Name: Sampaio M

Biodeserts supervisors: Brito JCVelo-Antón G

Title: Conservation biogeography of amphibians in Mauritania: integrating DNA Barcoding and spatial analyses for the identification of cryptic diversity and phylogenetic units

Institution: University of Porto

Status: Completed




By borrowing theoretical and methodological frameworks from biogeography to solve conservation problems, conservation biogeography holds the potential for challenging two major knowledge gaps in biodiversity: the Linnaean and the Wallacean shortfalls. The first stands for the mismatch between the existing and the formally described diversity whilst the second denotes the missing information on the geography of life. The present study aimed at reducing these knowledge shortfalls in the amphibians occurring in the biogeographic transition zone in Mauritania. Data derived from DNA barcoding and ecological spatial modelling were combined for addressing the following questions: 1) How much amphibian diversity is present in Mauritania? 2) How is this diversity geographically distributed? 3) Which environmental factors correlate with amphibian diversity distribution? and 4) Where are priority water-bodies for the conservation of amphibian diversity located?
Unlike in most animal barcoding studies narrowed to the mitochondrial COI, a second independent line of evidence from the nuclear marker RAG1 was added and identified a total of 15 taxa. Fourteen formally described taxa were registered and potential cryptic diversity was detected in Hoplobatrachus occipitalis which displayed high levels of intraspecific diversity. This thesis provides the first record for Mauritania of two new genera (Amnirana and Leptopelis) and two new species (Kassina fusca and Tomopterna milletihorsini). The first DNA barcoding library for amphibians of Mauritania was constructed from 418 sequenced individuals. Six environmental correlates of amphibian richness distribution were identified, proximity to savannah and gravel floodplains, and greater distances to yellow dunes and gravel and sand floodplains. Permanent waters related negatively with amphibian richness as opposed to seasonal waters. Results obtained highlighted the importance of a suitable terrestrial habitat and an ephemeral hydrographic network for sustaining amphibian diversity in Mauritania. According to the predictive ecological model, amphibian richness increases southwards following a latitudinal gradient ranging from zero to 13 co-existing taxa per locality. Two major diversity hotspots were detected in south-eastern Mauritania, in a wetland-rich area. Yet, these biodiverse regions have been giving way to agriculture, and no protected areas are implemented nor are they under discussion for implementation in these areas.
This study provides a preliminary assessment of amphibian diversity in Mauritania and highlights the use of DNA barcoding to infer biogeographic patterns at a regional scale.