Abstract
AbstractAimTo test the hypothesis that spatial variations in climate and land use explain the distribution and diversity of reptiles’ ecological traits in a biodiversity hotspot of the Mediterranean basin.LocationFrench Mediterranean region.TaxonReptiles (25 species).MethodsWe defined 288 species assemblages from 27,858 opportunistic occurrence records within 10 × 10 km square grid cells. Using a RLQ analysis, we investigated the distribution of nine ecological traits describing reptiles’ reproductive, dietary and behavioural strategies along environmental gradients formed by 10 climatic, topographic and land‐use descriptors. After homogenizing survey effort through rarefaction, we used generalized additive models to assess variations in species richness and several measures of functional diversity and composition along these gradients.ResultsAlthough ecological traits were not structured by environmental gradients at a species level, species richness and all measures of functional diversity varied nonlinearly with climate, elevation and secondarily land use. Species richness and body size peaked at intermediate altitudes, indicating a climatic transition zone between Mediterranean and medio‐European herpetofaunas. Conversely, functional diversity increased from Mediterranean plains, dominated by urbanization and agriculture, to higher elevations. These changes were associated with shifts towards less productive, more diurnal and more forest‐related species.Main conclusionsSpecies‐scale patterns are insufficient to assess regional variations in ecological traits in space. Our results support the hypothesis that climatic limitations in species’ distributions, rather than environmental filtering, explain the taxonomic and ecological diversity of reptiles at a regional scale. Although secondary to climate, land abandonment has a strong structuring effect which may contribute to homogenize the composition of reptile assemblages.
Highlights
Understanding how niches and traits affect species coexistence has remained one of the most central and debated issues since the advent of community ecology (Diamond, 1975; Garnier et al, 2016; McGill et al, 2006)
Ecological traits can be broadly defined as any qualitative or quantitative characteristics that describes a species’ relationship with its abiotic and biotic environment, encompassing functional traits and traits that have no direct relationship with fitness or performance but may impact the way individuals respond to environmental variation
We focused on the reptile assemblage in and around Mediterranean France, a region characterized by a complex topography which triggers strong gradients in climate and human land use, and by the legacies of past glacial refugia and barriers to dispersal
Summary
Understanding how niches and traits affect species coexistence has remained one of the most central and debated issues since the advent of community ecology (Diamond, 1975; Garnier et al, 2016; McGill et al, 2006). The idea that ecological traits provide a more meaningful interpretation of composition and diversity patterns than species richness alone has emerged with the long-lasting debate on how niche differences structure species assemblages (Diamond, 1975; Keddy, 1992; Münkemüller et al, 2020; Ricklefs, 2008). Ecological traits can be viewed as proxies of the major dimensions of the realized niche (Díaz et al, 2016; Pianka et al, 2017; Westoby et al, 2002) and as such are a suitable tool to investigate the role of environmental variation in explaining spatial gradients in species diversity and composition
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
