Climatic seasonality and dominant species drive the temporal dynamics in a lizard assemblage in the Arid Chaco - Monte ecotone

Lizard assemblages are dynamic, influenced by both seasonal climatic changes and intrinsic population shifts. Climate plays a crucial role in shaping lizard phenology, or the timing of their biological events, which critically affects the spatiotemporal structure of sympatric populations. Understanding how species richness and abundance fluctuate over time, and how these changes are influences by temporal factors, is essential for distinguishing between variations caused by unpredictable external factors and underlying natural changes. This study aimed to characterize lizard assemblage structure and dynamics, as well as species demographics, over three consecutive years within an Arid Chaco - Monte ecotone in central-western Argentina. We also sought to assess the effects of environmental drivers (e.g., temperature, precipitation) on assemblage and population dynamics. Monthly samples were taken using pitfall traps from October 2015 to May 2018 within the protected area of the Valle Fértil Multiple Use Reserve. We captured 1446 lizards, representing 12 species. Liolaemus chacoensis was dominant in the assemblage, followed by Teius teyou and Aurivela longicauda. Species richness and diversity varied seasonally, peaking during summer and autumn. The lizard assemblage exhibited activity throughout all seasons, with significant temporal niche overlap between species. Reproduction and activity in lizards were highly seasonal, primarily occurring in spring and summer, likely due to low winter temperatures and highly seasonal rainfall. Our study shows that climate seasonality and the demographics of the dominant species significantly influence the temporal dynamics of lizard assemblages in the Arid Chaco-Monte ecotone of Argentina.