Biodiversity integrity index: An illustration using ants in Western Australia

Abstract

Although Western Australia is a relatively unpopulated region, considerable areas of native vegetation have been modified by agricultural clearing, rangeland grazing, urbanization, road construction, and mining. Ant diversity is reduced and community composition changed by each of these land uses. Road construction has the greatest long-term effect on the alpha diversity of ants, followed by agricultural clearing, mining, urbanization, and rangeland grazing. We present data on the extent of these various land uses in each major Western Australian vegetation association. Then, examples of ant diversity and community composition for each land use are coupled with geographic information system data on the extent of each land use in the various vegetation associations to calculate indices of "biodiversity integrity." The extent of biodiversity integrity in each region concurs with a subjective opinion of the condition of each unit. Agricultural clearing, followed by rangeland grazing, were found responsible for the greatest loss of ant biodiversity integrity.