Effect Of Agricultural Landscape Configuration On Quantity Of Corn Borer's Natural Enemy In Representative County In The Lower Reaches Of Liaohe River Plain

In agricultural ecosystem,the non-cropped habitats provide refuge,food and breeding place for natural enemy which is important to maintain the biodiversity.Revealing the different proportions of non-cropped habitats effect on the quantity of corn borer?s natural enemy in agricultural landscape,provide a theoretical practical basis and method for corn borer population control.We selected the Changtu county as the research place in the paper and analyzed the proportion of non-cropped habitats and different types within Farmland landscape,Changtu county is one of the representative counties in the lower reaches of Liaohe River Plain.In the area,we selected 20 grids for investigation from the proportion of non-cropped habitats amongst 0-50%.The pitfall traps was used to estimate the quantity of corn borer`s enemy in cropped habitats and in non-cropped habitats based on different proportions of non-cropped habitats.Then we evaluated the effects of different proportion of non-cropped habitats on the quantity of corn borer? natural enemy by the models which were selected by the index of Akaike?s information Criterion(AIC).The main conclusions are as follow:(1)The quantity of natural enemies in farmland is significantly related to the proportion of non-cropped habitats.At the different proportions of non-cropped habitats,the quantity of corn borer?s natural enemy gradually increased initially and then decreased,the quantity of corn borer?s natural enemy increase when the proportion of non-cropped habitats is 0-10% and 10-20%.The quantity of corn borer`s natural enemy increases when the proportion of non-cropped habitats is 20-30%.The quantity of corn borer`s natural enemy decreases when the proportion of non-cropped habitats is 30-40% and 40-50%.Meanwhile,there is an optimal model(AIC=4.24)when the proportion of non-cropped habitats is 20-30%.Therefore,the quantity of corn borer`s natural enemy is more when the proportion of non-cropped habitats is 20-30%.(2)Woodland is beneficial to the gathering of the corn borer?s natural enemy in the farmland.We analyzed the correlation of the landscape elements and the quantity of natural enemies and the drew the conclusion that there is an optimal model PC2+D when the proportion of non-cropped habitats is 20-30%,the model PC2 represents that woodland is beneficial to the gathering of the corn borer?s natural enemy in the farmland,but was negative when correlated with landscape diversity index(D),it is explained that the diversity of landscape composition around farmland provides natural enemies with a more suitable living environment and adversely affects the accumulation of the corn borer?s natural enemy in the farmland.(3)Woodland increases the number of the Carabidae and the Labiduridae in the farmland,grass and village maintain a higher number of spiders in the farmland.when the proportion of non-cropped habitats is 20-30%,model PC2 is the best to study Carabidae,and model PC2+D is the best to study the Labiduridae.Model PC1+D is the best to study the Thomisidae,and model PC1+D is the best to study the Theridiidae.The optimal model showed that,woodland increases the number of the Carabidae and the Labiduridae in the farmland,grass and village maintain a higher number of spiders in the farmland when the proportion of non-cropped habitats is 20-30%.