Abstract
It is well known that adult dispersal is common in soft bottom intertidal and shallow subtidal communities. We here report on the first study that attempts to quantify the effects of both immigration and emigration on patches of soft sediment communities. Some species show adaptive emigration from the seabed, although dispersal direction, distance, and colonization success are probably strongly dependent on hydrodynamics, morphological adaptations to dispersal, and the ability to select appropriate target microsites. The naid oligochaete Paranais litoralis is a numerically dominant benthic species in southern New England and New York mud flats and tends to reproduce mainly or exclusively by means of budding of new individuals. When population density is high and resources in short supply, budding frequency is reduced, worms grow longer, and may emigrate from the sediment. We quantified emigration by means of a conical trap and quantified immigration with sediment dishes. We followed emigration/immigration during the typical late spring population explosion and crash cycle of worms within the sediment, which is driven by a seasonal cycle of provision and exhaustion of organic detrital food supply. Emigration was proportionally maximal either at or after the population peak, consistent with a response to food shortage. Over a span of ca. 50 m, we found no net movement in either direction along a transect, nor was emigration or immigration correlated with local density in the sediment. Nevertheless, both emigration and immigration were important in our 2004 sampling, and immigration especially had an important impact on population densities. We do not know the relative capture efficiencies of the emigration and immigration apparatus, so more needs to be done to understand the impacts of dispersal in this and other systems.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
More From: Journal of Experimental Marine Biology and Ecology
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.