PhD Thesis

Process and consequence of a local invasion of Chelicorophium curvispinum (Crustacea:Amphipoda) into a small estuary in South-East England by Phil Buckley, September 2006.

Abstract
The tube dwelling amphipod Chelicorophium curvispinum is a native of estuaries in the Northern Ponto-Caspian region. Over the last hundred years, C. curvispinum has invaded rivers
throughout Western Europe. C. curvispinum was first reported in Britain in 1935. A population of C. curvispinum was discovered in the Kentish Stour Estuary in 1998. The invasion of C. curvispinum into the Kentish Stour Estuary was detected by a routine monitoring survey carried out by the Ecology Research Group of Canterbury Christ Church University. Archive data from this survey covering the time-span 1996 to 2003 were examined and the process of the invasion was chronicled. Between 1996 and 2003, three distinct time periods were identified with respect to the invasion; Before, During and After. The period Before the invasion contained no records of C. curvispinum. The period During the invasion was characterised by the first reports of C. curvispinum in the Estuary, followed by a population spike. The period After the invasion was characterised by an initial population collapse followed by a stabilisation of numbers of C. curvispinum. Examination of physico-chemistry data collected in concert with biological samples found that, During and After the invasion, there was a drop in suspended solids, nitrites, nitrates and phosphates in the river. Multiple regression analysis found no direct relationship between any physico-chemical determinands and C. curvispinum abundance. Examination of the native fauna found no evidence of a weakening of the native benthic invertebrate community in the Stour Estuary before the invasion. There was also no evidence of any impact of the C. curvispinum invasion on the native fauna.

Data obtained from the Environment Agency showed that the national distribution of C. Curvispinum had changed drastically between 1985 and 2003. The data describe a steady increase of sites occupied by C. curvispinum that continued until the mid 1990s. Experimentation indicated that C. curvispinum was eclectic in its requirements.