Relações entre a filogenética via DNA Barcode e traços funcionais de minhocas na Amazonia Oriental

Abstract

Understanding the causes of variability in functional traits is an important question in earthworm ecology. While interspecific variation in anatomical dimensions for the same trait is well accepted, the role of environmental filters, soil degradation, and environmental stress in affecting the variability of functional traits is not well understood. In this study, we sought to determine the relative importance of environmental factors and earthworm species taxonomy on the variability in functional traits within species (intraspecific variability). We focused on eight functional traits including body mass, body length, body diameter, gizzard, gizzard thickness, septum thickness, typhlosole, and gut organic matter. We sampled earthworms of 11 different species in various regions of the eastern Amazon to determine the general responses of different species' characteristics when exposed to various ecosystem and soil conditions. Our results suggest that the functional traits of earthworms are influenced in different ways by environmental conditions. One set of traits, including body mass, body length, and body diameter, was more constant and independent of environmental variability, while another set, including gizzard diameter and length, gizzard muscle thickness, septum thickness, typhlosole, and intestinal organic matter, was more sensitive. The most affected by different environmental variables was septum thickness. We also examined which environmental factors are most important for trait variability. Our study highlights the importance of considering both environmental factors and taxonomic classification when studying the variability of functional traits within earthworm species. Overall, our results suggest that taxonomic classification alone is a good guide for estimating the major functional traits of earthworms in the Brazilian Amazon, but local conditions can their variability is which is essential for informing conservation efforts and maintaining ecosystem function. In the second chapter of this thesis, we focused on the utilization of the molecular tool known as DNA Barcodes, which enables the identification of species groups with unknown taxonomy. The utilization of DNA Barcodes produces UOTMs (Molecular Taxonomic Operational Units), which can serve as morphospecies to characterize the diversity and structure of communities, as well as to investigate the relationships between soil attributes and ecological processes. Thus, the objective of this study was to explore the potential of DNA Barcodes in assessing phylogenetic diversity. Specifically, we utilized the COI gene region to analyze new species of annelids and compare their identification with classical taxonomy. We extracted DNA from a total of 1,014 earthworm samples; however, only 56 samples were successfully sequenced. Despite encountering technical challenges during the sample amplification and sequencing process, our results revealed the formation of clusters among earthworm species and certain genus-level groups, which had already been identified through classical taxonomy and were further supported by phylogenetic analysis (e.g., Pontoscolex and Andiorhinus) due to their significant similarity to existing databases. In conclusion, the data presented in this chapter necessitate revisiting and repeating the amplification and sequencing procedures to ensure accuracy and reliability