Name: Henrique M

Biodeserts supervisors: Brito JCVelo-Antón G

Title: Diversity, distribution and conservation of reptiles in the West Sahara-Sahel

Institution: University of Porto

Status: Completed

 

Abstract

 

Although biodiversity plays a key role in maintaining ecosystem function and persistence, there is global biodiversity loss at an alarming rate. Overall knowledge about biodiversity in deserts and arid regions is still very poor in comparison to other biomes. Deserts hold 25% of terrestrial vertebrate’s species and may provide important findings about adaptions to extreme environments. The region of West Sahara-Sahel (WSS) in Africa has an increased biodiversity, due to the location in a transition zone between the Palaearctic and Afro-tropic biogeographic realms. Preliminary molecular studies detected cryptic diversity in some reptile species, suggesting that the diversity of the group is still poorly known in the region.
In this study, molecular and spatial tools were combined to unravel reptile diversity in the WSS. The aim was to answer the following questions: 1) How many reptile phylogenetic units occur in the WSS? 2) Which is the distribution of reptile phylogenetic units? 3) Where are the areas with accumulating diversity of reptile phylogenetic units located? 4) Is the current network of protected areas covering the regions which accumulate the highest diversity? A COI barcode was used to build a barcoding reference library for the WSS reptiles based on a total of 755 samples from 109 taxa. Phylogenetic analyses were conducted on 542 sequences to identify phylogenetic units. Delimitation approaches were used to identify the phylogenetic units occurring in the reptiles from WSS and detect cryptic diversity. Geographical Information Systems were used to map the distribution of phylogenetic units, the richness of lineages, and to quantify gaps in the current network of WSS protected areas for reptile diversity.
A DNA barcoding library representing more than 80% of the described reptile diversity of the WSS was assembled, including a barcode for Agama impalearis (new species recorded). Four new putative cryptic species were identified in the WSS (and another five outside), and 93 mitochondrial lineages were retrieved. Four mountain endemic species were found. Reptile richness was concentrated in mountains, especially in Assaba Mountain. The regions concentrating the highest reptile diversity were not represented in the current protected areas.
DNA barcoding library obtained in this study provides a valuable tool for identifying and assessing the diversity of WSS reptiles. Biodiversity distribution is spatially structured and mountains display an important biological role as refugium and as local biodiversity hotspots. The implementation of protected areas in mountains should be taken under advice to conserve reptile diversity.