Diversification of Rainforest Faunas: An Integrated Molecular Approach

Abstract

Understanding the evolutionary processes that generate and sustain diversity in tropical faunas has challenged biologists for over a century and should underpin conservation strategies. Molecular studies of diversity within species and relationships among species, when integrated with more traditional approaches of biogeography and paleoecology, have much to contribute to this challenge. Here we outline the current major hypotheses, develop predictions relevant to integrated molecular approaches, and evaluate the current evidence, focusing on central African, Australian, and South American systems. The available data are sparse relative to the scale of the questions. However, the following conclusions can be drawn: (a) in most cases, the divergence of extant sister taxa predates the Pleistocene; (b) areas with high habitat heterogeneity and recent climatic or geological instability appear to harbor more species of recent origin; (c) there is support for both allopatric and gradient models of diversification and more attention should be given to the role of diversifying selection regardless of geographic context; and (d) conservation strategies should seek to protect heterogeneous landscapes within and adjacent to large rainforest areas, rather than rainforests alone. SCOPE AND ISSUES The search for the basis of high species diversity in tropical forests has occupied biologists for over a century (91, 115, 143, 151). What biologists seek to understand is how there come to be so many species in a single place (alpha diversity) and so much turnover of species between habitats (beta diversity) and

Molecular systematics and phylogeography of Amazonian poison frogs of the genus Dendrobates

“…These possible times of divergence are very broad, but consistent with the time frame for the formation of both the paleogeographic arches and marine introgressions. The ancient age of divergence among species in our study is consistent with the results of similar analyses in other taxa (Moritz et al, 2000). The data set without cytochrome oxidase was used to test the a priori phylogenetic hypotheses with alternative tree topologies.…”

“…Certainly, the divergence of highland species from lowland ancestry (as suggested by our results) is consistent with the possibility of speciation driven by ecological gradients or discontinuities. Evidence for this kind of effect has been found previously, both in Amazonia and elsewhere (reviewed by Moritz et al, 2000).…”

“…A variety of hypotheses have been proposed to explain the elevated species diversity in the Amazon Basin (Gascon et al, 2000;Moritz et al, 2000). Many of these hypotheses propose specific isolating barriers as mechanisms that generated genetic divergence (Patton et al, 1994).…”

The emerging field of geogenomics: Constraining geological problems with genetic data

“…Thus, refugia became species pumps and centers of endemism (Haffer and Prance, 2001). Haffer's hypothesis has subsequently been disputed on several grounds-his centers of purported endemism overlap with areas of high collection intensity and may be artifacts of sampling (Nelson et al, 1990); many species complexes originated prior to the Pleistocene (reviewed in Moritz et al, 2000); and there is no strong evidence that the Amazon forest was fragmented, at least during the latest significant cold period, the Last Glacial Maximum ~20 Ka (reviewed in Mayle et al, 2009). However, some of these counter-arguments are also disputed.…”

Filogenia do Complexo Drosophila Buzzatii (Grupo Repleta): Inferências de Análises Multilocus Mitocondriais e Nucleares.

“…Estimativas recentes de tempo de divergência, a partir de análises de relógio molecular, indicam que um número pequeno de táxons se diversificou neste período (Costa, 2003;Moritz et al 2000;Pennington et al 2000, Pennington et al 2005Almeida et al 2007 (Webb, 1978).…”