Invasive Alien Species And their Control

More than 37,000 established alien species, including more than 3,500 invasive alien species, have been recorded around the world

Intergovernmental Platform on Biodiversity and Ecosystem Services (IPBES) has today launched a new report- the Assessment Report on Invasive Alien Species and their Control. In this report invasive alien species were identified as one of the main direct drivers of biodiversity loss worldwide.

An invasive species can be any kind of living organism—an amphibian (like the cane toad), plant, insect, fish, fungus, bacteria, or even an organism’s seeds or eggs—that is not native to an ecosystem and causes harm. They can harm the environment, the economy, or even human health. Species that grow and reproduce quickly, and spread aggressively, with potential to cause harm, are given the label “invasive.”

The number of alien species (species introduced to new regions through human activities)has been rising continuously for centuries in all regions, but are now increasing at unprecedented rates, according to the report.

The report clarifies that Not all alien species establish and spread with negative impacts on biodiversity, local ecosystems and species. Yet About 6% of alien plants; 22% of alien invertebrates; 14% of alien vertebrates; and 11% of alien microbes are known to be invasive , posing major risks to nature and to people.

More than 37,000 established alien species, including more than 3,500 invasive alien species, have been recorded around the world. The rapidly growing threat that invasive alien species pose to biodiversity, ecosystem services, sustainable development and human well-being is, however, generally poorly quantified and little understood by decision makers. Approximately 42 percent of threatened or endangered species are at risk due to invasive species.

Invasive alien species are one of the five major direct reasons of biodiversity loss globally, along with land and sea use change, direct exploitation of organisms, climate change, and pollution.

Highlights of Report :

· Invasive alien species have played a key role in 60% of global plant and animal extinctions recorded by the report;

· In 2019, the global economic cost of invasive alien species exceeded $423 billion annually – more than estimates for the global annual costs of natural disasters.

· Annual costs of invasive alien species have at least quadrupled every decade since 1970, and major drivers of change are predicted to worsen;

· More than 37,000 established alien species, including more than 3,500 invasive alien species, have been recorded around the world;

· 80% of countries have targets related to managing invasive alien species in their national biodiversity plans, but only 17% have national laws or regulations specifically addressing these issues.

Inger Andersen, Executive Director, United Nations Environment Programme “Humanity has been moving species around the world for centuries. This practice has brought some positives, but when imported species run rampant and unbalance local

ecosystems, indigenous biodiversity suffers. As a result, invasive species have become one of the five horsemen of the biodiversity apocalypse that is riding down harder and faster upon the world. While the other four horsemen – changing land- and sea-use, over exploitation, climate change and pollution – are relatively well understood, knowledge gaps remain around invasive species. The IPBES Invasive Alien Species Report is a welcome effort to close these gaps. I ask all decision-makers to use this report’s recommendations as
a basis to act on this growing threat to biodiversity and human well-being – and make a real contribution to achieving the Kunming-Montreal Global Biodiversity Framework by 2030.”

These species impact human health and wellbeing by :

● Reducing food supply – – for example the European shore crab (Carcinus maenas) impacting commercial shellfish beds in NewEngland or the Caribbean false mussel (Mytilopsis sallei) damaging locally important fishery resources in Kerala, India.

● Damaging health: for example, invasive alien mosquito species like Aedes albopictus and Aedes aegyptii spread diseases such as malaria, Zika and West Nile Fever.

● Affecting livelihoods: for example, in Lake Victoria, East Africa, the water hyacinth

(Pontederia crassipes) has led to the depletion of tilapia, impacting local fisheries

● Negatively impacting the natural world: For example North American beavers (Castor canadensis) and Pacific Oysters (Magallana gigas) change ecosystems by transforming habitats.

IPBES has set a target t by 2030 that the impacts of invasive alien species on biodiversity and ecosystem services would be eliminated, minimised, reduced and mitigated.The aim is to prevent and reduce the rate of introduction and establishment of invasive alien species by at least 50 per cent by 2030.
Prevention is the best, most cost-effective option border biosecurity and strictly enforced import controls have worked in many instances, for example in Australasia in reducing the spread of the brown marmorated stink bug (Halyomorpha halys) .

● The Plantwise Plus programme in Africa, Asia and Latin America assists smallholder farmers with the identification of pests or damaged crops, meaning that invasive alien species can be more easily detected.
● Eradication programmes are particularly applicable when invasive alien species populations are small and slow-spreading. They have a success rate of 88% when conducted on islands, according to the data gathered for the report – for example the eradication of the black rat (Rattus rattus) and rabbit (Oryctolagus cuniculus) in French Polynesia. Eradication of alien plants presents more of a challenge because seeds can lie dormant in the soil.
● Invasive alien species can often be contained and controlled, particularly in closed systems. One example of this is the containment of the Asian tunicate’s (Styela clava) invasion of aqua-cultured blue mussels in Canada.
● The use of biological control for invasive alien plants and invertebrates has been successful in more than 60% of documented cases [C19]. An example of this is the introduction of a rust fungus (Puccinia spegazzinii) to control bitter vine (Mikania micrantha) in the Asia-Pacific region.
● Ecosystem restoration can also improve the results of management of invasive alien species and increase the resistance of ecosystems to future biological invasions .

The writer of this article is Dr. Seema Javed, an environmentalist & a communications professional in the field of climate and energy

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