Many changes are happening in the timing of wildlife events, like migrations and egg laying. Swallows are now arriving seven days earlier in spring than they did a hundred years ago, while birds are laying their eggs nine days earlier than they did 25 years ago. The flowering of common hedgerow plants is three weeks earlier that it was a century ago, while spring flowers in general are flowering noticeably earlier.

The distribution of plants and animals is also changing, most noticeably among those species that are active fliers, like birds and butterflies. As the earth warms, species in the northern hemisphere are adapting by moving northward at a rate of 50 to 80 kilometres per decade. We can expect to see the loss of northern species at the southern edge of their ranges and to gain southern species at the northern edge of their ranges. In Cornwall actuality is more complex, as there is no continuity with land further south, so we can expect more chance sightings of southern species of non-migratory birds and insects blown by wind and storm across the Channel. Introduced southern species (like cage birds) that escape sometimes find they can live and breed in our warming climate.

Clearly there is no barrier to marine species; in fact there is continuity of habitat as far south as the equator and beyond. The large triton shell is now known to breed in

Falmouth Bay, as adults have been found there which could not have made their way there as adults. It is most likely that this species arrived as a planktonic larval stage, perhaps carried north from the outflow of the Mediterranean, and then settled to the bottom here to change into its adult form. However, it is the fish that are probably the best indicators that the Atlantic is warming, as they are active swimmers, sensitive to tempe-rature, and are well monitored by anglers and fishermen.

Stella Turk has extracted records of the appearance of warm-water fish species from the Records Centre for the last 40 years, with some striking results. There have been reports that the occurrence of warm-water fish in our waters is indicative of warming of our waters but we believe ours is the first quantitative analysis of the numbers of species involved. The data show that over the last 40 years the numbers of southern species arriving in Cornish waters each decade have steadily increased. Such an increase in numbers is a puzzle, as with gradual warming one might expect to see a constant rate of immigration. However, from recent temperature data we can see that the rate at which the North Atlantic is warming is accelerating (0.7°C over the last 30 years). This may explain why we are seeing small but increasing numbers of warm-water fish off our shores.

So how does this affect nature conservation and the role of the Trust? With species on the move and wildlife trying to shift north (or onto higher ground), we must have a policy emphasising the conservation of habitats rather than species. With isolated pockets of habitat, there is the danger that species with no northerly habitat to move to may be lost. We should therefore, whenever possible, look at new acquisitions with a view to creating corridors for the northward drift of species.

Of equal importance is our biological record keeping. I suspect that, as the impact of climate change and its effect on wildlife grows, our records will prove increasingly valuable in providing indices of climate change. This is not only important for regional purposes: our unique geographic position makes these records of national importance, Cornwall projecting as it does like a toe into the warming waters of the North Atlantic. We have new conservation challenges to meet as climate change takes hold.

Tony Stebbing Trust President

Is this the future for Cornwall's seas?! Increasing numbers of warm-water fish species are extending their ranges into our waters.

Photo by courtesy of the Blue Reef Aquarium, Newquay