Using an individual-based model to assess common biases in lek-based count data to estimate population trajectories of lesser prairie-chickens

PLoS ONE
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Abstract

Researchers and managers are often interested in monitoring the underlying state of a population (e.g., abundance), yet error in the observation process might mask underlying changes due to imperfect detection, availability for sampling, and heterogeneity in abundance. Additional heterogeneity can be introduced into a monitoring program when male-based surveys are used as an index for the total population. Often, male-based surveys are used for lekking species, as males are conspicuous and more easily monitored when lekking than females. To determine if lek surveys capture changes or trends in population abundance based on female survival and reproduction, we developed a virtual ecologist approach using the lesser prairie-chicken (Tympanuchus pallidicinctus) as an example. Our approach used an individual-based model to simulate lek counts based on female vital rate data from lesser prairie-chickens, included models where detection probability and lek attendance were <1, and analyzed using unadjusted counts and an N-mixture model to compare estimates of population abundance and growth rates. When lek attendance rates were <1, the estimate of abundance was biased low, even when using N-mixture models to account for detection probability. Additionally, using lek counts to estimate population growth rates without accounting for detection probability consistently overestimated population growth rates, indicating a stable population when the population was decreasing. Our results therefore suggest that lek-based surveys used without accounting for lek attendance and detection probability may miss important trends in population changes. Rather than population-level inference, lek-based surveys not accounting for lek attendance and detection probability may instead be better for inferring broad-scale range shifts of lesser prairie-chicken populations in a presence/absence framework.
Publication type Article
Publication Subtype Journal Article
Title Using an individual-based model to assess common biases in lek-based count data to estimate population trajectories of lesser prairie-chickens
Series title PLoS ONE
DOI 10.1371/journal.pone.0217172
Year Published 2019
Language English
Publisher PLoS
Contributing office(s) Coop Res Unit Atlanta
Description 0217172, 17 p.
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