The geographical diversification of Furnariides: the role of forest versus open habitats in driving species richness gradients

Abstract

Aim Explaining species richness gradients in space and time requires understanding the evolutionary processes that ultimately alter the number of species.Here we examine species richness differences between primary habitats (forest versus open) for Furnariides birds, a Neotropical endemic bird clade, to test three major historical hypothesesdiversification rate, out of the tropics and tropical niche conservatismand assess the role of evolutionary processes in driving the Furnariides species richness gradient.Location Neotropics. MethodsWe used phylogenetic and spatial data to tests the historical hypotheses. First, we used GeoSSE and Bayesian Analysis of Macroevolutionary Mixture models to evaluate differential diversification and dispersal rates between habitats. Second, we quantify the root distance of each species and examined the phylogenetic structure of the richness gradient and the correlation between total species richness and the richness of early-diverged and recently originated species.Results Furnariides species richness is higher in forest than in open habitats. However, we found higher speciation, extinction, and dispersal rates in open when compared to forest habitats, resulting in a higher diversification rate in open habitats and higher dispersal rate out of open habitats than into them. The phylogenetic structure of the richness gradient showed strong spatial pattern, with early diverged species richness peaking in forest habitats and driving the overall Furnariides gradient.Main conclusions The Furnariides species richness gradient results from the joint effect of differential rates of macroevolutionary processes. Our findings highlight dispersal and extinction as dominant forces driving richness differences between habitats, through the addition and extirpation of species from open to forest habitats. Differences in species richness between habitats support niche conservatism of forest habitat preferences of Furnariides species. We suggest that open habitats are effective evolutionary arenas and a key to the maintenance of bird diversity in forest habitats over evolutionary time.

Evolutionarily distinct amphibians are disproportionately lost from human‐modified ecosystems

“…; Pinto‐Ledezma et al . ). This expansion of grassland‐like ecosystems has been aided more recently by human‐driven losses of forests (Hansen et al .…”

“…; Pinto‐Ledezma et al . ). The exceptional mobility of many bird species may allow these diversifying grassland‐associated species to quickly colonise deforested landscapes and produce this bias against more evolutionarily distinct, forest‐associated species in human‐modified landscapes.…”

“…Evolutionarily distinct species have low diversification rates ), suggesting that the traits affecting clade diversification may similarly influence species' responses to contemporary environmental change. Grassland ecosystems emerged and spread across several continents only relatively recently during the Cenozoic (Str€ omberg 2011), and in turn this emergence has spurred faunal turnover and heightened diversification within many grassland-associated clades (Janis 1993;Cantalapiedra et al 2014;Pinto-Ledezma et al 2017). This expansion of grassland-like ecosystems has been aided more recently by human-driven losses of forests (Hansen et al 2013).…”

“…If rapidly diversifying grassland-associated species fare better in human-modified ecosystems, due to the compositional similarity of human landscapes and many grass-dominated habitats (Falk & Balling 2010), this could favour these species over more evolutionarily distinct, forest-associated species (Frishkoff et al 2014). For birds, this hypothesis appears intuitive as spatial patterns of diversification rates appear to be highest in drier open-habitat regions , and in several avian clades speciation rates are elevated in grassland and savannah biomes (Fuchs et al 2015;Pinto-Ledezma et al 2017). The exceptional mobility of many bird species may allow these diversifying grassland-associated species to quickly colonise deforested landscapes and produce this bias against more evolutionarily distinct, forest-associated species in human-modified landscapes.…”

Mapping diversification metrics in macroecological studies: Prospects and challenges

“…For instance, the geographic state speciation and extinction model –GeoSSE (Goldberg et al 2011; Table 1) allows estimating speciation, extinction and dispersal parameters across two regions. It is possible to disentangle the relative role of each one of these processes on the generation and maintenance of the geographical diversity gradients (Rolland et al 2014, Pulido-Santacruz and Weir 2016, Pinto-Ledezma et al 2017). In addition, a recently developed Bayesian approach (BAMM; Rabosky 2014, Rabosky et al 2014) allows to infer the balance of speciation and extinction in the generation of these biodiversity gradients (Rabosky et al 2015, Sánchez-Ramírez et al 2015, Morinière et al 2016, Pinto-Ledezma et al 2017).…”