I'm currently working in an area of rapid sedimentation, and I wonder which other factors can influence the density and distribution of mangrove species? I know the tide is one of those.
Good questions. fresh water inputs matter. solar radiation matters, exposure to waves matters.
Dear Carlos,
it is not easy to answer before having some more information. How fast is "rapid" sedimentation? What kind of sediment is it? How large is the area, where you have observed this sedimentation.
The sedimentation rate is 175 ha per year and this is happening in the Gulf of Guayaquil, Ecuador
The establishment and the density of the mangroves depend on the sedimentation rate of silt, water current, light intensity and the salinity of water. Freshwater:salinity ratio is one of the factors. In addition to that you need to check any physical or mechanical disturbances in your study area.
The sedimentation may changes the salinity content of the water body, which determine the selection or survival of species and its density. In addition to that, the sedimentation material or physical nature of the sedimentation also play some role in the establishment, development and growth of the species.
Salinity content is influencing the selection of mangroves to survive. The level of salt tolerant is varying to different mangrove species.
You mentioned the sedimentation rate. But what would be the thickness of the sediment? It influence on the survival of the saplings too. More sediment hindered the respiration of the saplings and may kill them.
Some of the following findings may help you.
lagoons. Science and Development Network. [Online]. Available:
www.scidev.net
comparison of the survival and early growth of selected mangrove
and non mangrove species under non saline conditions,” in Proc.
National Conference on Identification of Knowledge Gaps for
Sustainable Management of Mangrove Ecosystems in Sri Lanka,
University of Ruhuna, Sri Lanka, Abstracts, 2010, pp. 11.
Dear Carlos,
you gave the spatial distribution in ha. What would be nice to know is the accumulation rate, e.g. mm/year and how did you measure.
Best regards
Klaus
Now many aquaculture farms are coming near by coastal regions and the deltas including mangrove forest. Due to aquaculture effluents and other domestic, industrial discharges the soil substratum will be affected ultimately the mangrove growth will be affected that may lead to soil erosion in that area.
This was found and measure via GIS, in a lapse of 12 years. Not many studies have been done in this area and the accumulation rate haven't been calculated.
On the local scale, mangroves grow best on stable, penetrable substrates in the mid to high intertidal region. Local geomorphology would influence the hydroperiod and exposure, thus processes such as propagule dispersal (contributing to tree density). Mangroves also benefit from relief from salinity stress through some freshwater input. Differences among mangrove species in dealing with these factors therefore determine their local distribution.
On a broader spatial scale, mangrove distribution is restricted by low temperature, e.g. the frequency of frost. Biogeographic factors also influence mangrove diversity - the Indo-west-Pacific region supports much higher species richness and diversity than the Atlantic-east-Pacific region.
Lastly, anthropogenic pollution, sedimentation, and 'coastal squeeze' increasingly influence mangrove distribution, growth and their long-term viability.
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