What role has man?
Man is the species that most modifies environments and is responsible for the alteration and destruction of ecosystems. The destruction of habitats is the primary cause of the loss of environments and species extinction. The introduction of alien species, with the consequent ecological imbalance that is often created, is considered the second greatest impact factor.
Throughout history the human species has intentionally brought new species into a given territory, often for food, economic, recreational or ornamental purposes; in other cases, some species have been accidentally transported with man and have spread in new environments. This phenomenon, rather limited in the past, is becoming increasingly popular and important. With globalization, increased trade, tourism and transport of goods between different countries, the phenomenon of the spread of alien species increases now exponentially.
According to the Millenium Ecosystem Assessment, the 2005 report that evaluated the effects of environmental changes on human welfare, the introduction of alien species has become the second cause of biodiversity loss in the world.
Introduced alien species represent the key factor in 54% of known cases of extinction of animal species, and the sole cause in 20% of extinctions (Clavero & García-Berthou, 2005 Trends in Ecology and Evolution, 20(3): 110)
The presence of invasive species has an impact not only on a large scale and on the environment but also on man himself and on our life, causing significant health impacts: just think of the tiger mosquito, introduced accidentally, or ragweed, a herbaceous plant that causes allergies and respiratory problems.
In Europe, introduced species are causing damage to infrastructures, agriculture, forestry, fishery and human health by 9.6 billion euros per year; when considering the costs related to the management of introduced species, the losses rise to € 12.5 billion €/year (Kettunen et al. 2009).
Action is possible and in many cases necessary if we want to halt the loss of biodiversity. The scientific experiences show that it is possible to intervene, by adopting prevention strategies and in some cases removing particularly damaging invasive species.
The need for action is also confirmed by the European Union which has launched an information campaign on invasive species and made some proposals for a EU strategy on introduced invasive species (Genovesi e Shine 2004).
We can all do something: the protection of biodiversity depends on the awareness and cooperation of all of us and our behaviour can make a difference. Help us to make everyone more aware of the damage created by invasive species and prevent the release into the environment of exotic animals or plants.