadas para esta região em uma cobertura florestal de média a alta. A cobertura florestal, distância euclidiana do vizinho mais próximo e área estrutural foram as variáveis que melhor explicaram a ocorrência de algumas espécies de mamíferos dependentes de floresta. As comunidades de mamíferos exibiram um alto grau de alternação de espécies entre as paisagens, representando 95% da diversidade beta total. Os impactos da pecuária foram mostrados devido ao seu efeito negativo na detecção de espécies florestais e positivo na detecção de grupos de espécies não florestais. Discutimos a importância de manter fragmentos com alta cobertura vegetal para... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The landscape conversion to anthropic uses is the major cause of deforestation worldwide. Tropical forests are known to contain a significant portion of global terrestrial biodiversity, but little is known about how changes in landscape, such as habitat loss for livestock and its impacts affect the diversity and occupation of resilient mammals in forest fragments immersed in pasture matrices. Here we examine how species richness and mammal composition are explained by landscape configuration and how cattle presence affects the detection of medium and large mammals. We sampled 20 landscapes dominated by pastures along a forest cover gradient (8% to 98%) in southeastern Brazil. We recorded 75% of the mammalian species expected for this region in a medium-to-high forest cover. Landscapes metrics, as forest cover, Euclidean distance from the nearest neighbor and structural area were the variables that best explained the occurrence of some forest mammal species. Mammalian communities exhibited a high degree of species turnover between landscapes, representing 95% of total beta diversity. Livestock impacts were shown due to its negative effect on the detection of forest-dwelling species and positive on the detection of non-forest species groups. We discuss the importance of maintaining forest fragments with high vegetation cover to improve connectivity between disturbed landscapes, favoring mammalian species flow. There is an urgent need for a better understanding of livestock gene... (Complete abstract click electronic access below) / Mestre
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Ecology of Tigers in Churia Habitat and a Non-Invasive Genetic Approach to Tiger Conservation in Terai Arc, NepalThapa, Kanchan 13 October 2014 (has links)
Tigers (Panthera tigris tigris) can be viewed as a proxy for intact and healthy ecosystems. Their wild populations have plummeted to fewer than 3,200 individuals in the last four decades and threats to these apex predators are mounting rather than diminishing. Global conservation bodies (Global Tiger Initiative, World Wildlife Fund, Wildlife Conservation Society, Panthera etc.) have recently called for solidarity and scaling up of conservation efforts to save tigers from extinction.
In South Asia, tiger habitat ranges from tropical evergreen forests, dry arid regions and sub-tropical alluvial floodplains, to temperate mixed deciduous forest. The churia habitat is relatively unstudied and is considered a young and geologically fragile mountain range in Nepal. The contribution of the churia habitat to tiger conservation has not been considered, since modern conservation started in 1970's. This study focuses on the ecology of the tiger with respect to population density, habitat use, and prey occupancy and density, in the churia habitat of Chitwan National Park. This study also includes the first assessment of genetic diversity, genetic structure, and gene flow of tigers across the Terai Arc Landscape- Nepal. The Terai Arc Landscape harbors the only remaining tiger population found across the foothills of the Himalayas in Nepal and northwest India. I used a combination of camera-trapping techniques, which have been a popular and robust method for monitoring tiger populations across the landscape, combined with a noninvasive genetic approach to gain information on tigers, thus adding new information relevant to global tiger conservation.
I investigated tiger, leopard (Panthera pardus fusca), and prey densities, and predicted the tiger density across the Churia habitat in Chitwan National Park. I used a camera-trap grid with 161 locations accumulating 2,097 trap-nights in a 60 day survey period during the winter season of 2010-2011. Additionally, I used distance sampling techniques for estimating prey density in the churia habitat by walking 136 km over 81 different line transects. The team photographed 31 individual tigers and 28 individual leopards along with 25 mammalian species from a sampling area of 536 km² comprising Churia and surrounding areas. Density estimates of tigers and leopards were 2.2 (SE 0.42) tigers and 4.0 (SE 1.00) leopards per 100 km². Prey density was estimated at 62.7 prey animals per 100 km² with contributions from forest ungulates to be 47% (sambar Rusa unicolor, chital Axis axis, barking deer Muntiacus muntjak, and wild pigs Sus scrofa). Churia habitat within Chitwan National Park is capable of supporting 5.86 tigers per 100 km² based on applying models developed to predict tiger density from prey density. My density estimates from camera-traps are lower than that predicted based on prey availability, which indicates that the tiger population may be below the carrying capacity. Nonetheless, the churia habitat supports 9 to 36 tigers, increasing estimates of current population size in Chitwan National Park. Based on my finding, the Churia habitat should no longer remain ignored because it has great potential to harbor tigers. Conservation efforts should focus on reducing human disturbance to boost prey populations to potentially support higher predator numbers in Churia.
I used sign surveys within a rigorous occupancy framework to estimate probability of occupancy for 5 focal prey species of the tiger (gaur Bos gaurus, sambar, chital, wild pig, and barking deer); as well as probability of tiger habitat use within 537 km² of churia habitat in Chitwan National Park. Multi-season, auto-correlation models allowed me to make seasonal (winter versus summer) inferences regarding changes in occupancy or habitat use based on covariates influencing occupancy and detection. Sambar had the greatest spatial distribution across both seasons, occupying 431-437 km² of the churia habitat, while chital had the lowest distribution, occupying only 100-158 km². The gaur population showed the most seasonal variation from 318- 413 km² of area occupied, with changes in occupancy suggesting their migration out of the lowland areas in the summer and into the churia in the winter. Wild pigs showed the opposite, moving into the churia in the summer (444 km² area occupied) and having lower occupancy in the winter (383 km²). Barking deer were widespread in both seasons (329 - 349 km²). Tiger probability of habitat use Ψ SE(Ψ) was only slightly higher in winter 0.63 (SE 0.11) than in summer 0.54 (SE 0.21), but confidence intervals overlapped and area used was very similar across seasons, from 337 - 291 km². Fine-scale variation in tiger habitat use showed that tigers intensively use certain areas more often than others across the seasons. The proportion of available habitat positively influenced occupancy for the majority of prey species and tigers. Human disturbance had a strong negative influence on the distribution of the majority of prey species but was positively related to tiger habitat use. Tigers appear to live in areas with high disturbance, thus increasing the risk of human-tiger conflict in the churia habitat. Thus, efforts to reduce human disturbance would be beneficial to reducing human wildlife conflict, enriching prey populations, and would potentially support more tigers in churia habitat of Nepal. Overall, I found high prey occupancy and tiger habitat use, suggesting that the churia is highly valuable habitat for tigers and should no longer be neglected or forgotten in tiger conservation planning.
Thirdly, I assessed genetic variation, genetic structure, and gene flow of the tigers in the Terai Arc Landscape, Nepal. I opportunistically collected 770 scat samples from 4 protected areas and 5 hypothesized corridors across the Terai Arc Landscape. Historical landuse change in the Terai Arc was extracted from Anthrome data sets to relate landuse change to potential barriers and subsequent hypothesized bottleneck events in the landscape. I used standard genetic metrics (allelic diversity and heterozygosity) to estimate genetic variation in the tiger population. Using program Structure (non-spatial) and TESS (spatial), I defined the putative genetic clusters present in the landscape. Migrant analysis was carried out in Geneclass and Bayesass for estimating contemporary gene flow. I tested for a recent population bottleneck with the heterozygosity test using program Bottleneck. Of the 700 samples, 396 were positive for tiger (57% success). Using an 8 multilocus microsatellite assay, I identified 78 individual tigers. I found large scale landuse changes across the Terai Arc Landscape due to conversion of forest into agriculture in last two centuries and I identified areas of suspected barriers. I found low levels of genetic variation (expected heterozygosity = 0.61) and moderate genetic differentiation (F<sub>ST</sub> = 0.14) across the landscape, indicative of sub-population structure and potential isolation of sub-populations. I detected three genetic clusters across the landscape consistent with three demographic tiger sub-populations occurring in Chitwan-Parsa, Bardia, and Suklaphanta protected areas. I detected 10 migrants across all study sites confirming there is still some dispersal mediated gene flow across the landscape. I found evidence of a bottleneck signature, especially around the lowland forests in the Terai, likely caused by large scale landuse change in last two centuries, which could explain the low levels of genetic variation detected at the sub-population level. These findings are highly relevant to tiger conservation indicating that efforts to protect source sites and to improve connectivity are needed to augment gene flow and genetic diversity across the landscape.
Finally, I compared the abundance and density of tigers obtained using two non-invasive sampling techniques: camera-trapping and fecal DNA sampling. For cameras: I pooled the 2009 camera-trap data from the core tiger population across the lowland areas of Chitwan National Park. I sampled 359 km² of the core area with 187 camera-trap locations spending 2,821 trap-nights of effort. I obtained 264 identifiable photographs and identified a total of 41 individual tigers. For genetics, I sampled 325 km² of the core area along three spatial routes, walking a total of 1,173 km, collecting a total of 420 tiger fecal samples in 2011. I identified 36 tigers using the assay of 8 multilocus genotypes and captured them 42 times. I analyzed both data types separately for estimating density and jointly in an integrated model using both traditional, and spatial, capture-recapture frameworks. Using Program MARK and the model averaged results, my abundance estimates were 46 (SE 1.86) and 44 (SE 9.83) individuals from camera and genetic data, respectively. Density estimates (tigers per 100 km²) via traditional buffer strip methods using half of the Mean Maximum Distance Moved (½ MMDM) as the buffer surrounding survey grids, were 4.01 (SE 0.64) for camera data and 3.49 (SE 1.04) for genetic data. Spatially explicit capture recapture models resulted in lower density estimates both in the likelihood based program DENSITY at 2.55 (SE 0.59) for camera-trap data and 2.57 (SE 0.88) for genetic data, while the Bayesian based program SPACECAP estimates were 2.44 (SE 0.30) for camera-trap data and 2.23 (SE 0.46) for genetic data. Using a spatially explicit, integrated model that combines data from both cameras and genetics, density estimates were 1.47 (SD 0.20) tigers per 100 km² for camera-trap data and 1.89 (SD 0.36) tigers per 100 km² for genetic data. I found that the addition of camera-trap data improved precision in genetic capture-recapture estimates, but not visa-versa, likely due to low numbers of recaptures in the genetic data. While a non-invasive genetic approach can be used as a stand-alone capture-recapture method, it may be necessary to increase sample size to obtain more recaptures. Camera-trap data may provide a more precise estimates, but genetic data returns more information on other aspect of genetic health and connectivity. Combining data sets in an integrated modeling framework, aiding in pinpointing strengths and weaknesses in data sets, thus ultimately improving modeling inference. / Ph. D.
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Estimating abundance, density, and occupancy of lion, leopard and serval in the Niokolo Koba National Park in SenegalKane, Mamadou Daha 17 July 2014 (has links)
Carnivore are undoubtedly among the most threatened of the mammal species in Africa because of the low density at which they occur and their large home range requirements that do not match with human propensity to develop and alter wildlife habitat. However, the degree of threat is unevenly distributed within the continent, with western and central African carnivores being the most threatened and the least studied. I estimated population size, density, and proportion of area occupied in relation to environmental factors of one medium-size (serval – Leptailurus serval) and two large carnivores (lion – Panthera leo and leopard – P. pardus) in the Niokolo Koba National Park, Senegal, West Africa, using remote camera surveys and both traditional (CR), spatially explicit capture-recapture (SECR) techniques for servals and leopards, and non-spatial (MR) and spatial mark resight (SMR) methods for lions. Lions selected optimal sites with both high tree density and prey activity; leopards occupied areas with high tree density but with less prey activity; and servals selected habitats with more dense canopy cover where leopards were absent. The presence of lions was favorable to serval presence, as we presume leopards avoid lions, although we did not have strong evidence to support it. Moreover, the half mean maximum distance moved (½ MMDM) method under CR methods appeared to overestimate leopard and serval density while full MMDM estimates were close to SECR methods density estimates. For lions, both ½ MMDM and full MMDM methods in MR framework overestimated density whereas the SMR method resulted in more reasonable estimates, especially in light of previous assessments of lion densities in West Africa.. These results are of high importance for conservation and management purposes of the imperiled Niokolo Koba carnivore community. / Master of Science
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