Alien Species

The thematic report on Alien Species as part of the Quality Status Report 2017 (QSR 2017) provides for a comprehensive overview of the status of introduced species in the Wadden Sea, partly based on the Trilateral Monitoring and Assessment Program (TMAP). The status review includes aspects like occurrence and distribution of non-native plants and animals, implications, policy and management.

From the QSR 2017, thematic report on alien species:

The spread of organisms is in principle a natural process. It is, however, limited by natural geographical barriers. Human activities have breached those barriers and have transferred species into areas far beyond their natural range - intentionally and unintentionally (Box 1). With increasing global trade the introduction of alien species outside their natural range speeded up and now raises concern about biological homogenization (Capinha et al., 2015), threatening of native species and ecosystems, threats for humans, their health, and economic aspects (Nehring et al., 2009). The human introduction of alien species, in particular invasive ones, poses a serious threat to the guiding principle of the trilateral Wadden Sea policy “to achieve, as far as possible, a natural and sustainable ecosystem in which natural processes proceed in an undisturbed way” (CWSS, 2010b; see also Bouma et al., 2011). Most alien species became inconspicuous residents and cannot be eliminated without causing collateral damage to the ecosystem. And more alien species are likely to come. This could lead to an increasing number of species and diversity in the Wadden Sea but may also cause biotic homogenization with other areas (Reise et al., 2005; Nehring et al., 2009). Although so far there is no evidence for extinction of native organisms by aliens species in the Wadden Sea area (Wolff, 2000; Buschbaum et al., 2012), some alien species have the potential to alter dominance structures, habitats and trophic regimes, such as e.g., the Pacific oyster Crassostrea gigas and the Japanese seaweed Sargassum muticum (Reise et al., 2005, Figure 1) (for C. gigas compare report "Beds of blue mussels and Pacific oysters") . [….read more]

Quality Status Report 2017: Alien Species (Büttger et al.)
Quality Status Report 2009:Thematic Report No. 7: Alien Species (Nehring et al.)
Quality Status Report 2004:Chapter 6: Introduced Species (Reise et al.)
Nehls & Büttger, 2007.        Spread of the Pacific Oyster in the Wadden Sea. Causes and consequences of a successful invasion    
Workshop Report:                Pacific Oyster Invasion in the Wadden Sea. 22 March 2007