Community structure of Neotropical wetland insects in Northern Venezuela. II. Habitat type and environmental factors app:1

Abstract

This study examined the spatial distribution of wetland insects in relation to selected environmental variables in northeastern Venezuela. Sampling was carried out over two sampling periods (rainy and dry season) in seven wetland types (brackish and freshwater herbaceous swamps, mangrove swamps, freshwater ponds, clear-cut marsh forests, small irrigation canals, and swamp forests), covering three environmental gradients (salinity, aquatic vegetation type, and habitat permanence). Using the partial redundancy analysis, we determined that occurrence and abundance of insects was significantly (P <0.05) accounted for by the relative contributions of pure environmental (29-34 %) and habitat type-related (12-15 %) variations among wetlands. Water chemistry (salinity), wetland trophic state (phytoplankton), habitat heterogeneity (aquatic vegetation type), and habitat physical features (depth and habitat permanence) were significantly associated to community structure. Insect richness was higher in the less saline, more vegetated, and less temporary wetlands. Our findings add to previous results suggesting that adversity, productivity, heterogeneity and permanence of the habitat represent important axes along which Neotropical wetland insect communities are organized.