ADAPTATION STRATEGIES

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SOME LIKE IT HOT

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ADAPTATION STRATEGIES CHRIS GIBSON As naturalists we live in interesting, even exciting, times. Our flora and fauna, always dynamic, are now increasingly so, and we are seeing new species turning up on an increasingly frequent basis. Many, perhaps most, of these are species from more southern climes, the colonisation and spread of which is entirely consistent with climate change, although we should not be too quick to ascribe causal factors in the absence of hard evidence. A few well-known examples from our part of the country include: • • • •

Little Egret Mediterranean Gull Roesel’s Bush-cricket (followed by the Long-winged Conehead) Scarce Emerald Damselfly (followed in its wake by the Small Red-eyed Damselfly) Bee-wolf Wasp Spider

• • These are previously rare or absent species, which have colonised markedly, in a way which would be expected under climatic warming. What’s more, they have been doing so for some considerable time, 20 years or more. Remember 20 years ago? – a time when climate change, if talked about at all, was just a possibility, a theory. Understandably the climatologists were cautious – climate is very variable, and changes for a variety of factors over a range of timescales – they had their professional reputations to worry about. But not so the wildlife: if the climate changes they will respond, and we as naturalists are admirably placed to see it. During the period of scientific doubt, the signs were there – the wildlife was crying it from the rooftops – our world is warming up! The examples given thus far are just the tip of the iceberg, the more obvious cases of rare, extinct or previously absent species becoming relatively commonplace. Other more subtle, but no less important, changes are under way, including for example: • Phenological changes, as discussed at length elsewhere in this volume • Changes in wintering areas and habits: Avocets have long been valued as part of the breeding bird scene in East Anglia. It is a relatively coldintolerant species, and winter warming has encouraged the recent development of several huge wintering populations eg last winter on the Thames, they peaked at around 1500 birds. • Changes in breeding areas and habits: The UK Cormorant breeding population is currently rocketing, a phenomenon which started at Abberton Reservoir in the 1980s, where they adopted the tree-nesting habits of the Continental race sinensis, which form a significant part of that breeding population. The early colonisers of Abberton were largely sinensis, which in addition to tree-nesting is also an early nester, and it could be argued that warmer springs led to it being able to breed here, thus triggering the population explosion.

Trans. Suffolk Nat. Soc. 42 (2006)


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