Influence Of Landscape Pattern On Lithocolletis Populifoliella And Its Natural Enemies In Karamay Farm,Xinjiang

There are many kinds of pests and diseases in Karamay forest farm,Xinjiang,but the degree of damage is light.In order to explore the mechanism that pests in this area are not easy to break out,based on the principle of landscape ecology,the effects of landscape features on the Lithocolletis populifoliella and its two predatory natural enemies(Chrysoperla sinica,Vespula vulgaris)in the Karamay forest in Xinjiang were explored from the community level and landscape level,which provides a theoretical basis for forest technology-oriented pest ecological control.One-way analysis of variance(AVOVA),multiple comparison(Duncan method)and generalized linear regression model were used to analysis the relationship between the occurrence of poplar plantation and the host characteristics and stand structure,as well as the effects of landscape composition and landscape diversity on the natural enemies of pests and their ability to inhibit the growth of pest populations for a long time.Established a prediction model for density of L. populifoliella.Got the following results:(1)At the community level,the damaged leaf rate of P.russkii plantation was significantly different under different forest ages(3-12a)and different mixed modes.And the damaged leaf rate was significantly positively correlated with the stand density(P<0.05);it was significantly negatively correlated with the height of the first branch(P<0.05);it was not significant correlated with the degree of canopy(P?0.05);there is a very significant positive correlation between damaged leaf rate and proportion of P.russkii(P<0.01).There was a significant positive correlation between the abundance of C.sinica and the herbal height and herbal coverage(P<0.01).(2)At the landscape level,Large areas of fallow and farmland habitat around the forest will reduce the abundance of two predatory natural enemies.Higher landscape diversity also reduces the abundance of natural enemies,which is most evident in landscape features in the range of 0.25km and 1.0km.At these two spatial scales,the growth rate of L.populifoliella population was significantly negatively correlated with the stand density(P<0.05).In the early period,there is no obvious impacts had been observed between L.populifoliella population growth rate and its natural enemies,however,in the late period,the growth rate of L.populifoliella population was significantly negatively correlated with the natural enemies(P<0.05).(3)The prediction model of the density of the L.populifoliella in the P.russkii plot of the Karamay forest was established,and the prediction accuracy was 76.11%.