Alternative methods for assessing and monitoring mangrove forests

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Although considered one of the most productive ecosystems in the world, mangrove forests are also identified as one of the most threatened.  One particular concern is the inability to receive updated information regarding the extent and condition of many of these forested wetlands.  Consequently, one focus of the proposed research is a continued evaluation of the use of imagery acquired from satellites as a means of regularly mapping these wetlands at a scale detailed enough to assist researchers and resource managers.  For example, one objective of my study is to determine whether changes in mangrove productivity, indirectly estimated using Leaf Area Index (LAI) (i.e. leaf coverage), can be mapped at the species level using multi-date very high resolution optical satellite data.  In addition, for regions where quasi-permanent cloud cover limits optical sensors, I am proposing to examine the use of a radar satellite, RADARSAT-2, as an alternative platform for estimating similar mangrove biophysical parameter data (e.g. LAI, tree height) since radar can effectively image through clouds.      Recent studies on the use of mangrove forests by local inhabitants indicate that these people depend on the timber extracted from these forests for a variety of local uses (e.g. house construction).  The results of these studies also indicate that factors such as species composition, tree height and distance from settlements could explain the extent of harvesting occurring for select parts of the mangrove forest. Consequently, I propose to develop a unique spatial database to identify suitable areas for mangrove subsistence harvesting.  This management tool will be based on the integration of various sources of data including information derived from satellites and knowledge gathered from local fishermen.  Finally, I intend to assess the potential use of dendrochronology (i.e. tree ring dating) for identifying specific historical causes of mangrove forest degradation.  In particular, I anticipate that changes in tree ring characteristics will reflect past perturbations and thus assist researchers in identifying key causes of mangrove loss.