Comparison of the response of meio- and macrobenthos to disturbance and organic enrichment Melanie Clare Austen ⁎ , S. Widdicombe Plymouth Marine Laboratory, Prospect Place, West Hoe, Plymouth, PL1 3DH, UK Received 1 June 2005; received in revised form 23 June 2005; accepted 15 December 2005 Abstract The effects of the interaction between physical disturbance and organic enrichment with respect to various aspects of subtidal meiobenthic nematode community structure have been examined in a large-scale mesocosm experiment. The relationship between meiobenthic and macrobenthic community structure within this experiment has been explored. Meiofauna and macrofauna showed similar and strongly related responses. Highest diversity was observed in treatment combinations of low levels of disturbance and enrichment and this supports the “Dynamic Equilibrium Model” of Huston [Huston, M.A., 1979. A general hypothesis of species diversity. Am. Nat. 113, 81–101.]. Faunal community structure was more variable at treatment combinations of low levels of disturbance and high levels of organic enrichment. Physical disturbance subdued the effects of high levels of nutrient enrichment. The meio-macrobenthic comparison has been extended to other studies where both meiofaunal and macrofaunal responses have been determined. The response of meiobenthos is often, but not always, the same as that of macrobenthos. These inconsistencies can probably be explained by the constraints of the experimental design of the mesocosm, where macrobenthic recruitment is not possible, as well as the different ecology of these two faunal groups. © 2006 Elsevier B.V. All rights reserved. Keywords: Disturbance; Diversity; Enrichment; Interactive; Macrobenthos; Meiobenthos; Mesocosm; Nematodes 1. Introduction A study has demonstrated (Widdicombe and Austen, 1999) that macrobenthic communities respond to dis- turbance according to the “Intermediate Disturbance Hypothesis” (IDH) of Connell (1978). There is also some supporting evidence that macrobenthic communities re- spond to increased productivity according to the “Inter- mediate Productivity Hypothesis” of Grime (1973a,b). These hypotheses predict maximum diversity at inter- mediate levels of disturbance and productivity respec- tively. By combining these two hypotheses, Huston (1979) proposed the “Dynamic Equilibrium Model.” This model assumed diversity represented a balance between growth rates (productivity/organic enrichment) and disturbance, with maximum diversity being observed when an as- semblage received between low and intermediate levels of both productivity and disturbance. There is little empirical support for the dynamic equilibrium model as the nec- essary, multi-factorial experiments are intrinsically more difficult to conduct than experiments which manipulate only a single factor. Recently, a mesocosm experiment demonstrated an interactive effect of physical disruption and organic enrichment on macrobenthic diversity and Journal of Experimental Marine Biology and Ecology 330 (2006) 96 – 104 www.elsevier.com/locate/jembe ⁎ Corresponding author. Tel.: +44 1752 633100; fax: +44 1752 633101. E-mail address: mcva@pml.ac.uk (M.C. Austen). 0022-0981/$ - see front matter © 2006 Elsevier B.V. All rights reserved. doi:10.1016/j.jembe.2005.12.019