Mostly sunny. Mild.
other day I asked my son how many different kinds of Pokémon there were. His
rather accurate answer: “Tons!” Like many kids, I suspect he can rattle off
more names of these imaginary creatures than he can name actual species of
plants and animals.
nothing against the Pokémon Go craze at all. In fact, if it gets people to
spend more time out of doors, that would be brilliant. But seeing pics of these
make-believe critters all over my social media feeds lately has conjured up
disturbing images of a future world in which augmented reality animals are more
common than real ones.
paranoia? Perhaps, but not an entirely unfounded worry. Most of us are well
aware of the fact that human activities are having an impact on biodiversity –
the variety of living species in a particular ecosystem – everywhere.
Scientists are starting to get a better handle on exactly how much damage we’re
doing and the prognosis is not good.
telling measure is the so-called biodiversity intactness index (BII), which
estimates the proportion of an area’s biodiversity that has remained in its
original, natural state in the face of pressures from human land use practices
and related factors. A perfectly undisturbed ecosystem would have a BII of 100%
while human activities that reduce the number of different plant and animal
spies in it would cause that number to drop.
have come up with a planetary boundary level for the BII below which we risk a
major systemic shift in the Earth’s capacity to remain in a state that is
comfortably liveable for humans. Actually they’ve come up with a total of nine
such thresholds for, among other things, ocean acidification, freshwater use
and ozone depletion in the stratosphere.
climate change, for instance, the critical number is 350 parts per million of
carbon dioxide in the atmosphere. Anything above that is considered unsafe. In
the case of biodiversity, experts tell us that we have to keep the global BII
at 90% or higher.
2005, a paper published in the prestigious scientific journal Nature suggested that the BII for Southern Africa had dropped to
about 84% in the year 2000. “In other words,” the authors explained, ”averaged
across all plant and vertebrate species in the region, populations have
declined to 84% of their presumed pre-modern levels”.
Now a new study involving about two
million records for almost 40 000 species of plants and animals has found that
on 58.1% of the Earth’s land surface, human activities have caused the local
BII to fall below the supposedly safe 90% threshold. So on more than half of
all land areas, biodiversity is at a level lower than scientists consider safe.
realistic is this 90% figure? We don’t really know for sure. At this point it amounts
to a very educated guess, but what the results are telling us is that we may be
entering an era when degraded ecosystems may make it increasingly difficult for
agriculture to support human populations. That’s what is meant by the typically
understated academic language of the study which notes that “such widespread
transgression of safe limits suggests that biodiversity loss, if unchecked,
will undermine efforts toward long-term sustainable development”.
to one of the study’s co-authors, professor Andy Purvis of the Natural History
Museum in the UK, “until and unless we can bring biodiversity back up, we’re
playing ecological roulette.”
represent just one example of a group of animals that are under growing threat.
We’ve all heard about the trouble many bee populations are in around the world,
but the problem of drastically declining numbers actually extends to other
insects, including butterflies and moths, as well.
insects might sound like a good thing at first, but just consider the many
benefits they provide. A large variety of birds, bats and amphibians rely on
them as their primary source of food, plenty of insect species help control
agricultural pests, and then there’s the role they play as nature’s
January, the United Nation’s Intergovernmental
Science-Policy Platform on Biodiversity and Ecosystem Services (IPBES)
warned that over 40% of invertebrate pollinating species are threatened by
extinction and pointed out that some 70% of all wild flowering plants and 75%
of the world’s food crops are at least partially dependant on pollination by
animals. The IPBES estimates the annual global value of agricultural crops
directly affected by pollinators at between US$235bn and US$577bn.
hope our future is filled with Pokémon, but while we’re out there hunting for
these virtual critters, lets spare a thought for the real-life creatures that
make their – and our own – existence possible in the first place.
- Andreas is a freelance writer with a PhD in geochemistry. Follow him on Twitter: @Andreas_Spath
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