School of Biological Sciences, University of Bristol, Woodland Road, Bristol BS8 1UG, United Kingdom.
Ecol Appl. 2011 Mar;21(2):516-24. doi: 10.1890/09-2111.1.
Landscape management affects species interactions within a community, leading to alterations in the structure of networks. Modules are link-dense regions of the network where species interact more closely within the module than between modules of the network. Insufficient network resolution has meant that modules have proved difficult to identify, even though they appear important in the propagation of disturbance impacts. We applied a standardized approach across 20 farms to obtain well-resolved food webs to characterize network structure and explore how modularity changes in response to management (organic and conventional). All networks showed significantly higher modularity than random networks. Farm management had no effect on the number of modules per farm or module richness, but there was a significant loss of links between modules on conventional farms, which may affect the long-term stability of these networks. We found a significant association between modules and major habitat groups. If modules form as a result of interactions between species that utilize similar habitats, then ecosystem services to the crop components of the landscape, such as pest control by parasitoids originating in the non-crop vegetation, are less likely to occur on these farms.
景观管理会影响群落内物种的相互作用，从而改变网络的结构。模块是网络中链接密集的区域，在模块内物种的相互作用比在网络的模块之间更为紧密。由于网络分辨率不足，即使模块在传播干扰影响方面似乎很重要，但模块的识别仍然很困难。我们在 20 个农场应用标准化方法获取了分辨率良好的食物网，以描述网络结构，并探讨模块性如何响应管理（有机和常规）而发生变化。所有网络的模块性都明显高于随机网络。农场管理对每个农场的模块数量或模块丰富度没有影响，但在常规农场中，模块之间的链接显著减少，这可能会影响这些网络的长期稳定性。我们发现模块与主要生境组之间存在显著关联。如果模块是由于利用相似生境的物种相互作用而形成的，那么对景观作物组成部分的生态系统服务（例如源自非作物植被的寄生蜂对害虫的控制）就不太可能在这些农场发生。
