1°C warming increases spatial competition frequency and complexity in Antarctic marine macrofauna

Environmental conditions of the Southern Ocean around Antarctica have varied little for >5 million years but are now changing. Here we investigated how warming affects competition for space. Little considered in the polar regions, this is a critical component of biodiversity response. Change in competition in response to environment forcing might be detectable earlier than individual species presence/absence or performance measures (e.g. growth). Examination of fauna on artificial substrata in Antarctica’s shallows at ambient or warmed temperature found that, mid-century predicted 1°C warming (throughout the year or just summer-only), increased the probability of individuals encountering spatial competition, as well as density and complexity of such interactions. 2°C, late century predicted warming, increased variance in the probability and density of competition, but overall, competition did not significantly differ from ambient (control) levels. In summary only 1°C warming increased probability, density and complexity of spatial competition, which seems to be summer-only driven

European expansion of the introduced amphipod <i>Caprella mutica</i> Schurin 1935

The amphipod Caprella mutica is one of the most rapidly invading species in Europe and has extendedits range throughout North Sea and Celtic Sea coasts and the English Channel in less than fourteen years. It was first described from sub-boreal areas of north-east Asia in 1935 and has since spread to both northern and southern hemispheres. The first European record was from The Netherlands in 1994. Since then it has spread within the North Sea and later to the west coast of Scotland and to Ireland. C. mutica is frequently associated with man-made structures and is found in abundance on boat hulls, navigation/offshore buoys, floating pontoons and aquaculture infrastructure. It is highly likely that its dispersal is associated with vessel movements whilst attached to hull fouling. This species is expected to colonise the west coasts of France and Spain and offshore islands in the north-east Atlantic