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Experimental plant introduction: disentangling the roles of propagule pressure, soil disturbance and life-history traits

English title Experimental plant introduction: disentangling the roles of propagule pressure, soil disturbance and life-history traits
Applicant van Kleunen Mark
Number 117722
Funding scheme Project funding (Div. I-III)
Research institution Institut für Pflanzenwissenschaften Universität Bern
Institution of higher education University of Berne - BE
Main discipline Ecology
Start/End 01.01.2008 - 30.06.2011
Approved amount 322'153.00
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Keywords (6)

biodiversity; biological invasion; colonization; environmental disturbance; horticultural species; life-history traits

Lay Summary (English)

Lay summary
An important issue in ecology is which factors determine successful population establishment of plant species. Identification of these factors is particularly relevant for biological invasions. It has been hypothesized that the ideal invasive plant should possess life-history characteristics such as fast and profuse germination, rapid growth, facultative self-fertilization, adaptive phenotypic plasticity (i.e., adjustment of the morphology and physiology in response to environmental change) and high competitive ability. Empirical evidence for the role of species traits in invasiveness, however, is scarce because most potentially important traits have to be assessed experimentally. Moreover, the importance of species traits may depend on environmental factors such as soil disturbance, and might be obscured by the introduction history of the species including time since introduction and propagule pressure (i.e., the number of introduction events and the number of introduced seeds per event). The importance of intrinsic species characteristics and extrinsic factors on the likelihood of successful naturalization (i.e., establishment of a self-sustaining population) can be disentangled in experiments that use controlled introduction of species. Because these experiments have the risk of introducing new invasive species, such experiments have never been done. However, the risks can be reduced by using horticultural species that are already available in the target region instead of introducing completely new species and by eradication of the introduced plants at the end of the project. To quantify and disentangle the roles of species traits, soil disturbance and propagule pressure while controlling for time since introduction, we will experimentally introduce 100 horticultural, herbaceous species at different propagule pressures (1, 10, 100 and 1000 seeds) in 16 grassland sites with and without soil tilling. Of these species, we will determine the establishment success, and assess how this relates to propagule pressure and soil disturbance. To determine the roles of species traits in establishment success, we will in five other experiments assess seed and germination characteristics, growth rates, reproductive systems, competitive abilities and plastic responses to shading for the 100 study species. This project will be the first one to experimentally quantify and disentangle the influence of life-history traits, soil disturbance and propagule pressure on establishment success while controlling for time since introduction. It will contribute to better risk assessment for future introduction of exotic plant species.
Direct link to Lay Summary Last update: 21.02.2013

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