By Achim Steiner, UN Under-Secretary
General and Executive Director, UN Environment
Programme (UNEP)
22 May 2009 - International
Biological Diversity Day 2009 spotlights
perhaps one of the least know threats to
biodiversity and economies-alien invasive
species.
Some governments such
as New Zealand are facing up to the challenge
with tough customs controls on foreign plants
and animals.
Others such as South
Africa have well-funded eradication programmes.
But far too many countries have failed to
grasp the threat or are far too casual in
their response.
This is a mistake of
profound environmental and economic proportions.
By some estimates alien invasive species
may be costing the global economy $1.4 trillion
or more while representing a further challenge
to the poverty-related UN Millennium Development
Goals.
So where are they coming
from? In HG Wells' celebrated sci-fi saga,
"The War of the Worlds" aliens
invaded in space ships to wreak havoc and
mayhem.
In the real world they
are spread from one Continent to another
via the global agricultural, horticultural
and pet trades or by hitchhiking lifts in
ballast water and on ship's hulls.
Free from natural predators
and checks and balances, alien invasive
spaces can explode in numbers in their new
homes ousting native species, clogging waterways
and power station intakes, bringing novel
infections including viruses and bacteria,
poisoning soils and damaging farmland.
Take water hyacinth.
A native of the Amazon basin, it was brought
to Continents like Africa to decorate ornamental
ponds with its attractive violet flowers.
But there is nothing
attractive about its impacts on Lake Victoria
where it is thought to have arrived in around
11000 down the Kigera River from Rwanda
and Burundi.
Hyacinth can explode
into a floating blanket, affecting shipping,
reducing fish catches, hampering electricity
generation and human health.
Annual costs to the
Ugandan economy alone may be $112 million.
The plant has now invaded more than 50 countries
world-wide.
In sub-Saharan Africa,
the invasive witchweed is responsible for
annual maize losses amounting to US$7 billion:
overall losses to aliens may amount to over
$12 billion in respect to Africa's eight
principle crops.
The challenge is both
a developed and developing economy one and
the more scientists look at the issue the
more concerned they become.
In the United States
researchers believe they now know why a
weed from Europe - garlic mustard - is damaging
native hardwoods. The alien produces a poison
which kills native fungi which the trees
need to grow.
The scale is perhaps
only now unfolding. One of the most comprehensive
Continent-wide assessments to date has just
been completed.
The Delivering Alien
Species Inventories for Europe or DAISIE
says there are now 11,000 invaders in Europe
of which 15 per cent cause economic damage
and threaten native flora and fauna.
Globalization and international
trade will, when the economy recovers, increase
the chances of new aliens to travel from
one part of the world to another.
Meanwhile climate change
is likely to favour some alien species currently
constrained by local temperatures.
Scientists have termed
them 'sleepers'-foreign agents who become
embedded in a community to be activated
some years later. Introduced rainbow trout
into the UK is a case in point.
In War of the Worlds
the Martians are defeated by an Earthly
infection - perhaps a bout of flu - to which
they have no resistance. Real world aliens
are often made of sterner stuff.
Improved international
cooperation through the UNEP-linked Convention
on Biological Diversity is needed and stepped
up support for the Global Invasive Species
Programme.
Important too to boost
the capacity of the responsible national
customs and quarantine agencies, especially
in developing countries and to accelerate
via the UN's International Maritime Organization.
Preventing alien species
entering a new country is going to be demonstrably
cheaper than the cure of trying to eradicate
a well-entrenched species.
Alien invasive species
have for too long been given a free ride
- raising awareness among policy-makers
and the public and accelerating a comprehensive
response is long overdue.
The DAISIE network of
scientists is clear. Inaction "is becoming
increasingly disastrous for Europe's biodiversity,
health and economy". They could be
speaking for the whole world.
