Invasive alien species: 40 per cent of animal species lost in the last 300 years due to infiltrating plants and animals

By Syed Akbar
Hyderabad: Illegal immigration or infiltration from
low-income countries to high-income nations is a natural human
phenomenon, which governments find hard to tackle. But what happens if
the “infiltrators” are plants and animals? The problem is even more
difficult to tackle. They kill local plants and animals often causing
their extinction and inflicting huge economic loss to people and
governments.

The negative impact caused by “infiltrating” plants and animals on a
country’s economy, environment and delicate ecological balance is much
higher than the one caused by illegal human immigrants. They are
responsible for the extinction of 40 per cent of animal species in the
last 300 years. India together with the USA, the UK, Australia and
Brazil suffer an economic loss of 100 billion US dollars every year
due to damaged caused by “infiltrating” species.

Environmentalists, scientists, biologists and policy-makers from 193
countries will discuss and evolve a strategy to check the problem of
“illegal” plants and animals, technically called “invasive alien
species”, at the 11th Conference of Parties (COP) on Convention of
Biological Diversity (CBD) scheduled to start next month here. Alien
species are plants or animals that live outside their natural habitat.
For instance, if an animal or plant that originally lives in a
particular geographical area is introduced into another area, it
becomes an alien species. And if it spreads fast killing local plants
or animals, it is termed “invasive”.

The Zoological Survey of India (ZSI) recogises biological invasion by
alien species as one of the major threats to native species and
ecosystems. “The effects on biodiversity are enormous and often
irreversible,” a ZSI document points out adding that 235 invasive
alien species (including plants) have so far been reported in India by
Global Invasive Alien Species Database. The impact of invasion is
second only to that of human population growth and associated
activities.

Take for instance, a small insect called Leptocybe invasa. It was
first detected in 2002 from a few pockets in coastal Tamil Nadu and
within 10 years, the insect has spread to peninsular India. “It is a
tiny wasp that forms leaf and stem galls in Eucalyptus seedlings and
trees up to two years of age. The pest has affected more than 20,000
hectares of Eucalyptus plantations in Tamil Nadu, Andhra Pradesh,
Karnataka and Kerala,” the ZSI report said.

Imagine the economic loss the tiny insect had caused as Eucalypts are
extensively cultivated in India by wood-based industries, Forest
Development Corporations and tree farmers and the wood is mostly
consumed for manufacture of pulp, paper and rayon.

A document released by the Convention on Biological Diversity ahead of
the Cop-11 meet states that increasing travel, trade, and tourism
associated with globalisation and expansion of the human population
have facilitated intentional and unintentional movement of species
beyond natural biogeographical barriers, and many of these alien
species have become invasive.

“Invasive alien species can produce substantial environmental and
economic damage, and their negative effects are exacerbated by climate
change, pollution, habitat loss and human-induced disturbance.
Increasing domination by a few invasive species increases global
homogenization of biodiversity, reducing local diversity and
distinctiveness. They can change the community structure and species
composition of native ecosystems.
They can also cause cascading effects with other organisms when one
species affects another via intermediate species, a shared natural
enemy or a shared resource. These chain reactions can be difficult to
identify and predict,” the CBD pre-convention document warns.