Effects of a Habitat Integrity Gradient on the Diversity of Odonates in the Legal Amazonia Zone of the Brazilian State of Maranhão.

Abstract

The diverse ecosystems of the Amazon biome play a vital role in the maintenance of biodiversity and delivering essential ecosystem services at both local and global levels. Small-bodied generalist insects, such as those from the order Odonata, contribute significantly to these services and are recognized as sensitive bioindicators of environmental quality. The present study evaluated the diversity and distribution of adult odonates in the Legal Amazonia zone of the Brazilian state of Maranhão, to identify the key environmental drivers shaping local odonate communities. We sampled 27 streams along a landscape gradient ranging from degraded to preserved conditions within the Pindaré River basin. Our findings reveal that environmental integrity positively influences the odonate diversity and abundance, with degraded environment favoring generalist species. These generalist species are particularly vulnerable to habitat loss, particularly the reduction of dense vegetation. Notably, the discovery of Erythrodiplax unimaculata in Maranhão highlights the importance of the study in a region with limited research on the group. The study underscores the urgent need for continuous biodiversity monitoring and conservation strategies to mitigate the impacts of widespread environmental disturbances in the region.