Although a trade-off between colonization and competitive ability is widely recognized to promote species co-existence, this trade-off is rarely tested. Biomass allocation patterns, clonal dispersal, and competitive success of three salt marsh plant species grown in pots or trays were examined in the greenhouse. The competitive ranking was determined by a pairwise additive-series competition experiment in pots under low nutrient conditions. Competitive ability and patterns of biomass allocation differed significantly among species. The competitive dominant, Juncus gerardi, exhibited higher root:shoot and root:rhizome ratios than its competitive subordinates, Spartina patens and Distichlis spicata. Contrary to what was previously observed in the field, Spatrina patens was only slightly competitively superior to Distichlis spicata in the greenhouse (i.e., the difference was not statistically significant). Distichlis spicata and Spartina patens exhibited very similar patterns of biomass allocation, including similar patterns of allocation to roots and rhizomes. Although the ranking of the three species with respect to clonal dispersal rates in trays (i.e., Distichlis spicata > Spartina patens > Juncus gerardi) was inversely correlated with their competitive abilities in the field, differences in dispersal rates were small and not statistically significant. Thus, a hypothesized trade-off between competitive ability and colonization ability in these three species does not appear to be strongly correlated with interspecific differences in rates of clonal dispersal in trays in the greenhouse. It is hypothesized that the superior colonization ability of Distichlis spicata observed ill the field depends greatly on its ability to tolerate harsh edaphic conditions within gaps.
All Science Journal Classification (ASJC) codes
- Ecology, Evolution, Behavior and Systematics