Assessment of reptile response to habitat degradation in arid and semi-arid regions

Abstract

Reptiles are essential components of global biodiversity and dynamic ecosystems due to their ecological roles and functions. However, they face significant vulnerability to anthropogenic disturbances and habitat degradation, resulting in their classification as the third most threatened vertebrate group globally. The current study examines reptile response to anthropogenic habitat degradation in the highly biodiverse Souss-Massa National Park (SMNP), located on the North African Atlantic coast. During 2021 and 2022, linear transects were established within four habitat categories experiencing varying degrees of vegetation cover degradation (undegraded, slightly degraded, moderately degraded, and highly degraded), caused by livestock overgrazing and vegetation clearance. Based on the comparisons of the Normalized Difference Vegetation Index means, the vegetation cover differed significantly among the selected habitat categories, with a noticeable reduction in the natural vegetation cover as the level of habitat degradation increased. The visual encounter survey technique was used to search a total of 96 transects, with each of the studied habitat categories being represented by 24 transects. Species richness, diversity, abundance, composition and similarities of reptile communities were determined and compared between habitat categories. During the study period, 11 species (438 individuals) were encountered, accounting for 48 % of SMNP reptile fauna. Species richness, diversity and abundance differed significantly among habitat categories, with the lowest means recorded in the highly degraded areas. Reptiles responded differently to habitat degradation based on their taxonomic levels, thus indicating a species-specific impact of degradation. Species composition varied considerably among habitat categories, with highly degraded areas displaying significant differences and the lowest degree of similarity when compared to all other categories (p = 0.0006). Anthropogenic alterations in reptile abundance distribution and species occurrence likely account for the observed differences in species composition within the different habitat categories. The reported reptile responses to habitat degradation might be attributed to factors associated with natural vegetation, such as food availability, microhabitat preferences, or interactions with other species. Exploring these factors in future research could provide further insights into the mechanisms driving reptile community responses to habitat degradation. Such data can provide valuable information for implementing effective conservation measures to prevent anthropogenic habitat degradation and protect threatened species in arid and semi-arid areas.