Anticipating how natural ecosystems will respond to climate change, and determining which species are most at risk of extinction, are crucial aspects of conservation work.

Between about 10% and 50% of all species on Earth, including flowering plants, are predicted to be at high risk of extinction as a result of climate change. Such predictions are almost always generated by considering how individual species respond to a changing climate, without taking into account their potential interactions with other species. This gap in our understanding is not due to a lack of recognition of the importance of species interactions, but reflects the enormous challenge of measuring the strength of species interactions in realistic field conditions, let alone considering how a changing climate might alter those interactions.【G1】_____________________________

Van Dyke and colleagues provide a major advance in the prediction of species persistence under climate change by coupling a well-designed field experiment with predictive mathematical models in order to determine how climate change affects the outcome of competitive interactions. Sowing these seeds, the authors created experimental communities consisting of varying numbers of individuals of the same species orpairwise combinations of different species.【G2】________________________

The effects on individual plant survival in each of these contexts were measured, and the data used in mathematical models to generate predictions for whether one or both species would persist.

Surprisingly, climate change was less likely to affect competition between species pairs that were more similar in terms of their roles or functions in the ecosystem. Foundational theories of ecosystem resilience predict that communities that contain species with very different functions will be more resilient in a changing climate than will communities that consist of species with similar functions.【G3】________________

【G4】_____________________________Furthermore, the results have some direct relevance for conservation planning. For example, they confirm the crucial need to consider species interactions when attempting to predict the persistence of species in future climates.

【G5】_______________________________Although the influence of climate on competitive outcomes more broadly, it will also be important to establish whether measurable characteristics of species exist. These traits are indeed indicative of the species’ responses to climate change and other environmental drivers. Both of these factors will be required for making realistic predictions across whole communities of interacting species and for evaluating the potential for functionally diverse communities to either buffer or exacerbate the impacts of climate change.

[A] Van Dyke and colleagues’ findings provide a step forward in terms of linking hard-to-obtain field data and predictive models, yet the conclusions are inherently limited.

[B] Yet such estimates are clearly needed to provide realistic scenarios for the future that can guide conservation actions.

[C] The authors conclude that modest changes in climate strikingly alter the outcome of competitive interactions between species, whereas those same rainfall changes have little effect on how species fare when grown alone.

[D] The study reveals how climate change can have both direct and indirect effects on the persistence of species and community diversity.

[E] Each of these one-or two-species communities, which developed from seeds sown to generate different population sizes, were subjected to either the ecosystem’s current average precipitation or to a 20% reduction in the average precipitation—a scenario imitating the decreases in rainfall predicted for the area as a result of future climate change.

[F] The authors’ study convincingly demonstrates that climate can alter the effect of competition between species, providing a fundamentally new understanding of ecological interactions.

[G] However, Van Dyke and colleagues’ results reveal that, when species interactions are considered, communities with greater functional diversity might experience more turnover in species composition under climate change as a result of alterations in competitive interactions, compared with the amount of turnover for communities with less functional diversity.

【G1】