Abstract
Aim Many theories were proposed to explain the outstanding endemism of plants in the Cerrado. Among the diversification mechanics suggested, the most widely discussed are the plateau/valley, stable/unstable, and core/peripheral hypotheses. The first argues that plateaus harbor more ancient lineages than valleys and should therefore present higher levels of endemism. The second theory suggests that climate stability in certain regions promoted more suitable environments for the maintenance of paleoendemic species. The last scenario attributes the distribution of endemism in the Cerrado to gradients of optimal conditions available to locally adapted species, predicting higher endemism levels in core regions of the domain than in marginal areas. We compared the endemism patterns of Cerrado flora with the predictions of each theory to discuss their role in the distribution of endemism nuclei across the domain.
Location Brazil.
Time period Quaternary.
Major taxa studied Angiosperms.
Methods We generated an endemism map using records of 174 woody plant species, comprising most vegetation types of the Cerrado domain. We applied spatial analysis and distribution models to summarize the importance of each predictor of endemism.
Results We found correlations among endemism, elevation, and marginality, supporting the plateau/valley and core/peripheral hypotheses. Although plateaus are more stable climatic environments, their elevation and centrality, not their climatic stability, predict higher endemism. Our vegetation models using simulated datasets supported the expansion of Cerrado plateau vegetation and retraction in valleys during the Last Glacial. However, real occurrence data models for gallery and riverine forests indicated that species in valleys presented contrasting responses to past climatic shifts.
Main conclusions We identified regions of higher plant endemism within the Cerrado domain and verified elevation and centrality as stronger predictive factors of this endemism compared with climatic stability. Our results also indicate that different vegetation types within valleys presented different responses to the Quaternary climate.
Conflict of interest The authors have no conflicts of interest to declare.
Author contributions JDV designed the study, performed the analysis, and wrote the manuscript; APS and IK assisted with the discussion of results and wrote the manuscript.
Biosketch João de Deus Vidal Jr. is a postdoctoral researcher in the Laboratory of Genetics and Molecular Analysis at Universidade Estadual de Campinas. He is interested in spatial patterns of diversity of Neotropical plants, with a special focus on the role of past climatic changes in the generation of modern patterns of diversity, at both community and population levels. Ingrid Koch is a professor at the Institute of Plant Biology of Universidade Estadual de Campinas. She is interested in the systematics, evolution and species distribution of plants from Neotropical environments. Anete Pereira de Souza is a professor at the Institute of Plant Biology of Universidade Estadual de Campinas. She is interested in the population genetics and molecular evolution of plants, with an emphasis on bioinformatics and genome evolution.
