Evol Ecol Res 6: 1145-1166 (2004)     Full PDF if your library subscribes.

Reliability characteristics of natural functional group interaction webs

Andrew J. Davis,¹* Wei-chung Liu,² Joerg Perner¹ and Winfried Voigt¹

¹Institute of Ecology, Friedrich Schiller University, Dornburger Strasse 159, 07743 Jena, Germany and  ²Centre for Tropical Veterinary Medicine, University of Edinburgh, Easter Bush, Roslin, Midlothian EH25 9RG, UK

Address all correspondence to Andrew Davis, Institute of Low Temperature Science, Hokkaido University, Sapporo 060 0819, Japan.
e-mail: andrew@pop.lowtem.hokudai.ac.jp

ABSTRACT

We compare the reliability of interaction webs for functional groups derived from extensive field data. Reliability is the probability of a web continuing to function despite the failure of one or more functional groups. Interaction webs are diagrams of all the trophic and non-trophic relationships between groups. Functional groups are suites of species with similar roles in an ecosystem and, importantly, mediate the relationship between biodiversity and the functioning of ecosystems. How they interact will thus have major ecological consequences. We reveal interactions between groups by simple and partial Mantel tests and determine link type by applying sets of logical rules to the Mantel test results. We then calculate the reliability of the resulting interaction webs. We also derive the reliabilities for webs of different link types because web topology affects reliability, not just the number of groups and links. Using the qualities of sink webs derived from these interaction webs, we illustrate the overall patterns in the relationships between reliability and other web characteristics. We compare these with the relationships in food-webs. We demonstrate the relation of reliability to principal components representing the information common to web characteristics other than reliability. We show that reliabilities for webs of interactions between functional groups are very high, at least as high as those for food-webs, and that they show similar relationships to other web characteristics. Nevertheless, in our natural setting, it is the number of groups and the number of links a web has that most affects reliabilities. However, they also differ more between webs of different link types, where topology differs, than between sites. Thus, in nature, the reliability of webs of interactions between functional groups will depend on both web size and topology. This means that their contribution to mediating the relationship between biodiversity and ecosystem function will also depend on both web and topology.

Keywords: arthropods, biodiversity, ecosystem function, grasslands, plants, structure, topology.

DOWNLOAD A FREE, FULL PDF COPY
IF you are connected using the IP of a subscribing institution (library, laboratory, etc.)
or through its VPN.

 

        © 2004 Andrew J. Davis. All EER articles are copyrighted by their authors. All authors endorse, permit and license Evolutionary Ecology Ltd. to grant its subscribing institutions/libraries the copying privileges specified below without additional consideration or payment to them or to Evolutionary Ecology, Ltd. These endorsements, in writing, are on file in the office of Evolutionary Ecology, Ltd. Consult authors for permission to use any portion of their work in derivative works, compilations or to distribute their work in any commercial manner.

       Subscribing institutions/libraries may grant individuals the privilege of making a single copy of an EER article for non-commercial educational or non-commercial research purposes. Subscribing institutions/libraries may also use articles for non-commercial educational purposes by making any number of copies for course packs or course reserve collections. Subscribing institutions/libraries may also loan single copies of articles to non-commercial libraries for educational purposes.

       All copies of abstracts and articles must preserve their copyright notice without modification.