Protecting Peatlands of Invasive Alien Aquatic Species

The Weerribben and De Wieden Natura 2000 sites are the largest and best preserved peatlands in the Netherlands. Covering more than 12 000 hectares, the 2 adjoining protected nature areas are the result of centuries of peat cutting and reed cutting. Their patchwork habitat of reed beds, sedge marshland, quaking bogs, marsh forests and open waters are home to a wide range of endangered wetland flora and fauna, including the fen orchid (Liparis loeselii), great reed warbler (Acrocephalus arundinaceus) and large copper butterfly (Lycaena dispar).

However, their local survival is threatened by several invasive alien aquatic species (IAAS), in particular five listed under the EU Regulation on invasive alien species (IAS) which have spread alarmingly since 2020: fanwort (Cabomba caroliniana), broadleaf watermilfoil (Myriophyllum heterophyllum), curly waterweed (Lagarosiphon major), parrot’s feather (Myriophyllum aquaticum) and floating pennywort (Hydrocotyle ranuncoloides). Their rapid spread has led to loss of wildlife and vulnerable habitats that are protected by the EU Birds Directive and Habitats Directive, especially in clear waters with rich underwater vegetation, lakes with floating plants, transition mires and quaking bogs.

There is a clear local imperative to tackle these invasive species, which grow into large underwater monoculture blankets, outcompete local species and block entire waterways, preventing boats from moving. On the European scale, the IAS Regulation calls on all EU Member States to prevent, detect and eradicate these species, and to manage existing IAAS. As the five species have already arrived and spread in the project area, urgent action is needed to eradicate them and to control renewed expansion. Without preventative action, experts predict that IAAS will cover the total project area of 3 510 ha within 10 years.

přirozené eutrofní nádrže s vegetací typu Magnopotamion nebo Hydrocharition

přechodová rašeliniště a třasoviska

kabomba karolínská

stolístek různolistý

vodní mor africký

stolístek brazilský

pupečníkovec pryskyřníkovitý