General methods for sensitivity analysis of equilibrium dynamics in patch occupancy models.

Abstract/Summary

Sensitivity analysis is a useful tool for the study of ecological models that has many potential applications for patch occupancy modeling. I use the rich foundation of existing methods for Markov chain models to demonstrate new methods for sensitivity analysis of the equilibrium state dynamics of occupancy models. Estimates from three previous studies are used to illustrate the utility of the sensitivity calculations: a joint occupancy model for a prey species, its predators, and habitat used by both; occurrence dynamics from a well-known metapopulation study of three butterfly species (Hanski 1994); and golden eagle occupancy and reproductive dynamics (Martin et al. 2009a). I show how to deal efficiently with multistate models and how to calculate sensitivities involving derived state variables and lower level parameters. In addition, I extend methods to incorporate environmental variation by allowing for spatial and temporal variability in transition probabilities. The approach used here is concise and general and can fully account for environmental variability in transition parameters. The methods can be used to improve inferences in occupancy studies by quantifying the effects of underlying parameters, aiding prediction of future system states, and identifying priorities for sampling effort.

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