The Research On Forest Pest Occurrence Dyhamic And The Fitness Of Monochamus Alternatus Hope In Jiangxi

Over the past few decades, the climate change dramatically, the disaster has increased. Climate change and forest pests occurrence dynamic are different at the regional level.However China is vast in territory, and there are spatial differences in the forest distribution and the changes of climatic factors. For this purpose, in order to deeply analyse the dynamics of forest pests in different regions, and the relationship of climate change and forest pest occurrence in specific area range, and the Monochamus alternatus Hope's suitable level and risk rank of specific area range under the climate change. This research collects climate and forest pests'data over the past years (such as 1961-2010, etc) and chooses Jiangxi as the study area. With the software of ArcGis, Matlab, Spss and Excel and related analysis function (such as special analysis and special interpolation, etc), finally this research reveals the characteristics and trends of forest pests in different area, and explores the relationship between the climate and forest pests occurrence of Jiangxi, and finds the key elements of climate, and predicts the potential risk and so on. The main conclusions are as follows:First, during the past ten years, the rising trend of forest pest occurrence was significantly, for example the occurrence area of forest pests has increased from 6.69×106 hm2 to 8.52×106hm2,growth of 27.35%, from 2000-2010,especially the mild forest pest occurrence area, contribution rate 73.25%. Similarly the forest pest in Jiangxi is also on the rise and the mild occurred primarily. And from the regional view, the growth rate of forest pest occurrence area from high to low is in turn: northwest>northeast>southwest>north China>east China>central China. Significant difference was found between different regions of different degree of forest pest occurrence area, and the largest occurrence area of mild moderate and severe forest respectively are east China(9.301×105 hm2) northeast (4.282×105 hm2) and north China(2.104×105hm2).Second, the growth of loss also increased significantly as the growth of forest pest occurrence area. Such as the growth trend of direct economic losses has reached extremely significant level, and the growth trend of ecological service's value loss hasn't reached significant level, but swings up, as a result of the occurrence of national forest pest. From the regional view, direct losses increase mainly in the northwest southwest and east China, and the contribution rates respectively are:48.95%,33.81%,17.24%. Direct economic losses in east China is the largest,2.794×105 ten thousand Yuan. And the ecological service's value loss in north China is the largest,3.026×10 ten thousand Yuan.Third, over the past few decades, the influence of climate change on forest pest occurrence is obvious. Jiangxi as an example, the climate presented warming trend from 1961-2010, such as the annual average temperature and mean winter temperature rose respectively by 0.18? and 0.29? per ten years. At the same time, while the environmental humidity showed declining trend, such as hydrothermal coefficient average and mean relative humility declined by 0.07 and 0.45 per ten years. And the local forest pest occurrence significantly affected by the climate change, such as 17 climate factors related to forest insect pest happen, the principal component contribution rate of presenting the temperature and the joint action of temperature and humidity up to 41.43%.Fourth, build the regression model, forest pest as the vertical axis and the sliding average of hydrothermal coefficient as the horizontal axis, Y =-6.375×105X+2.95×106(R2=0.791,F=49.335, P?0.001), the linear fitting is 79.1% and the average prediction accuracy is 68.6%. According to the declining trend and the 29 years cycle changes of the sliding average of hydrothermal coefficient in Jiangxi, as 1993 are the negative anomaly node, so harmful trends will continue until 2022. With its special distribution characteristic of Jiangxi, anticipating that the south forest pests of Jiangxi is heavier, and the forest pests'volatility of east and north of Jiangxi may be greater.Fifth, based on the space distribution characteristics of annual average temperature and effective accumulative temperature of 10.8 ?, and the pine host distribution characteristics, such as the central and south central of annual average temperature and effective accumulative temperature are higher, etc, building the space distribution maps of the Monochamus alternatus Hope's suitable level and risk rank. The conclusion is that the suitable level was higher in the host area than the palace without host, but affected by latitude and the landform. Therefore the risk rating in the northwest, west, northeast and eastern north region are moderate and low, while the central, the south central or the low altitude or the basin are higher and high risk.Through the statistics of the grid suitable found:The average value of the Monochamus alternatus Hope's suitable level is 0.695 nearly 15 years in the host distribution zone. The whole is higher risk in within the scope of Jiangxi prowince, and the proportion is 77.432%. After the annual average temperature up 2?, the average value of the Monochamus alternatus Hope's suitable level is 0.895, and the whole is high risk and the proportion is 90.376%, and 90 of 100 counties' average suitable value is high risk. Risk level differemce is bigger in some countries.