The Research Of The Structure Of Community On The Ecotone Between Forest And Swamp In The Mudanjiang Forest Region

The community construction characteristics were studied on the two kinds of ecotones between forests and swamps in Mudanjiang forest region by using transect and model method. In order to understand community construction characteristics, such as the stand composition, age-class distribution, tree size mixes, plant biodiversity, biomass, and dynamics along the hydrological environmental gradients on the Betula platyphylla-swamp ecotone and Alnus hirsute, Betula platyphylla - swamp ecotone in this region.. The research results show that: (1) species number of communities increase in cubic curve along the environmental gradients from swamp to forest; (2) small size classes are dominant in tree size mixes at near swamp habitats, and the bigger size classes become dominant gradually with distance increasing from swamp, at near forest, big size classes percentage get highest value. Because tree growth is limited by hydrological condition. (3) small age classes are dominant at near swamp habitats, and the bigger age classes become dominant gradually with distance increasing from swamp, at near forest, big age classes percentage get highest value. (4) plant biodiversity increase in cubic curve along the environmental gradients from swamp to forest; (5) biomass increase in cubic curve along the environmental gradients from swamp to forest; (6) the communities analogous index decrease in comparison with swamp, and it increase in comparison with forest from swamp to forest. (7) the Betula platyphylla-swamp communities belong to second succession, because they were severely disturbed by human factors, so they are not stable.