| Saihanba is in the forest-steppe ectone in the north of HeBei, where forest and steppe exist together, and is selected to study the landscape pattern and species diversity in this paper. An ecological transect is selected from mountain forest zone to forest-meadow zone to meadow-steppe zone, and in here the species diversity and landscape pattern is researched and analyzed, and also the formation mechanism about two aspects is discussed in this paper.The data of forest landscape including the patches area and perimeter is established by MapInfo sofware of GIS according to the terrain and forestry map of Saihanba, and the proportion of landscape elements area, landscape diversity index, patch characteristic, fragmentation and segregation are calculated and analyzed. The results of this research indicate that the landscape pattern in forest-steppe ecotone has some complextity. Results are as follow:(1) The proportion of plantation in the forest-steppe ecotone is not only higher than natural forest in this area, but also is prominently higher than that of forest zone. With the increasing of area of plantation, zone to prevent fire, place of cutting trees, area of building.(2) Although there have the abundance of landscape types, maximal diversity and predominant index in forest-steppe ecotone, shannon-wiener index is smaller than the forest zone.(3) The patch characteristic of forest-steppe ecotone is distinctly different from forest zone. For example, each index such as the patch density, shape index and edage density in meadow-steppe zone is lower than forest-meadow zone, but is higher than forest zone.(4) The fragmentation in forest-steppe ecotone is litter lower than that in forest zone. And especially the fragmentation of plantation along the forest to forest-meadow is increasing and falling along the forest-meadow to steppe, and the fragmentation of nature forest is distinctly falling from the mountain forest to the steppe.(5)With the increasing range of distribution of plantation and steppe along the ecological gradient, the distance between their patches is minishing, but with the decreasing of natural forest patches in forest-steppe ecotone, the distance between its patches is gradually increasing.Last, Three types of landscape are compartmentalized according to the number and size of forest landscape patches, namely mountain forest landscape, plateau forest landscape and plateau forest-steppe landscape, which proves that the primary forest-meadow landscape gradually disappear and become forest landscape, and also the meadow-steppe become forest-steppe.Besides, the forest plant community in forest-steppe ecotone is investigated and researched. 217 species which belong to 38 families and 123 genera are discovered. These species become between them distinctly. Meantime, species diversity is analyzed and the results are as follow:(1) The richness, species diversity index and uniformity in forest zone and forest - steppe zone are higher than that of plantation. In the meadow-steppe zone, species diversity of natural forest is not high because of the special environment, where the water and temperature factors have changed, but young Picea asperata plantation have more species and highest species diversity index.(2) Whether the plantation or natural forest each index of species diversity and uniformity fall in turn from forest to steppe.(3) Comparing with the species diversity in plantation of different ages, not only the climate environment but also the species in forest-steppe ecotone has changed from young forest to mature forest.(4) The correlation between species diversity and environment factors are analyzed and the results indicate that altitude has more influence on species diversity except soil factors, slop and aspect in forest-steppe ecotone.
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