Perilous Times and Climate Change
Climate Change: Earlier springs could destroy delicate
balance of UK wildlife, study shows
Global warming could be changing seasonal timing with profound
consequences, according to analysis of 726 species of plants and animals
* David Adam, environment correspondent
* The Guardian, Tuesday 9 February 2010
A new assessment of Britain's wildlife has found that recent winters
have been ending earlier than ever. Photograph: Guardian
As snow flurries continued to cause disruption across the country
today, spring may feel further away than ever. But recent winters have
been ending earlier than ever before, according to a new assessment of
Britain's wildlife that reveals global warming could be disrupting the
delicate balance of nature.
The analysis confirms that spring and summer are occurring earlier, but
also shows that this trend appears to be accelerating. The shift could
pose problems for animals, birds and fish that rely on springtime
flowering of plants to supply food for their young.
Stephen Thackeray, a biologist at the Centre for Ecology and Hydrology
in Lancaster, who co-led the research said: "This is about the
desynchronisation of events during the year. Animals and birds time
their reproduction to coincide with periods when there will be an
abundance of food. If changes mean there is not enough food available
then this could have negative consequences for their offspring."
The new study compiled 25,000 records of springtime trends for 726
species of plants, animals, plankton, insects, amphibians, birds and
fish across land, sea and freshwater habitats. It analysed them for
changes in the timing of lifecycle events, such as egg laying, first
flights and flowering, a science known as phenology.
The results showed that more than 80% of trends between 1976 and 2005
indicated earlier seasonal events. On average, the study showed the
seasonal timing of reproduction and population growth shifted forward
by eleven days over the period, and that the change has accelerated
recently.
Thackeray said: "This is the first time that data have been analysed
with enough consistency to allow a meaningful comparison of patterns of
changing seasonal timing in the UK among such a diverse range of plants
and animals."
The study used records drawn from the work of thousands of volunteers
who, as part of the UK phenology network, have made painstaking
observations of the behaviour of wildlife in gardens and public spaces.
It also relies on professional scientists, who have analysed habitats
such as the plankton content of water drawn from lakes and coastal
waters.
The research, published in the journal Global Change Biology, found
large differences between species in the rate at which seasonal events
have altered. Changes have been most rapid for many organisms at the
bottom of food chains, such as plants and the animals that eat them.
Predators have shown slower overall changes in the seasonal timing of
their lifecycle events. This could spell problems, as the seasonal
timing of reproduction is often matched to the time of year when food
supply increases, so that offspring receive food needed to survive. A
key question, the scientists say, is whether animals higher up the food
chain can adapt to the faster rates of change in the plants and animals
they feed on.
Sarah Wanless, who also co-led the research, said: "It is important to
realise that this analysis doesn't identify which predator-prey
relationships are most at risk from disruption due to changes in
timing. What is does do is highlight that the recorded changes need
urgent investigation, particularly for species with high economic or
conservation importance."
Not all of the species showed a shift to earlier lifecycle events.
Some, such as seabirds, now lay their eggs later in the year than they
did before. But the scientists said the overall results show that
climate warming is having an impact, and that the effect could get
worse as temperatures continue to rise.
Richard Smithers of the Woodland Trust said: "Phenology is the canary
in the cage. The results of this new study make real our changing
climate and its potential to have profound consequences for the complex
web of life."
Thackeray said it was difficult to generalise about how the changing
climate has affected individual species across Britain, because most of
the observations were for specific locations. One study found that oak
trees were producing leaves 0.9 days earlier each year, while another
found blue tits had changed their time of egg laying by 0.3 days a
year. Other research found that hazel flowered a day earlier, and
orange tip butterflies took their first flights 0.7 days earlier.
The study involved scientists from 12 UK research institutions,
including Butterfly Conservation, Freshwater Biological Association,
People's Trust for Endangered Species and the National Pollen and
Aerobiology Research Unit at the University of Worcester.
Many of the organisations have now started follow-on research to see
which species could be negatively affected by the change in timings and
what could be done to help.
Writing in the journal, the scientists warn: "If current patterns and
rates of phenological change are indicative of future trends, future
climate warming may exacerbate trophic mismatching, further disrupting
the functioning, persistence and resilience of major ecosystems and
having a major impact on ecosystem services."