Evolutionary history and the effect of biodiversity on plant productivity

Abstract

Loss of biological diversity because of extinction is one of the most pronounced changes to the global environment. For several decades, researchers have tried to understand how changes in biodiversity might impact biomass production by examining how biomass correlates with a number of biodiversity metrics (especially the number of species and functional groups). This body of research has focused on species with the implicit assumption that they are independent entities. However, functional and ecological similarities are shaped by patterns of common ancestry, such that distantly related species might contribute more to production than close relatives, perhaps by increasing niche breadth. Here, we analyze 2 decades of experiments performed in grassland ecosystems throughout the world and examine whether the evolutionary relationships among the species comprising a community predict how biodiversity impacts plant biomass production. We show that the amount of phylogenetic diversity within communities explained significantly more variation in plant community biomass than other measures of diversity, such as the number of species or functional groups. Our results reveal how evolutionary history can provide critical information for understanding, predicting, and potentially ameliorating the effects of biodiversity loss and should serve as an impetus for new biodiversity experiments.community ecology ͉ ecosystem function ͉ phylogenetic diversity ͉ biodiversity experiments ͉ metaanalysis

Phylogenetic congruence between subtropical trees and their associated fungi

“…Of the 26 species, 24 had at least one gene represented in GenBank. For each of the two remaining species, Quercus chungii and Ormosia pachycarpa , we used gene sequences of congeneric relatives (Cadotte et al., 2008), which were Quercus myrsinifolia and Ormosia fordiana , respectively. The GenBank accession numbers for all the sequences used are shown in Table 1.…”

Phylogenetic constraints on ecosystem functioning

“…An alterna tive approach has been to evaluate, a posteriori, the contribution of evolutionary history (phylogenetic diversity, PD) of artificially assembled communities to EF. It is hypothesized that if closely related species are ecologically similar (that is, trait conservatism), EF such as productivity should increase with PD 14 . As we usually have imper fect knowledge of the distribution of functional traits responsible for resource acquisition and species interactions, the knowledge of the evolutionary relationships could thus be used as a proxy for func tional diversity 4,9,14 .…”

Genetic distance predicts trait differentiation at the subpopulation but not the individual level in eelgrass, Zostera marina

“…A growing number of studies use genetic dissimilarity as a proxy for ecological differentiation (e.g., Cadotte et al., 2008; Stachowicz et al., 2013; Violle et al., 2011), often assuming a positive correlation between the two, yet there are few critical tests of the shape or strength of this relationship. We assessed whether neutral genetic differentiation among individuals and subpopulations of the eelgrass, Z. marina , at 11 microsatellite loci predicts their ecological differentiation with respect to a number of traits associated with resource acquisition and growth strategy.…”

“…Furthermore, measuring continuous trait variation among individuals within a species requires extensive effort and may not be practical for assemblages with a large number of taxa. Both of these challenges raise the question of whether measures of genetic distance can be used as proxies for functional divergence, based on the assumption that phylogenies, genealogies, or estimates of relatedness can reflect integrated phenotypic differences among taxa or individuals (Cadotte, Cardinale & Oakley, 2008; Felsenstein, 1985; Harvey & Pagel, 1991; Stachowicz et al., 2013). …”

“…For example, the outcomes of interspecific interactions can sometimes be predicted by the phylogenetic distinctiveness of the interacting species, with more closely related species competing more intensely for a narrower range of resources, leading to lower group productivity or greater probability of competitive exclusion (Burns & Strauss, 2011; Cadotte, Cavender‐Bares, Tilman & Oakley, 2009; Cadotte et al., 2008; Flynn, Mirotchnick, Jain, Palmer & Naeem, 2011; Maherali & Klironomos, 2007; Violle, Nemergut, Pu & Jiang, 2011). However, the underlying assumption that phylogenetic diversity serves as a proxy for trait differentiation is not always supported; in some cases, phylogenetic diversity influences ecosystem structure and functioning even when phylogenetic distance is not correlated with trait differences (Flynn et al., 2011; Tan, Pu, Ryberg & Jiang, 2012).…”