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Full-Text Articles in Life Sciences

Examining Temporal Sample Scale And Model Choice With Spatial Capture-Recapture Models In The Common Leopard Panthera Pardus, Joshua F. Goldberg, Tshering Tempa, Nawang Norbu, Mark Hebblewhite, L. Scott Mills, Tshewang R. Wangchuk, Paul Lukacs Nov 2015

Examining Temporal Sample Scale And Model Choice With Spatial Capture-Recapture Models In The Common Leopard Panthera Pardus, Joshua F. Goldberg, Tshering Tempa, Nawang Norbu, Mark Hebblewhite, L. Scott Mills, Tshewang R. Wangchuk, Paul Lukacs

Wildlife Biology Faculty Publications

Many large carnivores occupy a wide geographic distribution, and face treats from habitat loss and fragmentation, poaching, prey depletion, and human wildlife-conflicts. Conservation requires robust techniques for estimating population densities and trends, but the elusive nature and low densities of many large carnivores make them difficult to detect. Spatial capture-recapture (SCR) models provide a means for handling imperfect detectability, while linking population estimates to individual movement patterns to provide more accurate estimates than standard approaches. Within this framework, we investigate the effect of different sample interval lengths on density estimates, using simulations and a common leopard (Panthera pardus) …


Integrating Resource Selection Into Spatial Capture-Recapture Models For Large Carnivores, K. M. Proffitt, Joshua F. Goldberg, Mark Hebblewhite, R. Russell, B. S. Jimenez, H. S. Robinson, K. Pilgrim, M. K. Schwartz Nov 2015

Integrating Resource Selection Into Spatial Capture-Recapture Models For Large Carnivores, K. M. Proffitt, Joshua F. Goldberg, Mark Hebblewhite, R. Russell, B. S. Jimenez, H. S. Robinson, K. Pilgrim, M. K. Schwartz

Wildlife Biology Faculty Publications

Wildlife managers need reliable methods to estimate large carnivore densities and population trends; yet large carnivores are elusive, difficult to detect, and occur at low densities making traditional approaches intractable. Recent advances in spatial capture-recapture (SCR) models have provided new approaches for monitoring trends in wildlife abundance and these methods are particularly applicable to large carnivores. We applied SCR models in a Bayesian framework to estimate mountain lion densities in the Bitterroot Mountains of west central Montana. We incorporate an existing resource selection function (RSF) as a density co-variate to account for heterogeneity in habitat use across the study area …


Testing Factors Influencing Identification Rates Of Similar Species During Abundance Surveys, Anne Louise Schaefer, Paul Lukacs, Michelle L. Kissling Aug 2015

Testing Factors Influencing Identification Rates Of Similar Species During Abundance Surveys, Anne Louise Schaefer, Paul Lukacs, Michelle L. Kissling

Wildlife Biology Faculty Publications

Most abundance estimation methods assume that all sampled individuals are identified correctly. In practice, this assumption may be difficult to meet and can bias abundance estimates, especially when morphologically similar species overlap in range. Over the past 2 decades, Kittlitz's Murrelet (Brachyramphus brevirostris) populations appear to have declined across parts of their Alaskan range, where they co-occur with the Marbled Murrelet (B. marmoratus). Recently, the reliability of Kittlitz's Murrelet declines have been questioned due to variability and uncertainty in species identification between the 2 species. We conduced a field experiment to quantify misidentification and partial identification …


Postnatal Growth Rates Covary Weakly With Embryonic Development Rates And Do Not Explain Adult Mortality Probability Among Songbirds On Four Continents, Thomas E. Martin, Oteyza C. Oteyza, Adam E. Mitchell, Ahva L. Potticary, Penn Lloyd Jan 2015

Postnatal Growth Rates Covary Weakly With Embryonic Development Rates And Do Not Explain Adult Mortality Probability Among Songbirds On Four Continents, Thomas E. Martin, Oteyza C. Oteyza, Adam E. Mitchell, Ahva L. Potticary, Penn Lloyd

Wildlife Biology Faculty Publications

Growth and development rates may result from genetic programming of intrinsic processes that yield correlated rates between life stages. These intrinsic rates are thought to affect adult mortality probability and longevity. However, if proximate extrinsic factors (e.g., temperature, food) influence development rates differently between stages and yield low covariance between stages, then development rates may not explain adult morality probability. We examined these issues based on study of 90 songbird species on four continents to capture the diverse life-history strategies observed across geographic space. The length of the embryonic period explained little variation (ca. 13%) in nestling periods and growth …