Macroinvertebrados aquáticos da região Andino- Amazônica: paisagem fluvial, diversidade taxonômica e diversidade funcional

Abstract

The Andean-Amazonian region of the Caquetá department is renowned for hosting a vast biodiversity of terrestrial and aquatic organisms. However, in recent years, this region has experienced various anthropogenic impacts, primarily associated with deforestation, most evident in the lowlands. Additionally, this has led to significant concerns over the loss of connectivity between the Colombian Amazon and the eastern Andes Mountain range. This prompted us to study the riverscape associated with different lotic ecosystems to understand their regional dynamics and how this may influence the assembly of aquatic macroinvertebrates. We established three study zones: the Andes, the Transition, and the Amazonia, defining ten sampling stations. At each study site, we characterized the different components of the riverscape. In addition, we collected samples of aquatic macroinvertebrates using a multi-habitat methodology. For data analysis, we estimated taxonomic and functional alpha and beta diversity. We implemented a Redundancy Analysis to identify environmental variables that predict the composition and beta diversity of aquatic macroinvertebrates, and we developed a generalized linear model linking the richness and abundance of the Odonata order to altitude, latitude, and longitude (regional scale). Our results revealed a successional process of various environmental variables from the Andean region towards the Amazon, also highlighting a pattern of environmental deterioration that increases from the higher parts of the region to the lowlands. Moreover, these variables act as crucial environmental filters in the establishment of the community of aquatic macroinvertebrates and the Ephemeroptera order on a local scale and, from a regional perspective, in the Odonata order, which also serves as a bioindicator group for the fragmentation of riparian forests. Our findings provide valuable insights into the dynamics of the riverscape between the Andes and the Amazonia in Caquetá. Additionally, we have established new taxonomic records and diversity estimates, which could be vital for adequately using and managing natural resources in the region. These will serve as a future reference for vulnerability analysis related to the loss of connectivity between the study areas.