| Huanghua city is located in the west bank of Bohai bay, with complex variety oflandscape types, this paper takes Huanghua city in Hebei province as an example,using ENVI4.7software to interpret three phase of remote sensing image data in1990,2000,2011of Huanghua city, getting out Huanghua city land landscape type map; Insupport of ArcGIS and Fragstats software function modules, from the landscape typesspatial and temporal variations and the landscape pattern characteristics changewere analyzed Respectively, and getting the following conclusion:(1) Main landscape types of study area are cultivated land, construction landand saline land during1990-2011. By contrasting the data of finial and initial, we findthat the areas of construction land and salt field increase obviously, while cultivatedland, grassland, wetland and saline land decrease obviously. The construction landturns to418.61km2from388.19km2，salt field turns to170.03km2from131.12km2.The proportion of wetland turns to4.20%in2011form5.32%in1990and becomesthe maximum reduced land type; areas of cultivated land and saline land has reduced21.42km2and22.01km2respectively during21years; while the garden plot andwater are almost unchanged. Judging from the pace of change, salt field has themaximum rate of change, while the change rate of each landscape types is moreevenly from2000to2011; the change rate is closer of2000to2011. From theperspective of distribution center of each landscape type, all kinds of landscapemigrate in different degrees in1990-2000and2000-2011. The construction landmoved2.929km during1999-2000whose migration distance is farthest; afterconstruction land is grassland which moved2.355km during1990-2000and then issaline land which moved2.349km during2000-2011.(2) From the view of landscape type level, in the past21years, the cultivatedland patch shape gradually incline to rules; The grassland landscape shape indexincreased is very obviously, from63.83%to99.41%, and the shape variation is larger;the expanding of construction land is serious, The patch density is graduallydecreased, the landscape is fragmentation increased; the patch density of wetland isgradually decreased, the shape index is increased, the average patch area decreasedinstructions that the wetland landscape fragmentation is increased, the patch shapebecomes more irregular and decreased; area of saline soil of all landscapes has decreased obviously, which reduced from22.60%in1990to21.59%in2011,whilethe fragmentation degree has gradually increased; area of salt field keeps increasing astime goes on, and its fragmentation degree is getting more serious; waters on thelandscape patch type level has changed little, maintaining the original level basically.From the view of overall landscape characteristics change, the landscape patchnumber, patch density and landscape shape index of Huanghua is increasing trend toincrease with years, showed that the whole landscape fragmentation degree increasing,increased heterogeneity.(3) From the perspective of landscape gradient we can find that further from thecenter city, more complex and diverse the landscape types are but worse the degree ofpolymerization is in the horizontal transects; but the diversity of landscape reduceswhile the degree of polymerization increases within the range of30km from thecoastline because of lots of salt field. In vertical transects, diversity index keepsincreasing from south to north because the south is main cultivated land while northare grassland, garden plot and saline land and influenced severely by human activities;the degree of polymerization of center city keeps increasing to south and increasingfirst then decreasing to north for the homogeneity to complexity of landscape. |
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