title: Maximum species richness at intermediate frequencies of disturbance: consistency among levels of productivity.
abstract: Development of a mechanistic understanding and predictions of patterns of biodiversity is a central theme in ecology. One of the most influential theories, the intermediate disturbance hypothesis (IDH), predicts maximum diversity at intermediate levels of disturbance frequency. The dynamic equilibrium model (DEM), an extension of the IDH, predicts that the level of productivity determines at what frequency of disturbance maximum diversity occurs. To test, and contrast, the predictions of these two models, a field experiment on marine hard-substratum assemblages was conducted with seven levels of disturbance frequency and three levels of nutrient availability. Consistent with the IDH, maximum diversity, measured as species richness, was observed at an intermediate frequency of disturbance. Despite documented effects on productivity, the relationship between disturbance and diversity was not altered by the nutrient treatments. Thus, in this system the DEM did not improve the understanding of patterns of diversity compared to the IDH. Furthermore, it is suggested that careful consideration of measurements and practical definitions of productivity in natural assemblages is necessary for a rigorous test of the DEM.
authors.affiliation: Department of Marine Ecology, Göteborg University, Tjärnö Marine Biological Laboratory, 452 96 Strömstad, Sweden. robin.svensson@tmbl.gu.se
authors.forename: J Robin
authors.initials: JR
authors.lastname: Svensson
authors.forename: Mats
authors.initials: M
authors.lastname: Lindegarth
authors.forename: Michael
authors.initials: M
authors.lastname: Siccha
authors.forename: Mark
authors.initials: M
authors.lastname: Lenz
authors.forename: Markus
authors.initials: M
authors.lastname: Molis
authors.forename: Martin
authors.initials: M
authors.lastname: Wahl
authors.forename: Henrik
authors.initials: H
authors.lastname: Pavia
mesh_terms: D000818:Animals; D044822:Biodiversity; D003163:Competitive Behavior; D003445:Crustacea / Q000254:growth & development*; D017753:Ecosystem; D056890:Eukaryota / Q000254:growth & development*; D008954:Models, Biological; D011157:Population Dynamics; D011158:Population Growth; D011161:Porifera / Q000254:growth & development*; D013045:Species Specificity