Plant Community Restoration Of Earthquake Landslide In Xiejiadian

The slope in Xiejiadian was managed through natural recovery and artificial recover, it has obvious favorable effects of ecological in ecological environment improvement, plant litter, microbial activity, enhanced soil fertility, and promoting the growth of plants. With Plant community species richness increase, diversity difference for community species is more apparent, it is more close for interdependence between the plants, and it is more prominent for vegetation to conserve water and soil resources and break wind and fixing, the mountain will be more stable. The results for plant community are showed as following:(1) There are 52 plant species in 2009 in Xiejiadian, these species belong to 17 families, 32 genera, and the number of genera for the five top families were composed of 19 genera, accounting for 59% of the total number of genera. there are 63 plant species in 2012, belong to 35 families, 42 genera, and the number of genera for the five top families accounts for 60% of the total genera. There are 84 plant species in 2014, these species belonging to 46 families, 66 genera, and the number of genera for the five top families accounted for 47% of the total genera. In 2015,there are 86 species which belong to 47 families, 67 genera, and the number of genera for the five top families accounted for 45% of the total genera. In the whole plant community succession stage, the numbers of plants families,, plants genera, species and species richness increase with the increase of the growth time, but it has a variety of genus or more, the proportion of smaller, including 1 genus and the proportion of 1 kind of big.(2) Plant community diversity index showed increasing fluctuations overall, The order of Shannon- Weiner index and Pielou index and Margalef index were the herb layer > shrub layer > tree layer. In Different growth stage, Pielou evenness index, Shannon- Weiner index and Margalef index fluctuation showed upward trend, quantity and species richness were increasing, individual plant is balanced, the distribution of the complexity of the plant community and the ability to resist the external environment, gradually formed a relatively stable plant community. Simpson diversity index Affected by the growing environment of, slows down, single species agglomeration phenomenon is abate, the status of the dominant species gradually decreases, and ecological dominance index decreases, and plant community gradually evolves from herb community to shrubs and trees community.(3) Shannon-Weiner index, Margalef index and Pielou evenness index has obvious positive correlation, the more abundant species, the higher the diversity index, species individual distribution more uniform, the higher the species diversity. Simpson diversity index of species evenness of change is most obvious, it is an important performance of species concentration degree, the lower the concentration degree, the higher evenness. Cody and Jaccard index through concrete numerical quantitative description of the change of plant community were kind of, show the change of plant community species and the regularity of change. Spatial dimension, between adjacent sample area highest Jaccard index of plant community, community species similarity between high, there are more, the beta diversity is low. Increases as the distance between the sample area, plant community Jaccard index decreases, and Cody index is larger, the smaller the similarity of the two plant communities, the higher the otherness. Time dimension, Jaccard index decreases with increasing growth time, Cody index is increasing with the increase of growth time, plant community there are fewer, between the species richness increased, the structure of plant community is more stable.(4) Plant community of the seismic landslide belongs to secondary succession in Xiejiadian, succession to follow the rule is by the secondary bare land stage > herbaceous community stage-bringing community stage > halosols deserts community stage. Calculated according to the important values of plant community composition of different years were: plant community in 2009 is Vitis heyneana- Buddleja lindleyana + Erigeron annuus. Plant community in 2012 is Alnus cremastogyne- Rubus parkeri-Equisetum hyemale + S. nipponica. Plant community in 2014 is A. cremastogyne + Rhus chinensis- R. parkeri- E. hyemale + Selaginella nipponica. Plant community in 2015 is A. cremastogyne + R. chinensis- R. parkeri- E. hyemale + S. nipponica. Tree layer alder and poison sumac important values gradually decreases; Plant species of shrub layer number increasing, the important value showed a trend of falling volatility; More than half of the herb layer gradually reduce the number of plant species, important value assumes the declining trend of fluctuations.(5) Plant communities were affected by natural conditions, the slope is slight, fertile soil, abundant water resources in the section of high species richness and plant water content is the highest. In 2015, the plant fresh weight, dry weight and water content are presented along with the increase of altitude decreases gradually. In 2015 many of herb layer shrub seedlings, such as O. frutescens and R. parkeri, these two kinds of plants is an important species in the shrub layer. Display shrub seedlings of plant community age structure belong to the growth stage, in order to maintain the stability of plant community shrub layer plant provides a strong backing. Growing ability of plants to maintain water and soil, and plants for the slope surface protection function is more stable.(6)Temperature, humidity and salinity in the soil and elevation, highly significant correlation with altitude, the increase of altitude, the air becomes thinner, the soil humidity and temperature gradually decreases, and salinity increases. Species number and the number of plants has very significant positive correlation(spearman rank correlation coefficient is 0.678, p< 0.01), the more the number of species, the more number of plants.Shannon-Weiner index and Pielou evenness index was significantly positively related to(spearman rank correlation coefficient is 0.77, p< 0.05), and Margalef index was also positively correlated(spearman rank correlation coefficient is 0.708, p< 0.05), were very significant negative correlation with Simpson diversity index(spearman rank correlation coefficient is 0.917, p< 0.01), plant species and quantity are increasing, at the same time increasing uniformity of the species in all.