Demographic performance of Cerrado lizards: A test of the center-periphery hypothesis

The center-periphery hypothesis (CPH) states that demographic performance is highest in the center of species’ ranges and decreases as the distance from the center increases due to declining environmental suitability. We tested the predictions under the CPH for two lizard lineages (Ameiva ameiva, Tropidurus itambere, and T. madeiramamore) with distinct distribution patterns. We assessed demographic performance using body condition and parasite information as indicators of demographic performance. The body condition refers to Peig and Green’s Scaled Mass Index, which associates body length and mass to indicate body status. Samples were collected from core Cerrado localities (South American savannas) and peripheral isolates in southwestern Amazonia. We built generalized linear mixed models with demographic performance as the response variable, environmental (climate, elevation, and soil variables) and spatial variables (landscape parameters and distance to the Cerrado’s center and periphery, e.g., centrality and peripherality), lizard genus and their interactions as fixed effects, and municipality and locality as random effects. We used Generalized Dissimilarity Modeling and variance partitioning to check the importance of geographic distance, environmental and spatial variables, and the dissimilarity among lizard communities on parasite beta diversity. 

Methods
This data refers to the lizard gastrointestinal parasite community, morphometric data, and the lizard community. These were sampled in isolates from the core Cerrado at Goiás and peripheral isolates at Rondônia. We used body condition and gastrointestinal parasitism as surrogates of lizard demographic performance.

To assess the predictions of the Center-Periphery Hypothesis, we built generalized linear mixed models with demographic performance as the response variable, environmental (climate, elevation, and soil variables) and spatial variables (landscape parameters and distance to the Cerrado’s center and periphery, e.g., centrality and peripherality), lizard genus and their interactions as fixed effects, and municipality and locality as random effects.

To get a more nuanced understanding of the variation in parasitism, we used Generalized Dissimilarity Modeling and variance partitioning to check the importance of geographic distance, environmental and spatial variables, and the dissimilarity among lizard communities on parasite beta diversity.