Name: Guerreiro R
Biodeserts supervisors: Brito JC
Title: Biodiversity distribution in the western Sahara-Sahel: the role of environmental variation
Institution: University of Porto
Fieldwork Biology implies certain techniques and methods that streamline work in a more effective and safe way. The main aim of the present internship was to learn some of these techniques and have a first contact with fieldwork in Biology. This was done in a 48 days field trip to North-West Africa, including the countries of Morocco, Mauritania and Mali, and covering overland up to 13,000 kilometres. The trip covered five different ecoregions of Desert and Savannah and focused on the sampling of amphibians and reptiles. The herpetofauna found in each ecoregion was characterized and quantified in terms of diversity, and measures of niche breadth were applied to some herpetological taxa. The distribution of four gecko species (genus Tarentola) was evaluated against environmental factors with a Geographical Information System. Overall, 47 taxa were found in the expedition and taxon diversity was observed to increase in a latitudinal gradient from north to the south. Niche breadth analyses on 11 taxa showed distinct taxa discrimination in relation to environmental variation. The geckos of genus Tarentola sp. exhibited very different niche and spatial occupation in closely related species, namely a preference for lower annual mean temperatures by T. chazaliae and T. annularis and a requirement for higher annual mean temperatures. Overall, distribution of biodiversity is latitudinally structured and tends to follow a north-south gradient of precipitation, and there are apparent ecological niche differences in Tarentola taxa.