Landscapers on the frontline of emerging weed detection

A new Department of Conservation tool can help landscape contractors spot emerging weed threats at or near the sites they manage, providing early warning before infestations become established

Landscape contractors’ everyday work puts them on the frontline of detecting new weeds – and a new Department of Conservation (DOC) tool aims to help them identify emerging threats sooner.

The Smart Weed Alert Tool (SWAT) scans biodiversity records and sends customised email alerts when new plant observations match a user’s chosen species or location.

For contractors maintaining gardens, reserves and restoration sites, those alerts could help direct attention towards unfamiliar plants appearing nearby.

“Landscape contractors are often on the frontline when it comes to spotting new weeds,” said DOC senior science advisor Kate McAlpine. “They can use SWAT to receive alerts for weeds occurring near sites they manage, helping them find new infestations early.”

From chance sightings to targeted alerts

McAlpine said detecting an emerging weed has often depended on a knowledgeable person happening to notice something unusual.

“Finding a weed when it first arrives can mean the difference between eradication and decades of costly management,” she said.

SWAT provides a more systematic approach by scanning plant records published through the Global Biodiversity Information Facility (GBIF). These include iNaturalist (a free online community that helps people identify and record plants, animals and fungi) observations, herbarium records and information from councils, researchers and other organisations.

A contractor can set up an alert for plant species newly recorded in the wild within a suburb or region where they work. Alternatively, they could monitor specific high-risk species relevant to their sites, using the information to prioritise surveillance and control.

The tool also allows users to look beyond familiar problem plants.

“One of SWAT’s strengths is that users don’t need to know in advance which emerging species they should be watching for,” McAlpine said.

“New Zealand has more than 25,000 exotic plant species present and we can’t predict which will be weeds of the future.”

Supporting work on the ground

An alert brings a record to someone’s attention but assessing its significance still requires judgement.

McAlpine said users can review the species information, its management status in New Zealand, the location and the observation record before deciding whether further investigation is warranted.

“SWAT’s role is to bring potentially important records to people’s attention sooner and provide information about the species and observation,” she said.

Its coverage also depends on the records available. An area’s underlying data may be incomplete and SWAT can only flag observations shared through its data sources.

Contractors can help expand that information by recording plants on iNaturalist, contributing observations that may feed into future alerts.

“SWAT is best viewed as an early warning tool that complements, rather than replaces, field surveillance and expert knowledge,” McAlpine said.

For landscapers already watching how planting changes between maintenance visits, the tool offers another source of information about what may be emerging beyond the site boundary.