Three Decades Of Remote Sensing Change Detection Of Poyang Lake Wetland

The Poyang Lake wetland provides many valuable services. Some of theseservices include supporting a high biodiversity and playing a regulatory role onthe local climate and hydrology. Many of the vulnerabilities in the area are tiedto the water dynamics of the surrounding sum-basins exposing its vulnerabilitiesto floods. The fragile balance in the area is threatened by land reclamation,sedimentation, changes to ecological factors, landscape distribution andanthropogenic decisions such as the construction of the Three Gorges Dam.Many of the diversity in the area are brought about by the annualfluctuations of water levels that sustain the wetlands which attracts largegathering of migrating and overwintering birds in the East Asia-Australianflyway. This interaction of avian diversity also exposes the area to thepossibility of widespread avian virus outbreaks with viruses such as H5N1. As aresult, the site becomes a prime site for mass virus transmissions. Thisinteraction of avian diversity also exposes the area to the possibility ofwidespread avian virus outbreaks with viruses such as H5N1. In order to betterunderstand the vulnerabilities to widespread virus outbreaks from wild birdinteractions; it is necessary to understand the factors that affect theirdistribution. One aspect is to provide a more in depth understanding of thedistribution of water bodies, inundated and non-inundated vegetation.To aid in the understanding of land cover distributions, a series of satelliteimagery on the area spanning close to30years was collected. The two mainsatellite systems which were chosen for data acquisition were AVHRR andMODIS with the third system Landsat TM being used for accuracy assessmentpurposes. The classification results of the satellite data was further analyzed forany patterns, trends and anomalies. These data coupled in series were used todetect the relationships and interactions that may exist between the various landcover and how these change through time. Years with a marked increase inwater body area has been seen to have a negative effect on inundated vegetated areas decreasing their size. Such a changes, also seems to positively affectnon-inundated area resulting in a larger non-inundated area. Periods with a lowwater body area, appear to coincide with higher inundated areas and lowernon-inundated areas. The tendency for the later parts of the dry season toexperience an increase incidence of fluctuations with greater variation inmagnitudes may be linked to the nature of water exchange between Poyang Lakeand the Yangtze River. While the effects of the Three Gorges Dam may haveinfluence increase in the appearance and magnitude of extreme fluctuationstarting from2008.