Phylogenetic diversity (PD) describes the total amount of phylogenetic distance among species in a community. Although there has been substantial research on the factors that determine community PD, exploration of the consequences of PD for ecosystem functioning is just beginning. We argue that PD may be useful in predicting ecosystem functions in a range of communities, from single-trophic to complex networks. Many traits show a phylogenetic signal, suggesting that PD can estimate the functional trait space of a community, and thus ecosystem functioning. Phylogeny also determines interactions among species, and so could help predict how extinctions cascade through ecological networks and thus impact ecosystem functions. Although the initial evidence available suggests patterns consistent with these predictions, we caution that the utility of PD depends critically on the strength of phylogenetic signals to both traits and interactions. We advocate for a synthetic approach that incorporates a deeper understanding of how traits and interactions are shaped by evolution, and outline key areas for future research. If these complexities can be incorporated into future studies, relationships between PD and ecosystem function bear promise in conceptually unifying evolutionary biology with ecosystem ecology.

Exotic species dominate many communities; however the functional significance of species' biogeographic origin remains highly contentious. This debate is fuelled in part by the lack of globally replicated, systematic data assessing the relationship between species provenance, function and response to perturbations. We examined the abundance of native and exotic plant species at 64 grasslands in 13 countries, and at a subset of the sites we experimentally tested native and exotic species responses to two fundamental drivers of invasion, mineral nutrient supplies and vertebrate herbivory. Exotic species are six times more likely to dominate communities than native species. Furthermore, while experimental nutrient addition increases the cover and richness of exotic species, nutrients decrease native diversity and cover. Native and exotic species also differ in their response to vertebrate consumer exclusion. These results suggest that species origin has functional significance, and that eutrophication will lead to increased exotic dominance in grasslands.

1. Exotic annual plants are an increasingly important ecological issue and new, creative approaches to management are required. In desert ecosystems of the southwestern USA, the forbs Brassica tournefortii, Erodium cicutarium and Schismus spp. dominate and alter native annual communities. Hand weeding B. tournefortii is currently the most common control method employed, but weeding is inadequate and expensive for managing large-scale invasions. New methods must be developed to conserve and restore desert ecosystems. 2. Exotic annuals in desert systems have rapid germination and phenology compared to natives, indicating that a window for selective control of exotic annuals may occur immediately after exotic seedling emergence. We tested the role of timing in control methods by comparing a cotyledon-stage glyphosate application to a bolting-stage application and to hand weeding B. tournefortii, plus an untreated check. Treatments were tested at two sites dominated by either exotic or native annuals and followed for 2 years; early application was repeated the second year. Cover and richness were evaluated during seedling and peak flowering stages underneath and between shrubs. 3. Early glyphosate application did not affect native cover, but did reduce exotic cover. Late herbicide negatively impacted both exotics and natives. Natives had little positive response, and then only through hand weeding under shrubs, but the same treatment caused an increase in the exotic E. cicutarium. 4. Synthesis and applications. The rapid phenology of exotic annuals may be exploited to control exotics while minimizing impacts on native plants in desert communities. This approach may be useful for other invasions in other ecosystems by species with rapid, early germination, or may act as a supplement to improve the efficacy of existing management regimes.