MEPS 189:159-170 (1999)  -  doi:10.3354/meps189159

Influence of substratum heterogeneity scales and complexity on a temperate epibenthic marine community

Louise Lapointe, Edwin Bourget*

GIROQ, Département de biologie, Université Laval, Ste-Foy, Québec G1K 7P4, Canada

ABSTRACT: The influence of 4 scales of substratum heterogeneity on the establishment of a temperate sessile marine epibenthic community (Beaufort, North Carolina, USA) was examined over a period of 1 yr. Artificial panels with crevices representing 4 scales of heterogeneity of 0, 1, 10 and 100 mm and with combinations of these crevices representing 4 levels of complexity (0+1+10, 0+1+100, 0+10+100 and 0+1+10+100 mm) were deployed in January 1991 and sampled in March, June, September 1991, and January 1992. Significant temporal changes in abundance (% cover) and species dominance were observed during each sample period. Initially (within 5 mo after immersion), significantly lower abundances occurred on panels with the 1 mm scale compared with panels without this scale. Changes in diversity appeared to be related mainly to the 100 mm scale of heterogeneity regardless of the complexity level: diversity values found on panels which included the 100 mm crevices were initially low, but exceeded that of all other panels by January (1 yr after immersion). In summary, panel complexity was not the major factor influencing community structure, but the scale of heterogeneity (1 mm for abundances and 100 mm for diversity) had important and significant effects. These results indicate the specific importance of the 1 mm scale not only during the larval settlement phase but also during the development of the community. We compared these results with laboratory experiments using inert particles and similar panels, whose results suggest that larval behaviour is involved in the selection of settlement sites.

KEY WORDS: Substratum heterogeneity · Substratum complexity · Epibenthic marine community · Larval behaviour · Intertidal

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