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Occupancy modeling species-environment relationships with non-ignorable survey designs

Overview of attention for article published in Ecological Applications, July 2018
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Title
Occupancy modeling species-environment relationships with non-ignorable survey designs
Published in
Ecological Applications, July 2018
DOI 10.1002/eap.1754
Pubmed ID
Authors

Kathryn M. Irvine, Thomas J. Rodhouse, Wilson J. Wright, Anthony R. Olsen

Abstract

Statistical models supporting inferences about species occurrence patterns in relation to environmental gradients are fundamental to ecology and conservation biology. A common implicit assumption is that the sampling design is ignorable and does not need to be formally accounted for in analyses. The analyst assumes data are representative of the desired population and statistical modeling proceeds. However, if datasets from probability and non-probability surveys are combined or unequal selection probabilities are used, the design may be non ignorable. We outline the use of pseudo-maximum likelihood estimation for site-occupancy models to account for such non-ignorable survey designs. This estimation method accounts for the survey design by properly weighting the pseudo-likelihood equation. In our empirical example, legacy and newer randomly selected locations were surveyed for bats to bridge a historic statewide effort with an ongoing nationwide program. We provide a worked example using bat acoustic detection/non-detection data and show how analysts can diagnose whether their design is ignorable. Using simulations we assessed whether our approach is viable for modeling datasets composed of sites contributed outside of a probability design Pseudo-maximum likelihood estimates differed from the usual maximum likelihood occu31 pancy estimates for some bat species. Using simulations we show the maximum likelihood estimator of species-environment relationships with non-ignorable sampling designs was biased, whereas the pseudo-likelihood estimator was design-unbiased. However, in our simulation study the designs composed of a large proportion of legacy or non-probability sites resulted in estimation issues for standard errors. These issues were likely a result of highly variable weights confounded by small sample sizes (5% or 10% sampling intensity and 4 revisits). Aggregating datasets from multiple sources logically supports larger sample sizes and potentially increases spatial extents for statistical inferences. Our results suggest that ignoring the mechanism for how locations were selected for data collection (e.g., the sampling design) could result in erroneous model-based conclusions. Therefore, in order to ensure robust and defensible recommendations for evidence-based conservation decision-making, the survey design information in addition to the data themselves must be available for analysts. Details for constructing the weights used in estimation and code for implementation are provided. This article is protected by copyright. All rights reserved.

Twitter Demographics

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Mendeley readers

The data shown below were compiled from readership statistics for 43 Mendeley readers of this research output. Click here to see the associated Mendeley record.

Geographical breakdown

Country Count As %
Unknown 43 100%

Demographic breakdown

Readers by professional status Count As %
Researcher 15 35%
Student > Ph. D. Student 9 21%
Student > Master 5 12%
Student > Doctoral Student 5 12%
Student > Bachelor 3 7%
Other 6 14%
Readers by discipline Count As %
Agricultural and Biological Sciences 24 56%
Environmental Science 11 26%
Unspecified 6 14%
Psychology 1 2%
Decision Sciences 1 2%
Other 0 0%

Attention Score in Context

This research output has an Altmetric Attention Score of 1. This is our high-level measure of the quality and quantity of online attention that it has received. This Attention Score, as well as the ranking and number of research outputs shown below, was calculated when the research output was last mentioned on 29 May 2018.
All research outputs
#10,374,189
of 13,004,658 outputs
Outputs from Ecological Applications
#1,864
of 2,111 outputs
Outputs of similar age
#203,495
of 271,609 outputs
Outputs of similar age from Ecological Applications
#38
of 39 outputs
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