Page 32 - downmagaz.com
P. 32
“ It means there is much more habitat in
which endangered species can recover”
returning to their historical habitats in
southern Europe as a result of humans
moving out of the countryside and decreasing
persecution of wildlife. Eagles and vultures
have tended to nest on cliffs to avoid humans,
but are now increasingly nesting in trees as
their forebears did. Likewise, conservation
efforts mean that the critically endangered
Mediterranean monk seal, which had
retreated to caves to avoid human
persecution, is returning to beaches.
“Everything we see in the present is an
artefact, rather than the animals’ true
preferences. They are not where they want
to be. They are where they can be,” he says.
JAMES NIFONG
Stop the pigeonholing
This may pose challenges for conservationists.
For example, the archipelagos where the crabs to prey on them, grazing invertebrates
Audouin’s gulls sought refuge are nature such as sea hares became larger and more
reserves, whereas their mainland homes abundant. Sea hares feed on the harmful algae
are not always protected. But it also brings growing on the seagrass, leaving the leaves
opportunities. “We pigeonholed most of these healthy and clean. “The importance of sea
large predators as being habitat specialists: otters to estuaries makes me think about all
mountain lions love the mountains, sea otters the efforts that people are spending to restore
are kelp bed specialists, alligators love the estuary ecosystems and wetlands,” says
swamp and fresh water,” says Silliman. “This Carswell. “It makes me think how important
is a paradigm change. The animals are not it is to have the full complement of species
habitat specialists, they are habitat generalists back in those systems to enact restoration.”
and can withstand a much wider range of In Patagonia, the return of mountain lions
physical and biological conditions.” It means to the grasslands is bringing benefits too.
there is more habitat out there in which MARK ELBROCH / PANTHERA Elbroch discovered that they generate far
endangered species can recover. more carrion than do grey wolves – the
This provides new hope for species such as equivalent top predator – in Yellowstone
the orangutan, whose numbers declined by National Park. “That carrion bolsters the
an estimated 100,000 between 1999 and 2015. Alligators are returning to salt marshes and health of ecosystems and creates biodiversity
Orangutans were traditionally viewed as able raptors are nesting in trees rather than on cliffs hotspots across the landscape,” he says. As a
to live only in undisturbed forest habitats. result, the mountain lions help support the
However, research reveals that coexisting shark attacks, which are a leading cause of recovery of the threatened Andean condor,
with humans for tens of thousands of years otter death in California. which needs carrion to survive.
has left them able to adapt their behaviour The move back into historical habitats isn’t It seems like a win-win. However, Elbroch
to survive in different areas. “Orangutans just good for the predators, though. Hughes emphasises the need to educate local people.
are ecologically far more flexible than we has examined the impact of sea otters on the “If we truly want mountain lions to be
imagined,” says Erik Meijaard at the University health of Elkhorn Slough. Seagrass meadows successful in this recolonisation of historic
of Queensland, Australia. This realisation are declining worldwide, partly because of habitat, we need a community of people who
presents new conservation opportunities. pollution. Yet those in the slough have been are willing to live with them,” he says. And that
To take advantage of this, we need to find out expanding. “I couldn’t figure out why the applies wherever predators are returning to
what ecosystems animals used to call home. seagrass was recovering in Elkhorn Slough past haunts. “We need to think about building
“We don’t know enough about the natural and I looked at every possible driver,” he says. tolerance with people because without
habitat range for most of these top predators,” Eventually, he discovered that the presence tolerance there will be no carnivores.”
says Brent Hughes of Sonoma State University of some 100 otters was a crucial factor. Silliman agrees. He is still haunted by his
in California. Nevertheless, ecologists may In the highly polluted estuary, excessive alligator encounter, but sees it as instructive.
find clues outside their field. For example, nutrients from farm run-off spur the growth “The alligators remind us about the past so
historical and archaeological records indicate of algae on seagrass leaves, which kills the we can learn from it for the future when
that sea otters used to live in large numbers plants. But Hughes documented a remarkable these animals return in larger numbers.” ■
in estuaries such as San Francisco Bay. What’s chain reaction leading to seagrass recovery.
more, their move into Elkhorn Slough makes The otters moving to the slough became the Isabelle Groc is a writer and photographer based in
ecological sense because it protects them from apex predator, eating many crabs. With fewer Vancouver, Canada
30 | NewScientist | 27 October 2018
