Tuesday, March 17, 2009 3:35 AM
Article 2
Trophic interactions involving plants and animals in tropical mangrove forests have important controlling influences on several population, community and ecosystem-level processes. Insect herbivores remove up to 35% of leaf area from some mangrove tree species and can cause the death of seedlings. Leaf chemistry and toughness and soil nutrient status all appear to be important in explaining the between- and among-species variance in leaf damage. Insects also attack and damage, mainly by boring, a large proportion of mangrove seeds. Shadehouse experiments have shown that such post-dispersal predation can have a significant effect on seedling survival, growth and biomass allocation to leaves, stems and roots. Sesarmid crabs are also responsible for severe post-dispersal seed predation. In field trials, crabs consumed more than 70% of the seeds of five tree species. For four of these five species there was an inverse relationship between seed predation rate and the dominance of conspecific adult trees, while the within-site distribution pattern of one tree species appears to be partially controlled by crabs. The same crab species also consume 30–80% (depending on forest type and intertidal elevation), of the annual litter fall in mangrove forests and, thus, have an important role in controlling the rate of remineralization of detritus within forests and the export of particulate matter from the forests to other nearshore habitats. The other major component of litter in the forests is wood, which is broken down relatively rapidly by teredinid molluscs (shipworms). More than 90% of the weight loss from decomposing trunks of Rhizophora species during the first four years of decay is through ingestion by teredinids. The annual turnover of dead wood mass in Rhizophora forests is equivalent to that of the processing of leaf detritus by crabs. Because of the relatively low species richness of trees and consumers in tropical mangrove forests, they are likely to serve as productive sites for further investigations of the influence of plant-animal interaction the dynamics of tropical forests.
Article abstract from http://www3.interscience.wiley.com/journal/119361815/abstract
Reflection 2
After reading the article, I have learned that the plants and animals in tropical mangrove forests have important controlling influences on several population, community and ecosystem-level processes. Insect herbivore can cause the death of seedlings and leaf chemistry, toughness and soil nutrient status all appear to be important in explaining the between- and among-species variance in leaf damage. Insects mainly attack or damage a large proportion of mangrove seeds, causing the increase in death of the seedlings. Sesarmid crabs are also responsible for severe post-dispersal seed predation as they consumed more than 70% of the five tree species. Out of five of this species, four of them have an inverse relationship between seed predation rate and the dominance of conspecific adult trees. The same crab species also consume 30–80% (depending on forest type and intertidal elevation), of the annual litter fall in mangrove forests leading to shorter lifetime for the trees and, thus, have an important role in controlling the rate of remineralization of detritus within forests and the export of particulate matter from the forests to other nearshore habitats. The other major component of litter is wood, which is broken down relatively rapidly by shipworms. More than 90% of the weight loss from decomposing trunks of Rhizophora species during the first four years of decay is through ingestion by shipworms. The total turnover of dead wood mass in Rhizophora forests is as much as to that of the processing of leaf detritus by crabs. The insects do play a part in making the forest look like a mangrove but by damaging the plants, the forests would be gone by just a while, so I think if there is a possibility, separate the insects and the trees they damage away from each other. By doing that, I think the mangroves are saved.
(303 words) ( Some of the information in my reflective journal was taken from the article)
