Responses of Estuarine Infauna to Disturbance. II. Spatial and Temporal Variation of Succession

Abstract

Infaunal successional patterns in Alewife Cove, a small estuary in southeastern Connecticut, USA, varied significantly seasonally and along the estuarine environmental gradient. Each study site exhibited different patterns of change in species composition and abundance. However, suites of species found during success~on did not differ greatly from those found in ambient sediments. Species w h~c h exhibited the most variable population changes during succession were numerically dominant tubiculous polychaetes (Streblospro benedicti, Capitella spp., Polydora ljgni], and an oligochaete (Peloscolex gabriellae). Other species which exhibited significant activity were the polychaetes Scoloplos fragilis, Hobsonia florida and Nereis virens, the hemichordate Saccoglossus kowaleski, and the amphipods Microdeutopus gryllotalpa and Corophium insidiosum. At certain times, densities of these species exceeded or were equivalent to dominant species densities in ambient sediments and experimental plots. Timing of disturbance greatly influenced succession Succession after a n early spring disturbance was characterized by peak species dens~ties and numbers. Succession following a fall disturbance was abbreviated with few species at low densities, while after a summer disturbance intermediate trends were found. Classification analysis of similarity between ambient and successional community structure indicated that recovery to ambient conditions occurred rapidly in the lower reach (14 to 30 d ) , while successional changes in the middle and upper basins continued at least until the end of the winter. It is apparent that estuarine succession can be quite varidble and that re-establishment of community structure may occur over various time scales w~t h no set sera1 stages. The physical and biological processes appearing to b e important determinants of estuarine succession include (1) timing of disturbance, (2) habitat in w h~c h the disturbance takes place, (3) reproductive periodicity of infauna, (4) ambient population dynamics which generate the pool of recolonizers, ( 5 ) abiotic and biotic factors (e.g. food and space resources that affect the preceding 4 factors).

Influence of invasive Spartina growth stages on associated macrofaunal communities

“…At this point we infer a causal relationship, but a definitive demonstration of these relationships awaits future experiments. Many mechanisms have been shown to influence soft-bottom benthos including pollution, organic enrichment, anoxia/hypoxia, predation, competition and physical disturbance (e.g., Pearson and Rosenberg 1978;Zajac et al 1982;Harkantra and Rodrigues 2003), with dynamic shifts occurring in both composition and the nature of animal-sediment interactions (Rhoads and Boyer 1982). The patterns of benthic macrofaunal distribution observed in this and other studies (i.e., Neira et al 2005Neira et al , 2006Grosholz et al in press) reflect complex plant-animal interactions.…”

Habitat change in estuaries: predicting broad-scale responses of intertidal macrofauna to sediment mud content

“…Broad-scale differences in assemblages in sand and mud habitats are readily apparent (e.g. Gray 1974, Beukema 1976, Zajac & Whitlatch 1982, Meire et al 1994, Mannino & Montagna 1997, Ysebaert et al 2002. However, when relationships between sediment characteristics and the distribution and abundance of macrofauna have been identified, elucidating the underlying mechanisms has proved elusive (Butman 1987, Snelgrove & Butman 1994.…”

Quantifying and Monitoring Ecological Response to No-Take Marine Reserves

“…C. capitata is an opportunistic species, and its abundance has been frequently correlated to high levels of anthropogenic impact such as bottom disturbance, eutrophication, etc. (Zajac and Whitlatch, 1982;Giangrande, 2005). In hard bottom environments, a number of species of syllid polychaetes have been shown to demonstrate similar properties (Giangrande et al, 2005).…”