Data from: Estimating abundance of an open population with an N-mixture model using auxiliary data on animal movements
Ketz, Alison C., Colorado State University
Johnson, Therese L., Colorado State University
Monello, Ryan J., National Park Service
Mack, John A., National Park Service
George, Janet L., National Park Service
Kraft, Benjamin R., Colorado State University
Wild, Margaret A., National Park Service
Hooten, Mevin B., Colorado State University
Hobbs, N. Thompson, Colorado State University
Published Jan 03, 2018 on Dryad.
Cite this dataset
Ketz, Alison C. et al. (2018). Data from: Estimating abundance of an open population with an N-mixture model using auxiliary data on animal movements [Dataset]. Dryad. https://doi.org/10.5061/dryad.f1h1t
Accurate assessment of abundance forms a central challenge in population ecology and wildlife management. Many statistical techniques have been developed to estimate population sizes because populations change over time and space, and to correct for the bias resulting from animals that are present in a study area but not observed. The mobility of individuals makes it difficult to design sampling procedures that account for movement into and out of areas with fixed jurisdictional boundaries. Aerial surveys are the gold standard used to obtain data of large mobile species in geographic regions with harsh terrain, but these surveys can be prohibitively expensive and dangerous. Estimating abundance with ground based census methods have practical advantages, but it can be difficult to simultaneously account for temporary emigration and observer error to avoid biased results. Contemporary research in population ecology increasingly relies on telemetry observations of the states and locations of individuals to gain insight on vital rates, animal movements, and population abundance. Analytical models that use observations of movements to improve estimates of abundance have not been developed. Here we build upon existing multi-state mark recapture methods using a hierarchical N-mixture model with multiple sources of data, including telemetry data on locations of individuals, to improve estimates of population sizes. We used a state-space approach to model animal movements to approximate the number of marked animals present within the study area at any observation period, thereby accounting for a frequently changing number of marked individuals. We illustrate the approach using data on a population of elk (Cervus elaphus nelsoni) in Northern Colorado, USA. We demonstrate substantial improvement compared to existing abundance estimation methods and corroborate our results from the ground based surveys with estimates from aerial surveys during the same seasons. We develop a hierarchical Bayesian N-mixture model using multiple sources of data on abundance, movement and survival to estimate the population size of a mobile species that uses remote conservation areas. The model improves accuracy of inference relative to previous methods for estimating abundance of open populations.
The zipped folder contains all data used for the analysis, including 12 comma separated value files, that are to be used with the R code provided in the supplemental materials DataS1 and DataS2.
National Science Foundation, Award: DEB 1145200, DMS 1614392