NIOZ

Today we join the newly refurbished R/V Pelagia for a research cruise to investigate coral habitats off the United States continental shelf. This programme is being run by my colleague Dr Furu Mienis who has recently moved to MARUM in Germany, and involves scientists from UNC-W, MCBI, NIOZ, Heriot-Watt, Aarhus University and of course, Bangor.

This cruise follows the joint European-USA programme that we participated in in 2008, Dr Gerard Duineveld and Dr Furu Mienis left their landers ALBEX and BOBO down last year, so our primary aim is to recover the landers, deploy a third one baited for fish observations, do our usual CTD/mooring operations and take samples for biodiversity/genetics analysis.

More on this later…

Frederic Mineur, Andrew J. Davies, Christine Maggs, Marc Verlaque and Mark Johnson

Not all introduced (invasive) species in a region will spread from a single point of introduction. Long-distance dispersal or further introductions can obscure the pattern of spread, but the regional importance of such processes is difficult to gauge. These difficulties are further compounded when information on the multiple scale process of invasive species range expansion is reduced to one-dimensional estimates of spread (e.g. km yr⁻¹). We therefore compared the results of two different metrics of range expansion: maximum linear rate of spread and accumulation of occupied grid squares (50 × 50 km) over time. An analysis of records for 54 species of introduced marine macrophytes in the Mediterranean and northeast Atlantic revealed cases where the invasion process was probably missed (e.g. Atlantic Bonnemaisonia hamifera) and suggested cases of secondary introductions or erratic jump dispersal (Dasysiphonia sp. and Womersleyella setacea). A majority of species analysed showed evidence for an accumulation of invaded sites without a clear invasion front. Estimates of spread rate are increasing for more recent introductions. The increase is greater than can be accounted for by temporally varying search effort and implies a historical increase in vector efficiency and/or a decreased resistance of native communities to invasion.

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Full citation

Mineur F, Davies AJ, Maggs CA, Verlaque M, Johnson MP (In press) Fronts, jumps and secondary introductions suggested as different invasion patterns in marine species, with an increase in spread rates over time. Proceedings of the Royal Society B: Biological Sciences. 277: 2693-2701

DOI

DOI: 10.1098/rspb.2010.0494