German Study on the Seychelles Shows Removal of
Invasive Species Increases Pollination
Researchers from the Technische Universität Darmstadt, or Technical University Darmstadt in Germany, conducted a study in the Seychelles, an island nation on the east coast of Africa, on the impact of the removal of invasive species on pollinators.
A team led by Dr. Christopher Kaiser-Bunbury selected eight inselbergs, or isolated hills that rise abruptly from a plain, on the island of Mahé. Four of these were left alone; the other four had all non-native exotic flora removed, including cinnamon, eucalyptus, and Prune de France. Once the vegetation was thinned, the team spent eight months observing plants and counting and cataloguing the pollinators who visited the inselbergs.
The four inselbergs that had their habitats restored saw 22 percent more pollinator species, with pollinators visiting plants 23 percent more frequently. In addition, the plants produced more flowers. Not only was this more pollination, but it was pollination of a higher quality: plants needed fewer visits from pollinators in order to yield more fruit. The thinned vegetation means that pollinators can find native flowers more easily, and that they will lose less pollen as they go from one plant to the next.
The study did not specify if it was simply the removal of excess vegetation that brought more pollinators to the area, or if the rehabilitation of the native plants was the main factor. However, if thinning the vegetation is all it takes to increase pollinator activities, it only makes sense to remove the invasive species instead of the native ones.
The study, which was conducted from 2012-2013, was recently published in the scientific journal Nature. The report in its entirety can be purchased at https://www.nature.com/nature/journal/vaop/ncurrent/full/nature21071.html.