Plant Community Classification And Environmental Explanation Of Limestone Hill Seasonal Rain Forest In Longgang Natue Reserve

Longgang Natural Reserve is located on the Guangxi Province which borders Vietnam. The geographical coordinates of106degree42’28" to107degree4’54" E,22degree13’56’ to22degree9’09" N. Natural Reserve is the typical karst landscape, natural area larger up10077hm2. Plant ecological system integrate forming the rare unique limestone hill seasonal rain forest. At the same time, there have rich reserves of biological resources, becoming the gene pool of limestone hill seasonal rain forest and the typical representative of our countryNature reserve by phytosociological method in2010,2011,7-8months. Nture reserve could divide into two formations, three associations and five communities based on34sites. The results are as follows:(1) Through a comprehensive survey of the flora in Longgang Nature Reserve, the result show that the374vascular plants pecies, belonging to253genera in102families, in the plot here are27fern plant ofpecies belonging to16genera and12families, there are347species of seed plant belonging to237genera and92families in the plot gymnosperm species belonging tol genusera in1families, there are346angiosperm species to236genera and89families. Through to the angiosperms families and genera analysis, we can see that tropical and subtropical families reach up to71, accounting for80%of the total number of families in the area, tropical and subtropical genera of the disrribution has204, accounting for86%of the total genera. Visible the results demonstrated that Longgang Nature Reserve flora the performance for the strong tropical properties.(2) Form. Cephalomappa sinensis-Excentrodendron tonkinense, Form. Arenga westerhoutii-Deutzianthus tonkinensis; Ass. Cleistanthus petelotii-Laportea violacea, Ass. Baccaurea ramiflora-Trigonostemon fragilis, Ass. Phlogacanthus colaniae-Aglaia lawii; Comm.Streblus tonkinensis-Champereia manillana var. longistaminea, Comm.Guihaia argyrata-Dracaena cochinchinensis, Comm. Ardisia affinis-Archidendron eberhardtii, Comm. Cinnamomum wilsonii, Comm. Sinosideroxylon pedunculatum-Pistacia weinmannifolia. (3) To all of unit composition, structure, the distribution characteristics of community and the influence of environmental factors are analyzed. Studies have shown that the different vegetation formations in the Longgang Nature Reserve occupies a different habitat. Form. Cephalomappa sinensis-Excentrodendron tonkinense the typical type of communities in protected areas, distributed in the slopes of the central upper middle parts. Communites structure is stationary, environment is drought. Form. Arenga westerhoutii-Deutzianthus tonkinensis has a typical tropical rain forest characteristics distributed in a depression or in the valley. Comm. Cinnamomum wilsonii and Comm. Sinosideroxylon pedunculatum-Pistacia weinmannifolia are special in the vegetation classification system. For species composition more special, so not sure whether they are new community Comm. Cinnamomum wilsonii distributed in a depression but Comm. Sinosideroxylon pedunculatum-Pistacia weinmannifolia distributed in the ridge. Comm. Sinosideroxylon pedunculatum-Pistacia weinmannifolia have poor site conditions and lots of plants are xerophytes.(4) For more than30years of vegetation changes the comparison analysis with the vegetation survey of the Guangxi Institute of Botany1978, the community types increased. Such as Comm.Dracaena cochinchinensis, Comm.Cinnamomum wilsonii,Comm.Caryota obtusa. One reason is the depth of the survey or survey area another reason is that the communities occurrence of the natural succession. This change requires long-term observations to determine.Studies have shown that although protected areas have a certain area of native forest, but secondary phenomenon is obvious. The tree height and diameter at breast height slants small therefore continue to strengthen the construction of the reserve is nccessary.(5)Analysis the influence of environment on vegetation. On the basis of analysis of limestone evironmental vulnerability and particularity, analysis of water, light, terrain and human interference factor. However, for a community or a vegetation type, affecting their survival and distribution of environmental impact factors are not isolated, is intrinsically linked to an integral. Therefore, to consider the impact of various environmental factors on vegetation at the same time should also be taken into account the linkages between the various factors and vegetation.(6)Analysis of protected area management situation and propose appropriate measures for the current problems.