and resources than figuring out the specific role of greenhouse gases in driving
biological change. Other researchers in
the field also are calling for an integrated
approach to future research that takes
into account interacting environmental
pressures, interconnected species and
the varied sensitivities of different species to changing conditions. And because
temperature isn’t the only driver — some
animals are showing behavioral and
physiological changes in response to
changing carbon dioxide levels or altered
precipitation patterns — there are plenty
more interactions to factor in.
Another factor to consider is how
quickly climate change is moving across
the land, says Scott Loarie, a postdoctoral researcher who works with global
ecologist Chris Field at Stanford. In
2009, Loarie, Field and colleagues found
that, overall, species will need to move
about two-fifths a kilometer per year to
keep up with changing conditions, 10 to
100 times faster than they’ve ever had
to move before to cope with changing
climates. Mountain dwellers won’t have
to move as far as critters in flatter landscapes to find a new home — just 10 or so
kilometers over the next century, compared with more than a hundred.
One recent study suggests ocean-dwelling animals may need to move as
fast or faster than land species — and to
advance the timing of breeding, spawning, migration and other seasonal life
events even more. The work, from the
marine biological impacts working
group at the National Center for Ecological Analysis and Synthesis at the
University of California, Santa Barbara,
was published last year in Science.
The conclusions of Loarie and
coauthors echo the 2003 findings of
Parmesan and Yohe. But instead of documenting changes that have already
occurred, Loarie’s group developed an
index that can be used to predict future
range shifts. Applying their predictions
to nature preserves worldwide, the
researchers arrived at the dire conclusion that traveling temperatures will
force wildlife out of all but 8 percent of
those reserves within a century.
About 9 percent of
Western Hemisphere
mammal species may not
be able to move to new
habitats fast enough to
keep up with the pace at
which climate change is
altering local conditions
20
15
(velocity of climate change
is a measure of the pace
required to maintain similar climatic conditions).
10
Mammal species that,
on average, won’t move
fast enough fall below the
diagonal black line in the
graph at right.
Mammal dispersal velocity (km/year)
5
Mammal dispersal and speed of climate change
0
Rodents Even-toed ungulates Carnivora Primates Shrews and moles Sloths, anteaters, armadillos American marsupials Hares, rabbits, pikas
SOURCE: C.A. SCHLOSS ET AL/
PNAS 2012
0
Velocity of climate change (km/year)
246810
Looking at the problem from a slightly
different angle — how far animals actually are able to travel to establish new
homes and how inclined they are to do
so—researchers at the University of
Washington in Seattle also came up with
grim figures. This year in the
Proceedings of the National Academy of Sciences
(SN Online: 5/14/12), Carrie Schloss and
colleagues found that about 9 percent of
mammal species in the Western Hemisphere won’t be able to move fast enough
to keep pace with climate change. In
some areas, more than half the mammal
species will be unable to keep up.
The Loarie and Schloss studies don’t
just spin out gloomy scenarios, though.
They also point to conservation strategies, such as designing reserves that
include a range of landscapes—and
associated climate regimes — and creating linked networks of protected areas.
Given the complex, interconnected
pressures on animals these days, the
varied ways species are responding and
the projections that temperature may
rise another 1. 8 to 4 degrees by the end
of the 21st century, it’s time to com-
pletely rethink conservation aims and
approaches, says paleoecologist Anthony
Barnosky. People have been accustomed
to setting aside reserves and expecting
them to simultaneously protect the
natural landscape, the species that live
there and the associated “ecosystem
services” — ecological interactions that
provide humans with food, clean water,
recreational opportunities and the like.
But now, with plants and animals mov-
ing around, old associations breaking up
and new ones forming, it may no longer
be possible to protect all three facets of
nature at once.
Explore more
s Anthony Barnosky. Heatstroke: Nature
in an Age of Global Warming. Island
Press, 2009.
Nancy Ross-Flanigan is a freelance
writer based in Newaygo, Mich.
www.sciencenews.org
June 30, 2012 | SCIENCE NEWS | 21
