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Habitat fragmentation reduces genetic diversity and connectivity among toad populations in the Brazilian Atlantic Coastal Forest |
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| Authors: | Marianna Dixo Jean Paul Metzger |
| Institution: | a Department of Ecology, University of São Paulo. Rua do Matão, Travessa 14, 321, Caixa Postal 11461, CEP 05508-090 São Paulo, SP, Brazil b Department of Genetics and Evolutionary Biology, University of São Paulo. Rua do Matão, 277, CP 11461, CEP 05422-970 São Paulo, SP, Brazil c Department of Ecology and Evolutionary Biology, Cornell University, Ithaca, NY, 14853-2701, USA |
| Abstract: | Tropical rainforests are becoming increasingly fragmented and understanding the genetic consequences of fragmentation is crucial for conservation of their flora and fauna. We examined populations of the toad Rhinella ornata, a species endemic to Atlantic Coastal Forest in Brazil, and compared genetic diversity among small and medium forest fragments that were either isolated or connected to large forest areas by corridors. Genetic differentiation, as measured by FST, was not related to geographic distance among study sites and the size of the fragments did not significantly alter patterns of genetic connectivity. However, population genetic diversity was positively related to fragment size, thus haplotype diversity was lowest in the smallest fragments, likely due to decreases in population sizes. Spatial analyses of genetic discontinuities among groups of populations showed a higher proportion of barriers to gene flow among small and medium fragments than between populations in continuous forest. Our results underscore that even species with relatively high dispersal capacities may, over time, suffer the negative genetic effects of fragmentation, possibly leading to reduced fitness of population and cases of localized extinction. |
| Keywords: | Rhinella ornata Anuran Spatial analysis Gene flow Anthropogenic Conservation |
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