Linking high diversification rates of rapidly growing Amazonian plants to geophysical landscape transformations promoted by Andean uplift

Abstract

Amazonia is extremely biodiverse, but the mechanisms for the origin of this diversity are still under debate. We propose a diversification model for Amazonia based on the interplay of intrinsic clade functional traits, habitat associations and past geological events, using as a model group the species-rich Neotropical family Marantaceae. Our results show that the species richness of the lineage is predicted by functional strategy, rather than clade age, and thus the fast vs. slow growth functional trade-off is a major determinant of clade diversification in Marantaceae. Rapidly growing clades were mostly associated with highly productive habitats, and their origin and diversification dynamics matched the expansion of fertile soils mediated by Andean uplift c. 23 Mya. Fast-growth strategies probably led to fast molecular evolution, speeding up speciation rates and species accumulation, resulting in higher numbers of extant species. Our results indicate that pure allopatric-dispersal models disconnected from past geological and ecological forces may be inadequate for explaining the evolutionary and diversity patterns in Amazonian lowlands. We suggest that a coupling of the functional trait-niche framework with diversification dynamics provides insights into the evolutionary history of tropical forests and helps elucidate the mechanisms underlying the origin and evolution of its spectacular biodiversity.

Geography and ecology shape the phylogenetic composition of Amazonian tree communities

“…The correspondence between the phylogenetic composition of tree communities and edaphic forest types shows that ecological selection influences the distribution of Amazonian tree lineages (Figueiredo et al., 2022), also supported by the species and higher‐level lineages that were indicators of forest types. Such habitat specialization seems to take place mainly in the upland forest habitats (terra‐firme and white‐sand forests) rather than in the flooded forests (várzea, swamp and igapó forests).…”

“…Given how large the regions are that we have studied, this does not preclude a role for allopatric or peripatric speciation in Amazonian trees (Dick & Pennington, 2019). Meanwhile, the relatively low number of significant indicators for edaphic forest types suggests that at least some lineages may be speciating via edaphic‐regime switching (Figueiredo et al., 2022; Fine et al., 2005; Glassmire et al., 2017). In contrast, the consistent phylogenetic composition of white‐sand forests can be interpreted as a signature of lineage speciation within an edaphic regime with an archipelago‐like distribution across the Amazon (Costa et al., 2020; García‐Villacorta et al., 2016; Guevara et al., 2016).…”

“…Detailed characterization of compositional patterns can help to infer the ecological and evolutionary processes at play (Carlucci et al., 2017; Dray et al., 2012; Graham & Fine, 2008; Kraft & Ackerly, 2010; McIntire & Fajardo, 2009). The assembly of tree communities in Amazonian tropical rain forests is structured by ecological drift (Hubbell, 2001), the local and regional dispersal of lineages (Dexter et al., 2017), differential recruitment into heterogeneous forest habitats and environments (Fine & Kembel, 2011; ter Steege et al., 2006; Tuomisto et al., 2003), biotic interactions (Fine et al., 2004; Kursar et al., 2009) and historical contingency (Baker et al., 2014; Dexter et al., 2012; Figueiredo et al., 2022).…”

HERBase: A collection of understorey herb vegetation plots from Amazonia

“…The study of herb ecology and distribution in tropical forests has advanced in recent decades (e.g., Cicuzza et al 2013;Tuomisto et al 2003aTuomisto et al , 2019Figueiredo et al 2022) but is still lagging behind studies of other biological components (Perea et al 2022), such as trees (ter Steege et al 2003(ter Steege et al , 2006(ter Steege et al , 2013Draper et al 2021) and birds (Ribas et al 2005). It is still an open question to what degree ecological theories and generalizations derived from trees apply to tropical forest herbs (e.g., Janzen-Connel mechanisms).…”