As climate shifts, should we fight it?
Disappearing savannas in South Africa's Kruger National Park
are forcing scientists to reconsider what conservation means
Elephants and leopards are moving in to the Kruger National
Park, South Africa's premier game reserve, while zebras and wildebeest are
moving out. They are all possibly victims of global warming. (Tribune photo by E. Jason
Wambsgans / January 26, 2007)By Laurie
Goering Tribune foreign correspondent
8:08 AM CDT, November 2, 2007
KRUGER NATIONAL PARK, South Africa - Fourth in a series
Something unexpected is happening in the
grasslands of South Africa's premier game reserve, forcing grazers like zebras
and wildebeest to move out of some areas while tree-loving species like
elephants and leopards move in.
savannas, home to the continent's great grazing herds, are starting to
disappear, possible victims of global warming.
For the first time in eons, fast-increasing levels of carbon dioxide in the
atmosphere seem to be giving shrubs and trees a competitive advantage over
grass, leaving once-open areas vulnerable to encroaching
Noting the invasion of underbrush with alarm, conservation
scientists say climate change is presenting them with a new challenge: to adapt
their thinking about an environment that is changing before their eyes. Long
trained to protect intact ecosystems, they must now ponder once unthinkable
questions, such as whether it is still appropriate to protect every species and
manage every terrain, or whether the future of some plant and animal life should
be left to the whims of a natural world in flux.
environmental rethink is part of a much bigger shift, an awareness of global
warming that was given a dramatic jolt last month when former Vice President Al
Gore was given the Nobel Peace Prize along with a UN panel for their roles in
educating the public on climate change.
Businesses, governments and
people around the planet are searching for solutions to the vexing problems
presented by climate change, including efforts to harness new technologies,
accept daily lifestyle changes or, in the case of the African grasslands,
reconsider long-standing beliefs.
"The whole idea of conservation is
based around stasis, of things being the way they always were. But that's not a
tenable way of doing conservation in the future," said Robert Scholes, a leading
systems ecologist and climate specialist in South Africa, which is at the
forefront of the international effort to rethink conservation's
With nature reorganizing itself around the world, "a relaxation
of our very purist paradigms about conservation is almost certainly called for,"
said Scholes, who works for South Africa's Council for Scientific and Industrial
In South Africa, researchers and park managers are racing to
understand the changes under way in some of Africa's best-known nature reserves
and to come up with plans to deal with savannas that are quickly coming to
resemble thickets more than open plains. What they discover and what they decide
will likely guide a new international conservation ethic for an altered
"We've passed the point where we can avoid things being different,"
said Barend Erasmus, a researcher on climate change and biodiversity at the
University of the Witwatersrand in Johannesburg. But "I think we will know
enough to do something. I think we can come up with good common-sense
Ecosystems being reshaped
climate shifts already are having a dramatic effect on natural areas across the
planet. In most places, some species are thriving in altered climate conditions
while others falter, a process that is reshaping ecosystems. Butterflies, frogs,
antelopes, flowers and other plants and animals are trying to migrate toward
more suitable habitat, but many find their way blocked by the boundaries of
existing parks or the sprawl of roads and cities.
hoping to preserve as much biological diversity as possible, are talking about
things they once dismissed as lunacy: gene banks, cloning and even "assisted
migration" -- loading plants and animals on trucks to help them get to new, more
But worldwide recognition is growing that there are
limits to what can be saved. A longtime focus on ensuring no species goes
extinct is giving way among some leading scientists to an acceptance that
thousands, if not tens of thousands, of species will likely succumb to climate
shifts in coming years.
A key laboratory for this work and worry is
Kruger National Park, a 240-mile-long finger of land along South Africa's
eastern border with Mozambique.
Kruger, one of the best-studied
conservation areas in Africa is home to Africa's iconic Big Five -- elephants,
lions, leopards, Cape buffalo and rhinos -- and draws more than 1.2 million
visitors a year. The Wales-size park is also home to dozens of South African and
international researchers, who over most of the last century have helped keep
meticulous records on everything from the size of the park's elephant population
to the water quality of its rivers.
The park, unlike many in Africa, is
intensively managed. Artificial watering holes help support game in some of the
driest areas of the park, and controlled fires are used to help weed out brush.
Scientists in recent years have developed a management program for the reserve
based on "thresholds of potential concern" -- key rises or dips in animal and
plant populations or things like river flow as an indicator of impending
By that standard, Kruger already has major worries. Water flow
and quality are declining as development accelerates along the unprotected
headwaters of the park's main rivers. A growing elephant population is
contributing to the loss of many of the reserve's big trees.
managers in recent years have encountered a new problem as well: bush
encroachment, or the invasion of Kruger's open grasslands by woody shrubs and
In South Africa, fast-increasing levels of carbon dioxide in the atmosphere
are giving an edge to shrubs and trees, which build their woody skeletons out of
carbon, while pushing out savanna grasses, which many scientists believe evolved
to live in a low carbon dioxide world. In parts of Kruger, slow-growing shrubs
and small trees once kept in check by fire and hungry elephants are now shooting
up in a tenth of the time it used to take them and turning open grasslands into
"Somewhere in the 20th Century, we've created super trees,"
said William Bond, a University of Cape Town botanist, who has been digging up
young acacias in Kruger to study their increasingly hefty roots. "I'm convinced
things have changed in an extraordinary way."
end of the savannas'
Whether those changes extend to the
earth's other savannas -- a dominant ecosystem that today covers a fifth of the
planet's land surface -- remains in question, because studies in many places
have yet to begin or are not yet conclusive. But savannas from northern
Australia to South America and the U.S. Midwest potentially could be similarly
affected, Bond said.
So far, bush encroachment hasn't reached the top of
the list of Kruger's concerns but Bond thinks that is about to change. Research
in several of South Africa's nature reserves and in his lab, in a series of
greenhouses where acacias are growing in different carbon dioxide
concentrations, has persuaded him that mounting levels of carbon dioxide in the
atmosphere mean that savannas are on their way out as one of the earth's
With hands rough and discolored from days of digging
in the soil, he pulls out maps from 2004 that show brush and scrub forest
covering 58 percent of another study area in South Africa's Hluhluwe-Imfolozi
game reserve, up from 15 percent in 1937. Adjoining privately owned range land
and communally held village land, regularly scoured by scrub-eating goats, show
similarly impressive jumps. Altogether, a 1989 study shows, 65 percent of South
Africa's savannas are now severely encroached by brush.
"This is a
complete biome switch, the end of the savannas," Bond predicted. In South
Africa, "we see the same fires, the same rainfall variation, the same animals.
But the trees have gone crazy. It looks like a global driver."
everyone agrees with Bond. Many scientists say that while intensifying carbon
dioxide in the atmosphere appears to favor trees and brush over grasses, the
advantages may be subtle or disappear altogether depending on other factors like
rainfall, temperature and soil nutrients.
But if bush encroachment continues, managers at
Kruger admit they may soon need to find a way to confront it, whether or not it
is "natural" in a transforming climate.
"Rangers who have been here a
long time say it's thicker, that Kruger is changing. Tourists complain they
can't see game like they used to, that all they see are thick curtains of bush,"
said Stefanie Freitag-Ronaldson, science operations manager at
"If by 2020 or 2050, what is natural is uniform thicket across
Kruger, we might try to find a way to flout that," added Harry Biggs, Kruger's
expert on adaptive biodiversity. "One of our values is the park should be
natural. But what is natural is a hard question anymore."
managers are gradually coming to accept that some of the coming changes may be
unstoppable. For reasons they don't fully understand, the park's populations of
roan and sable antelope have plunged in recent years despite costly attempts to
rebuild the herds. The handsome grazers may soon simply be allowed to go extinct
in the park.
Most of the world's conservation efforts over the last
century have focused on setting aside key pieces of land to preserve ecosystems
and help ensure no species goes extinct. But as the Earth's climate changes, a
growing flood of extinctions are inevitable, many scientists say. A 2004 study,
"Extinction Risk from Climate Change," published in the journal Nature by some
of the world's top conservation climate experts estimates that by 2050 between
15 percent and 37 percent of species in the world's most biologically rich
habitats will be on the path to extinction if the climate alters even
That could be reduced if nations quickly and dramatically cut
greenhouse gas emissions -- something most people now agree is unlikely -- or if
conservation reserves can be added or expanded to give species fleeing new
climate stresses somewhere to go.
Competition for land is increasingly
intense, and conservation will have to compete with other political
Still, efforts are under way in some places. With warming
oceans fast destroying coral reefs worldwide, conservation organizations are
racing by year's end to set up some of the world's first marine parks designed
to buffer the effects of climate change. The parks, in the Indian Ocean, will
set aside areas where natural up-wellings of cold water offer the potential to
protect fragile coral, said Lee Hannah, a climate specialist with
Washington-based Conservation International, and one of the authors of the paper
on predicted extinctions.
South Africa similarly has expanded nature
reserves in the direction that some highly endangered members of its unique Cape
floral kingdom are migrating. And Kruger itself has in recent years taken down
fences on its border with neighboring Mozambique conservation areas to create a
bigger new "trans-frontier" park with more room for animals to move.
a growing number of scientists believe the future success of conservation
efforts will be determined by how well plants and animals are protected outside
parks. As species migrate in response to climate stresses, some will inevitably
move onto private land, where their reception may determine their ultimate
Around Kruger, conservationists used to convincing the
reserve's neighbors of the economic benefits of having wildlife next door are
now trying to convince them of the benefits of having wildlife on their own
land. Citrus farmers, forest plantation owners and villagers around the park are
being urged to try no-till farming, use fewer pesticides and leave natural
corridors for plants and animals moving in response to climate stresses, all
part of an effort to create a broader "matrix" of habitat where pressured
species can survive.
Persuading governments and wildlife groups to
abandon old ideas about conservation in favor of a new ethic won't be easy.
Kevin Rogers, a University of the Witwatersrand ecologist who helped write
Kruger's adaptive management plan, predicts the rise of a new era of "greenies
and bunny huggers" virulently opposed to allowing species to slip into
extinction. Even pragmatic nature lovers may wince at the idea that emblematic
species like the blue crane -- South Africa's endangered national bird that
nests in grasslands -- may no longer have a place in an altered world.
course it's possible that species may ultimately prove more adaptable than
scientists think. While the most fragile, sensitive and specialized likely will
perish, their demise will leave openings for competitors to exploit, Rogers
said. The Earth's plants and animals have evolved in changing climate conditions
over thousands of years, and may still retain hidden abilities to
At Kruger, rethinking old models is already the new way of doing
business. In essence, park managers recognize that ecosystems and the processes
that affect them, including climate change, are more complicated and
unpredictable than scientists previously imagined.
Nature is "in a
continuous state of flux and not in balance," Rogers said. With Kruger managers
now thinking along those lines, "they're as well set up as anywhere, if not
better than anywhere" to respond, he said.
"We're still in Act 1 of this
play," Biggs said, pausing in a hallway at the park's headquarters. "We can hear
the big monster coming, but we're still getting the chairs arranged on
Robert Karl Stonjek