Diversity and Speciation of Invertebrates in Freshwater Habitats

Abstract

Freshwater habitats support approximately ~10% of all described species but only occupy <1% of the earth’s surface. Effective conservation of freshwater habitats is therefore a high priority and requires accurate taxonomic data on species and their temporal and spatial distributions. Advances in high-throughput sequencing technologies are revolutionising how we can survey biodiversity. The aim of the research presented in this thesis has been to further our understanding of the diversity and speciation of invertebrates in freshwater habitats. Two major themes were covered. The first explores the use of artificial ponds for habitat restoration, examining colonisation patterns and spatial-temporal changes in invertebrate community structure using environmental DNA (eDNA) metabarcoding. I report the results of an eDNA (CO1) metabarcoding survey conducted over a full annual cycle in proximate ponds (new and mature) and streams. The results indicate shared faunal connectivity between streams and ponds and reveal that newly built ponds can be rapidly colonised from the surrounding landscape. This study was temporally extended, and I also report the results of an eDNA metabarcoding survey covering 25 months at the same sites, revealing both spatial and temporal patterns of invertebrate communities among habitats. These results demonstrate eDNA-based methods can provide non-invasive alternatives for invertebrate assessment, but they require further methodological advancement to reliably survey the invertebrate fauna. The second major theme in this thesis examines the diversification of Afrotropical crabs (genus Arcopotamonautes) found within and proximate to the Lake Malawi catchment. I reveal patterns of population structure within the genus using genome-wide single nucleotide polymorphisms (SNPs), highlighting the potential of genome wide information to reveal diversity, including the identification of at least one potential cryptic species. Collectively, my results showcase promising applications of genetic tools to generate robust datasets that can contribute to conservation, management and restoration of freshwater ecosystems.

Date of Award	18 Jun 2024
Original language	English
Awarding Institution	University of Bristol
Supervisor	Martin J Genner (Supervisor) & Mark A Beaumont (Supervisor)