Estimating species richness: The importance of heterogeneity in species detectability

By: , and 



Estimating species richness (i.e. the actual number of species present in a given area) is a basic objective of many field studies carried out in community ecology and is also of crucial concern when dealing with the conservation and management of biodiversity. In most studies, the total number of species recorded in an area at a given time is taken as a measure of species richness. Here we use a capture-recapture approach to species richness estimation with North American Breeding Bird Survey (BBS) data in order to estimate species detectability and thus gain insight about its importance. We carried out analyses on all survey routes of four states, Arizona, Maryland, North Dakota, and Wisconsin, in two years, 1970 and 1990. These states were chosen to provide contrasting habitats, bird species composition and survey quality. We investigated the effect of state, year and observer ability on the proportions of different models selected, and on estimates of detectability and species richness. Our results indicate that model Mh, which assumes heterogeneous detection probability among species, is frequently appropriate for estimating species richness from BBS data. Species detectability varied among states and was higher for the more skilled observers. These results emphasize the need to take into account potential heterogeneities in detectability among species in studies of factors affecting species richness.
Publication type Article
Publication Subtype Journal Article
Title Estimating species richness: The importance of heterogeneity in species detectability
Series title Ecology
Volume 79
Issue 3
Year Published 1998
Language English
Contributing office(s) Patuxent Wildlife Research Center
Description 1018-1028
Larger Work Type Article
Larger Work Subtype Journal Article
Larger Work Title Ecology
First page 1018
Last page 1028
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