Estimation of Density and Abundance of Biological Populations on National Parks and Wildlife Refuges Through Distance Sampling Active
The Challenge: Assessing the status and trends of populations of biological organisms is an important management goal and a recurrent theme in USGS research. Often, the most basic question of “how many are there?” remains elusive, thus making management decisions more difficult. This study continues a long-term commitment of technical support for the use of distance sampling for wildlife population abundance estimation in our National Parks and Wildlife Refuges.
The Science: Along with encounter rate and cluster size, distance sampling allows for the estimation of the probability of detection, a major confounding factor in most ad-hoc wildlife abundance surveys. Whether for overabundant deer in parks or endangered butterflies in refuges, distance sampling and detection rates have improved our ability to accurately assess population size, the primary driver of management actions. We have conducted workshops for over 200 wildlife professionals on distance sampling applications.
The Future: Distance sampling data are being used to estimate abundance of the endangered Karner blue butterfly on US Fish & Wildlife Service Refuges to better guide recovery planning. In addition, hierarchical distance sampling is being used to map deer abundance by county in West Virginia, in urban areas of upstate New York and elsewhere.Future plans include expanded use of model-based abundance estimators along with conventional, design-based estimators for improved mapping of wildlife abundance.
Below are publications associated with this project.
Modeling the effects of land cover and use on landscape capability for urban ungulate populations
Pairing call-response surveys and distance sampling for a mammalian carnivore
White-tailed deer ecology and management on Fire Island
Below are partners associated with this project.
- Overview
The Challenge: Assessing the status and trends of populations of biological organisms is an important management goal and a recurrent theme in USGS research. Often, the most basic question of “how many are there?” remains elusive, thus making management decisions more difficult. This study continues a long-term commitment of technical support for the use of distance sampling for wildlife population abundance estimation in our National Parks and Wildlife Refuges.
The Science: Along with encounter rate and cluster size, distance sampling allows for the estimation of the probability of detection, a major confounding factor in most ad-hoc wildlife abundance surveys. Whether for overabundant deer in parks or endangered butterflies in refuges, distance sampling and detection rates have improved our ability to accurately assess population size, the primary driver of management actions. We have conducted workshops for over 200 wildlife professionals on distance sampling applications.
The Future: Distance sampling data are being used to estimate abundance of the endangered Karner blue butterfly on US Fish & Wildlife Service Refuges to better guide recovery planning. In addition, hierarchical distance sampling is being used to map deer abundance by county in West Virginia, in urban areas of upstate New York and elsewhere.Future plans include expanded use of model-based abundance estimators along with conventional, design-based estimators for improved mapping of wildlife abundance.
- Publications
Below are publications associated with this project.
Modeling the effects of land cover and use on landscape capability for urban ungulate populations
Expanding ungulate populations are causing concerns for wildlife professionals and residents in many urban areas worldwide. Nowhere is the phenomenon more apparent than in the eastern US, where urban white-tailed deer (Odocoileus virginianus) populations are increasing. Most habitat suitability models for deer have been developed in rural areas and across large (>1000 km2) spatial extents. OnlyAuthorsH. Brian Underwood, Chellby R. KilhefferPairing call-response surveys and distance sampling for a mammalian carnivore
Density estimates accounting for differential animal detectability are difficult to acquire for wide-ranging and elusive species such as mammalian carnivores. Pairing distance sampling with call-response surveys may provide an efficient means of tracking changes in populations of coyotes (Canis latrans), a species of particular interest in the eastern United States. Blind field trials in rural NewAuthorsSara J. K. Hansen, Jacqueline L. Frair, Harold B. Underwood, James P. GibbsWhite-tailed deer ecology and management on Fire Island
Deer populations have grown dramatically on Fire Island National Seashore (FIlS) since 1983. Trend data reveal a dichotomy in deer dynamics. In the eastern half of the island, deer density appears to have stabilized between 25-35 deer/km2. In the western half of the island, deer densities are 3-4 times as high in residential communities. Concomitant with that increase has been a general decline iAuthorsH.B. Underwood - Partners
Below are partners associated with this project.