Office for Environmental Programs - Theses
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ItemPopulation Viability Analysis for a small population of the Endangered huemul deer (Hippocamelus bisulcus) in the Chilean Patagonia( 2015-11-02)The huemul deer (Hippocamelus bisulcus) is the most threatened cervid of South America, having experienced a 50% reduction in habitat range and a 99% decrease in population abundance since European settlement. A range of human impacts has led to serious fragmentation of the species habitat and the total population is estimated to be less than 2,500 individuals. Despite increased efforts to protect huemul, species recovery has not been achieved and populations continue to decline. The need for population-specific studies has been highlighted as an important aspect of huemul conservation. Accordingly, this project aimed to analyse the viability of a subpopulation of huemul under current conditions as well as potential management scenarios. The study site was Lake Cochrane National Reserve, Chilean Patagonia, where population vital rates were estimated for the species. This information was used to build a model in RAMAS GIS and develop a population viability analysis. All simulations included 1,000 replications to account for stochasticity and were run across a 100 year period. The model predictions suggested that the population would increase in the next 40 years and then stabilize, however, risks of falling below minimum abundances to maintain genetic richness were high. Fire was the most serious threat for huemul survival in the simulations; increased levels of predation were also shown to have potentially serious implications for the study population. Habitat availability was the most important factor impacting population abundances of huemul, and adult individuals were the most influencing life stage on population viability. Species protection action plans may not sufficiently emphasise important strategies such as fire management and the establishment of captive breeding programs to increase genetic variability. Collaboration between managers of protected areas around Lake Cochrane appears as crucial to ensure joint measures are able to ensure the long-term presence of huemul in the area. Long- term studies are required to better approximate important estimates underpinning the reliability of PVAs for huemul, especially in regards to density dependence factors. This will allow the construction of more accurate and precise PVAs for the species, and improve their utility for managers.