How native European species became invasive
The invasive attribute of a species is a relative concept. Something which is native to a region can become invasive in another area. Therefore, European native species may become of concern in other continents.
The European Union-funded project “Strengthening Activism for Environmental Rights” (SAFER) is helping remove the invasive plant species in Sri Lanka Knuckles and Victoria-Randenigala-Rantambe Region. The Environmental "Bio-Conservation Program", will take place in Horton Plains National Park on February 27, 2025 with the involvement of national authorities local activist groups, and the communities in the area. The aim is to eliminate Ulex europaeus, known as common gorse, a thorny evergreen shrub native to Western Europe.
120 volunteers, including community members and officials, will clear 50,000 square meters of this invasive plant in the National Park. The common gorse has been introduced to other areas of Europe, and also to America, New Zealand, South Africa and Australia, where it is considered a serious invasive species.
Another example of a native species becoming invasive is represented by Carcinus maenas, known as European green crab, a common littoral species, native to European and North African coasts, and considered one of the most invasive species in the marine environment. It could potentially damage Alaska fisheries industries economy, especially for salmon, crab, and mariculture operations.
The Italian wall lizard, Podarcis sicula, is a reptile species that has been introduced worldwide. Its native range comprises the Italian Peninsula, Sicily and the north Adriatic Sea coast. P. sicula is an opportunistic lizard, capable of adapting to a range of habitats, often occupying humanized areas and using man-made objects or ornamental plants as refuges. This lizard seems to be popular as a pet, especially in the USA; therefore, the risk of its accidental transportation is high. Its ecological traits and behavioural characteristics have led to the successful introduction and spread of the species to new environments where it can negatively impact native lizards through competition, displacement and hybridization. It is also reported as affecting the critically endangered Aeolian wall lizard (P. raffonei) and the endangered Lilford's wall lizard (Podarcis lilfordi).
Surprisingly enough, European and Asian earthworms can have dramatic effects on physical soil structure and aboveground in newly occupied areas, like in the Midwest and Eastern United States with demonstrable effects on soil characteristics and ecosystem functions. Their invasion can shift plant communities composition, favouring sedges and graminoids at the expense of native herbs in the understorey. In natural systems earthworms decrease organic horizon thickness and reduce the abundance of native soil invertebrates, while burrowing and casting activities can facilitate soil aggregation.
Eradicating non-native invasive earthworms is generally not an attainable management goal. Where earthworms have not yet arrived, managers can make efforts to avoid their introduction (e.g., minimizing cross-site movement of soil and plant litter).
These examples underline the fact that we need to have the right attitude not only towards European biodiversity, but also to prevent the spread of native European species from threatening the world's biodiversity, by inadvertently transporting them while travelling.