农林复合生态系统防护林斑块边缘效应对节肢动物的影响

Influence of edge effects on arthropods communities in agroforestry ecological systems

于2008和2009年在黄淮海平原典型地区商丘民权林场(34°31'—34°52'N,115°00'—115°28'E)进行。选择杨树林、槐树林和杨槐混交林3种人工林模式,调查节肢动物群落构成、生物多样性及边缘效应对节肢动物群落结构的影响。结果显示,节肢动物科级水平上不同年份间的类群数和个体数差异都不显著(P>0.05),防护林不同模式间个体数(df=2,F=59.48,P<0.001)和类群数(df=2,F=15.44,P<0.001)差异均显著。3种防护林中以杨树林物种丰富度指数较高,S杨树林(9.65)>S杨槐混交林(8.78)>S槐树林(7.47);生物多样性指数H'杨树林(1.78)>H'杨槐混交林(1.65)>H'槐树林(1.46),其中杨树与槐树林的S和H'差异显著(P<0.05)。杨树林和槐树林边缘效应对节肢动物群落的影响大于杨槐混交林,林地边缘节肢动物的类群数和个体数均较高。节肢动物类群组成表现为林地边缘的偶见种和农田种多于林内。杨树林和槐树林边缘节肢动物多样性指数较高,向林内40m显著下降;而杨槐混交林边缘效应对节肢动物多样性指数的影响较小。综合分析认为,杨树林和槐树林边缘效应对节肢动物群落结构和多样性的影响距离为40m,杨槐混交林距离为20m。单一树种农田防护林斑块不小于80m宽,混交林斑块不小于40m宽,可以保护林内物种生存,维持农田生态系统生物多样性。

Biodiversity conservation of fertile farmland is becoming an important global issue.Farmland forest in agro-forestry systems plays an important role in biodiversity conservation but the importance of borders between agricultural land and forest for arthropods has been less studied.The aim of this research was to examine the influence of edge effects on arthropods community structure of farmland forest.In this study,we surveyed arthropod diversity in 2008 and 2009 at Shengan forest farm（34°31′—34°52′ N,115°00′—115°28′ E）,Minquan,Shangqiu,which is a typical region of the Huang Huai Hai Plain.We selected three types of man-made forest： poplar（Populus euram ericana（Dode） Guiner CL＇zhonglin-46＇） forest（PF）,Black locust（Robinia pseudoacacia L.） forest（BF）,and mixed forest with poplar and Black locust forest（PBF）.We investigated arthropod community composition,biological diversity and the influence of edge effects on arthropod community structure using the sweep net sampling method and trapping method.A total of 15100 arthropod individuals belonging to three classes,14 orders and 64 families were collected.The higher number of total individuals was found in PF and BF,the highest number of groups was in the PBF.The results indicated that the group and individual differences of arthropod diversity at the family level did not significantly differ between years（P 0.05）.However,the number of individuals among the different types of forest（df = 2,F = 59.48,P 0.001） and the number of groups（df =2,F =15.44,P 0.001） did significantly differ.Compared with other forests,PF have higher species richness： S PF（9.65） SPBF（8.78） SBF（7.47）.The order of values for the biodiversity index H′ was： H′PF（1.78） H′ PBF（1.65） H′ BF（1.46）,in which the difference between PF and BF was significant（P 0.05）.There are stronger edge effects on community composition and the number of groups and individuals,in PF and BF compared with in PBF.Rare species and farmland species are more abundant in the edge than in the forest.The numbers of individuals of common species,such as Acrididae,Tetrigidae and Gryllidae（Orthoptera）,were greater in the forest edges than inside the forest.By contrast,Tettigoniidae（Orthoptera） and Geometridae（Lepidoptera） were less abundant in the forest edges than inside the forest.The arthropod diversity indices of PF and BF were higher than that of PBF,but it significantly declined 40 m into the forest.The PBF has smaller edge effects on arthropod diversity.The edge effects on arthropod community structure and diversity were present up to 40 m into PF and BF,but only up to 20 m into PBF. Farmland forest strips should not be less than 80 m wide unless two types of trees are planted in which case it should not be less than 40 m wide.This approach ensures the persistence of forest species and maintains species diversity in farmland ecosystems.