COMPETITION AND ALLELOPATHY IN AQUATIC PLANT-COMMUNITIES

The paper reviews the published literature on the studies of competiti on and allelopathy in aquatic plant communities. Taking a broader view of the community, the studies on interactions between macrophytes and microphytes, macrophytes and macro-invertebrates and microbial commun ities are also reviewed. The role of these interactions in the structu re and dynamics of aquatic communities has been discussed in light of the current hypotheses concerning competition in terrestrial communiti es. The available information suggests that the aquatic plants of vari ous growth forms differ greatly among themselves in their responses an d adaptations to competition and allelopathy. The possible application of these interactions in biological control of plant pests and in agr iculture is also summarized. We conclude that the observed differences in these interactions between the terrestrial and aquatic environment are due to the effects of water as a non-resource variable as well as due to special adaptive characteristics of aquatic plants. Further we hypothesize that the aquatic plants adopt both competitive and allelo pathic strategies under different conditions and in interactions with different plants. The review highlights that our knowledge of both com petition and allelopathy among aquatic plant communities is inadequate and fragmentary, and therefore, both extensive and intensive studies are required.