Questions: 1. Are there competitive response strategies for light in juvenile plants? 2. If so, do plant traits (e.g. seed weight, relative growth rate, height and biomass) correlate with the strategies?
Location: Controlled greenhouse study using perennial vegetation typical of wet meadows in Northeast Ohio, USA.
Methods: We used two light manipulations in a greenhouse to screen ten replicates of 19 plant species for three proposed competitive response strategies (‘escape’, ‘forage’, ‘persist’). We measured the time it took a seedling to die and the maximum height achieved when grown in the dark to assess two strategies, persist and escape. The biomass of seedlings when grown under a controlled, low-intensity, shifting light source was measured to test a third strategy, forage.
Results: We found significant variation across species in the measurements used to assess each strategy. The species ranking for each strategy was not concordant across strategies. Traits were found that correlated with the escape strategy (seed weight, height and biomass) and persist strategy (time to reach maximum height). No traits were found that correlate with the forage strategy.
Conclusions: There appear to be trade-offs by plants in the three strategies tested in this study. Species which had the best performance on one strategy typically scored poorly on the other strategies. However, many species fall in the middle range, ranking similarly across the ‘persist’, ‘escape’, and ‘forage’ strategies.
Abbreviations: CR = Competitive response, RGR = Relative growth rate.
Nomenclature: Gleason & Cronquist (1991); Anon. (1997).
