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Interspecific competition reduces seed dispersal in an annual plant and slows simulated range expansions
  • Erin McHugh,
  • Carla Urquhart,
  • Jennifer Williams
Erin McHugh
University of Toronto - St George Campus

Corresponding Author:[email protected]

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Carla Urquhart
The University of British Columbia - Vancouver Campus
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Jennifer Williams
The University of British Columbia
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Abstract

Understanding the factors influencing how fast populations can spread across the landscape will be crucial as species ranges shift due to climate change. While the role of abiotic factors in determining expansion speed has been well studied in theory and empirical research, how interspecific interactions such as competition impact speed has received far less attention. Here, we investigated how seed dispersal distances change in response to competition and how these changes to seed distributions impact expansion speed. We dispersed four genotypes of the annual plant Arabidopsis thaliana with variation in life history traits into greenhouse mesocosms of either empty habitat or habitat containing the annual grass competitor, Lolium multiflorum. We found that competition decreased both mean and maximum dispersal distance. We then built a simulation model of range expansion with experimental data from this and a prior experiment to understand whether competition slows species expansions primarily through decreasing dispersal or fecundity. We found that competition primarily slows expansion speed through decreases in dispersal, but that when competition impacts both dispersal and fecundity, expansions slow more than with dispersal alone. The genotype with traits associated with longer distance dispersal was the most affected by competition in both experimental dispersal and simulations. This research suggests that not only does competition slow range expansions through decreases in both fecundity and dispersal, but that there may be consequences for evolutionary processes at the leading edge.
27 Mar 2024Submitted to Oikos
02 Apr 2024Submission Checks Completed
02 Apr 2024Assigned to Editor
02 Apr 2024Review(s) Completed, Editorial Evaluation Pending
15 Jul 20241st Revision Received
16 Jul 2024Submission Checks Completed
16 Jul 2024Assigned to Editor
16 Jul 2024Review(s) Completed, Editorial Evaluation Pending
17 Jul 2024Reviewer(s) Assigned
01 Sep 2024Editorial Decision: Revise Minor
12 Sep 20242nd Revision Received
16 Sep 2024Submission Checks Completed
16 Sep 2024Assigned to Editor
16 Sep 2024Review(s) Completed, Editorial Evaluation Pending
28 Sep 2024Editorial Decision: Accept