Juxtaposition and Disturbance: Disentangling the Determinants of Lizard Community Structure

TLDR: In this paper, the authors examined the effects of seasonal flooding on the lizard community structure by comparing two adjacent habitats, a seasonally flooded and a non-flooded forest, in a Cerrado-Amazon ecotone area, the Cantao State Park, Tocantins state, Brazil.

Abstract: Disturbance alters the structure and dynamics of communities. Here, we examined the effects of seasonal flooding on the lizard community structure by comparing two adjacent habitats, a seasonally flooded and a non-flooded forest, in a Cerrado–Amazon ecotone area, the Cantao State Park, Tocantins state, Brazil. Despite the strong potential impact of seasonal flooding, the only significant environmental difference detected was more termite mounds in non-flooded forests. Species richness was significantly higher in the non-flooded forest. Colobosaura modesta, followed by Mabuya frenata and Anolis brasiliensis, were the only species that differed in number of captures between sites. Colobosaura modesta was exclusively found in the non-flooded forest, while Anolis brasiliensis was the most captured in the flooded forest. Mabuya frenata is indicated as an indicator species in the flooded forest, and Colobosaura modesta in the non-flooded forest. We found a significant association between lizard abundances and habitat characteristics, with flooding, canopy cover, and logs being the best predictors. A phylogenetic community structure analysis indicated a lack of structure in both lizard assemblages. Overall, we show that seasonal flooding can strongly impact species richness and species occurrence patterns, but not phylogenetic community structure. The Amazon–Cerrado transition is undergoing pronounced transformations due to deforestation and climate change. Despite being species-poor compared with central areas in Amazon or Cerrado, this ecotone harbors species with important adaptations that could hold the key to persistence in human-disturbed landscapes or during periods of climate change. Resumo Disturbios podem alterar de maneira intensa a estrutura e a dinâmica das comunidades. Nos examinamos os efeitos de inundacoes sazonais na estrutura da comunidade de lagartos comparando duas areas adjacentes, uma sazonalmente inundada e outra nao inundavel, em um ecotono entre o Cerrado e a Amazonia, o Parque Estadual do Cantao, Tocantins, Brasil. Apesar do intenso impacto do alagamento sazonal, o numero de cupinzeiros foi a unica variavel ambiental que difere entre as areas, sendo significativamente maior na area nao inundavel. A riqueza foi significativamente maior na floresta nao inundavel. Colobosaura modesta, seguida por Mabuya frenata e Anolis brasiliensis, foram as unicas especies que diferiram em numero de captura entre as areas. Colobosaura modesta foi exclusivamente encontrada na floresta nao inundavel, enquanto Anolis brasiliensis foi a mais capturada na floresta inundavel. Mabuya frenata foi evidenciada como especie indicadora da floresta inundavel e Colobosaura modesta da floresta nao inundavel. Nos encontramos uma associacao significativa entre a abundância dos lagartos e as caracteristicas do habitat, sendo a inundacao, cobertura do dossel e a presenca de troncos caidos os melhores preditores. Uma analise de estrutura filogenetica da comunidade indicou ausencia de estrutura em ambas comunidades. Em suma, nos mostramos que inundacoes sazonais podem impactar fortemente a estrutura das comunidades de lagartos. A transicao Amazonia–Cerrado esta sofrendo acentuadas transformacoes devido ao desmatamento e mudancas climaticas. Apesar de apresentar baixa riqueza em relacao a areas mais centrais na Amazonia ou no Cerrado, esse ecotono abriga especies com importantes adaptacoes que podem ser a chave para a persistencia em paisagens impactadas pelo homem ou durante periodos de mudancas climaticas. Abstract in Portuguese is available in the online version of this article.