Since 2015, 170 new species of exotic species have established themselves on the Wadden Islands. This mainly concerns plant species, according to the Dutch Food and Consumer Product Safety Authority (NVWA) and ecological research agency Waardenburg. They have inventoried plants and animals on the islands.
Because dozens of exotic species found pose a major risk to native nature on the Wadden, the NVWA advises the relevant provinces and managers of nature reserves on the islands to draw up a plan to prevent new settlements and further spread of exotic species.
Exotics are animals or plants that do not naturally belong in an area and that often very quickly dominate native species. According to the researchers, the exotic plant species found on the Wadden Islands are all for sale in garden centers and therefore ended up on the islands via floriculture. This can be because seeds or plant parts are spread by the wind, are found in bird droppings or in garden waste that people throw away.
Measures
The NVWA research agency advises the ministry to take measures against the sale of the most invasive plant species in garden centers.
The emergence of invasive exotic species is even worse on the islands than elsewhere, the researchers say, as the Wadden has a unique biodiversity that is being affected. Moreover, the populations of native species on an island are small. It turns out that the exotic species feel particularly at home in the vulnerable dry dunes and dune forests.
These include rosa rugosa and various types of cotoneaster. Needle seed flower has also been found, a low plant with sharp spines that grows in the grass and causes a lot of nuisance on campsites.