Dynamics of meiobenthic copepod populations: a long-term study (1973-1983)

Abstract

Eleven years of monthly (or fortnightly) monitoring of meiobenthic copepods at 2 subtidal estuarine sites (sand and mud) in South Carol~na, USA indicates that the 2 communities are controlled by different mechanisms. The mud community is distinctly seasonal, whereas at the sand site seasonality is not pronounced. Sand-site copepods have been declining over the 11 yr and their number of species has decreased at the rate of about 1 yr-l. There has been no significant change at the mud site. The decrease in copepod species at the sand site was correlated with a concommitant decrease in sediment median grain size and sorting. l l e r e were no significant long-term abundance cycles at either site. Twelve mo was the maximum statistically reliable periodicity recorded at either site; although some of the sand species had no periodicity. It appears that meiobenthic copepods respond primarily to short-term seasonal events. Thus, a 2 yr monitoring period should be sufficient to determine meiobenthic copepod seasonality patterns.