Differential speciation rates, colonization time and niche conservatism affect community assembly across adjacent biogeographical regions

Abstract

Aim: To test the importance of evolutionary and biogeographical processes in shaping the assembly of local frog communities in two adjacent regions (hereafter, coastal and inland regions) with different historical signatures. We asked two main questions: (1) why does the coastal region harbour more frog species than the inland region? and(2) how do these processes affect the spatial variation in taxonomic, phylogenetic and functional diversities within and across these regions? Location: southeastern Brazil.Taxon: Anurans. Methods:We generated time-calibrated phylogenies to estimate the relative timing of colonization, rates of speciation, extinction and dispersal between regions. We tested the phylogenetic signal in reproductive modes. These traits were also used to examine variation in functional composition across sites. We calculated metrics of phylogenetic community structure that capture the relationships near the root and tips of the tree. Finally, we tested the relationships between the spatial variation of multiple diversity dimensions and topographic complexity, Pleistocene and contemporary climate gradients for three spatial extents: (1) only coastal sites; (2) only inland sites; and (3) the two regions combined. Results:The structure of communities was related to the region in which they are located, with regional pool size being two times greater for the coastal than inland region. This pattern seems to reflect both a higher speciation rate and earlier colonization time in the coastal than in the inland region. Reproductive modes within frog genera were less variable than among families, indicating phylogenetic signal. This pattern influenced local community assembly within the inland region due to the absence of species with direct development, tadpoles in bromeliads or eggs and tadpoles in streams in this region. Main conclusions:Macroevolutionary dynamics, such as colonization time, differences in speciation rates and niche conservatism generate the disparity in species richness and assembly patterns of local communities between regions, but not within regions, in which local communities were more similar to each other.

Pleistocene climate oscillations and habitat connectivity contributed to avian beta‐diversity in the megadiverse Colombian Paramo ecosystems

“…Thus, LTT remains a good approach for inferring the relationship between periods of increased species diversification and geologic events hypothesized to influence speciation in the Andean region (e.g. Benício et al, 2021; Skeels & Cardillo, 2019).…”

“…A key challenge in ecological research is determining the relative importance of historical and contemporary processes in shaping geographical variation in biodiversity (HilleRisLambers et al, 2012; Ricklefs, 1987; Wiens & Donoghue, 2004). On the one hand, historical factors, such as uplift of mountain ranges and Quaternary climatic oscillations, impacted the rates of speciation, extinction and dispersal, affecting species richness and composition (Benício et al, 2021; Graham et al, 2006; Hoorn et al, 2010; Rangel et al, 2018; Ricklefs, 1987). On the other hand, contemporary factors, such as species–environment associations and species interactions, determine which species can coexist in a given assemblage (HilleRisLambers et al, 2012; Weiher & Keddy, 1995).…”

“…taxonomic and phylogenetic) of β‐diversity (i.e. variation in species composition between two communities) is a promising approach to tease apart the importance of historical and contemporary processes that generate and maintain patterns of species distributions (Benício et al, 2021; da Silva et al, 2014; Graham & Fine, 2008; Penone et al, 2016; Qian et al, 2013; Swenson et al, 2012; Weinstein et al, 2014). For example, Weinstein et al (2014) found that high β‐diversity in all dimensions resulted from hummingbird adaptation to different environments in isolated assemblages in the northern Andes.…”

“…Evaluating smaller spatial extents provides the opportunity to integrate biogeographical and ecological approaches to infer the role of different processes generating bird diversity (e.g. Benício et al, 2021; Ricklefs & Jenkins, 2011; Warren et al, 2014; Weeks et al, 2016). The spatial distribution of β‐diversity provides insight into the relative importance of historical mechanism, such as speciation, and contemporary ones, notably dispersal, on spatial variation among paramo assemblages.…”

Niche Divergence at Intraspecific Level in the Hyrcanian Wood Frog, Rana pseudodalmatina: A Phylogenetic, Climatic, and Environmental Survey

“…In recent decades, ecological factors have received increasing attention as a driver of lineage diversification and speciation (e.g., Wiens et al, 2010;Peterson, 2011;Broennimann et al, 2012;Zink, 2014;Hu et al, 2016;Fei et al, 2017;Wang et al, 2017;Gutiérrez-Ortega et al, 2020;Wei et al, 2020;Benício et al, 2021;Engler et al, 2021;Yin et al, 2021). In this debate, one of the main questions is whether newly developed species or clades exhibit signs of niche conservatism or divergence (Kozak and Wiens, 2006;Peterson, 2011;Wang et al, 2017;Zhu et al, 2020;Grossman, 2021;Meirmans, 2021;Van Dijk et al, 2021).…”