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Assessing the fit of site-occupancy models

Journal of Agricultural, Biological, and Environmental Statistics

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Abstract

Few species are likely to be so evident that they will always be detected at a site when present. Recently a model has been developed that enables estimation of the proportion of area occupied, when the target species is not detected with certainty. Here we apply this modeling approach to data collected on terrestrial salamanders in the Plethodon glutinosus complex in the Great Smoky Mountains National Park, USA, and wish to address the question 'how accurately does the fitted model represent the data?' The goodness-of-fit of the model needs to be assessed in order to make accurate inferences. This article presents a method where a simple Pearson chi-square statistic is calculated and a parametric bootstrap procedure is used to determine whether the observed statistic is unusually large. We found evidence that the most global model considered provides a poor fit to the data, hence estimated an overdispersion factor to adjust model selection procedures and inflate standard errors. Two hypothetical datasets with known assumption violations are also analyzed, illustrating that the method may be used to guide researchers to making appropriate inferences. The results of a simulation study are presented to provide a broader view of the methods properties.

Additional Publication Details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Assessing the fit of site-occupancy models
Series title:
Journal of Agricultural, Biological, and Environmental Statistics
Volume
9
Issue:
3
Year Published:
2004
Language:
English
Contributing office(s):
Patuxent Wildlife Research Center
Description:
300-318
Larger Work Type:
Article
Larger Work Subtype:
Journal Article
Larger Work Title:
Journal of Agricultural, Biological, and Environmental Statistics
First page:
300
Last page:
318
Number of Pages:
19