Geographical patterns of phylogenetic beta‐diversity components in terrestrial mammals

Abstract

Aim To inve stigate geographical patterns of phylogenetic beta diversity (PBD) and its turnover and nestedness-resultant components for terrestrial mammals. We expect an increase in the importance of the nestedness-resultant component towards temperate regions given the historical loss of lineages caused by environmental and spatial constraints. Analogously, we expect to find a similar increase in the contribution of the nestedness-resultant component towards higher elevations. We expect these patterns to be stronger for Rodentia because they have poor dispersal ability and may have been less efficient in recolonizing areas after glaciations.Location World-wide.Methods We generated the species composition of terrestrial Mammalia for 200 km 3 200 km cells to calculate PBD and its turnover and nestednessresultant components. All measures were computed for each cell and the cells in the surrounding radius of one, two or three adjacent layers. We calculated the relative importance of the nestedness-resultant component as the proportion of the total PBD (PBD ratio ) and also PBD deviation given taxonomic beta diversity (PBD dev ). PBD dev measures the importance of phylogenetic beta diversity after factoring out taxonomic beta diversity. We used simple linear regressions and piecewise regressions to investigate relationships between PBD ratio and mean annual temperature and elevation. ResultsWe found a major contribution of the nestedness-resultant component linked to temperate climate, especially for groups with better dispersal capacity. Higher elevations were associated with a major contribution of the turnoverresultant component, particularly for Rodentia. Main conclusionsWe provide the first global representation of PBD in terrestrial mammals and demonstrate that at higher latitudes PBD is mostly a result of lineage loss, whereas in highlands it is linked to lineage turnover. By analysing global patterns of the contribution of PBD components, we demonstrate that dispersal capacity is essential in determining the response of different lineages to geographical and environmental barriers.

Relative influence of spatial over environmental and historical processes on the taxonomic and phylogenetic beta diversity of Neotropical phyllostomid bat assemblages

“…Patterns of diversity, however, are scale-dependent, and at broad geographical scales community assembly will also be influenced by biogeographical and evolutionary dynamics affecting the rates of speciation, extinction and dispersal, processes that result in high taxonomic and phylogenetic variation in community composition (Barton et al, 2013;McKnight et al, 2007;Peixoto, Villalobos, Melo, et al, 2017). Hence, the continental scale encompassed by our study may be one reason why our results implicate different processes other than niche underlying the variation in community composition among Neotropical bat communities in comparison with studies conducted at small scales in this region.…”

“…Within such a scenario, mountain ranges throughout this region have prevented species dispersal, promoting faunal isolation and high beta diversity among communities (Castro-Insua et al, 2016;McKnight et al, 2007;Zuloaga & Kerr, 2017). For example, Diniz-Filho (2009) andPeixoto, Villalobos, Melo, et al (2017) showed that high levels of species and lineage turnover in mammals are found in the highlands and topographically complex regions within the Neotropics, probably because of differential allopatric speciation, extinction and adaptation among different clades to such conditions. In a global analysis of PBD for bats, Peixoto, Braga, Cianciaruso, Diniz-Filho, and Brito (2014) found that their phylogenetic dissimilarity among biogeographical realms is linked mainly to the spatial turnover of lineages, a result similar to which we found for phyllostomid bats in Neotropics.…”

Dispersal is more important than climate in structuring turtle communities across different biogeographical realms

“…After calculating pairwise beta diversity for the communities in the different realms, we also calculated beta diversity (taxonomic and phylogenetic) for each cell of the Neotropical and Nearctic realms in order to investigate drivers of beta diversity for each cell and properly evaluate the effects of areas more affected by climatic instability in relation to the LGM. Beta diversity was calculated as the mean beta diversity between each cell and its neighbours, an approach commonly used in recent studies (Melo et al, 2009;Dobrovolski et al, 2012;Wen et al, 2016;Peixoto et al, 2017). This other metric of beta diversity was calculated mainly for these two realms because (1) environmental processes were important in shaping beta diversity in these realms (see results); (2) they are large areas, having a large sample size; and (3) they are well-studied realms where beta diversity patterns have already been evaluated for other clades.…”

“…Macroecological studies have evaluated potential drivers of beta diversity patterns on large scales in a wide range of vertebrates. However, although these studies covered a few biogeographical realms (Melo et al ., ; Svenning et al ., ; Dobrovolski et al ., ; Siefert et al ., ) or even global patterns (Buckley & Jetz, ; Leprieur et al ., ; Baselga et al ., ; Peixoto et al ., ), they did not consider whether different processes may influence beta diversity in the different realms (but see Qian & Ricklefs, ). Biogeographical realms are commonly geographically isolated in relation to each other and also have unique histories and diversities, highlighting the occurrence of independent evolution and different processes shaping their diversity (Hawkins et al ., ; Holt et al ., ).…”

“…Climatic stability is assumed to provide time for speciation and the origin of small-range species (Jansson & Dynesius, 2002), both processes increasing turnover components of beta diversity. Topographic heterogeneity is assumed to provide biogeographical barriers that also promote speciation and turnover (Melo et al, 2009;Peixoto et al, 2017). Still, climatic instability should have caused extinctions in some natural communities which were then recently occupied by species with good dispersal rates from neighbouring sites, generating a prevalence of a nestedness component (Baselga, 2010;Dobrovolski et al, 2012).…”