Pleistocene Radiation of Coastal Species of Pilosocereus (Cactaceae) in Eastern Brazil
Total Page：16
File Type：pdf, Size：1020Kb
Journal of Arid Environments 135 (2016) 22e32 Contents lists available at ScienceDirect Journal of Arid Environments journal homepage: www.elsevier.com/locate/jaridenv Pleistocene radiation of coastal species of Pilosocereus (Cactaceae) in eastern Brazil * Marcelo O.T. Menezes a, f, , Daniela C. Zappi b, Evandro M. Moraes c, Fernando F. Franco c, Nigel P. Taylor d, Itayguara R. Costa e, Maria I.B. Loiola e, f a Instituto Federal de Educaçao,~ Ci^encia e Tecnologia do Ceara, Departamento de Ensino Medio e Licenciaturas, Av. Treze de Maio 2081, 60040-215, Fortaleza, CE, Brazil b Jardim Botanico^ do Rio de Janeiro, Rua Pacheco Leao~ 915, 22460-030, Rio de Janeiro, RJ, Brazil c Universidade Federal de Sao~ Carlos, Departamento de Biologia, Rodovia Joao~ Leme dos Santos, Km 110, 18052-780, Sorocaba, SP, Brazil d Singapore Botanic Gardens, National Parks Board, 1 Cluny Road, 259569, Singapore e Universidade Federal do Ceara, Departamento de Biologia, Av. Humberto Monte S/N, Campus do Pici, Centro de Ci^encias e Bloco 906, 60440-900, Fortaleza, CE, Brazil f Programa de Pos-Graduaç ao~ em Ecologia e Recursos Naturais, Universidade Federal do Ceara, Av. Humberto Monte S/N, Campus do Pici, Centro de Ci^encias e Bloco 902, 60455-970, Fortaleza, CE, Brazil article info abstract Article history: The semiarid region in Northeast Brazil (Caatinga) suffered several high moisture periods during the Received 24 November 2014 Pleistocene, while neighbouring regions experienced drying events. Effects of this climatic history on the Received in revised form evolution of Caatinga xeric flora are poorly understood. Demography and evolutionary relationships 24 February 2016 between Pilosocereus arrabidae and Pilosocereus catingicola (Cactaceae) were investigated using two non- Accepted 4 August 2016 coding intergenic spacers of cpDNA (1424 bp) employing distinct statistical methods, such as Bayesian Inference analysis, haplotype network, AMOVA, neutrality tests and Bayesian Skyline Plot. Our data suggests that species formerly arranged as the informal Pilosocereus arrabidae group do not form a Keywords: Neotropics monophyletic clade. P. arrabidae and P. catingicola are not reciprocally monophyletic and present very fi Semiarid low genetic diversity. The Tajima's D and Fu's Fs statistics provided no signi cant results. Results suggest Caatinga a very recent origin for P. arrabidae and P. catingicola. The beginning of P. arrabidae and P. catingicola DNA diversification dates back to the Pleistocene. Genetic diversity of P. catingicola subsp. salvadorensis is Phylogeography geographically structured between major rivers of the region, suggesting a history of isolation in in- terfluves during Pleistocene climatic cycles. © 2016 Elsevier Ltd. All rights reserved. 1. Introduction throughout the New World, where its high diversity, with c. 1450 species (Hunt et al., 2006), is distributed in several diversity centres The astonishing biodiversity found in the Neotropical region (Barthlott et al., 2015). Eastern Brazil, with its semiarid Caatinga and includes vast arid and semiarid habitats (Antonelli et al., 2015; seasonal Cerrado is amongst the three most important areas in Antonelli and Sanmartín, 2011; Hughes et al., 2013). The cacti are terms of cactus diversity, and it concentrates a very large propor- among the most iconic of many drought-adapted plant groups that tion of threatened species of this fascinating family (Goettsch et al., evolved and diversified under the xeric conditions of these eco- 2015). systems. According to Hernandez-Hern andez et al. (2014), the basal In order to endure life in semiarid or arid environments plants lineages of Cactaceae probably originated in the Andean region of need a set of adaptive strategies (e.g. Eggli and Nyffeler, 2009; Chile and Argentina. Yet, this family has a broad distribution Mauseth, 2006). Since adaptations to survive drought usually make them less competitive in non-seasonal habitats (Taylor, 2012), they often become isolated and endemic in arid lands. * Corresponding author. Instituto Federal de Educaçao,~ Ciencia^ e Tecnologia do Thus, the environmental changes that occurred during the Qua- Ceara, Departamento de Ensino Medio e Licenciaturas, Av. Treze de Maio 2081, ternary probably affected the distribution and evolution of cacti 60040-215, Fortaleza, CE, Brazil. and other drought enduring plants. The global cooling and drying E-mail address: [email protected] (M.O.T. Menezes). http://dx.doi.org/10.1016/j.jaridenv.2016.08.006 0140-1963/© 2016 Elsevier Ltd. All rights reserved. M.O.T. Menezes et al. / Journal of Arid Environments 135 (2016) 22e32 23 events of the Late Miocene and the lowering of CO2 levels may have allies survived wet periods in a putative dry refuge in the 'Chapada caused expansion of dry habitats (Hughes et al., 2013) and favoured Diamantina' and spread to the coast in the last interglacial period; CAM plants (Arakaki et al., 2011), respectively. These events may be 5) Unlike P. aurisetus group in southeastern Brazil (Bonatelli et al., responsible for the radiation of xeric species throughout South 2014), populations of P. arrabidae and allies should have experi- America (e.g. Hernandez-Hern andez et al., 2014; Mogni et al., enced long-term gene flow due to their almost continuous 2015). Further, during the Pleistocene, the recurrent climate geographic distribution. changes probably contributed to the allopatric differentiation of Based on these hypotheses, we predicted that: 1.1) Pilosocereus populations or species in the Neotropics (Bonatelli et al., 2014; arrabidae and its allies should be part of the most basal lineages in Franco and Manfrin, 2013; Taylor, 2012; Turchetto-Zolet et al., the phylogeny of the genus; 1.2) Taxa of the P. arrabidae group 2013). should exhibit reciprocal monophyly in cytoplasmic DNA, as is Although phylogeographic studies of plants from dry South expected in well-established sister species (Avise, 2000; Hubbell, American ecosystems are relatively few (Turchetto-Zolet et al., 2001); 1.3) Pilosocereus arrabidae and its allies should have an 2013), Hughes et al. (2013) postulate that the evolution of plants earlier divergence time when compared to the P. aurisetus group; in Neotropical Seasonally Dry Tropical Forests (SDTF) is marked by 2.1) Inland populations of the P. arrabidae group should exhibit a high geographical phylogenetic structure, allopatric speciation, higher number of haplotypes when compared to coastal pop- niche conservatism and well-supported monophyly of individual ulations; 2.2) Coastal populations from extremes of its geographic species in densely sampled gene trees. For these authors, such distribution should exhibit lower numbers of haplotypes; 3.1) De- patterns suggest a scenario of population fragmentation in arid mographic analyses should reveal evidence of demographic patches (with dispersal limitation), in-situ diversification of species expansion of Pilosocereus arrabidae and allies (that should have pairs or small clades, and persistence of stable populations of happened since the end of the last glacial period); 4.1) P. arrabidae species or lineages over long periods of time. and allies should exhibit a high number of haplotypes concentrated Bonatelli et al. (2014) studied the phylogeography of Pilosocereus in a single place (i.e. 'Chapada Diamantina'); 5.1) Phylogeography of aurisetus (Werderm.) Byles & G.D. Rowley and allies in southeast P. arrabidae group should not be geographically structured if the and central Brazil. They were able to find several of the phyloge- habitat occupied by its species can be considered continuous and its netic/phylogeographic patterns expected for SDTF taxa according to representatives experienced predominantly favourable climatic Hughes et al. (2013). This group of Pilosocereus Byles & G.D. Rowley conditions (during interglacial periods, which were longer than the seems to have suffered successive cycles of population fragmen- glacial). tation during wet interglacial periods, followed by demographic explosions during dry glacial periods. According to Bonatelli et al. (2014), the isolation in multiple refuges between successive glaci- ations would result in the allopatric origin and spread of different 2. Materials and methods haplotypes, explaining the polytomic phylogeny of the genus. This model of diversification can explain the evolution of several 2.1. Biological model Neotropical plant lineages that exhibit similar phylogenetic pat- terns, like some Bromeliaceae (Jabaily and Sytsma, 2012) and Pilosocereus is one of the most diverse genera in tribe Cereeae, Lamiaceae (Drew and Sytsma, 2012). However, Pilosocereus is with 42 species recognized (Hunt et al., 2006; Zappi and Taylor, widely distributed in tropical America from southeastern USA and 2011) of which most inhabit eastern Brazil (Zappi, 1994). This Mexico to southeastern Brazil and Paraguay (Zappi, 1994), with speciose genus, which is disjunct between Brazil's eastern region representatives in geographic regions that have experienced and northwestern South America (reaching Mexico and the different climatic histories during the Quaternary. Thus, a more Caribbean) is in many ways an ideal model to study the diversifi- complete phylogeographic analysis of this genus may provide a cation of lineages into more seasonal habitats during the Quater- wider understanding of xeric plant evolution in the Neotropics. nary, as seen by Bonatelli et al. (2014). At this point, we turn our attention to the informal group pro- According to Hunt