Applications of Compositional Data Analysis to Ecological and Environmental Research

• Activity Number: 160
• Type: Invited
• Date/Time: Tuesday, August 13, 2002 : 8:30 AM to 10:20 AM
• Sponsor: Section on Statistics & the Environment*
• Author(s): Emily Silverman*+
• Affiliation(s): University of Michigan
• Keywords: applications ; ecology ; compositional data

Abstract

I present examples of compositional data analysis from a variety of applications, including community ecology, behavioral ecology, and waste management. Compositional data are commonly encountered in ecological and environmental studies. In many instances, investigators fail to recognize the restricted nature of their data and misapply statistical analyses. For example, researchers conduct multiple hypothesis tests on the individual proportions in a composition without considering the dependence among the tests. In other cases, compositions are summarized by univariate indices with a consequent loss of information; many biodiversity studies reduce species compositions to a single measure that may fail to indicate differences in biota. I will review compositional data in ecological investigations and discuss the major research areas that collect this type of data. I consider the analysis of: 1.) interspecific associations among seabirds in the southern ocean; 2.) behavioral responses to a predatory cue by captive-bred and wild Oldfield mice Peromyscus polionotus; and 3.) differences in waste composition between material from residential sites and material hauled to collection sites.