40 | New Scientist | 7 September 2019Hidden hotspots
To preserve the diversity of the world’s wildlife, Kate Ravilious
finds we should focus on unusual terrain, not animals and plants
T
HE disused quarry in Cheffois in
western France doesn’t seem like
it would be high on anyone’s
conservation watchlist. A swampy marsh
leads to a sinister-looking pit pond, guarded
by a dense thicket and overhung by trees and
shrubs. Above the pond, a staircase of rock
walls stretches skywards, while mosses and
ferns monopolise the dank, shady corners.
Although a far cry from classic nature havens
like the Galapagos Islands, this somewhat
uninspiring landscape could rival them in
value. Not only is the quarry brimming with
wildlife, including many rare and threatened
species, but the secrets to its biodiversity
could help save all life on our planet.
It is now widely accepted that Earth is
experiencing a sixth mass extinction event.
The United Nations estimates that about
1 million species are threatened, and many
have already been lost to human activity. We
can’t save everything, so how do we prioritise?
Until now, the focus has been on biodiversity
hotspots, locations with good habitats that
support exceptional concentrations of
different species. But maybe our efforts have
been misguided. Instead of focusing on
specific species or habitats, one of the bestTOMY CHARPENTIER
Features
ways of putting the brakes on the current mass
extinction may be to protect our planet’s rocks
and soils: its geodiversity. They may not look
like much, but neglected quarries and unloved
scrubland may be key to ensuring the long-
term survival of life on Earth.
This change in perspective emerged around
a decade ago. Mark Anderson at the Nature
Conservancy, a conservation charity in the US,
was assessing which areas of landscape they
should prioritise. “I realised that we were
buying up land to protect the species living
there now, but climate change impacts might
mean this wouldn’t be the right place in the
future,” says Anderson. That led to an epiphany.
Instead of buying land with great biodiversity
today, he decided to look for areas that would
retain their diversity as the planet warmed.
His initial focus was on landscapes with a
wide range of microclimates: places withnooks and crannies, slopes and hills, sunshine
and shade, wet and dry. The thinking was
that even if the climate of the region changed
significantly, the local climate variability would
be greater, giving species a greater chance of
finding a suitable new habitat locally.
To test the idea, Anderson and his colleagues
started tracking how species richness changed
with landscape and climate variables across
14 US states and three Canadian provinces.
They found that over 90 per cent of species
diversity in temperate climates could be
explained by just four landscape features:
number of rock types, latitude, elevation
range and amount of chalk or lime bedrock.
“We expected landscape to influence species
diversity, but we were surprised by just how
strong that link was,” says Anderson.
In retrospect, it makes good sense. Geology
affects the chemical and physical properties
of soil and water. As Anderson suspected,
it also influences local climate via the
topography it creates. The more geodiverse
the underlying landscape, the greater the
range of habitats and the more species a
region can support. “It seems that unusual
or contrasting geologies can stimulate
evolutionary diversification,” says Anderson.“ Unusual or contrasting
geologies can
stimulate evolutionary
diversification”
TOM BEAN ALAMY STOCK PHOTO