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ABSTRACT Forecasting plant responses under global change is a critical but challenging endeavour. Despite seemingly idiosyncratic responses of species to global change, greater generalisation of ‘winners’ and ‘losers’ may emerge from considering how species functional traits influence responses and how these responses scale to the community level. Here, we synthesised six long‐term global change experiments combined with locally measured functional traits. We quantified the change in abundance and probability of establishment through time for 70 alpine plant species and then assessed if leaf and stature traits were predictive of species and community responses across nitrogen addition, snow addition and warming treatments. Overall, we found that plants with more resource‐acquisitive trait strategies increased in abundance but each global change factor was related to different functional strategies. Nitrogen addition favoured species with lower leaf nitrogen, snow addition favoured species with cheaply constructed leaves and warming showed few consistent trends. Community‐weighted mean changes in trait values in response to nitrogen addition, snow addition and warming were often different from species‐specific trait effects on abundance and establishment, reflecting in part the responses and traits of dominant species. Together, these results highlight that the effects of traits can differ by scale and response of interest.
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Global change re‐structures alpine plant communities through interacting abiotic and biotic effects
Abstract Global change is altering patterns of community assembly, with net outcomes dependent on species' responses to the abiotic environment, both directly and mediated through biotic interactions. Here, we assess alpine plant community responses in a 15‐year factorial nitrogen addition, warming and snow manipulation experiment. We used a dynamic competition model to estimate the density‐dependent and ‐independent processes underlying changes in species‐group abundances over time. Density‐dependent shifts in competitive interactions drove long‐term changes in abundance of species‐groups under global change while counteracting environmental drivers limited the growth response of the dominant species through density‐independent mechanisms. Furthermore, competitive interactions shifted with the environment, primarily with nitrogen and drove non‐linear abundance responses across environmental gradients. Our results highlight that global change can either reshuffle species hierarchies or further favour already‐dominant species; predicting which outcome will occur requires incorporating both density‐dependent and ‐independent mechanisms and how they interact across multiple global change factors.
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- PAR ID:
- 10375516
- Publisher / Repository:
- Wiley-Blackwell
- Date Published:
- Journal Name:
- Ecology Letters
- Volume:
- 25
- Issue:
- 8
- ISSN:
- 1461-023X
- Format(s):
- Medium: X Size: p. 1813-1826
- Size(s):
- p. 1813-1826
- Sponsoring Org:
- National Science Foundation
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