The xeric side of the Brazilian Atlantic Forest: The forces shaping phylogeographic structure of cacti. Issue 22 (4th October 2017)

• Record Type: Journal Article
• Authors: Franco, Fernando Faria; Jojima, Cecília Leiko; Perez, Manolo Fernandez; Zappi, Daniela Cristina; Taylor, Nigel; Moraes, Evandro Marsola
• Is Part Of: Ecology and evolution. Volume 7:Issue 22(2017:Dec.)
• Page Start: 9281
• Page End: 9293
• Publication Date: 2017-10-04
• Subjects: ABC -- cactus -- discrete phylogeography -- Inselbergs -- PHYC -- restinga -- species tree -- trnS‐trnG -- xeric enclaves; Ecology -- Periodicals; Evolution -- Periodicals; 577.05
• DOI: 10.1002/ece3.3458
• Languages: English
• ISSNs: 2045-7758

Abstract

Abstract: In order to investigate biogeographic influences on xeric biota in the Brazilian Atlantic Forest (BAF), a biodiversity hotspot, we used a monophyletic group including three cactus taxa as a model to perform a phylogeographic study: Cereus fernambucensis subsp. fernambucensis, C. fernambucensis subsp. sericifer, and C. insularis . These cacti are allopatric and grow in xeric habitats along BAF, including isolated granite and gneiss rock outcrops (Inselbergs), sand dune vegetation (Restinga forest), and the rocky shore of an oceanic archipelago (islands of Fernando de Noronha). The nucleotide information from nuclear gene phytochrome C and plastid intergenic spacer trnS‐trnG was used to perform different approaches and statistical analyses, comprising population structure, demographic changes, phylogenetic relationships, and biogeographic reconstruction in both spatial and temporal scales. We recovered four allopatric population groups with highly supported branches in the phylogenetic tree with divergence initiated in the middle Pleistocene: southern distribution of C. fernambucensis subsp. fernambucensis, northern distribution of C. fernambucensis subsp. fernambucensis together with C. insularis, southern distribution of C. fernambucensis subsp. sericifer, and northern distribution of C. fernambucensis subsp. sericifer . Further, the results suggest that genetic diversity of population groups was strongly shaped by an initial colonization event from south to north followed by fragmentation. The phylogenetic pattern found for C. insularis is plausible with peripatric speciation in the archipelago of Fernando de Noronha. To explain the phylogeographic patterns, the putative effects of both climatic and sea level changes as well as neotectonic activity during the Pleistocene are discussed. Abstract : We found evidence of rapid diversification of a monophyletic group composed by three cactus taxa during the middle Pleistocene, consistent with a south‐to‐north colonization pattern in xeric habitats of Brazilian Atlantic Forest. The putative impact of global climatic changes in the Pleistocene under the biomes distribution as well as in the regression of sea level might explain our biogeographic results. Further, we discuss for the first time the role of neotectonic activity in the Brazilian Northeast to explain discontinuities in geographical distribution of BAF biota.