Beyond pond size: the roles of disproportionate effects and habitat heterogeneity in controlling biodiversity in urban ponds

Abstract

The species-area relationship (SAR) describes the increase in species richness with habitat area, a pattern observed in both true islands and island-like ecosystems such as ponds and lakes. This relationship may arise from passive sampling, disproportionate effects, and habitat heterogeneity. In this study, we investigated the species-area relationship in urban ponds, focusing on benthic macroinvertebrates. To examine the mechanisms underlying this relationship, we used both total richness and effort-controlled biodiversity measures as response variables. We found significant associations between both richness and effort-controlled biodiversity measures with pond area. Additionally, total richness was significantly related to pond area when accounting for total abundance in a multiple regression model. These results suggest that disproportionate effects and habitat heterogeneity, in addition to passive sampling, may also contribute to the species-area relationship in urban water bodies, providing valuable insights for enhancing biodiversity and ecosystem services through urban planning.