The term "non-native" or "alien" species is used to summarise all organisms that have been introduced to Austria after 1492 (discovery of America) with either direct or indirect human assistance. Along with inconspicuous species these new arrivals also include invasive animals and plants that severely disrupt the ecological balance of the native flora and fauna.
In surveys carried out in the Enns valley back in the 1980s Indian or Himalayan balsam (Impatiens glandulifera) and Japanese knotweed (Fallopia japonica) were detected in the vicinity of the Gesäuse National Park. First evidence was found in Weng in 1931, and the first sightings in the Gesäuse date from the 1970s. The Austrian distribution map from 2000, however, showed the Gesäuse to be largely free from the invasive balsam species.
As far as the eye can see
Ten years later, however, this tall growing annual has become so dominant and omnipresent in the Gesäuse National Park that it has even led to large changes in the vegetation.
Partly with the help of man, invasive species have penetrated deep into the remote mountain valleys of the Gesäuse National Park over the past few years, and they have done so at a rapid pace and to an alarming extent.
Consistent control of invasive plants
The LIFE project "Gesäuse" was launched to initiate active control measures to curb the spread of the invasive plant species Himalayan Balsam, Canada and giant goldenrod (Solidago canadensis and S. gigantea) and Japanese knotwood. Regular cutting and weeding before seed dispersal helps to prevent further spread and distribution.
Experience has shown that consistent control measures are effective even in dominant stands if they are continued until the invasive species is completely eradicated. These measures have to date succeeded in containing the problem in the Gesäuse National Park and opening up new space for species like the native yellow balsam.