Patterns of diversity along experimental gradients of disturbance and nutrient supply - the confounding assumptions of the Intermediate Disturbance Hypothesis.

Pfaff, MC, Hiebenthal, Claas, Molis, Markus, Branch, GM and Wahl, Martin (2010) Patterns of diversity along experimental gradients of disturbance and nutrient supply - the confounding assumptions of the Intermediate Disturbance Hypothesis. African Journal of Marine Science, 32 (1). pp. 127-135. DOI 10.2989/18142321003714856.

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Abstract

A model of the interactive effects of disturbance and productivity on diversity predicts peak diversity to shift towards higher disturbance regimes as productivity increases, confining the Intermediate Disturbance Hypothesis to intermediate productivity levels. We conducted a two-factorial (disturbance, nutrients) field experiment to test the validity of this model for two subtropical intertidal rocky shores. Treatment responses varied between distinct community types at two sites. Intensified disturbance increased evenness, and under high nutrient enrichment decreased species richness of communities dominated by encrusting algae, whereas turf-dominated communities remained unaffected. Nutrient additions increased biomass and modulated community composition at both sites, in addition to increasing species richness in encrusting-algal and decreasing evenness of turf-forming assemblages. Thus, only highly enriched encrusting-algal communities followed the model predictions. Different mechanisms appear to control species coexistence in different types of communities, some violating the assumptions of the tested model, i.e. resource limitation and competitive exclusion.

Document Type: Article
Keywords: Ecology; Coexistence; Community structure; Disturbance; Evenness; Intertidal rocky shores; Nutrient enrichment; South Africa; Species richness
Research affiliation: OceanRep > GEOMAR > FB3 Marine Ecology > FB3-EOE-B Experimental Ecology - Benthic Ecology
OceanRep > The Future Ocean - Cluster of Excellence
Refereed: Yes
Open Access Journal?: No
DOI etc.: 10.2989/18142321003714856
ISSN: 1814-232X
Projects: GAME, Future Ocean
Date Deposited: 08 Jun 2010 08:03
Last Modified: 05 Sep 2016 11:53
URI: http://oceanrep.geomar.de/id/eprint/8474

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