Biodiversity of Deserts and Arid Regions

Climate change predictions forecast significant warming and increase of aridity conditions for Sahara‐Sahel and other bordering areas of current deserts. Thus, the Mediterranean and the Sahel are upfront desertification areas were biodiversity research is urgent. The UN settled the 2010‐2020 as the Decade for Deserts and Fight against Desertification, thus research is needed to quantify present biodiversity levels and to provide conservation planning options. We are developing leading scientific research in desert and arid regions by combining cutting‐edge spatial and molecular analyses to derive integrative models of biodiversity distribution and conservation priorities. Research is organised in three complementary lines:

i) Biodiversity distribution patterns

Atlas of distribution of species, multi‐scale identification of biodiversity hotspots, identification of environmental and physiological factors related to distribution, and multi‐time scale modelling of biodiversity distribution. Atlases of the distribution of amphibians and reptiles for Mauritania and local protected areas (Banc d’Arguin NP, Diawling NP) in Mauritania are being prepared, as well as the identification of environmental factors related to biodiversity distribution for numerous water‐dependent taxa across the Sahara‐Sahel. DNA barcoding approaches are being used to catalogue the diversity of amphibians and reptiles in Mauritania and Algeria, and Geographical Information Systems are being used to map the distribution of multiple diversity levels (genes, species).

ii) Evolutionary and Landscape processes

Determination of biogeographic relationships and spatial patterns in morphological and genetic variation, identification of barriers to gene flow, and investigation of the role of paleogeographic mechanisms in diversification events. Studies on phylogeographic patterns in desert‐ranged taxa are being developed. Analyses are focused on Mauritanian mountains and aim to assess diversification levels and refugia character of these “mountain‐islands”.
Particular care is placed on molecular data analyses with geostatistics and GIS for deriving spatial patterns of genetic diversity. Least‐cost corridors and gene flow estimates are being combined to understand metapopulation patterns in isolated populations of vertebrates in the mountains of Mauritania, including fishes (Tilapia), amphibians (Hoplobatrachus), reptiles (Crocodylus), and mammals (Papio). Assessments of gene flow and contact zone dynamics in desert reptiles (Acanthodactylus and Agama) under climate change scenarios will be developed.

iii) Conservation planning

Identification of threatened taxa and of factors making populations or species prone to extinction, design of optimised reserve solutions for biodiversity conservation, and simulation of the effects of climate change on biodiversity distribution. Studies on reserve design for biodiversity conservation seek to integrate demographic and molecular data to cover distinct biodiversity levels (genes and species) under climate change scenarios. Studies target the Iberian Peninsula hotspot and Mauritania. Research at determining genetic conservation units in endangered desert‐dwelling taxa is being developed. Red List evaluation of Sahara mountains taxa is also a priority. The effect of repeated‐fire regimes, an important source of disturbance on biodiversity distribution in arid areas, is under development.