Source: NZ Department of Conservation
Finding one new weed among the thousands of exotic plants growing in New Zealand might sound like finding a needle in a haystack. For years, that’s essentially what we’ve been trying to do. DOC weed expert Kate McAlpine says timing is everything…
One of the biggest challenges in weed management is finding new invasions early enough to do something about them.
Once an environmental weed spreads beyond a couple of hectares, control becomes difficult and expensive.
The best chance of success is right at the beginning, when a weed first appears in the wild and there is still an opportunity to eradicate it before it becomes established.
The consequences of missing that window can be significant. Wilding conifers are transforming large areas of open country, old man’s beard smothers native forests beneath dense curtains of foliage, and aquatic weeds such as lagarosiphon clog waterways and threaten freshwater ecosystems.
Weeds currently cost New Zealand more than $1 billion each year in lost productivity and management costs. Finding new incursions early is one of the best ways to prevent small problems becoming much larger and more costly ones.
A new tool for early detection
After 25 years working on environmental weeds, I’ve learnt that timing is everything.
Finding a weed when it’s first established can mean the difference between eradication and decades of ongoing management. Yet detecting new weed incursions early has often relied on chance – the right person being in the right place at the right time and recognising something unusual.
That’s what inspired the development of the Smart Weed Alert Tool (SWAT), a new digital tool designed to help detect new and emerging weed threats earlier.
The idea behind SWAT is surprisingly simple.
Huge amounts of plant data are being collected every day, but much of it is difficult to use for early weed detection. Observations are uploaded through platforms such as iNaturalist, while museums, herbaria, councils, researchers, and other organisations contribute records to the Global Biodiversity Information Facility (GBIF), an international platform for sharing biodiversity data.
Together, these sources contain millions of plant records. Hidden among them can be the first signs of a new weed invasion, but finding those signals among so much information is a challenge.
SWAT regularly scans new records and looks for observations that match a user’s interests.
A regional council biosecurity officer might want to know when a new environmental weed is recorded in their region. A DOC ranger might want alerts for particular high-risk species. A researcher might be interested in unusual records anywhere in the country.
When a matching record appears, SWAT sends an email alert.
Many eyes are better than a few
One of SWAT’s greatest strengths is that it makes better use of information that’s already being collected and shared.
Every plant observation uploaded to iNaturalist and made available through GBIF becomes part of a much larger picture.
In effect, thousands of people recording plants for their own reasons are also helping strengthen our ability to detect new weed incursions.
Developing SWAT has been a genuine collaboration between weed specialists, biodiversity data experts, software developers, and end users across New Zealand.
It’s also a reminder of what can be achieved when we combine technology, good data, and citizen science.
The next significant weed detection could come from a council officer, a DOC staff member, a scientist, or someone simply recording plants on a weekend walk.
That’s the beauty of SWAT. It helps ensure that valuable observations don’t go unnoticed and gives people an opportunity to respond while problems are still small.
SWAT is now live and free to use. Whether you’re involved in weed management professionally or simply interested in keeping an eye on what’s growing in your local area, you can create an account, set up alerts, and start exploring the Smart Weed Alert Tool.
After all, when it comes to protecting biodiversity, many eyes are better than a few.
Have a go with SWAT and let us know what you find. We’d love to hear if SWAT helps you detect a potentially serious new weed in your area.
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Original source: https://nz.mil-osi.com/2026/10/06/how-do-you-find-weeds-before-they-become-a-problem/