The importance of wetland habitat area for waterbird species‐richness

Abstract

The area of habitat patches is a significant factor when determining species‐richness in any given habitat. However, this area effect is not the same for every taxonomic group and can change if is considered together with other habitat variables. The main objective of this study was to identify the importance of wetland area for waterbird species‐richness when it is considered in conjunction with other habitat variables. Studies published in the Scopus and Web of Science databases in marine/coastal and inland wetlands were reviewed. A vote‐counting approach was conducted to evaluate how many studies include area as a major variable, and a meta‐analysis was performed to measure the effect size of the relationship between area and species‐richness. Area was a significant predictor of waterbird species‐richness in most of the studies (28 of 40 studies, 70%) as assessed by the vote‐counting approach, and the mean effect size was high (r = 0.81, n = 1 studies) in the meta‐analysis. Few studies reported the shape of the relationship between habitat area and species‐richness, but most reported a positive correlation. Although the species–area relationship is widely recognized, our review shows that an important proportion of studies (30%) also found that other habitat variables were significant variables when they were considered together with habitat area. Consequently, in the case of wetlands, habitat area should be considered in conservation, but not as the only measure of management and restoration if the objective is to conserve waterbird biodiversity by improving species‐richness.