摘要：Understanding of salt marsh plant zonation caused by abiotic and biotic factors is essential for successful conservation plans in the face of ongoing environmental change. The frequency of flooding is more important than elevation in predicting marsh plant zones. Tidal marsh plants are distributed across a wide gradient of soil–water salinities. Studies done to date indicate that redox potential, ionic composition of soil, moisture content of soil, latitude, topographical, and climatic factors may play some role in forming vegetation zones. Competition and facilitation are important in mediating zonation, and the importance of facilitation of plant growth increases with increasing physical stress within the abiotic range limits. A refined understanding of facilitation along stress gradients would help inform successful restoration and management of vegetation. In the salt marsh plant community, a trade-off between belowground competitive ability and the ability to tolerate physical stressors appears to drive plant growth patterns across the landscape. Understanding and predicting shifts between bare flats and vegetated marshes is of great importance, because it provides a useful scientific basis for understanding vegetation zonation. A bimodal distribution of intertidal elevations, positive feedbacks, and alternative stable states and abrupt shifts in elevation from bare flats to vegetated states are present in salt marsh ecosystems. Strategies to assess whether alternative stable states are present are now converging in fields as disparate as desertification, limnology, oceanography, ecology and climatology. Further research should therefore focus on the conditions for and the specific mechanisms behind alternative stable states in salt marsh ecosystems.
