Plant Size and Competitive Dynamics along Nutrient Gradients

Authored by William S Currie, Deborah E Goldberg, Kenneth J Elgersma, Jason P Martina

Date Published: 2017

DOI: 10.1086/692438

Sponsors: United States National Aeronautics and Space Administration (NASA)

Platforms: Microsoft Visual Basic

Model Documentation: Other Narrative

Model Code URLs: https://www-journals-uchicago-edu.ezproxy1.lib.asu.edu/doi/suppl/10.1086/692438

Abstract

Resource competition theory in plants has focused largely on resource acquisition traits that are independent of size, such as traits of individual leaves or roots or proportional allocation to different functions. However, plants also differ in maximum potential size, which could outweigh differences in module-level traits. We used a community ecosystem model called MONDRIAN to investigate whether larger size inevitably increases competitive ability and how size interacts with nitrogen supply. Contrary to the conventional wisdom that bigger is better, we found that invader success and competitive ability are unimodal functions of maximum potential size, such that plants that are too large (or too small) are disproportionately suppressed by competition. Optimal size increases with nitrogen supply, even when plants compete for nitrogen only in a size-symmetricmanner, although adding size-asymmetric competition for light does substantially increase the advantage of larger size at high nitrogen. These complex interactions of plant size and nitrogen supply lead to strong nonlinearities such that small differences in nitrogen can result in large differences in plant invasion success and the influence of competition along productivity gradients.

Tags

invasion Communities Body-size Individual-based model Species-diversity Phragmites-australis Nitrogen deposition Clonal plants Competitive ability Invasive plants Wetland Optimal size Lakes coastal wetland Productivity gradients Growth traits