Effects Of Habitat And Landscape Pattern On Predation Pressure Of Natural Enemies By Using Artificial Prey In Tea Plantations

There are different microhabitats in the canopy,midstory of tea trees and ground of tea plantations,which resulted in different abilities of controlling pests in tea plantations.Due to the annual expansion of tea plantation area and the single planting mode,the forest area decreased,which also leads to the decline of ecological service function provided by natural enemies of tea plantations.However,the effects of different vertical stratification of tea trees,the ground of tea plantations and surrounding trees on the predation pressure of natural enemies in tea plantations have not been well studied.Predation pressure is usually the predation pressure of natural enemies,which is measured by the predation rate of natural enemies.In this study,artificial preys were used to measure predation pressure in different habitats(tea canopy,tea midstory and ground of tea plantation)in Fuzhou.The effects of different habitats(tea canopy,ground of tea plantation and forest),color of artificial preys(green or red)and landscape composition on predation pressure of natural enemies were investigated in 12 sites in Fuding(Chamentou,Chixi,Dazhang,Nanguang,Nanyang,Niuchengxia,Guanyang,Guling,Wenyang,Tangyuan,Yidingshan,Ziguo).In Fuzhou tea plantation,all predators include arthropods,birds,mammals,and unknown animals.The predation rates of all predators were2.48%,0.87% and 20.83% in the canopy and midstory of tea trees and ground of tea plantations,respectively.The predation rates of arthropods were 2.16%,0.64% and 20.07% in the canopy,midstory tea trees and ground of tea plantations,respectively.The predation rates of all predators and arthropods in the midstory and canopy of tea trees were significantly lower than those in the ground of tea plantations.The highest predation rate of all predators was 13.01% in autumn,and the lowest was 3.26% in winter.The highest predation rate of arthropods was 12.99% in autumn,and the lowest was 2.93% in winter.The variation trend of all predators and arthropods predation pressure was consistent in different months,which increased first and then decreased with time,and reached the peak in September.In Fuding tea plantations,the predation rates of all predators in the tea canopy,ground and forest were 6.67%,47.78% and 47.36%,respectively.The predation rates of arthropods were 4.65%,44.31% and 42.50% in the tea canopy,ground and forest,respectively.The predation rates of all predators and arthropods in the tea canopy were significantly lower than those in the ground and the forest,but there was no significant difference in predation rates between the ground of tea plantations and the forest.The predation rate of all predators in September was significantly higher than that in May due to the influence of sampling month.The predation rate of green artificial preys were higher than that of red artificial preys regardless of habitats and sampling months.The highest predation rate of all predators was 45.00% in Nanguang and the lowest was 23.89% in Nanyang.The highest predation rate of arthropods was 40.00% in Nanguang,and the lowest was 21.67% in Nanyang.Landscape analysis showed that the higher the proportion of forest area,the higher predation rate of all predators,arthropods and red artificial preys.The predation rate of red artificial prey was positively correlated with forest area ratio,while the predation rate of green artificial prey was unrelated to forest area ratio.The area proportion of urban,tea plantation,grass,water and bare land had no effect on predation rate.In conclusion,the ground of tea plantation has a large number of potential natural enemy resources,so we should pay attention to the protection and utilization of natural enemies on the ground of tea plantation,so as to effectively improve the biological control efficiency of tea plantation.Forest can provide natural enemy control service for agricultural ecosystem.In the rational expansion of tea plantation area,forest species that can provide biological control ecosystem service should also be protected and utilized,so that they can better serve the ecological regulation of tea plantation pests.