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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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This content will become publicly available on May 1, 2026
Forecasting range shifts using abundance distributions along environmental gradients
Globally, many species’ distributions are shifting in response to contemporary climate change. However, the direction and rate of shifts remain difficult to predict, impeding managers’ abilities to optimize resource allocation. Here, we developed a new approach for forecasting species range‐limit shifts that requires only abundance data along environmental (for example, elevational) gradients. We posited that the distribution of species’ abundances could offer insights into the potential for future range‐limit shifts. We then tested this prediction using data from several transect studies that compared historical and contemporary distributions. Consistent with our prediction, we found that strong asymmetry in abundance distributions (that is, “leaning” distributions) indeed preceded species’ lower‐limit range shifts. Accordingly, surveying abundances along environmental gradients may represent a promising, cost‐effective method for forecasting local shifts. Ideally, this approach will be incorporated by practitioners into species‐specific management planning and will inform on‐the‐ground conservation efforts.
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- Award ID(s):
- 2022036
- PAR ID:
- 10621589
- Publisher / Repository:
- Frontiers in Ecology and the Environment
- Date Published:
- Journal Name:
- Frontiers in Ecology and the Environment
- Volume:
- 23
- Issue:
- 4
- ISSN:
- 1540-9295
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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