Alien invasions in progress

Globalization is a fact, because of technology, because of an integrated global supply chain, because of changes in transportation. And we are not going to be able to build a wall around that.”

This quote by Barack Obama, has even more relevance today than it had ten years ago. It would be difficult to find a politician or decision-maker that opposed globalisation and the policies of a free market. While most supporters of a connected world promise you a golden age of wealth and progress by breaking down barriers and making the world smaller, the downsides for the environment are glossed over.

New Zealanders know what it is like to deal with invasive species. Due to the country’s geographical separation from other landmasses, the native flora and fauna have evolved in isolation and are often ill-equipped to deal with threats from the outside.

Apteryx haastii ( Great spotted kiwi) almost wiped out by invasive species, Source: Picture taken by Peter Pauker

Although New Zealand is on the extreme of isolation, the principle applies everywhere. Rivers, oceans, alpine ridges, and deserts create natural barriers between ecosystems over millions of years, allowing for the creation of individual ecosystems, native wildlife and plant species.

Unfortunately, the time of ecosystems, undisturbed by humans, is over. Ever since humankind decided to explore and settle the unknown, the fight for pest-free ecosystems has been on.

You only have to look as far as your garden to get an idea about the damage invasive species can cause. While a few rotten veggies may be tolerable, on a large scale things can look grim. The massive potential for translocation of harmful pests, weeds, and pathogens that exists in a globalized world, threatens our most valuable economic and societal backbone: food security!

Since natural barriers do not prevent the spread of alien species, every country that engages in international trade puts itself on the risk of jeopardising its domestic agricultural production. The range of negative consequences can be broad-ranging, from low output (through plant diseases), reduced marketability of crops, to such harsh measures, such as quarantine restrictions to prevent further spreading.

Fighting invasive species in the field. Source: Picture taken by DuPage County Forest Preserve


Sue Worner from Lincoln University is working hard to preserve the integrity of our economy as well as our ecology! A group of international experts, including ecologists, economists, modellers, and practising risk analysts have come together and created The International Pest Risk Mapping Workgroup (IPRMW). Their research aims to save the world from the threat of invasive species. But how do you even get a hand on such a sophisticated threat that reaches across the globe?

The answer sounds simple but is highly complicated: pest risk models! These models can help generate maps that illustrate where invasive species might become established and cause harm. They serve as a powerful tool to assist policymakers and biosecurity authorities.

How a map generated by a pest risk model can look like. Source: Figure by Frank Koch

Combined with economic analysis tools to calculate the potential impacts from invasive alien species, they help to identify the rate of spread of invasive species through time. But even with the most sophisticated model at hand, as it is in all areas of life, communication is vital.

The closer the interactions between risk assessors, risk managers, and acting authorities, the better these threats can be contained. At the same time, the policymaker needs to articulate which information is required to establish effective decision making, the challenge for the pest risk modellers is to obtain this information with an acceptable degree of accuracy and decision. What may sound straight forward is often difficult to develop, even under the best of circumstances.

There remains a significant gap between what we know and what we don’t know about invasion pathways, especially those that are linked to human activities like international and domestic trade flows. The more research we do, the more we realise what we don’t know! The IPRMW has made significant advances in pest risk modelling and mapping, yet a high degree of uncertainty remains, primarily through a fundamental lack of knowledge regarding the risk factors.

Anoplophora malasiaca.jpg
Anoplophora chinensis (citrus longhorn beetle) – wreaking havoc in Northern Europe thanks to climate change. Source: Wikipedia Commons

Even though research in these scientific disciplines is rapid, there is yet another threat looming on the horizon to spice things up! Climate change is expected to provide a massive potential of damage since pests are more able to migrate into different regions due to warmer weather. They are also less likely to die off during the winter, and if that’s not enough, more temperate climate generates heat stress for plants, reducing the ability for them to fight off pests on their own. The perfect storm!

For better or worse, neither globalisation nor climate change is unlikely to slow down in the future, making the control of invasive alien species a field of increasing importance. If you are still looking for your area of expertise and this speaks to you, heads up, there is plenty of work ahead!

Snails meet technology | Lincoln Ecology

Peter Pauker is a postgraduate student completing an international postgraduate exchange. He wrote this article as part of his assessment for ECOL 608 Research Methods in Ecology.

Leave a Reply

Your email address will not be published. Required fields are marked *