The
New Scientist March 2,
2011
http://www.newscientist.com/article/dn20190-evolution-races-to-
keep-up-with-climate-change.html
Evolution
races to keep up with climate
change
By Ferris
Jabr
Climate
change may accelerate evolution
in some species - but that
doesn't
guarantee that threatened
populations will cope in the long
run. That's
the message of a study that
suggests the changing
environment
is hitting fast forward on
evolutionary
adaptations.
Arild Husby
of the University of Edinburgh,
UK, and his team looked
at data
gathered from a wild population
of great tits (Parus major)
in the
Netherlands that has been
monitored since 1955.
Increasingly
warm springs over the past four
decades mean the
songbirds'
biological rhythms are out of
sync with nature. Plants are
blossoming,
fruits are blushing and
caterpillars are gorging
themselves
earlier. Great tit chicks that
hatch too late in the
season miss
out on this unusually early peak
in food - especially the
abundance
of caterpillars - resulting in
fewer surviving youngsters
and second
clutches.
The
researchers correlated average
daily temperatures to egg-laying
dates from
more than 3800 visits to the
nesting boxes of nearly 2400
females
recorded between 1973 and
2007.
The
analysis confirmed that rising
temperatures have strongly
selected
for great tits that hatch
earlier: chicks that enjoy
spring's
early-bird special went on to
produce more chicks of their
own.
What's
more, they found that the
statistical correlation was
strongest
for the warmest springs. This,
the team says, suggests that
increasing
temperatures are speeding up the
bird's adaptation to warm
springs.
Can they
keep up?
It's not
all good news, though. Despite
this potential coping
mechanism,
the population overall is
producing fewer and fewer
offspring,
leading the researchers to
question whether the birds can
adapt fast
enough to keep pace with climate
change.
"We were
quite excited and surprised by
these results," says Marcel
Visser of
the Netherlands Institute of
Ecology in Wageningen. He
explains
that the rate of evolution
compared with that of climate
change will
determine how well biodiversity
can cope.
Timothy
Coulson of Imperial College
London explains that the
songbirds
are probably experiencing
markedly accelerated rates of
microevolution
- change in gene frequency from
one generation to the
next - as
opposed to long-term evolution,
which spans many thousands
or millions
of years.
"Evolutionary
biologists have known for some
time that as the climate
shifts it
appears to lead to evolutionary
change - some species go
extinct,
others come online," says
Coulson. "What we can do now is
detect
microevolution - the type of very
rapid evolution you might
struggle to
pick up in the fossil
record."
With
climate change, responses to
environmental change are
happening
at an
unprecedented rate, he adds,
suggesting that microevolution
may
be
happening a little faster than
before.
But, he
cautions: "When we see very rapid
changes, it doesn't mean
the
individuals have developed an
evolutionarily stable
strategy."
Rowan
Barrett of Harvard University
agrees that even rapid evolution
does not
guarantee safe passage to species
threatened by climate
change.
"Sometimes evolution won't be
able to save a population, even
if it's
very fast," he says. "We are
seeing more and more examples -
like coral
bleaching - where species just
can't evolve fast enough to
cope with a
change in the
climate."
Journal
reference: PLoS Biology; DOI:
10.1371/journal.pbio.1000585
