With exploding human populations and landscapes that are changing, an increasing number of wildlife species are brought to the brink of extinction. In Canada, the eastern hog-nosed snake, 'Heterodon platirhinos', is found in a limited portion of southern Ontario. Designated as threatened by the Committee on the Status of Endangered Wildlife in Canada (COSEWIC), this reptile has been losing its habitat at an alarming rate. Due to the increase in development of southern Ontario, it is crucial to document what limits the snake’s habitat to direct conservation efforts better, for the long-term survival of this species. The goals of this study are: 1) to examine what environmental parameters are linked to the presence of the species at a landscape scale; 2) to predict where the snakes can be found in Ontario through GIS-based habitat suitability models (HSMs); and 3) to assess the role of biotic interactions in HSMs. Three models with high predictive power were employed: Maxent, Boosted Regression Trees (BRTs), and the Genetic Algorithm for Rule-set Production (GARP). Habitat suitability maps were constructed for the eastern hog-nosed snake for its entire Canadian distribution and models were validated with both threshold dependent and independent metrics. Maxent and BRT performed better than GARP and all models predict fewer areas of high suitability when landscape variables are used with current occurrences. Forest density and maximum temperature during the active season were the two variables that contributed the most to models predicting the current distribution of the species. Biotic variables increased the performance of models not by representing a limiting resource, but by representing the inequality of sampling and areas where forest remains. Although habitat suitability models rely on many assumptions, they remain useful in the fields of conservation and landscape management. In addition to help identify critical habitat, HSMs may be used as a tool to better manage land to allow for the survival of species at risk.

Predictions of species’ ranges from distribution modeling are often used to inform marine management and conservation efforts, but few studies justify the model selected or quantify the uncertainty of the model predictions in a spatial manner. This thesis employs a multi-model, multi-area SDM analysis to develop a higher certainty in the predictions where similarities exist across models and areas. Partial dependence plots and variable importance rankings were shown to be useful in producing further certainty in the results. The modeling indicated that glass sponges (Hexactinellida) are most likely to exist within the North Pacific Ocean where alkalinity is greater than 2.2 μmol l-1 and dissolved oxygen is lower than 2 ml l-1. Silicate was also found to be an important environmental predictor. All areas, except Hecate Strait, indicated that high glass sponge probability of presence coincided with silicate values of 150 μmol l-1 and over, although lower values in Hecate Strait confirmed that sponges can exist in areas with silicate values of as low as 40 μmol l-1. Three methods of showing spatial uncertainty of model predictions were presented: the standard error (SE) of a binomial GLM, the standard deviation of predictions made from 200 bootstrapped GLM models, and the standard deviation of eight commonly used SDM algorithms. Certain areas with few input data points or extreme ranges of predictor variables were highlighted by these methods as having high uncertainty. Such areas should be treated cautiously regardless of the overall accuracy of the model as indicated by accuracy metrics (AUC, TSS), and such areas could be targeted for future data collection. The uncertainty metrics produced by the multi-model SE varied from the GLM SE and the bootstrapped GLM. The uncertainty was lowest where models predicted low probability of presence and highest where the models predicted high probability of presence and these predictions differed slightly, indicating high confidence in where the models predicted the sponges would not exist.

Bacillus anthracis is the causal agent of anthrax which primarily affects ungulates, occasionally carnivores and less frequently humans. The endospores of this soil-borne bacterium are highly resistant to extreme conditions, and under ideal conditions, anthrax spores can survive for many years in the soil. The bacterium is generally found in soil at sites where infected animals have died. When these spores are exposed, they have the potential to be ingested by a mammalian species which could lead to an anthrax outbreak. Anthrax is almost never transmitted directly from host to host, but is rather ingested by herbivores while drinking, grazing or browsing in a contaminated environment, with the exception of scavengers and carnivores consuming infected prey. Anthrax is known to be endemic in the northern part of Kruger National Park (KNP) in South Africa (SA), with occasional epidemics spreading southward into the non-endemic areas. The aim of this study is to identify and map areas that are ecologically suitable for the harbouring of B. anthracis spores within the KNP. Anthrax surveillance data and selected environmental variables were used as inputs to the maximum entropy (Maxent) species distribution modelling method. Five-hundred and ninety-seven anthrax occurrence records, dating from the year 1988 to 2011, were extracted from the Skukuza State Veterinary Office’s database. A total of 40 environmental variables were used and their relative contribution to predicting suitability for anthrax occurrence was evaluated using Maxent software (version 3.3.3k). Variables showing the highest gain were then used for subsequent, refined model iterations until the final model parameters were established. The environmental variables that contributed the most to the occurrence of anthrax were soil type, normalized difference vegetation index (NDVI), land type and precipitation. A map was created using a geographic information system (GIS) that illustrates the sites where anthrax spores are most likely to occur throughout the Park. This included the known endemic Pafuri region as well as the low lying soils along the Shingwedzi-Phugwane-Bubube rivers and the Letaba-Olifants river drainage area. The outputs of this study could guide future targeted surveillance efforts to focus on areas predicted to be highly suitable for anthrax, especially since the KNP uses passive surveillance to detect anthrax outbreaks. Knowing where to look can improve sampling efficiency and lead to increased understanding of the ecology of anthrax within the KNP. / Dissertation (MMedVet)--University of Pretoria, 2013. / Production Animal Studies / unrestricted

Aim: Identifying how climate change, habitat loss, and corridors interact to influence species survival or extinction is critical to understanding macro-scale biodiversity dynamics under changing environments. In North America, the ice-free corridor was the only major pathway for northward migration by megafaunal species during the last deglaciation. However, the timing and interplay among the late Quaternary megafaunal extinctions, climate change, habitat structure, and the opening and reforestation of the ice-free corridor have been unclear. Location: North America. Time period: 15–10 ka. Major taxa studied: Woolly mammoth (Mammuthus primigenius). Methods: For central North America and the ice-free corridor between 15 and 10 ka, we used a series of models and continental-scale datasets to reconstruct habitat characteristics and assess habitat suitability. The models and datasets include biophysical and statistical niche models Niche Mapper and Maxent, downscaled climate simulations from CCSM3 SynTraCE, LPJ-GUESS simulations of net primary productivity (NPP) and woody cover, and woody cover based upon fossil pollen from Neotoma. Results: The ice-free corridor may have been of limited suitability for traversal by mammoths and other grazers due to persistently low productivity by herbaceous plants and quick reforestation after opening 14 ka. Simultaneously, rapid reforestation and decreased forage productivity may have led to declining habitat suitability in central North America. This was possibly amplified by a positive feedback loop driven by reduced herbivory pressures, as mammoth population decline led to the further loss of open habitat. Main conclusions: Declining habitat availability south of the Laurentide Ice Sheet and limited habitat availability in the ice-free corridor were contributing factors in North American extinctions of woolly mammoths and other large grazers that likely operated synergistically with anthropogenic pressures. The role of habitat loss and attenuated corridor suitability for the woolly mammoth extinction reinforce the critical importance of protected habitat connectivity during changing climates, particularly for large vertebrates.

Forests in the southern United States with diverse forest ownership entities are facing threats associated with climate change and natural disturbances. This study represented the relationship between climate and species dominance, predicted future species distribution probability under a changing climate, and projected forest dynamics under ownership-based management regimes. Correlative statistics and mechanistic modeling approaches are implemented. Temporal scale includes the recent past 40 years and the future 60 years; spatial scale downscaled from southern United States to the coastal region of the northern Gulf of Mexico. In the southern United States, dominance of four major pine species experienced shifts from 1970 to 2000; quantile regression models built on the relationships among pine dominance and climatic variables can be used to predict future southern pine dominance. Furthermore, multiple climate envelope models (CEMs) were constructed for nineteen native and one invasive tree species (Chinese tallow, Triadica sebifera) to predict species establishment probabilities (SEPs) on the various land types from 2010 to 2070. CEMs achieved both predictive consistency and ecological conformity in estimating SEPs. Chinese tallow was predicted to have the highest invasionability in longleaf/slash pine and oak/gum/cypress forests during the next 60 years. Forest dynamics, in the coastal region, was projected by linking CEMs and forest landscape model (LANDIS) to evaluate ownership-based management regimes under climate change and natural disturbances. The dominance of forest species will diminish due to climate change and natural disturbances at both spatial scales—in the coastal region and non-industrial private forest (NIPF). No management on NIPF land was predicted to substantially increase the ratio of occupancy area between pines and oaks, but moderate and intensive management regimes were not significantly different. Pines are expected to be more resistant than oaks by maintaining stable age structures, which matched the forest inventory records. Overall, this study projected a future of southern forests on climate-species relationship, invasion risks, and forest community dynamics under multiple scenarios in the United States. Such knowledge could assist forest managers and landowners in foreseeing the future and making effective management prescriptions to mitigate potential threats.

No description available.

No description available.

Approximately 25% of bats globally are threatened, but limited data on African bats, which account for 20% of bat species, hinders our understanding of their conservation status across this ecologically diverse continent. This study combined: modelling techniques, to predict current species distributions for 58 southern African bat species and project past, current and future distributions of 22 endemic and near-endemic species; bat acoustic surveys, to assess landscape features influencing bat activity in arid and semi-arid regions; and conservation planning software to design a large-scale monitoring network for bats across this subcontinent. Species distribution models were employed using a robust and well established presence-only modelling technique (Maximum Entropy – Maxent) to model the current distributions of 58 species in southern Africa. Although the important eco-geographical variables were species- or in some cases family-specific, overall water availability (both temporary and permanent), seasonal precipitation, vegetation and karst (caves/limestone) areas were the most important factors associated with distribution patterns. These species distributions were then used to identify range-restricted and narrow niche breadth species, alongside other life-history strategies considered to put species at risk, such as Old World pteropodids and cave-dwelling bats to identify species most at risk. Nine of the 58 species in this study were identified as ‘at risk’. Considering range-restriction and endemism separately, the results showed that range-restricted species were a higher proportion (50%) of ‘at risk’ species than endemics (41%) but six of the nine identified species were endemic and range restricted (67%). If only areas of high species richness are prioritised, important areas with low species richness but rare, ‘at risk’ or endemic species would be excluded. Species distributions are not fixed but may shift due to changes in environmental conditions. Accurately predicting changes in species’ distributions due to anthropogenic climate change remains a fundamental challenge for conservation biologists, and this is amplified when dealing with taxa such as bats that are inherently difficult to study and in areas, such as Africa, with sparse ecological data. To better understand endemic bat species risk to climate change in southern Africa and to highlight historical and future likely refugia, Maxent was employed to forecast range-shifts for 22 southern African endemic or near-endemic species. Species distributions were projected during the Last Glacial Maximum (LGM ~22,000 BP), present (1950-2000) and future (2070: averaged 2061-2080, using IPCC5 scenarios) climatic conditions. Climate change was predicted to change species composition extensively within a relatively short timescale (within 60 years). By 2070, 86% of species modelled are predicted to have range contractions and six species were highlighted to be most at risk, with range contractions of more than 20%. The majority of southern Africa is composed or arid or semi-arid regions. Generally arid and semi-arid areas are overlooked and understudied due to low species richness, yet these areas are known to have a high proportion of endemic species. As part of this study, driven transects were carried out across arid and semi-arid areas to assess bat activity in these areas. Bat activity was recorded at 94% of the acoustic surveys, demonstrating that driven transects are an effective method of surveying bats in southern Africa. Bat activity increased at lower altitudes and higher latitudes, which characteristically have more rainfall, permanent water and vegetation. Although water has been shown in other studies to be important for bats, temporary water was not shown to influence bat activity and permanent water was positively correlated with bat activity for hipposiderids and rhinolophids and FM bats, which may reflect the fact that water features important for bats at smaller scale. The same two vegetation types that were consistently negatively correlated with bat activity were drier vegetation types (Karoo-Namib shrubland) and high salinity halophytic vegetation. Finally, a systematic conservation planning software tool (Marxan) was used to design multi-species monitoring networks that incorporated all 58 target species across the 11 ecoregions found in southern Africa. To ensure rare, endemic and range-restricted species were monitored at the same level as widespread species, species distributions (mapped using Maxent) were extracted by ecoregion. Monitoring targets (i.e. a percentage of species distribution across ecoregions) were standardised to ensure the same percentage of predicted distribution was included across all species (rare and widespread). To account for different resources and capacity, three optimal monitoring networks (minimum monitoring stations to achieve the monitoring targets) were proposed to survey 1, 5 or 10% of all species distributions within each ecoregion. The optimal solution for monitoring 1% of species distributions within ecoregions was found by monitoring 1,699 stations (survey sites), or for 5% 8,486 stations and finally for 10% 17,867 stations would be needed. In conclusion, the findings presented in this thesis have important conservation implications and have the potential to inform the practical steps required towards the introduction of a bat monitoring programme in southern Africa. While this study has highlighted challenges to African bat conservation, it has also demonstrated that an integrated and multi-disciplinary approach, using emerging techniques and conservation tools (e.g. conservation planning and automated call analysis software) can be used to fill knowledge gaps and inform conservation priorities in the absence of systematically collected data.

No description available.

A UGRHI-17 da bacia hidrográfica do Médio Paranapanema (São Paulo, Brasil) é reconhecidamente uma área de alta biodiversidade de espécies de Biomphalaria e possui grande vulnerabilidade a acometimentos ambientais e em saúde, no caso da esquistossomose. O objetivo do estudo foi identificar áreas de maior risco para a ocorrência da esquistossomose utilizando dados de transmissão da esquistossomose e de diversidade genética molecular, associando-os às ferramentas geoespaciais, e com isso estabelecer áreas potenciais para a vigilância malacológica e da infecção em coleções de água doce na região do Médio Paranapanema. Os moluscos do gênero de Biomphalaria foram identificados por meio de características morfológicas e moleculares; enquanto os outros grupos taxonômicos (Drepanotrema, Lymnaea, Melanoides, Physa e Pomacea) foram identificados por características conchiológicas ou morfológicas. A análise filogenética das espécies de Biomphalaria foi realizada por meio da análise de sequências dos genes mitocondriais COI, 16S rRNA e COI+16S. As sequências do gene COI referentes ao trecho DNA Barcode foram testadas quanto à similaridade com sequências depositadas no GenBank e analisadas em ABDG, bPTP e GMYC para delimitação de espécies putativas. Na análise espacial foram utilizadas as estatísticas de varredura, Gi e de fluxo. Foram utilizadas as fichas notificação e investigação dos casos de esquistossomose na região de estudo entre 1978-2016. Foi calculado as taxas de incidência e foi avaliado a dependência espacial entre os casos autóctones e importados com a função K12 de Ripley. Foram gerados mapas da distribuição espacial dos caramujos do gênero Biomphalaria; dos casos de esquistossomose ocorridos na região de estudo; e da diversidade genética em haplótipos do gene 16S. Além disso, foi realizada modelagem de nicho para estimar cenários futuros de alteração na distribuição dos caramujos, utilizado o algoritmo de máxima entropia. Foram utilizados os dados de variáveis climáticas e topográficas obtidas no WorldClim, HydroSHEDS e TOPODATA e o modelo climático regional HadGEM2-ES do período de 2041-2060, considerando dois cenários de mudança climática possíveis: RCP2.6 e RCP8.5. Foram identificados aglomerados de alto risco para ocorrência de esquistossomose em Ourinhos, Assis e Ipaussu. Entretanto, ao longo dos anos, os casos passaram a ocorrer em baixa densidade em Ourinhos e deixaram de ocorrer nos demais municípios da região. Dos caramujos coletados, 75.5% eram Biomphalaria, 11.2% Drepanotrema e 13.3% de outros gêneros não planorbídeos. O modelo de máxima entropia mostrou que há probabilidade futura da espécie B. glabrata permanecer nos municípios de Ourinhos e Assis, e uma probabilidade em torno de 50% de a espécie expandir sua colonização a corpos de água doce de outros municípios da região de estudo, isto em função das mudanças climáticas. Os resultados para B. straminea mostram que esta espécie tem maior probabilidade de expansão de colonização no futuro, especialmente nos municípios próximos a Ourinhos. A análise filogenética mostrou árvores com cinco ramos monofiléticos com alto suporte estatístico. A diversidade de haplótipos está distribuída de forma diferente em cada um dos cinco taxa analisados. Conclui-se, em um dos resultados deste trabalho, que atualmente a esquistossomose, como problema de saúde pública no Médio Paranapanema, está restrita a Ourinhos. Tal fato pode estar relacionado à presença de B. glabrata em pontos específicos e à cobertura deficiente do saneamento básico. Desta forma, o estudo contribuiu para eleger áreas prioritárias para o combate aos caramujos e à doença para evitar ou reduzir transmissões futuras nesta região. / The UGRHI-17 of the Middle Paranapanema watershed (São Paulo, Brazil) is recognized as an area of high biodiversity of Biomphalaria species and great vulnerability to environmental and health impacts for schistosomiasis. The objective of the study is to identify areas of greatest risk for the occurrence of schistosomiasis using transmission data from schistosomiasis and molecular genetic diversity, associating them with the geospatial tools, and thereby establishing potential areas for malacological surveillance and infection in collections of freshwaters in the region of Middle Paranapanema. Molluscs of the genus Biomphalaria were identified by morphological and molecular characteristics; while the other taxonomical groups (Drepanotrema, Lymnaea, Melanoides, Physa and Pomacea) were identified through conchiological or morphological characteristics. Molecular genetic analysis of the species was done through sequence analysis of the mitochondrial genes COI, rRNA16S and COI+16S. The COI gene sequences related to DNA Barcode portions were tested for similarity to sequences deposited in GenBank and analyzed ABDG, BPTP and GMYC for delimiting putative species. In the spatial analysis we used the scan statistics, Gi and flow maps. Reporting and investigation records of cases schistosomiasis in the study regions between 1978 and 2016 were used. Incidence were calculated and the existence of spatial dependence between autochthonous and imported cases was evaluated using Ripley\'s K12-function. Maps of the spatial distribution of snails of the genus Biomphalaria; cases of schistosomiasis occurred in the study region; and the genetic diversity in haplotypes of the 16S gene were generated. In addition, the ecological niche modeling to estimate future scenarios of alteration in the distribution of snails, used the maximum entropy algorithm in MaxEnt software. Climate and altitude data obtained from WorldClim, HydroSHEDS and TOPODATA and the regional climate model HadGEM2-ES from the period of 2041-2060 were used, considering two possible scenarios of climate change: Representative Concentration Pathways - RCP2.6 and RCP8.5. High-risk clusters were identified for the occurrence of schistosomiasis in Ourinhos, Assis and Ipaussu. However, over the years, cases occurred in low density in Ourinhos and ceased to occur in other municipalities in the region. Of the snails collected, 75.5% were Biomphalaria, 11.2% Drepanotrema and 13.3% of other non-planorbid genera. The maximum entropy model showed that B. glabrata is a future likely to remain in the municipality of Ourinhos and Assis and a probability around 50% of species to expand their colonization to freshwater bodies of other municipality of the study region, due to the climatic changes. The results for B. straminea showed that this is the species most likely to expand colonization in the future, especially in the municipalities near Ourinhos. The phylogenetic analysis showed trees with five monophyletic branches with high statistical support. The diversity of haplotypes is distributed differently at each of the five taxa analyzed. As one of the results of this work it was concluded that, currently, schistosomiasis as a public health problem in the Middle Paranapanema is restricted to Ourinhos. This may be related to the presence of B. glabrata at specific point and poor coverage of basic sanitation. In this way, the study contributed to the selection of priority areas for combating snails and disease in order to avoid or reduce future transmissions in this region.