In a world constantly grappling with the dangers of climate change, another major challenge is flying under the radar: the pervasive spread of invasive alien species (IAS).
The threat posed by invasive species is alarmingly emphasized in a landmark report by the Intergovernmental Platform on Biodiversity and Ecosystem Services (IPBES).
The report reveals a staggering number: over 37,000 alien species have been introduced across the globe due to human activities.
Among these, over 3,500 are invasive and pose a substantial risk to nature, human well-being, economies, and food security. Such species have traditionally been overlooked, which can lead to irreversible damages.
“Invasive alien species are a major threat to biodiversity and can cause irreversible damage to nature, including local and global species extinctions, and also threaten human wellbeing,” said Professor Helen Roy.
However, it’s crucial to note that not all alien species are invasive. In fact, only specific subsets, roughly 6% of alien plants and 14% of alien vertebrates, among others, are known to be invasive.
One of the biggest concerns is their ability to adversely affect those most dependent on nature, such as Indigenous Peoples and local communities. For them, invasive species threaten not just their quality of life but also their cultural identities.
Another significant cause for concern is the economic aftermath. The report indicates that by 2019, the global economic cost had exceeded $423 billion annually, showcasing a drastic increase over the decades.
Historically, many of these alien species were introduced due to their perceived benefits. But the negative impacts of those that become invasive are profound, both for nature and humans.
Professor Anibal Pauchard noted that invasive species have factored in 60% of global animal and plant extinctions recorded, with at least 218 invasive species accounting for over 1,200 local extinctions.
Examples of these adverse impacts are numerous: from the transformation of habitats by North American beavers to the damage caused to commercial shellfish beds by the European shore crab.
The implications are far-reaching, affecting food supplies, health (such as the spread of malaria by invasive mosquitoes), and even livelihoods.
Highlighting the global nature of this issue, Pauchard emphasized that biological invasions should not be regarded as a localized problem.
“It would be an extremely costly mistake to regard biological invasions only as someone else’s problem,” said Pauchard. “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.”
The impact is genuinely global, even touching remote regions like Antarctica. However, the majority of negative impacts are concentrated on land, especially forests, with islands being particularly vulnerable.
So what does the future hold? Professor Roy suggests that under ‘business-as-usual’ conditions, the total number of alien species will continue its upward trend, spurred on by increasing global trade and human travel.
But this scenario may not even capture the full picture, with multiple drivers of change predicted to intensify, amplifying the impact of invasive species.
Climate change, in particular, could exacerbate the situation, with invasive plants potentially resulting in more intense wildfires, leading to increased CO2 emissions.
However, the news isn’t all grim. The report suggests that with targeted and effective management, the threat from invasive alien species can be mitigated.
Professor Pauchard optimistically points out that prevention remains the most cost-effective option, with other strategies such as eradication, containment, and ecosystem restoration also showing promise in specific contexts.
“The good news is that, for almost every context and situation, there are management tools, governance options and targeted actions that really work,” said Pauchard.
“Prevention is absolutely the best, most cost-effective option – but eradication, containment and control are also effective in specific contexts. Ecosystem restoration can also improve the results of management actions and increase the resistance of ecosystems to future invasive alien species. Indeed, managing invasive alien species can help to mitigate the negative effects of other drivers of change.”
The report applauds efforts such as the Australasia’s border biosecurity measures, which reduced the spread of the brown marmorated stink bug.
Though efforts to tackle this issue exist, the current measures remain vastly insufficient. While 80% of countries have set targets related to managing invasive species, only 17% have established laws or regulations addressing the issue.
A silver lining is that with proper tools and governance options, managing these species becomes achievable. Professor Peter Stoett urges for a cohesive, integrated approach across countries and sectors, emphasizing the importance of public engagement and coherent policies.
With the Global Biodiversity Framework committing to a 50% reduction in the introduction and establishment of invasive species by 2030, this IPBES report provides invaluable insights and tools to achieve this goal.
“The immediate urgency of invasive alien species, with extensive and growing harm to nature and people, makes this report so valuable and timely,” said Dr. Anne Larigauderie, the Executive Secretary of IPBES.
“The Governments of the world agreed, in December last year, as part of the new Kunming-Montreal Global Biodiversity Framework, to reduce the introduction and establishment of priority invasive alien species by at least 50% by 2030.”
“This is a vital, but also very ambitious commitment. The IPBES Invasive Alien Species Report provides the evidence, tools and options to help make this commitment more achievable.”
Inger Andersen, executive director of the United Nations Environment Programme (UNEP), reiterated that invasive alien species pose a substantial threat to livelihoods and food security around the world.
“They can, for example, manifest as destructive crop or forest pests or displace species targeted by fisheries. They are an important driver of biodiversity loss and hence a threat to the various ecosystem services that support agricultural production and sustainable livelihoods,” said Andersen.
“The information contained in this report will contribute greatly to efforts to combat the spread of invasive alien species and to meeting Target 6 of the Kunming-Montreal Global Biodiversity Framework.”
“It will be especially valuable for all of us who work to integrate the conservation and sustainable use of biodiversity into the world’s agrifood systems to enhance their productivity and resilience.”
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