| In order to understand the present condition and ecosystem change of Maanshan wetland and strengthen oversight,management and protection,wetland area,number and type and distribution from 1993 to 2013 were analyzed using ArcGIS and RS combined with field investigation.On this base,it will conducive to understand the dynamic changes of wetland resources and to provide decision-making basis for the regional ecological civilization construction,urban planning and sustainable development.The results showed that:1.According to the interpretation of remote sensing images in 20135 Maanshan wetland included five types:rivers,lakes,ponds,aquaculture and reservoirs,among which the river area is the largest(19289.32 hectares),followed by aquaculture(17272.94 hectares).From the perspective of administrative region,the wetland area of Dangtu County is the largest,accounting for 31.32%of the total area of Dangtu County and 56.90%of the total Maanshan wetland area,followed by Hexian County and Bowang District,which accounted for 16.38%and 15.39%of the total Maanshan wetland area respectively.Bowang District wetland area was 8,334 hectares.Aquaculture,lakes,rivers,ponds and reservoirs accounted for 42.31%,38.39%,11.56%,7.00%and 0.75%of the total wetland area.Huashan District wetland area was 2,029.96 hectares.Rivers,lakes and pounds accounted for 84.38%,9.56%and 6.06%of the total wetland area respectively.Yushan District wetland area was 688.44 hectares.Rivers,ponds and lakes accounted for 56.14%,36.20%and 7.65%of the total wetland area respectively.The aquaculture,rivers,lakes and ponds in Dangtu County accounted for 42.02%,31.00%,22.53%and 4.45%of the total wetland area respectively.Rivers,ponds,reservoirs,aquaculture and lakes in Hexian County accounted for 65.83%,22.59%,5.73%,5.44%and 0.41%of the total wetland area respectively.The wetland area of Hanshan County was 2,338.45 hectares.Pounds,rivers,reservoirs and aquaculture accounted for 32.03%,29.71%,25.90%and 2.37%of the total wetland area respectively.2.According to data analysis in 1993 and 2013,the total Maanshan wetland area increased from 43,834.37 hectares in 1993 to 53,837.79 hectares in 2013,and the total area increased from 10%to 13%.Bowang District wetland area increased from 15.9%to 22.4%,but the area of cultivated land and forest land decreased,and the residential land increased.Hexian County wetland area decreased from 10.21%to 9.01%,and the changes of land uses mainly focused on the increase of residential land and forest land.The change of Yushan District wetland area was relatively small,from 3.19%to 3.58%,but the changes of land uses showed that the cultivated land area decreased greatly and the residential land increased greatly.Dangtu County wetland area showed a small increase,from 24.81%to 31.32%.The changes of land uses showed that the area of cultivated land and forest land decreased,but the area of residential land increased.Hexian County wetland area remained stable,but the residential land area increased while the forest land area decreased.The area of Hanshan County wetland increased slightly from 2.78%to 3.34%,but the area of residential land increased more,while the forest land and cultivated land decreased slightly from 56.40%to 50.94%and 34.56%to 28.64%,respectively.3.The study shows that Maanshan wetland area increased by 22.8%from 1993 to 2013.The increase in wetland area mainly was ponds,lakes and aquaculture.With the increase of aquaculture area,wetland water environment will be challenged.In addition,some rivers,lakes and wetlands in Maanshan city had been polluted.Although wetland plants can absorb and degrade certain harmful substances,their purification capacity is limited.It is worth noting that although the total Maanshan wetland area increased over the past 20 years,the wetland area in the urban decreased,which indicated that wetland in the urban has been occupied with the growth of population. |
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