Community Structure And The Relationship Between The Spiders And Environment In Agroforestry System In Beijing

Form April to September in Daxing2010and April to September in Shunyi2011, investigations of spiders were made in three typical agroforestry system, using the method of pitfall,based on the "farmland-spider-forest belt". The study were analyzed the spider community parameters and the dominant species dynamic changes in different habitats, as well as the influence of the forest on the distribution of the natural enemies,climate factors affected on the spider community, so as to be able to protect and use of predatory natural enemy resources to provide the scientific basis. Conclusions are as follows:1. The dominant spider species are Pardosa astrigera L.koch and Alopecosa albostrit Grube in agroforestry system.2. Diversity and heterogeneity were higher in forest belt,compared with farmland the spider population habitat was more stable.3. The dominant spider species dynamic changeing in three habitat during the research time showed:species distribution in farmland habitat and that in field ridge and forest belt showed "As one falls,another rises ".There were significant difference of the spider population density before and after the harvest in the Ridge Belt and forest belt.The conclusion shows that:The harvest activities and habitat changes that lead to a spider population to a nearby forest belt of migration, reflect the spider has strong ability to avoid adversity and the forest belt played an important role in maintaining stability of spiders population;There were significant difference of Pardosa astrigera population density in Sabina chinensis and that in Populus tomentosa (P=0.011, a=0.05), no significant difference on Alopecosa albostrit in Sabina chinensis and that in the Populus tomentosa (P=0.618>0.05,a=0.05).The two dominant species differences in response to habitat heterogeneity,may be boths of the spiders on different environmental structure sensitive different.4.There were two aspects of influence of forest belt on the spider density:(1) Spiders diversity had negative correlation with the distance away from the forest belt (P=0.045, and alpha=0.05).(2) there were no significant difference of the population densitydifference far away the20meters (P=0.58, a=0.05),and The role of the forest belt ranged for30meters distance away from the forest belt in Biota orientalis (P=0.61, and a=0.05).5. There were no significant difference of male spiders in farmland and forest belt (P=0.337, P=0.229, P=0.626), breeding peak in August. 6. The clustering of time series analysis shows that the community of spiders can be divided into:a class of crop growing season for spider heyday, human disturbance of a class for spider population decline, a class of crop harvest for the decline of the spider populations.7.There were no obvious linear relationship between Temperature、humidity and spiders population density, temperature Pearson coefficient is0.382, the humidity Pearson coefficient is0.174; the index fitting model fitting degree highest R=0.847, according to this model, the temperature and humidity in a certain range, the present situation of the density of spiders can make more accurate and the change trend of the estimate.