Estimating Abundance-Based Patterns of Species Co-Occurrence Using Phylogenetic Data and Spatial Covariates

• Activity Number: 396
• Type: Topic Contributed
• Date/Time: Tuesday, August 2, 2011 : 2:00 PM to 3:50 PM
• Sponsor: Section on Statistics and the Environment
• Author(s): Robert M. Dorazio*+ and Edward F. Connor
• Companies: Southeast Ecological Science Center, U.S. Geological Survey and San Francisco State University
• Keywords: abundance ; co-occurrence ; detectability ; foraging guilds ; point counts

Abstract

We develop a statistical model to estimate the abundances of species encountered while surveying a set of ecologically relevant locations -- as in a metacommunity of species. In the model we assume that abundances of related species (e.g., species of the same foraging guild) are correlated. We also assume that abundances vary among locations owing to systematic and stochastic sources of heterogeneity. For example, if abundances differ among locations owing to differences in habitat, then measures of habitat can be included in the model as covariates. Naturally, the quantitative effects of these covariates are assumed vary among species. In the model we also account for the effects of detectability on the observed counts of each species. This aspect of the model is especially important for rare species that may be difficult to detect in multi-species surveys. We illustrate the model using point counts of avian species obtained while sampling a community of forest birds during the breeding season.