*NEWS*CLIMATE RESPONSE RISKS TO NATURE

[Anonymous]

Climate response risks to nature
Many species are shifting at an inappropriate rate, and this must in the end be detrimental
Some animals are responding to climate change in ways which could threaten their survival, a new study finds.
Scientists
showed that migration and breeding of the great tit, puffin, red
admiral and other creatures are moving out of step with food supplies.
The
researchers say the rapid pace of climate change, together with
pressures on habitat, make it difficult for species to adapt.
The study is published in the Royal Society’s journal Proceedings B.
A
large number of studies in recent years have shown that the behaviour
of plants and animals is changing in response to climatic alteration.
Birds
are migrating at different times, flowers and larvae are emerging
earlier, and fish and insects are moving into new ranges.
The key
question is how much this matters – whether these changes impair the
prospects for these species, or whether they are appropriate
adaptations which will ensure survival.
Marcel Visser, from the
Netherlands Institute of Ecology in Heteren, and Christiaan Both, from
Groningen University, have trawled through more than 50 research papers
to find examples where it is possible to measure the suitability of how
a species responds.
Eat or be eaten
“We
wanted to find species for which we have some sort of yardstick to
assess how much they should be responding,” Professor Visser told the
BBC News website.
“For example, we know that great tits are changing
their behaviour because of the availability of food, so that should be
the yardstick here; but there might also be instances when issues such
as predation are more important.”
Visser and Both identified 11
cases with an appropriate yardstick, and found that in eight of these
the species in question is either responding more or less than would
appear to be optimal.
Caterpillars are the staple food for infant
great tits; and as the emergence of caterpillars in the European Spring
is getting earlier, so, logically, should the time at which great tits
lay their eggs In fact, one population that has been extensively
studied, at Wytham Wood in the UK, has brought its egg laying forward,
but by too much. By contrast, another population at Hoge Veluwe, in the
Netherlands, is laying at the same time as in previous years.
Neither of these responses appears to be the best available for the bird.
In
North America, the wood warbler has not adapted its migration pattern
to the earlier emergence of caterpillars in its breeding ground; and in
the Netherlands, the honey buzzard is also failing to exploit the
earlier appearance of wasps which it eats.
The red admiral
butterfly, however, is arriving on the UK’s shores earlier from its
winter grounds in north Africa; but the staple food of its larvae, the
common nettle, continues to flower at the same time each year.
Loss of synchrony
The reasons why these species do not appear to be adapting optimally are unclear.
They
may be unable to, they may not be subject to a pressure large enough to
induce change, or each may be subject to several pressures pushing them
in contradictory directions.
Whatever the explanations, Marcel Visser believes his findings sound a clear warning.
“The
conclusion must be that many species are shifting at an inappropriate
rate, out of synchrony with their food sources, and this must in the
end be detrimental.
“The point has often been made that temperatures
have increased before in the Earth’s past; but the rate now is 100
times greater.
“And whereas in those times there were large areas of
natural habitat, now it’s much more difficult for animals to change or
migrate; plus there’s loss of genetic diversity, habitat fragmentation
– it’s just much more difficult for species than 1,000 years ago.” 

[Author]

November 4, 2005 at 10:11 AM