The Impact of Invasive Alien Species

The influence of invasive alien species is so large that it is considered that they are, along with the direct destruction of habitats, the main cause of the planets biodiversity loss. The ecological influence of invasive alien species is manifested in different ways. Alien plant species inhabit the area of native species, alter the conditions in their habitat as well as the structure of their communities and interbreed with native species. Alien animal species take food and shelter from native species and transfer different diseases.

The direct influence of invasive species on human health is also significant. The most obvious example is the plant Ambrosia artemisiifolia whose pollen is an extreme allergen and causes serious health problems.

Although the economic cost of ecological damages caused by invasive species can be appraised (and they are significant), their direct influence on human activities is also not negligible. Direct economic damages are manifested by the decrease of crops caused by invasive weed species and diseases or by obstructions in fresh water traffic caused by water plants. It is considered that damages and costs regarding invasive species in Europe reaches 12,5 billion Euros per year, which does not include costs caused by diseases cause in humans (like the flu or HIV virus).

Common Ragweed (Ambrosia artemisiifolia), photo: Igor Boršić, archive of SINP