WEEDING WHIZZES, Motutapu Island, Hauraki Gulf By Nanda MacLaren, Volunteer, Motutapu Restoration Trust

Motutapu Island is located in the Hauraki Gulf, only a short ferry ride from downtown Auckland.  Our volunteers weed the volunteer-planted Home Bay Forest as well as some bush remnants on the island. Their main target is moth plant (Arajuia hortorum – located in the two photos on the left-hand side below), which can severely damage native ecosystems and hinder restoration. In 2014, GiC approached us and offered to explain the benefits of geospatial mapping for conservation groups like ours. In 2014, we started discussing our needs with our GiC volunteer Lucas Mostyn (pictured in the overalls below on a recent trip to the island to meet with weeding volunteers). Lucas, who is based in Palmerston North, developed an in-field app for our volunteers. We started using it last year.


GIS maps created by Lucas, and data collected by Motutapu Restoration Trust volunteers using the GIS Collector App (pictured on the far right above) on their smart phones, mean that 60ha of the Home Bay Forest is now being effectively weeded for moth plant and other weeds. Complete eradication of moth plant is unlikely, but it can be kept at low enough levels that the native ecosystem can flourish. The main benefits of the new system are that costly GIS recording devices are no longer required, data can be shared between volunteers allowing work continuity regardless of who is doing it, data is immediately captured in the app, and a short synchronisation process is all that is required to update data.

Before going to the island, volunteers synchronise the data to their phones. During a grid search for weeds, they can see where they are on the map. When they see that they are near a recorded hotspot, they take extra care in searching that area. New hotspots are recorded as required. At the end of the day, the data is synchronised back to the shared online database. The Collector App also gives the ability to track a volunteer’s path, so progress of the grid search, which can take more than a year to complete, can clearly be seen.  Any other weeds found and identified as belonging to the group for total eradication from the island – for example, panic veldtgrass (Ehrharta erecta) – are also recorded in the Collector App. All data can be shared with DOC for future follow up. The system continues to be fine tuned, and Motutapu Restoration Trust is also looking at new maps to record seed collection sources and to calculate the size of future planting areas. We highly recommend this tool for volunteer weed programmes – it is cheap, simple, and very effective. It saves that most precious of our commodities – time!

A version of this story first appeared in Forest & Bird magazine in March 2017 (http://bit.ly/2h3SBAu). You can find out more about Forest & Bird’s work at www.forestandbird.org.nz