Asymmetric competition causes multimodal size distributions in spatially structured populations

Vel�zquez, Jorge; Allen, Robert B.; Coomes, David A.; Eichhorn, Markus P.

Abstract

Plant sizes within populations often exhibit multimodal distributions, even when all individuals are the same age and have experienced identical conditions. To establish the causes of this, we created an individual-based model simulating the growth of trees in a spatially explicit framework, which was parametrized using data from a long-term study of forest stands in New Zealand. First, we demonstrate that asymmetric resource competition is a
necessary condition for the formation of multimodal size distributions within cohorts. By contrast, the legacy of small-scale clustering during recruitment is transient and quickly overwhelmed by density-dependent mortality. Complex
multi-layered size distributions are generated when established individuals are restricted in the spatial domain within which they can capture resources. The number of modes reveals the effective number of direct competitors, while
the separation and spread of modes are influenced by distances among established individuals. Asymmetric competition within local neighbourhoods can therefore generate a range of complex size distributions within even-aged cohorts.

Citation

Velázquez, J., Allen, R. B., Coomes, D. A., & Eichhorn, M. P. (2016). Asymmetric competition causes multimodal size distributions in spatially structured populations. Proceedings of the Royal Society B: Biological Sciences, 283(1823), 20152404. https://doi.org/10.1098/rspb.2015.2404

• Journal Article Type: Article
• Acceptance Date: Nov 30, 2015
• Online Publication Date: Jan 27, 2016
• Publication Date: Jan 27, 2016
• Deposit Date: Feb 4, 2016
• Publicly Available Date: Feb 4, 2016
• Journal: Proceedings of the Royal Society B: Biological Sciences
• Print ISSN: 0962-8452
• Electronic ISSN: 1471-2954
• Publisher: The Royal Society
• Peer Reviewed: Peer Reviewed
• Volume: 283
• Issue: 1823
• Pages: 20152404
• DOI: https://doi.org/10.1098/rspb.2015.2404
• Keywords: bimodality, individual-based model, forests, Fuscospora cliffortioides, southern beech, zone-of-influence
• Public URL: https://nottingham-repository.worktribe.com/output/771543
• Publisher URL: http://rspb.royalsocietypublishing.org/content/283/1823/20152404