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Intraspecific trait plasticity to N and P of the wetland invader, Alternanthera philoxeroides under flooded conditions
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  • Nathan Harms,
  • Ian Knight,
  • Ashton DeRossette,
  • Dean A. Williams
Nathan Harms
US Army Engineer Research and Development Center Environmental Laboratory

Corresponding Author:[email protected]

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Ian Knight
US Army Engineer Research and Development Center Environmental Laboratory
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Ashton DeRossette
US Army Engineer Research and Development Center Environmental Laboratory
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Dean A. Williams
Texas Christian Univ
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Abstract

Interactions between invaders and resource availability may explain variation in their success or management efficacy. For widespread invaders, regional variation in plant response to nutrients can reflect phenotypic plasticity of the invader, genetic structure of invading populations, or a combination of the two. The wetland weed Alternanthera philoxeroides (alligatorweed) is established throughout the southeastern USA and California, and has high genetic diversity despite primarily spreading clonally. Despite its history in the USA, the role of genetic variation for invasion and management success is only now being uncovered. To better understand how nutrients and genotype may influence A. philoxeroides invasion, we measured the response of plants from 26 A. philoxeroides populations (three cp haplotypes) to combinations of nitrogen (4 or 200 mg/L N) and phosphorus (0.4 or 40 mg/L P). We measured productivity (biomass accumulation and allocation), plant architecture (stem diameter and thickness, branching intensity) and foliar traits (toughness, dry matter content, percent N, percent P). A short-term developmental assay was also conducted by feeding a subset of plants from the nutrient experiment to the biological control agent Agasicles hygrophila, to determine whether increased availability of N or P to its host influenced agent performance, as has been previously suggested. A. philoxeroides haplotype Ap1 was more plastic than other haplotypes in response to nutrient amendments, producing more than double the biomass from low to high N and 50-68% higher shoot:root ratio than other haplotypes in the high N treatment. A. philoxeroides haplotypes differed in 7 of 10 variables in response to increased N. We found no differences in short-term A. hygrophila development between haplotypes but mass was 23% greater in high than low N treatments. This study is the first to explore the interplay between nutrient availability, genetic variation, and phenotypic plasticity in invasive characteristics of the global invader, A. philoxeroides.
04 Jan 2023Submitted to Ecology and Evolution
05 Jan 2023Submission Checks Completed
05 Jan 2023Assigned to Editor
19 Jan 2023Reviewer(s) Assigned
03 Mar 2023Review(s) Completed, Editorial Evaluation Pending
03 Mar 2023Editorial Decision: Revise Minor
10 Mar 20231st Revision Received
11 Mar 2023Submission Checks Completed
11 Mar 2023Assigned to Editor
11 Mar 2023Review(s) Completed, Editorial Evaluation Pending
15 Mar 2023Editorial Decision: Accept