A global panel of scientists and experts on Monday sounded a planet-wide alarm over the staggering economic and environmental cost of invasive species in a report that has been approved by 143 governments.

The Intergovernmental Science-Policy Forum on Biodiversity and Ecosystems Services (IPBES) launched its seminal Assessment Report on Invasive Alien Species and their Control, following a 2019 request from governments to capture the best available scientific knowledge on the impact of invasive species.

Invasive species are established outside of their natural range due to human activities and have detrimental impacts on biodiversity, local ecosystems, and human well-being. They are a subset of alien species, which overcome their natural range but may not become established or have negative consequences.

Monday’s report said that more than 37,000 alien species have become established, of which more than 3,500 are considered invasive species that have caused vast damage to nature and vital ecosystem services that nature provides.

“Invasive species have become one of the five horsemen of the biodiversity apocalypse that is riding down harder and faster upon the world,” said Inger Anderson, executive director of the UN Environment Programme, in a statement.

”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.”

The report released on Monday was approved over the weekend by representatives of 143 governments that sent delegates to IPBES’s 10th closed-door plenary session last week, providing significant global political weight to the findings.

INVASIONOMICS

The cost of invasive species dominating natural ecosystems is far-reaching, both on land and below water. But until now this cost has been difficult to quantify at the global scale, and not agreed on at the global scale.

Since 1970 the economic cost of “biological invasions” has quadrupled every decade, now hitting upwards of $423 billion, according to the report. 92% of this is attributable to impacts on nature’s contributions to people and human wellbeing, and 8% is related to money spent on controlling invasive species globally.

The most invasive species globally is the water hyacinth, originally from South America, which has had a profound economic impact on Lake Victoria in Africa. The aquatic plant clogged shipping lanes, created stagnant water for an area where 30 million people live, and wrecked the local artisanal tilapia fishing industry.

The challenge has reached such a scale that economic assets across a number of industries are at risk. In June 2023, the US Department of Agriculture issued an alert that it was continuing to battle outbreaks of Giant African Land Snail in Florida, citing parasitic transmission to humans and crop decimation as major concerns. Moreover, sea walnut has depleted zooplankton resources and has contributed to the collapse of the anchovy population in the Black Sea.

“It would be an extremely costly mistake to regard biological invasions only as someone else’s problem,” said Anibal Pauchard, one of the report’s three co-chairs, in a statement.

“Although the specific species that inflict damages vary from place to place, these are risks and challenges with global roots but very local impacts, facing people in every country, from all backgrounds and in every community – even Antarctica is being affected.”

ALIENS AMONG US

The IPBES report also shed light on the biological impact of invasive species.

As a major driver of biodiversity loss globally, invasive species of plants and animals can outcompete native populations. The report estimates that invasive species contributed to or were solely responsible for more than 60% of recorded extinctions.

“At least 218 invasive alien species have been responsible for more than 1,200 local extinctions. In fact, 85% of the impacts of biological invasions on native species are negative,” said Pauchard.

Under a “business-as-usual” scenario, it’s expected that alien species will increase 36% by 2050, compared to 2005. Despite the report stating there is no projection for invasive species, it is expected to mirror the same trend. However, “business-as-usual” is more like a best-case scenario according to the authors, who said that demographic changes, land use change, and climate change are exacerbating the crisis beyond the norm.

RAPID RESPONSE

There have been some successful prevention, control, and eradication programmes, according to the report’s authors.

The authors outlined that success had been achieved in the past and stressed the need for urgency in response. For example in French Polynesia, the black rat and rabbit have been successfully eradicated, and “bitter vine” has been successfully controlled in 60% of cases, according to the report.

However, the current expert picture shows most national responses have been ineffective.

Prior to the Kunming-Montreal Global Biodiversity Framework (GBF), the world’s nature targets were known as the Aichi targets after the CBD conference in Japan in 2010. Under the Aichi process, only 11% of countries were on target for controlling invasive species, according to its website. Some 58% (114/196) of countries failed to even report against the target at all.

In Dec. 2022, the GBF reinvigorated political agreement at the highest level to ramp up country-level responses to invasive species through Target 6 to reduce invasive species by 50% by 2030.

It’s expected that countries will produce strengthened National Biodiversity Strategies and Action Plans (NBSAPs) with effective measures to address Target 6.

However, the IPBES experts pointed out that NBSAPs have not been effective in the past. While 80% of countries outlined targets for managing invasive species in their NBSAPs previously, only 17% had national laws or regulations specifically for them. The report’s authors argued that this increases the risk of invasive outbreaks in neighbouring countries.

With this strong evidence base now adopted by IPBES member states, and the GBF targets in place, it’s hoped by many that national policymakers will have the political clout to implement more effective invasive species policies.

“Ambitious progress in tackling invasive alien species is achievable,” said Peter Stoett, one of the report’s co-chairs.

“What is needed is a context-specific integrated approach, across and within countries and the various sectors involved in providing biosecurity, including trade and transportation; human and plant health; economic development and more.”

IPBES will now begin its “Business and Biodiversity Assessment” to provide scientific methodological approaches for measuring how businesses depend on, and impact biodiversity. This report is due to be finalised in the second half of 2025.

By Tom Woolnough – tom@carbon-pulse.com

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