Evolutionary heritage influences Amazon tree ecology

Abstract

Lineages tend to retain ecological characteristics of their ancestors through time. However, for some traits, selection during evolutionary history may have also played a role in determining trait values. To address the relative importance of these processes requires large-scale quantification of traits and evolutionary relationships among species. The Amazonian tree flora comprises a high diversity of angiosperm lineages and species with widely differing life-history characteristics, providing an excellent system to investigate the combined influences of evolutionary heritage and selection in determining trait variation. We used trait data related to the major axes of life-history variation among tropical trees (e.g. growth and mortality rates) from 577 inventory plots in closed-canopy forest, mapped onto a phylogenetic hypothesis spanning more than 300 genera including all major angiosperm clades to test for evolutionary constraints on traits. We found significant phylogenetic signal (PS) for all traits, consistent with evolutionarily related genera having more similar characteristics than expected by chance. Although there is also evidence for repeated evolution of pioneer and shade tolerant life-history strategies within independent lineages, the existence of significant PS allows clearer predictions of the links between evolutionary diversity, ecosystem function and the response of tropical forests to global change.

Compositional response of Amazon forests to climate change

“…Note that in this case we would not be interested in the growth of trees surviving from t 0 to t 1 , and so the net flux would be represented as R t1 − L t1 inventory plots across the Amazon Basin (Fauset et al, 2015); Water deficit affiliation (WDA; mm): derived from relative abundances across 513 inventory plots distributed along a large gradient of MCWD across the Western Neotropics (Esquivel-Muelbert, Baker, et al, 2017). For these cases, the mean trait values from the family were used, following established conventions (Baker et al, 2004;Flores & Coomes, 2011) and considering the phylogenetic conservatism of PS and WD for Amazonian trees (Coelho de Souza et al, 2016). Taxa Genus-level trait data were missing for 6%, 9% and 0.04% of all stems for PS, WDA and WD, respectively.…”

“…If this is the case, we would expect the forest to be following a successional trajectory characterized by a shift from pioneers (low wood density) to mature forest species (high wood density; e.g. However, WD is considerably conserved across the phylogeny, and genus-level wood density has been found to be adequate to distinguish between late successional and pioneer genera (Coelho de Souza et al, 2016). While the observed relative increase in basal area of larger taxa is consistent with widespread recovery from disturbance (Chave et al, 2008;Wright, 2005), the 106 Amazonian inventory plots show no significant shift in wood density (WD) across the whole community, or perhaps more importantly, among the recruits (Tables 1 and 2).…”

“…affiliated to dry conditions show the most negative values of WDA, while the most wet-affiliated ones have values of WDA equal to zero; Wood density (WD; g/cm 3 ): values were extracted from the Wood Density DatabaseZanne et al, 2009). Our approach is expected to be adequate to capture the actual functional shifts in Amazonia as it captures most of the trait variation of Amazonian trees, which is mostly accounted for at the family and genus level (seeBaker et al, 2004;Coelho de Souza et al, 2016;Fyllas et al, 2009;Patiño et al, 2009). Therefore, our analyses were performed at the genus level, and the mean trait value of the genus was assigned to each individual.…”

Wood allocation trade‐offs between fiber wall, fiber lumen, and axial parenchyma drive drought resistance in neotropical trees

“…Xylem properties reflect both a plant's life‐history strategy as well as its underlying hydraulic strategies (Baas et al, ; Chave et al, ). Wood density is regarded a useful proxy of performance measures related to life‐history such as stem diameter growth and tree longevity (Chave et al, ; Coelho de Souza et al, ) because of its relationships with biomechanical properties such as wood strength and stiffness (Putz, Phyllis Coley, Montalvo, & Aiello, ; Van Gelder, Poorter, & Sterck, ). Furthermore, wood density has also been associated with hydraulic properties such as hydraulic conductivity (Mcculloh et al, ; Meinzer, Campanello, et al, ), capacitance (Borchert, ; Meinzer et al, ; Meinzer, Campanello, et al, ) and resistance to embolism (Hacke et al, ; Markesteijn, Poorter, Paz, Sack, & Bongers, ; Sperry & Hacke, ).…”

Amazon plant diversity revealed by a taxonomically verified species list

“…The uncertainty surrounding Amazon rain forest plant species richness and identity compromises downstream science focused on conservation (15) and the evolutionary and ecological patterns and processes that drive biodiversity (10)(11)(12)16), leaving studies dependent on incomplete and/or extrapolated datasets (e.g., refs. 9, 14, 17), often resulting in incomplete and irreproducible conclusions.…”