Ecology and Conservation Genetics of Mesoamerican Amphibians

Zamora Jerez, Olga Alejandra (2020) Ecology and Conservation Genetics of Mesoamerican Amphibians. Doctoral thesis (PhD), Manchester Metropolitan University.

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Abstract

Mesoamerica is a biodiversity hotspot harbouring a great diversity of ecosystems and species. Amphibians are one of the most diverse groups in the region, unfortunately many populations are declining, and a considerable number have gone extinct. Amphibian populations are a fundamental and irreplaceable part of the ecosystems present in Mesoamerica and their loss would be devastating for Central American biodiversity therefore, understanding the pressures these populations are under and conserving them more effectively is of the upmost importance. Molecular genetics is a useful tool to understand more about a population’s diversity and its interactions with its environment. For the first part of this project I developed microsatellite markers for the black-eyed tree frog Agalychnis moreletii to study the genetic diversity and population structure of the species. Then I used mitochondrial markers to study the genetic and evolutionary history of the species. I found that several populations have low genetic diversity as well as high inbreeding levels. There is genetic differentiation and population structure across its distribution range. Four different Evolutionary Significant Units (ESUs) were identified for A. moreletii, and it is crucial to create different management plans for each one since there are different pressures threatening them. We also believe this data challenges the conservation status of the A. moreletii as it is currently defined by the IUCN and shows this species is far more endangered than currently thought. Changing this categorisation will increase the protection of the species and the ecosystem it inhabits. iv I characterised the skin-bacterial communities of A. moreletii in Guatemalan populations and how the presence of the pathogen Batrachochytrium dendrobatidis has an effect on the bacterial composition. Skin-microbiome in A. moreletii seems hostmediated. Infected frogs harbour lower diversity of bacteria that non-infected frogs, which leaves these individuals more vulnerable. For the final part of the PhD I studied the skin-bacterial composition of Bolitoglossa salamanders and Plectrohyla matudai and how it changes once the animals are taken from the wild into captivity. I documented that the bacterial diversity and composition declines when animals are in quarantine, which can be a stressful stage of a captive study since it usually involves a small container with paper towels. This shows that tank enrichment is important in maintaining a diverse skin-microbiome in captive amphibians and therefore tank diversity is crucial in maintaining the health of individuals. The data gathered for my PhD will contribute to the conservation of amphibians and their ecosystems in Mesoamerica.