The damage from invasive species costs ten times more than prevention, says a study. Losses, summing up to trillions of dollars, hit agriculture, forestry, fisheries, and health systems. Scientists point out that control, eradication measures often come too late.
By Claudia Caruana / SciDev.Net
The cost of damage caused by invasive species around the world, including to agriculture, fisheries, and forestry, is at least 10 times that of preventing or controlling them, an international study suggests.
The research, published in Science of the Total Environment earlier this month, highlights the huge economic burden of invasive species and says their prevention could save trillions of US dollars.
Invasive species are non-native species that often harm the new environment they populate. They are a threat to biodiversity, can cause degradation of ecosystems and, in some regions, threaten the lives and livelihoods of people affected.
Lead researcher Ross Cuthbert, from the School of Biological Sciences at Queen’s University Belfast, in Northern Ireland, said: “Once invasive species have established and are spreading, it can be difficult to eradicate them. Delayed control measures often are not only costly, but frequently are unsuccessful in the long-term.”
The research team, consisting of scientists from 17 institutions, constructed and used a global database compiling economic costs of invasive species, which enabled comparisons to be made across different scales and contexts.
They found that since 1960 the global management of invasive species has cost at least US$95 billion worldwide, while damage costs have reached at least US$1,131 billion over the same period.
Losses have hit the agriculture and forestry sectors in the form of production declines and infrastructural damage, as well as global healthcare systems through the spreading of diseases, the researchers said.
The team quantified costs according to different management types at a global scale and developed and applied a model to predict the additional costs of management delay, using the available data.
Only a fraction of the expenditure on invasive species management went on proactive prevention measures, the study found. Most (US$73 billion) was spent on control or eradication measures when damage is already underway.
“By the time we see the impact that invasive species are having on the environment, it is often too late as they have already established and spread widely,” said Cuthbert.
“It is difficult to convince decision-makers to invest in something that is not yet a problem, but our research clearly shows the value in taking a preventative approach.”
Biological invasions are one of the largest threats to biodiversity, but there has been insufficient investment to reduce rates of invasion and their impacts on ecosystems and economies, he added.
The researchers found that developing countries in particular are investing little in the management of biological invasions.
According to CABI, the parent organisation of SciDev.Net which works to address environmental challenges such as invasive species, millions of the world’s most vulnerable people face problems with invasive weeds, insects, plant diseases and animals.
“These alien species arrive in different ways, including ballast water and wood packing materials,” said Cuthbert, warning: “In the future, as trade, tourism, and material transport intensify to these regions alongside economic development, more invasive species will establish and cause adverse impact because invasions are closely linked to globalisation.”
Effective prevention measures pre-invasion
Cuthbert said Africa, Asia, and South America had incurred hundreds of billions of dollars in damage from invasions but had invested only a few million in pre-invasion management.
“Without more effective prevention measures pre-invasion, these costs will continue to rise and hamper their sustainable development,” he added. “Developing countries must improve their capacity to respond to and manage biological invasions to avoid being disproportionately impacted in future.”
Investments should focus on measures such as effective biosecurity to prevent invasive species from arriving in the first place, as well as research to record new invasions, develop management measures, and understand the economic and ecosystem impacts, the researcher suggested.
Lee Hannah, a senior scientist at Conservation International’s Betty and Gordon Moore Centre for Science, in the US, told SciDev.Net: “The bottom line is that we are spending far too little to care for nature by preventing species invasions, and we are paying trillions of dollars in damages as a result.”
Hannah cited South Africa as an example where the costs of managing invasions have exceeded the alternative costs of prevention. He said the country spends more than US$25 million each year removing aggressive invasive plants such as the black wattle (Acacia mearnsii) tree, which has a number of harmful environmental impacts.
“This makes sense because replacing black wattle with native species increases water available from watersheds and the removal programme creates jobs,” said Hannah. “But a less expensive answer would have been to guard against black wattle spread from forestry plantations in the first place. A few million dollars invested in keeping black wattle from spreading could have avoided hundreds of millions in damages.”
This piece has been sourced from SciDev.Net
Image: The army fall worm, an invasive species that causes degradation of ecosystems and threaten the lives and livelihoods of people — CABI