Cenozoic imprints on the phylogenetic structure of palm species assemblages worldwide

Abstract

Despite long-standing interest in the origin and maintenance of species diversity, little is known about historical drivers of species assemblage structure at large spatiotemporal scales. Here, we use global species distribution data, a dated genus-level phylogeny, and paleo-reconstructions of biomes and climate to examine Cenozoic imprints on the phylogenetic structure of regional species assemblages of palms (Arecaceae), a species-rich plant family characteristic of tropical ecosystems. We find a strong imprint on phylogenetic clustering due to geographic isolation and in situ diversification, especially in the Neotropics and on islands with spectacular palm radiations (e.g., Madagascar, Hawaii, and Cuba). Phylogenetic overdispersion on mainlands and islands corresponds to biotic interchange areas. Differences in the degree of phylogenetic clustering among biogeographic realms are related to differential losses of tropical rainforests during the Cenozoic, but not to the cumulative area of tropical rainforest over geological time. A largely random phylogenetic assemblage structure in Africa coincides with severe losses of rainforest area, especially after the Miocene. More recent events also appear to be influential: phylogenetic clustering increases with increasing intensity of Quaternary glacial-interglacial climatic oscillations in South America and, to a lesser extent, Africa, indicating that specific clades perform better in climatically unstable regions. Our results suggest that continental isolation (in combination with limited long-distance dispersal) and changing climate and habitat loss throughout the Cenozoic have had strong impacts on the phylogenetic structure of regional species assemblages in the tropics.biodiversity | biogeography | climate change | evolution | extinction D espite long-standing interest, the mechanisms behind the origin and maintenance of high tropical biodiversity remain elusive (1, 2). Much recent macroecological research has focused on explaining large-scale species richness gradients by contemporary climate (3-5), but the importance of evolutionary diversification and past environments has also been highlighted (2,(6)(7)(8). Over the past decades it has become increasingly clear that local community structure depends on both local processes and large-scale factors that influence regional species diversity (9, 10). Regional species assemblages are jointly shaped by within-region diversification and dispersal between regions, the former being constrained by time for speciation (7, 11) and by climatic or other factors influencing net diversification rates (12, 13), and the latter by the formation and disappearance of dispersal barriers (14, 15), time for dispersal (16), and phylogenetic niche conservatism (17). Understanding the historical assembly and present-day structure of regional species assemblages thus requires integration of ecological, paleogeographic, and phylogenetic information (10).Increasing availability of phylogenies has ignited interest in the phylogenetic str...

A revised delimitation of the rattan genus Calamus (Arecaceae)

“…It also resolves issues in recent evolutionary studies in which inherent assumptions of generic monophyly have been violated in the case of the Calaminae (e.g. Couvreur et al 2011, Kissling et al 2012, Baker & Couvreur 2013a, b, Couvreur et al 2014, potentially leading to biased results.…”

Tropical Refuges with Exceptionally High Phylogenetic Diversity Reveal Contrasting Phylogenetic Structures

“…Ecophylogenetics fills part of this gap and its use for investigating community structure has been increasing quickly [78]. However, ecophylogenetics and macroecology are still somewhat separate from each other, and few authors (e.g., [25,79]) dared to analyse PS at large geographical scales. Although attention has been given more recently to species evolutionary distinctiveness, different components of a multifaceted biodiversity cannot be confidently used as surrogate of others (e.g., [80][81][82]).…”

“…However, PD and PS are complementary measures of biodiversity and can be properly used for biogeography, ecology, and conservation biology. Phylogenetics has been used to assess historical and ecological drivers at different spatial scales [12,18], from latitudinal gradient of species richness (SR) [24], biogeographic processes during the Cenozoic [25], and coastal dune ecosystem [26] at a global scale to habitat heterogeneity [27,28], successional pathways [29], and altitudinal gradient [30] at regional or, mainly, local scales. Although Brazil harbours the richest flora in the world, with more than 32,000 species of angiosperms [31], studies applying phylogeny to interpret plant composition (e.g., [32,33]) are still scarce.…”

What Is on the Horizon for Ecophylogenetics?

“…Nevertheless, other scale-dependent spatial processes, such as dispersal limitation (Vamosi et al 2009;Kissling et al 2012) have been barely discussed. For example, a recent technique (Peres-Neto et al 2012) allows partitioning the variation in community phylogenetic structure into environmental and spatial components at multiple scales.…”