Landscape features and environmental conditions shape the functional diversity of aquatic and semiaquatic bugs (Hemiptera: Heteroptera) in Eastern Amazon

We aimed to evaluate the influence of riparian vegetation cover and water variables on the functional diversity of Heteroptera (Gerromorpha and Nepomorpha), testing the following hypotheses: (1) The reduction of native vegetation surrounding the streams changes physical and physicochemical water variables and (2) These changes in the physical structure of streams negatively affect the species richness and functional diversity of Heteroptera. We sampled 22 streams located in areas with differing proportions of forest and oil palm in the Eastern Amazon. We observed that the expansion of oil palm plantations over natural areas is associated with physical and physicochemical alterations in streams. These environmental shifts are correlated with changes in functional metrics and species richness. Specifically, for Gerromorpha, richness and functional richness were associated with water temperature and shelter availability, while for Nepomorpha, functional metrics were linked to habitat integrity (HII) and dissolved oxygen. Streams with higher forest cover and greater integrity exhibited greater functional diversity, higher dissolved oxygen and lower temperatures. These results indicate that oil palm agriculture is linked to the degradation of physical habitats and water quality, which in turn relates to the taxonomic and functional homogenization of Heteroptera communities.