We found a match
Your institution may have access to this item. Find your institution then sign in to continue.
- Title
Mechanisms mediating plant distributions across estuarine landscapes in a low-latitude tidal estuary.
- Authors
Hongyu Guo; Pennings, Steven C.
- Abstract
Understanding of how plant communities are orgamzed and will respond to global changes requires an understanding of how plant species respond to multiple environmental gradients. We examined the mechanisms mediating the distribution patterns of tidal marsh plants along an estuarine gradient in Georgia (USA) using a combination of field transplant experiments and monitoring. Our results could not be fully explained by the "competition-to-stress hypothesis" (the current paradigm explaining plant distributions across estuarine landscapes). This hypothesis states that the upstream limits of plant distributioiis are determined by competition, and the downstream limits by abiotic stress. We found that competition was generally strong in freshwater and brackish marshes, and that conditions in brackish and salt marshes were stressful to freshwater marsh plants, results consistent with the competition-to-stress hypothesis. Four other aspects of our results, however, were not explained by the competition-to-stress hypothesis. First, several halophytes found the freshwater habitat stressful and performed best (in the absence of competition) in brackish or salt marshes. Second, the upstream distribution of one species was determined by the combination of both abiotic and biotic, (competition) factors. Third, marsh productivity (estimated by standing biomass) was a better predictor of relative biotic interaction intensity (Rh) than was salinity or flooding, suggesting that productivity is a better indicator of plant stress than salinity or flooding gradients. Fourth, facilitation played a role in mediating the distribution patterns of some plants. Our results illustrate that even apparently simple abiotic gradients can encompass surprisingly complex processes mediating plant distributions.
- Subjects
GEORGIA; PHYTOGEOGRAPHY; ESTUARINE ecology; PLANT communities; PLANT species; MARSH plants; PLANT competition
- Publication
Ecology, 2012, Vol 93, Issue 1, p90
- ISSN
0012-9658
- Publication type
Article
- DOI
10.1890/11-0487.1