Eco-evolutionary Dynamics of a Thermoconforming Anole Recolonizing Secondary Forest

Over half of tropical forests worldwide are secondary forests recovering from disturbance. As these forests regenerate, they develop complex structures that meet the requirements for recolonization by previously extirpated fauna. While community-level patterns of fauna recolonization of tropical secondary forests are well-documented, less is known about the underlying evolutionary processes. Eco-evolutionary theory predicts that expanding populations may experience a reduction in genetic diversity due to the small number of founding individuals, a pattern largely supported by studies of biological invasions and post-glacial recolonizations. However, recolonization of recovering forests differs fundamentally: populations may remain connected to extant sources and share evolutionary history with the habitat. Therefore, if such expansions also reduce genetic diversity remains unclear. To address this gap in knowledge, we analyzed genome-wide SNP data from Anolis gundlachi , an endemic shade-specialist lizard recolonizing secondary forests in Puerto Rico, comparing adjacent forests of varying ages (10–30, 30–50, >70 yrs). We tested whether recently colonized young forests exhibit reduced genetic diversity or distinct allele frequences compared to old-growth forests. Overall, our results revealed comparable genetic diversity and structure among anole populations living in forests of varying ages. This pattern likely reflects isolation by distance, ongoing gene flow among forests, or phenotypic plasticity. This study suggest that the evolutionary dynamics of recolonization are complex and strongly influenced by local factors such as landscape connectivity, rather than following classic founder-effect scenarios.