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Title: Effects of scale of movement, detection probability, and true population density on common methods of estimating population density

Knowledge of population density is necessary for effective management and conservation of wildlife, yet rarely are estimators compared in their robustness to effects of ecological and observational processes, which can greatly influence accuracy and precision of density estimates. For this study, we simulate biological and observational processes using empirical data to assess effects of animal scale of movement, true population density, and probability of detection on common density estimators. We also apply common data collection and analytical techniques in the field and evaluate their ability to estimate density of a globally widespread species. We find that animal scale of movement had the greatest impact on accuracy of estimators, although all estimators suffered reduced performance when detection probability was low, and we provide recommendations as to when each field and analytical technique is most appropriately employed. The large influence of scale of movement on estimator accuracy emphasizes the importance of effective post-hoc calculation of area sampled or use of methods that implicitly account for spatial variation. In particular, scale of movement impacted estimators substantially, such that area covered and spacing of detectors (e.g. cameras, traps, etc.) must reflect movement characteristics of the focal species to reduce bias in estimates of movementmore » and thus density.« less
Authors:
 [1] ;  [2] ;  [3] ;  [4] ;  [5] ;  [2] ;  [1]
  1. Savannah River Site (SRS), Aiken, SC (United States). Savannah River Ecology Lab. (SREL). Univ. of Georgia and D.B. Warnell School of Forestry and Natural Resources
  2. US Dept. of Agriculture (USDA) National Wildlife Research Center, Fort Collins, CO (United States). Animal and Plant Health Inspection Service (APHIS) and Wildlife Services (WS)
  3. Savannah River Site (SRS), Aiken, SC (United States). Savannah River Ecology Lab. (SREL). Univ. of Georgia and Odum School of Ecology
  4. US Dept. of Agriculture (USDA) National Wildlife Research Center, Mississippi State, MS (United States). Animal and Plant Health Inspection Service (APHIS) and Wildlife Services (WS)
  5. US Dept. of Agriculture Southern Research Station, New Ellenton, SC (United States). Forest Service
Publication Date:
Grant/Contract Number:
FC09-07SR22506; 15-7488-119-CA
Type:
Accepted Manuscript
Journal Name:
Scientific Reports
Additional Journal Information:
Journal Volume: 7; Journal Issue: 1; Journal ID: ISSN 2045-2322
Publisher:
Nature Publishing Group
Research Org:
Univ. of Georgia, Athens, GA (United States). The Univ. of Georgia Research Foundation, Inc. (UGARF)
Sponsoring Org:
USDOE Office of Environmental Management (EM); U.S. Dept. of Agriculture (USDA) Animal and Plant Health Inspection Service's (APHIS) Wildlife Services (WS) National Wildlife Research Center (NWRC); United States Forest Service
Country of Publication:
United States
Language:
English
Subject:
59 BASIC BIOLOGICAL SCIENCES; Ecological modelling; Invasive species
OSTI Identifier:
1427804

Keiter, David A., Davis, Amy J., Rhodes, Olin E., Cunningham, Fred L., Kilgo, John C., Pepin, Kim M., and Beasley, James C.. Effects of scale of movement, detection probability, and true population density on common methods of estimating population density. United States: N. p., Web. doi:10.1038/s41598-017-09746-5.
Keiter, David A., Davis, Amy J., Rhodes, Olin E., Cunningham, Fred L., Kilgo, John C., Pepin, Kim M., & Beasley, James C.. Effects of scale of movement, detection probability, and true population density on common methods of estimating population density. United States. doi:10.1038/s41598-017-09746-5.
Keiter, David A., Davis, Amy J., Rhodes, Olin E., Cunningham, Fred L., Kilgo, John C., Pepin, Kim M., and Beasley, James C.. 2017. "Effects of scale of movement, detection probability, and true population density on common methods of estimating population density". United States. doi:10.1038/s41598-017-09746-5. https://www.osti.gov/servlets/purl/1427804.
@article{osti_1427804,
title = {Effects of scale of movement, detection probability, and true population density on common methods of estimating population density},
author = {Keiter, David A. and Davis, Amy J. and Rhodes, Olin E. and Cunningham, Fred L. and Kilgo, John C. and Pepin, Kim M. and Beasley, James C.},
abstractNote = {Knowledge of population density is necessary for effective management and conservation of wildlife, yet rarely are estimators compared in their robustness to effects of ecological and observational processes, which can greatly influence accuracy and precision of density estimates. For this study, we simulate biological and observational processes using empirical data to assess effects of animal scale of movement, true population density, and probability of detection on common density estimators. We also apply common data collection and analytical techniques in the field and evaluate their ability to estimate density of a globally widespread species. We find that animal scale of movement had the greatest impact on accuracy of estimators, although all estimators suffered reduced performance when detection probability was low, and we provide recommendations as to when each field and analytical technique is most appropriately employed. The large influence of scale of movement on estimator accuracy emphasizes the importance of effective post-hoc calculation of area sampled or use of methods that implicitly account for spatial variation. In particular, scale of movement impacted estimators substantially, such that area covered and spacing of detectors (e.g. cameras, traps, etc.) must reflect movement characteristics of the focal species to reduce bias in estimates of movement and thus density.},
doi = {10.1038/s41598-017-09746-5},
journal = {Scientific Reports},
number = 1,
volume = 7,
place = {United States},
year = {2017},
month = {8}
}