Abstract
The east coast of Brazil comprises an extensive area inserted in the Tropical Atlantic Domain and is represented by sandy plains of beach ridges commonly known as Restingas. The coastal environments are unique and house a rich amphibian fauna, the geographical distribution patterns of which are incipient. Biogeographical studies can explain the current distributional patterns and provide the identification of natural biogeographical units. These areas are important in elucidating the evolutionary history of the taxa and the areas where they occur. The aim of this study was to seek natural biogeographical units in the Brazilian sandy plains of beach ridges by means of distribution data of amphibians and to test the main predictions of the vicariance model to explain the patterns found. We revised and georeferenced data on the geographical distribution of 63 anuran species. We performed a search for latitudinal distribution patterns along the sandy coastal plains of Brazil using the non-metric multidimensional scaling method (NMDS) and the biotic element analysis to identify natural biogeographical units. The results showed a monotonic variation in anuran species composition along the latitudinal gradient with a break in the clinal pattern from 23°S to 25°S latitude (states of Rio de Janeiro to São Paulo). The major predictions of the vicariance model were corroborated by the detection of four biotic elements with significantly clustered distribution and by the presence of congeneric species distributed in distinct biotic elements. The results support the hypothesis that vicariance could be one of the factors responsible for the distribution patterns of the anuran communities along the sandy coastal plains of eastern Brazil. The results of the clusters are also congruent with the predictions of paleoclimatic models made for the Last Glacial Maximum of the Pleistocene, such as the presence of historical forest refugia and biogeographical patterns already detected for amphibians in the Atlantic Rainforest.
Highlights
Biogeography is the discipline interested in documenting and understanding spatial biodiversity patterns [1] and in explaining the evolutionary history that led to this current spatial configuration [2,3,4,5]
The aims of our study were: (1) to identify distribution patterns of anuran species occurring on sandy plains of beach ridges of the eastern Brazilian coast; (2) to detect natural biogeographical units throughout the study area and to identify groups of anuran species with non-random overlapping geographical distribution; and (3) to provide the first formal test of two predictions of the vicariance model to evaluate the hypothesis that the diversification of these species can be a result of fragmentation of the ancestral biota by emerging barriers
Our results support the hypothesis that distribution patterns of anuran species along the Restingas of the eastern Brazilian coast are a result of the fragmentation of ancestral biotas as a consequence of vicariant events
Summary
Biogeography is the discipline interested in documenting and understanding spatial biodiversity patterns [1] and in explaining the evolutionary history that led to this current spatial configuration [2,3,4,5]. Detailed data regarding how organisms are distributed, the basis of biogeographical studies, enable such distribution patterns to be identified, including natural biogeographical units [6,7,8,9,10,11]. Dispersal and extinction are natural events that can cause noise in the identification of areas of endemism and hinder the recognition of natural biogeographical units [20,22] For this reason, biotic element analysis has been used in many studies as an alternative method to detect natural biogeographical units (e.g., [10,11,19,21,26,27,28])
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
