Historical climate modelling predicts patterns of current biodiversity in the Brazilian Atlantic forest

• Published in: Journal of biogeography 2008-07, Vol.35 (7), p.1187-1201
• Main Authors: Carnaval, Ana Carolina, Moritz, Craig
• Format: Article
• Language: English
• Subjects: Analysing and Modelling Species Distributions; Animal and plant ecology; Animal, plant and microbial ecology; Atlantic forest; Biogeography; Biological and medical sciences; Brazil; Climate models; Cloud forests; Forest ecology; forest refugia; Fundamental and applied biological sciences. Psychology; General aspects; General aspects. Techniques; Holocene; Methods and techniques (sampling, tagging, trapping, modelling...); Modeling; palaeoclimate modelling; Paleoclimatology; palynology; phylogeography; Pleistocene; Pollen; Refuge habitats; Synecology; Tropical forests; Tropical rain forests
• ISSN: 0305-0270; 1365-2699
• DOI: 10.1111/j.1365-2699.2007.01870.x

We aim to propose validated, spatially explicit hypotheses for the late Quaternary distribution of the Brazilian Atlantic forest, and thereby provide a framework for integrating analyses of species and genetic diversity in the region. The Atlantic forest, stretching along the Brazilian coast. We model the spatial range of the forest under three climatic scenarios (current climate, 6000 and 21,000 years ago) with BIOCLIM and MAXENT. Historically stable areas or refugia are identified as the set of grid cells for which forest presence is inferred in all models and time projections. To validate inferred refugia, we test whether our models are matched by the current distribution of the forest and by fossil pollen data. We then investigate whether the location of inferred forest refugia is consistent with current patterns of species endemism and existing phylogeographical data. Forest models agree with pollen records and predict a large area of historical forest stability in the central corridor (Bahia), as well as a smaller refuge (Pernambuco) along the Brazilian coast, matching current centres of endemism in multiple taxa and mtDNA diversity patterns in a subset of the species examined. Less historical stability is predicted in coastal areas south of the Doce river, which agrees with most phylogeographical studies in that region. Yet some widely distributed taxa show high endemism in the southern Atlantic forest. This may be due to limitations of the modelling approach, differences in ecology and dispersal capability, historical processes not contemplated by the current study or inadequacy of the available test data sets. Palaeoclimatic models predict the presence of historical forest refugia in the Atlantic rain forest and suggest spatial variation in persistence of forests through the Pleistocene, predicting patterns of biodiversity in several local taxa. The results point to the need for further studies to document genetic and species endemism in the relatively poorly known and highly impacted areas of Atlantic rain forests of north-eastern Brazil.