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Invasive species

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Every year, new plant and animal species migrate to Switzerland, or are introduced in various ways from other continents. While some are harmless, others cause considerable damage. We help to foster an understanding of the biology of these problematic species, and to prevent or curb their spread.


Non-native organisms are considered invasive if they cause economic damage, are harmful to the health of people, livestock or plants, or if they displace native species. The Federal Office for the Environment (FOEN) lists over 800 established alien species in Switzerland, of which around 100 species of plants, animals and fungi are problematic – the are invasive.

Alongside habitat destruction, invasive species such as Himalayan balsam, the Asian longhorn beetle and the ash dieback pathogen are currently among the most serious threats to species diversity worldwide. That is why Switzerland has adopted the Convention on Biological Diversity and the International Plant Protection Convention. By doing so, it has pledged to prevent the introduction of invasive species, or – in the event that they do nevertheless spread to Switzerland – to eliminate or contain them to the greatest possible extent.

A closer look at invasion

We study invasive organisms and help the authorities to develop management strategies. We examine, for instance, the impact of invasions of non-native species. Since the number of thermophilic invasive species spreading throughout southern Switzerland is particularly high, this is a focus of our research at our site in Cadenazzo (Ticino). At the "Cadenazzo Research Campus", we work with Agroscope, Agridea and the Swiss Federal Plant Protection Service (SPPS) in the area of invasive species south of the Alps.

Improved protection thanks to Plant Protection Laboratory

The invasive species include many types of insects, fungi, nematodes, bacteria and viruses which trigger plant diseases in forests and ornamental trees and shrubs. We diagnose, study and monitor these in our research unit "Forest health and biotic interactions". We also look for biological control measures (see also diseases, pests and other disturbances).

The Plant Protection Laboratory opened in 2014 on the WSL site, allowing researchers to work with alien organisms. Here we can diagnose and examine suspected cases of quarantine diseases and pests under strict safety conditions.

Identifying pest infestations as early as possible

"Swiss Forest Protection" runs a monitoring system in order to protect our forests from native and non-native forest pests and diseases. This consists of a dense network of observers, such as forest protection officers, district and local forest rangers, as well as forest owners and private individuals. Swiss Forest Protection advises forest owners and rangers, helps to identify organisms, regularly conducts surveys with forestry services and organises training courses.