Communities And Species Diversity Of Seed Plant In Foping And Changqing National Nature Reserve

Qinling Mountains is one of the distribution centers of seed plants in China, it also is one of the key areas of biological diversity that with international significance. Foping and Changqing National Nature Reservea are both the representative areas in the middle part on the south slope of Qinling Mountains with rich biological diversity, and also the areas that giant panda's get the highest population density. There are many plant communities in the two reserves with clear vertical zone spectrum, and there are also a large number of rare and endangered plants distributing in the two reserves. While Foping National Nature Reserve has not been deforestation before the establishment, basically, it is an area that had not been effected by human disturbance; but Changqing National Nature Reserve, which established at 1967, conducted a large-scale logging, the layer of woody plants below 2800m in elevation within the region almost disappeared. But the impact of these long-term and large-scale logging activities on the species diversity is not clear. So there is an urgent need not only for the investigating of the current species diversity and its distribution pattern, but also comparing and analysising them between the two reserves, which is very important to the protection of the giant pandas and the other rare and endangered wild animals and their habitats, and also important for the research and protection of the plant species diversity.We compared the seed plant species diversity, the population of the dominant species and the plant communities between Foping National Nature Reserve and Changqing National Nature Reserve in Shaanxi province of China. The results show that:long-term and large-scale logging extensivly and profoundly impacted both the species diversity of the seed plants, and the population of the dominant species, and also the plant communities in Changqing Nature Reserve. As to the plant species diversity, there are significant differences in the composition of seed plant species between the two Reserves, the similarity coefficient of the seed plant species is only about 20%. The dominant species of herbaceous plants are quite different at the two reserves. While the dominant species of woody plants are almost the same at the two reserves, but the population structures of these dominant woody plants are quite different. The population structures of Abeis fargesii,Betula albosinensis, Pinus armandii and Populus purdomii are different between the two reserves, their height and DBH(diameter at breast height) are significant greater in Foping National Nature Reserve than that in Changqing National Nature Reserve; but the height and DBH of Quercus aliena, Platycarya strobilacea, Acer oliverianum, Meliosma cuneifolia, Sorbus hupehensis and Tsuga chinensis, which distributing in lower altitude areas, are almost the same at the two reserves. As to the communities at the two reserves, the Larix chinensis communities at high elevation areas at the two reserves are well preserved, the composition and structure of them are almost the same. The deciduous broad-leaved forests at lower elevation areas at the two reservs, especialy the oak tree forests, are almost the same, for they had restored better in Changqing National Nature Reserve. The scope of Abeis fargesii forest in Foping National Nature Reserve is broader than that at Changqing National Nature Reserve, but the density of these abies forest is significantly higher at Changqing National Nature Reserve than that at Foping National Nature Reserve, while their average height and DBH is less at Changqing National Nature Reserve than that at Foping National Nature Reserve.The distributing proportion of broadleaf and coniferous mixed forest is larger at Foping National Nature Reserve than that at Changqing National Nature Reserve; but it density is also higher in Changqing National Nature Reserve; while average height, DBH and the summation of area at breast height are less than that at Foping National Nature Reserve. Betula albosinensis forests are very common in Foping National Nature Reserve, reaching 13.33% of all the plots, but they had been seriously destroyed and also recovered slower in Changqing National Nature Reserve.Based on the above results, we put forward the following proposal:the herb species, and also their quantity and distribution are sensitive to the environment, so we can choose them as the monitors for the habitat. The increase of the hygrophyte herbs and the expansion of their distribution scope in Changqing National Nature Reserve can serve as the symbol of environmental recovery. We can also choose the heliophytes as monitoring species, the reduction of these species and the shrink of their scope can also serve as the symbol of environmental recovery.The population structure of Abeis fargesii, Betula albosinensis, Pinus armandii and Populus purdomii are significantly different between the two reserves, we can select them as the focus for monitoring. The plant communities at higher elevation at the two reserves are quite different, so we can focus on and choose them for monitoring.