Deciduous Broad-leaved Forested Wetlands Mapping And Its Community Characteristics Analysis In The Nofth Temperate Zone

Forested wetland, locating in the forest-wetlands ecotone, is a community with intrazonal vegetation. The spatial distribution pattern of forested wetlands has always been one of the challenging issues in wetland research and community characteristics in ecotone have always been hot. The major objectives of this paper, which service for an efficient access to mapping spatial distribution of forested wetlands and get to know about its community characteristics, were exploring a method for forested wetlands mapping and analyzing its community characteristics compared with marsh and forest communities.As for deciduous broad-leaved forested wetlands mapping, based on basic environment characteristics of forested wetlands,30decision tree models were built by integrating slope, vegetation, hydrological and phonological characteristics. Then results of models were verified with field data, the classification errors were discussed. In a community level, along the environmental gradients from marsh to forest wetlands and forest communities around ecotone were chosen to get better know about the community characteristics of forested wetlands. The results were following:Constructed Decision tree models performed well, the overall accuracy of the classification between forests plat and forested wetlands reached83.6%, the product accuracy for forested wetlands was85.5%, while82.3%for forests plat. The hydrological feature understory made a great contribution to the classification between forested wetlands and plat-forest; phonological feature understory made an improvement on the result of classification.Effects of classifiers based on radar images were shown to be linked with the characteristics of surface environmental features under forest canopies. The lower separability between forested wetlands dominated by herbal surface and forests plat covered with litter was the major reason for the misclassification of decision tree models, the responses of radar images to phenology phase changes were conductive to forests plat mapping. The object-based approach with decision tree was not tested, by considering its’ ability to reduce speckle noises and other uncertain factors, modifications to the classification tree will be investigated in continuing research.The suitable range of the threshold for an decision variable tend to be locate near the intersection of two curves, which presented the intensity distribution of the same variable for two land-cover, moreover, the value of the intersection was an ideal choice for the variable. Therefore if multiple sample plots were gained for a region, decision tree methods are promising approach to forested wetlands mapping and monitoring.Broad-leaved forested wetlandss were dominated by fraxinus mandshurica, the pattern of the number of species was tree<shrub<herb. The species composition of woody plant was relatively simpler and evenness was lower in forested wetlands compared with forests community.In forested wetlands communities, pioneer species Betula platyphylla enjoyed hi-light, fraxinus mandshurica has a low ability of drought-endurance, and Maackia amurensis has a certain tolerance of shade. Dominant species in forested wetlands could make better use of light and and were more adaptive to inundated environment.The patterns of biodiversities in different layers of communities were following. Compared with forest communities and marsh communities, the highest biodiversity and abundance in herbaceous layer was occured in forested wetlands, lower biodiversity and abundance in tree and shrub layers was presented in forested wetlands than in forest. Generally, the pattern of biodiversities in different communities was showed marsh<forested wetlands<forest.