Name: Naia MC

Biodeserts supervisors: Brito JC; Carvalho S

Title: Addressing landscape connectivity in biodiversity conservation strategies in the African Sahel

Institution: University of Porto, Portugal

Status: Completed

Abstract

Global biodiversity is currently facing the sixth mass extinction, where human-related factors, such as habitat loss and fragmentation and climate change, act as the main drivers. The Sahel ecoregion is a transition zone between the Palearctic and Afrotropical realms exhibiting high diversity of species. However, it is undergoing many threats that affect local biodiversity, such as increasing human population and infrastructures, land-cover and land-use changes, and climate change. The changes in suitable habitats for species may lead to their isolation and increased extinction risk. Landscape connectivity could mitigate the negative effects promoted by habitat fragmentation, by allowing the dispersal of individuals and the persistence of metapopulation structures. The present research focuses on two case studies that aim to improve conservation methodologies in arid regions and to find the best approaches to achieve conservation goals for biodiversity conservation in the Sahel. In the first study, the massive land-use and land-cover changes created by the Great Green Wall for the Sahara and the Sahel Initiative (Wall) were mapped against terrestrial vertebrate distribution to understand which species are going to be mostly affected by the regional connectivity changes. The habitat fragmentation created by the Wall will promote a barrier effect for desert-adapted species and the strong anthropogenic activities in the area can have short-term impacts in many others. Ensuring dispersal corridors with suitable habitats along the Wall are needed to mitigate its effects. In the second study, the location of priority areas for conservation of freshwater vertebrates was tested for multiple scenarios in Mauritania. Different connectivity rules were addressed to understand their impact in the priority areas selected and a new framework was presented to emphasise the importance of hydrologic upstream areas. Priority areas for conservation for water-dependent species were selected taking into account freshwater connectivity. The new framework highlights the importance of considering upstream areas to ensure the protection of connections between management units within their hydrological context, linking freshwater and terrestrial ecosystem protection. The two studies developed show that on the one hand, the lack of connectivity in a large international scale can negatively impact species not adapted to a particular habitat, increasing its extinction risk. On the other hand, addressing connectivity in the definition of new priority areas for conservation in local scale can help to mitigate the effects of species isolation. The current habitat fragmentation demands connectivity as a core strategy for biodiversity conservation in the Sahel. Both studies emphasise the importance of preserving connectivity to ensure long-term conservation of species and populations adapted to arid regions.