ABSTRACT
Background: Inselbergs (granitic and gneissic rock outcrops) are common elements in the Atlantic Forest and present large taxonomic (TD), functional (FD) and phylogenetic (PD) diversity.
Aims: We investigated how plant diversity changed across ecological and biogeographic scales by comparing TD, FD and PD of communities within and between two inselbergs. We expected converging FD and PD but distinct TD between outcrops, because of similar local environmental conditions in inselbergs and the long-term lineage isolation.
Methods: We calculated TD, PD and FD, and partitioned diversity into α (each inselberg), β (between inselbergs) and γ (whole sample) components. Phylogenetic signal was estimated for all traits. To link environmental predictors to functional traits a redundancy analysis was run. Variation in TD, FD and PD was analysed by general linear models with patch area and the two inselbergs as predictors.
Results: The inselbergs were taxonomically different, but showed convergence in their functional and phylogenetic diversity. The limited retention of phylogenetic signal suggests that different species may converge and respond similarly to environmental variables. Within inselbergs, larger patches displayed higher TD, FD and PD.
Conclusions: Seeking conservation strategies for inselbergs is challenging since, despite their functional and phylogenetic similarity, endemic species make individual rock outcrops unique.
Acknowledgements
We thank L. Azevedo, R. Fernandes, I. Jaffar, D. Mantuano and P. Vargas for helping in fieldwork. We are also thankful to B. Vanschoenwinkel, D.M. Neves and L. Gillerot for the valuable suggestions on the manuscript. The comments by several reviewers, S. Dullinger and L. Nagy significantly improved manuscript quality.
Disclosure statement
No potential conflict of interest was reported by the authors.
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Notes on contributors
Luiza F. A. de Paula
Luiza F. A. de Paula is a Postdoctoral Fellow. The major theme of her research is to understand ecological determinants of plant species diversity on terrestrial islands such as inselbergs.
Sara L. Colmenares-Trejos
Sara L. Colmenares-Trejos is a Ph.D. student. Currently, she is working with functional ecology and community dynamics along elevation gradients in the Atlantic Forest.
Daniel Negreiros
Daniel Negreiros is a Adjunct Professor working with plant functional types and ecological strategies schemes in infertile grasslands.
Bruno H. P. Rosado
Bruno H. P. Rosado is an Adjunct Professor focusing on functional ecology, ecophysiology and community assembly.
Eduardo Arcoverde de Mattos
Eduardo Arcoverde de Mattos is an Associate Professor interested in how plants respond to environmental factors.
Francesco de Bello
Francesco de Bello is an Assistant Professor focusing on functional diversity and its links to community assembly and ecosystem functioning.
Stefan Porembski
Stefan Porembski is a Professor interested on the floristic and ecology of vegetation islands occurring on inselbergs worldwide.
Fernando A. O. Silveira
Fernando A. O. Silveira is an Adjunct Professor focusing on plant ecology and evolution on ancient, infertile landscapes.