Special Issue: Defaunation's impact in tropical terrestrial ecosystems An index for defaunation

abstract Defaunation, originally conceived as the loss of large vertebrates due to hunting or fragmentation, hasbeen widely used in conservation studies yet the term has been arbitrarily used and poorly defined. Herewe refine this term by creating a quantitative index that can be used to compare ecological communitiesover large zoogeographical regions. We propose a defaunation index (D) as a weighted measure of dis-similarity between the current assemblage of a given location and a reference assemblage that representsa historical and/or unperturbed state. We analyzed the index by means of three case studies that includedtwo empirical assessments of mammal communities in Neotropical rainforests and one hypotheticalexample, encompassing a variety of criteria to quantify differences in species density and importance.These cases illustrate the broad range of index applicability and show that incorporating functional dif-ferences among species, such as those based on body size, conservation status or evolutionary originalitycan add important information beyond simply species richness. 2013 Elsevier Ltd. All rights reserved.