Reducing the impact of invasive species on New Zealand’s national parks

As the management of risks often becomes more challenging beyond the international border, threats to iconic landscapes post-border need greater understanding. 

From a New Zealand perspective, Te Whare Wānaka o Aoraki Lincoln University’s Distinguished Professor Philip Hulme investigated the visitation patterns of international tourists to national parks to better understand the risks associated with their movements around the country. In Networks of risk: international tourists as a biosecurity pathway into national parks, his research highlights the need for greater tourist education.

“I’ve considered how people move pests and diseases around the country for some time. As international visitors move around the country, it is important to consider the potential risks they bring to our national parks,” says Professor Hulme.

The Kunming Montreal Biodiversity Framework sets our global targets to be reached by 2030. Target six of this framework requires countries to address the pathways of species introductions with the ambitious goal of reducing the introduction and establishment of invasive alien species by 50% by the end of the decade.  

“Target six is close to my heart. With many of the 2030 goals challenging to achieve, we need to consider how to better protect our natural environment.

“If we go back 100 years, we could have stopped pest species like wasps and Russell lupins from becoming established. There are economic and biodiversity benefits from slowing the rate of species introductions, even if they cannot be stopped.”

Distinguished Professor Philip Hulme

Professor Hulme shares that a current invasive species, myrtle rust, is impacting New Zealand native myrtles with great cultural significance, including pohutukawa and rata. Other invasive alien species on the horizon posing a serious challenge include the red imported fire ant, now established in Australia and capable of painful stings. 

“Sleeper pests are a risk to native species too and can be moved unintentionally around the country by international visitors. They are already established in New Zealand and can hang around for decades, becoming widespread with little warning. Himalayan balsam is an example, currently growing along riparian areas in parts of New Zealand.” 

Analysing the movements of international tourists to New Zealand pre and post-COVID, Professor Hulme found that different nationalities pose different risks. 

“The most surprising findings were that the biosecurity concerns and associated tourists differ pre- and post-border. At the border, Asian tourists, who may be less aware of our biosecurity rules, are often viewed as posing a high biosecurity risk. Post-border, British and European tourists are most likely to tramp and camp, staying overnight at national parks. They, therefore, pose a much greater risk of bringing invasive species into these protected areas,” says Professor Hulme.

While the Ministry of Primary Industries screens for biosecurity risks at the border, post-border Professor Hulme says, greater education is necessary to help tourists understand the risks they may bring to national parks.

“About 20 years ago, this country experienced a didymo algae problem. To help prevent it from spreading throughout the country, signage was used to raise awareness and proved highly effective. Now, we need a similar programme where signage and other tools are used to make people aware of the types of invasive species they may be transporting through their shoes, clothes or camping equipment.” 

Professor Hulme also shares that more work is needed to understand the risks that may enter the country if they slip through the border.

“We don’t monitor our campsites and national parks well enough to understand the risks. A great system would be to collect samples from visitors’ tents or boots at the border and test them for biological material using environmental DNA. Currently, this material is destroyed, but analyses could point to potential risks,” explains Professor Hulme. 

To improve monitoring and to aim towards the target of reducing the introduction and establishment of invasive alien species by 50% by 2030, Professor Hulme believes it is fair for overseas visitors to contribute to the costs of managing biosecurity risks through an international visitor levy and entry fees. 

“Currently, our national parks are free to visit which is very rare worldwide. To take greater steps to protect our biodiversity and national parks, we need a more reliable funding stream to support the Department of Conservation in protecting our unique landscapes.”

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