Analysis Of Mangrove Change And Influence Factors Based On Landsat Data In Tieshangang

The mangrove wetland is an important ecological system in Guangxi Beibu Gulf coastal, which can prevent wind and wave, promote siltation and beach remained, prevent the pollution, purify sea water quality, regulate the climate and protect the biodiversity.But in recent decades, because the blind reclamation and transformation to mangrove wetland, the mangrove area has been reduced quickly and mangrove ecosystems have been seriously damaged, which make the survival and development of the mangroves threatened. The mangrove should be rotected soon.Using the Landsat MSS/TM/ETM/OLI Multi-temporal satellite data as datasource, the remote sensing information of mangroves in Tie-shan Port of Beibu Gulf and Yingluo Gulf is mined.The distribution and area of mangroves are obtained and the evolvement of mangroves are analyzed based on the spectral signatures for the landcovers (mangrove、terrestrial vegetation-. aquaculture、sea wate、 building land) in study area and the classification method of support vector machine(SVM)is used for interpreting. The study conclusions are as follow:(1) Spatial analysis of different periods of mangrove distribution results Mangroves are mainly grow in the land-sea alternating intertidal zone.Mangroves grow lushly and steady in Dandou Gulf, Shankou protection area and Yingluo Gulf and the distribution is intensive;while mangroves grow sparsely and changeable in Tieshan Port and the distribution is scattered.(2)In1977-2013, the trends of mangrove area are in four stages: up-down-up-down.Generally, the trend is fluctuated to increase.The mangrove area is only404.24hm2in1977, which is the smallest The area increased to2209.71hm2in1998.And the area reached a maximum of2784.21hm2in2008.(3)1988-2013, mangrove areas increase in Guangxi Beibu Gulf,and distribute intensively.(4) Mangrove changes is the results of joint action by the natural factors and human factors. The reclamation and aquaculture are the main reason for the destruction of mangroves.And the establishment of mangrove protection areas and planting mangrove manual are the most important means to protect and promote mangrove.