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Data from: An assessment of sampling designs using SCR analyses to estimate abundance of boreal caribou

Citation

McFarlane, Samantha et al. (2021), Data from: An assessment of sampling designs using SCR analyses to estimate abundance of boreal caribou, Dryad, Dataset, https://doi.org/10.5061/dryad.v9s4mw6st

Abstract

Accurately estimating abundance is a critical component of monitoring and recovery of rare and elusive species. Spatial capture-recapture (SCR) models are an increasingly popular method for robust estimation of ecological parameters. We provide an analytical framework to assess results from empirical studies to inform SCR sampling design, using both simulated and empirical data from non-invasive genetic sampling of seven boreal caribou populations (Rangifer tarandus caribou) which varied in range size and estimated population density. We use simulated population data with varying levels of clustered distributions to quantify the impact of non-independence of detections on density estimates, and empirical datasets to explore the influence of varied sampling intensity on the relative bias and precision of density estimates.  Simulations revealed that clustered distributions of detections did not significantly impact relative bias or precision of density estimates. The genotyping success rate of our empirical dataset (n = 7,210 samples) was 95.1%, and 1,755 unique individuals were identified. Analysis of the empirical data indicated that reduced sampling intensity had a greater impact on density estimates in smaller ranges. The number of captures and spatial recaptures were strongly correlated with precision, but not absolute relative bias. The best sampling designs did not differ with estimated population density but differed between large and small ranges. We provide an efficient framework implemented in R to estimate the detection parameters required when designing SCR studies. The framework can be used when designing a monitoring program to minimize effort and cost while maximizing effectiveness, which is critical for informing wildlife management and conservation.

Usage Notes

Text files and R scripts for SCR analysis.  Read attached README text file for additional information. 

This dataset is only available to the public at a summary resolution for the following reason. The spatial information held within this dataset relates to a species at risk, that is highly sensitive.  Provision of precise locations would subject the species to threats such as disturbance and lethal exploitation. Data are supplied to the public with the geo-reference denatured to 0.1 degrees (~10 km grid).

Depending on stated need, data may be supplied at finer scales upon request to the Government of Alberta under provisions of a data sharing agreement.

Funding

Government of Alberta