Integrated Assessment Of Ecosystem In Hainan Bamen Bay Based On CA-Markov And In VEST Models

Bamen bay are both the main agriculture industry area and ecological tourism area. To build an everlasting effective sustainable mechanism will be a key factor to keep ecological resources well there. It could provide not only a theoretical reference for ecological management and ecological plan, but also a reasonable guidance for harmonious development between human and nature by adopting advanced and efficient valuing way to expand scope of knowledge of assessing ecosystem.This thesis takes Bamen bay in Hainan as the research object, creates its fundamental data base throughout GIS platform. On this basis, the thesis simulates the land use change in Bamen bay area through CA-Markov model, assesses the ecosystem fundamentally through LCM, and further adopts InVEST model to assess the terrestrial ecological quality and ecological risk of bay in Bamen bay area. Finally, our study forms a comprehensive assessment combined with results of fundamental ecological valuing, biodiversity model and HRA model. Our research innovates the traditional ecological valuing ways by means of advanced ecological valuing models and GIS analysis models. Meanwhile, our final results could enrich theories and technologies for thalassic ecology assessment, and it is also a reasonable guidance for decision-making system of ecological planning or ecological protective policy.The main conclusions of this study could be briefed as follows:(1) We analyzed the land use change among1988,1998and2009, and the results showed that the aquiculture areas, orchards and paddy fields drew an obviously increase. On the contrary, natural forests, mangroves and farm-land cut down significantly. The simulated results of land use types in2020through CA-Markov revealed that windbreak forests, natural forests and mangroves would increase, and the dynamic indexes were0.1585,0.0243and0.0184respectively. Meanwhile, the aquiculture areas, orchards and paddy fields would cut down, and the dynamic indexes were0.0322,0.0174and0.0172respectively.(2) The results of current land use change and biodiversity assessment showed that most of regions in Bamen bay area were times habitat but not primary habitat, and the ratios of subordinate habitat to total areas of effective habitat were72.76%in1998and78.89%in2009respectively. In2009, the total areas of ecological suitable regions had cut down, but the ratio of times habitat had enhanced. The indexes of β, γ, Sorensen’s Dissimilarity were intend to be synchronized in up or down, which came to a common result that eastern regions of Bamen bay had lower indexes but higher in western regions.(3) The biodiversity valuing results through InVEST showed that the level of habitat degradation was lower in Bamen bay area and most of regions were the score levels of0-6 and7-12.Overall, habitat degradation showed a rising trend from1998to2009. The degradation degree of high score regions had intensified further. The scores of habitat quality in Bamen bay area were low, and the change range was less between1998and2009. The ratios of grid amounts were91.15%in1998and93.12%in2009respectively for the lowest level which scored0-0.2. The scores of habitat scarcity of most regions were low, however, contrast by1998and2009, the habitat scarcity of this area enhanced to some extent. Meanwhile, some regions of high habitat scarcity had cut down, and the other regions not only had expanded on areas, but also had intensified further to some extent, such as the eastern regions of Wencheng town.(4) The valuing results through InVEST-HRA showed that the scores of five habitat factors (including coconut groves, mangroves, rivers, reservoirs and sea area) was1.8～3.0. Coconut groves for one half of artificial management had stronger self-recovered ability. The self-recovered ability of mangroves, rivers and reservoirs was common, but the sea area had the lowest self-recovered ability. Along the Dongjiao Coconut Grove coastline turned out to be had the most vulnerability risk. But it was lower in coconut groves and mangroves in Qinglan town. The closer to coastline, the more risk would have in Wenchang River and Wenjiao River. Finally, it showed that the five habitat factors were heavily influenced by paddy fields and towns, which might lead to in high ecological risk areas.(5) The results of integrated assessment of ecosystem showed that the levels of total score were the third level and the fifth level, and the ratios were33.23%and45.46%respectively, meanwhile, the ratios of levels above the second level were only10.89%. It showed that the ecological quality of this area was bad overall. The main land use type at the fifth level was paddy fields, and its ratios were69.27%. The main land use type at the fourth level was coconut groves with the ratios of45.68%. In addtion, mangroves took the most proportion which was at the first level with ratios of69.39%, and the second level was mainly with land use type of orchards with ratios of55.91%. As well as the main land use type at the third level was farm-land which took the proportion of42.60%.