Open Access. Powered by Scholars. Published by Universities.®

Life Sciences Commons

Open Access. Powered by Scholars. Published by Universities.®

Articles 1 - 8 of 8

Full-Text Articles in Life Sciences

Roe Deer Summer Habitat Selection At Multiple Spatio-Temporal Scales In An Alpine Environment, Sara Mancinelli, Wibke Peters, Luigi Boitani, Mark Hebblewhite, Francesca Cagnacci Nov 2015

Roe Deer Summer Habitat Selection At Multiple Spatio-Temporal Scales In An Alpine Environment, Sara Mancinelli, Wibke Peters, Luigi Boitani, Mark Hebblewhite, Francesca Cagnacci

Wildlife Biology Faculty Publications

Habitat selection is a hierarchical process that may involve different patterns depending on the spatial and temporal scales of investigation. We studied habitat selection by European roe deer (Capreolus capreolus) in a very diverse environment in the Italian eastern Alps, during summer. We sampled both coarse-grained habitat variables (topographic variables, habitat types and cover) and fine-grained habitat variables (forage components of habitat) in used and available locations along the movement trajectories of 14 adult roe deer equipped with GPS telemetry collars. We used conventional logistic regression to assess roe deer habitat selection at the seasonal home range scale, …


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 …


Reproductive Performance Of Kittlitz's Murrelet In A Glaciated Landscape, Icy Bay, Alaska, Usa, Michelle L. Kissling, Scott M. Gende, Stephen B. Lewis, Paul Lukacs Apr 2015

Reproductive Performance Of Kittlitz's Murrelet In A Glaciated Landscape, Icy Bay, Alaska, Usa, Michelle L. Kissling, Scott M. Gende, Stephen B. Lewis, Paul Lukacs

Wildlife Biology Faculty Publications

Kittlitz's Murrelet (Brachyramphus brevirostris) is a dispersed-nesting seabird endemic to Alaska and eastern Russia that may have experienced considerable population declines in some parts of its range in the past few decades. Poor reproduction has been suggested as the demographic bottleneck, yet there are no direct estimates of reproduction in a glaciated area where this species reaches its highest densities at sea during the breeding season. The lack of demographic information in glacial habitats has limited our ability to interpret population trends and to clarify whether the presence of glaciers affects reproductive performance. Between 2007 and 2012, we …


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 …


Integrated Survival Analysis Using An Event-Time Approach In A Bayesian Framework, Daniel P. Walsh, Victoria J. Dreitz, Dennis M. Heisey Jan 2015

Integrated Survival Analysis Using An Event-Time Approach In A Bayesian Framework, Daniel P. Walsh, Victoria J. Dreitz, Dennis M. Heisey

Wildlife Biology Faculty Publications

Event-time or continuous-time statistical approaches have been applied throughout the bio-statistical literature and have led to numerous scientific advances. However, these techniques have traditionally relied on knowing failure times. this has limited application of these analyses, particularly, within the ecological field where fates of marked animals may be unknown. To address these limitations, we developed in integrated approach within a Bayesian framework to estimate hazard rates in the face of unknown fates. We combine failure/survival times from individuals whose fates are known and times of which are interval-censored with information from those whose fates are unknown, and model the process …


Sex Ratios Of Mountain Plovers From Egg Production To Fledging, Margaret Mercedes Riordan, Paul Lukacs, Kathryn P. Huyvaert, Victoria J. Dreitz Jan 2015

Sex Ratios Of Mountain Plovers From Egg Production To Fledging, Margaret Mercedes Riordan, Paul Lukacs, Kathryn P. Huyvaert, Victoria J. Dreitz

Wildlife Biology Faculty Publications

Skewed sex ratios can have negative implications for population growth if they do not match a species’ life history. A skewed tertiary sex ratio has been detected in a population of Mountain Plover (Charadrius montanus), a grassland shorebird experiencing population declines. To study the cause of the observed male skew, we examined three early life stages between egg and fledgling in eastern Colorado from 2010 to 2012. This allows us to distinguish between egg production and chick survival as an explanation for the observed skew. We examined the primary sex ratio in eggs produced and the secondary sex …