Coralita, we’re gonna beat ya!
Having started in 2015, Utrecht University researchers Elizabeth Haber and Jetske Vaas (a.k.a. The Coralita Girls) thought it time to discuss their findings with stakeholders on Statia and Saba. The botanist and social scientist have always studied the alien invasive Coral vine (Antigonon leptopus) with a view of supporting the local communities in decision-making on management of the pesky vine. Plus, an invitation to participate in Sea & Learn once more was of course too hard to resist.
So mid-October they arrived on Saba, where they guided an invasive species hike, led ecologist-for-a-day-activities with primary school students and built Elephant ear umbrellas with SCF’s junior rangers. And they sat down with the SCF rangers, Island Council members and the Governor to exchange ideas on how to deal with Coralita in different areas. From maps of values Sabans attach to nature that the researchers collected over the years, a clear need arises to keep Mt. Scenery free from Coralita. Therefore, on the short term the small specks of Coralita onthe upper part of the Crispeen trail and next to Mr. Barnes' sheep pen should definitely be removed. In high erosion-risk areas, such as the Harbour gut and Middle Island Trail, it is highly recommendable to remove Coralita from the trees that prevent erosion. Wanting to set an example, Haber and Vaas organised a successful Tamarind tree clean-up on Saba on October 27th, acting on the winning slogan of a small contest: “Coralita, we’re gonna beat ya.”.
In Statia the team met with STENAPA, CNSI, LVV and Deputy Government Commissioner Stegers, sharing ideas for management approaches and priority areas. The attendees agreed that reforestation of the Coralita fields along the trail to The Quill on Upper Round Hill would be a good idea, as well as keeping a buffer zone on the lower slopes of Signal Hill. There was also enthusiasm for a testing-and-research area below the cliffs near Scubaqua, to test the effectiveness of mowing, covering the vine with a tarp or having pigs dig for the tubers. Also, the idea of Community Nature Rangers was suggested, with people in different neighbourhoods adopting trees to keep clear of Coralita.
Jetske ran a short participatory action research project on Saba, where a piece of land in St. John’s where lemon trees were planted on a former Coralita field. This showed the expenses involved with fencing against the feral goats, water for irrigation, and also the time required to maintain the area. But, it also set an example of what can be done when a group comes together. Based on this experience, Elizabeth and Jetske recommended Statia government to set up a similar pilot on a visible place, for example the Deep Yard in Oranjestad. Turning this in a fruit orchard shows that it is feasible and worthwhile to get Coralita off your land.
As for removal methods, digging and mowing is still the best approach. The steep slopes of both islands result in a high risk of run-off with herbicides, potentially damaging other plants and coral reefs. This calls for constant monitoring and immediate removal when Coralita is found somewhere along trails, and therefore they recommended to make Coralita-monitoring part of trail maintenance. But apart from keeping the trails clean, for larger areas the best method to keep Coralita under control is getting people to use their land. To that end, Elizbeth and Jetske handed out seeds, encouraging people to grow vegetables. After all, the farmers are least fazed by the vine, since they weed regularly anyway.
Jetske is back in Utrecht finishing her dissertation, while Elizabeth has just conducted a research campaign in which she tries to specify the impacts of Coralita. Although it has spread around the world, data on Coralita’s impacts on nutrients in the soil, light availability for other plants and effects on erosion is lacking entirely. By summer 2019 we should know more.
This news-item was published in BioNews-21.