title: Plant species loss decreases arthropod diversity and shifts trophic structure.
abstract: Plant diversity is predicted to be positively linked to the diversity of herbivores and predators in a foodweb. Yet, the relationship between plant and animal diversity is explained by a variety of competing hypotheses, with mixed empirical results for each hypothesis. We sampled arthropods for over a decade in an experiment that manipulated the number of grassland plant species. We found that herbivore and predator species richness were strongly, positively related to plant species richness, and that these relationships were caused by different mechanisms at herbivore and predator trophic levels. Even more dramatic was the threefold increase, from low- to high-plant species richness, in abundances of predatory and parasitoid arthropods relative to their herbivorous prey. Our results demonstrate that, over the long term, the loss of plant species propagates through food webs, greatly decreasing arthropod species richness, shifting a predator-dominated trophic structure to being herbivore dominated, and likely impacting ecosystem functioning and services.
authors.affiliation: Department of Biology, North Carolina State University, Box 7617, Raleigh, NC 27695 7617, USA. nick_haddad@ncsu.edu
authors.forename: Nick M
authors.initials: NM
authors.lastname: Haddad
authors.forename: Gregory M
authors.initials: GM
authors.lastname: Crutsinger
authors.forename: Kevin
authors.initials: K
authors.lastname: Gross
authors.forename: John
authors.initials: J
authors.lastname: Haarstad
authors.forename: Johannes M H
authors.initials: JM
authors.lastname: Knops
authors.forename: David
authors.initials: D
authors.lastname: Tilman
mesh_terms: D000818:Animals; D001181:Arthropods / Q000502:physiology*; D044822:Biodiversity; D053476:Extinction, Biological; D020387:Food Chain; D063245:Plant Development; D010944:Plants; D011156:Population Density