TERRESTRIAL ALIENS
What is Invasive Specie?
According to the Department of the Environment of Australian Government, invasive specie is a species occurring, as a result of human activities, beyond its accepted normal distribution and which threatens valued environmental, agricultural or other social resources by the damage it causes.
In a more easily way, I would say that Invasive Species are animals, plants, parasites or disease-causing organism that establish outside their natural range and became pests. Native species can also become invasive if transferred outside their natural range (GEIB).
Many of the most damaging invasive animal species were originally introduced either for sport, as pets, or as livestock and pack animal. Some were introduced to control other pests and became pests themselves. Others arrived to other countries accidentally (Vila, M. et all, 2006).
Invasive plants, on the other hand, were introduced in a variety of ways, for instance as crops, pasture and garden plants and to prevent erosion. Some established so well that they have spread to the bush, where they have thrived (Department of Environment and Heritage, Govern of Australia).
But another important point is that Invasive Species also include disease-causing organisms such as fungi and viruses. In fact, it is recognized that Invasive Species are the second reason of Biodiversity loss after the fragmentation of the habitats and it is estimated that Invasive Species are responsible of 40% of the last five centuries extinctions (Department of Agriculture, Cattle Raising and Environment, Aragón Government).
Invasion Curve. Source: Government of Ireland.
What kind of damages can they produce?
ENVIRONMENTAL DAMAGE
Invasive Species could produce the extinction of other autochthon similar species because of depredation, competence or because they could transmit diseases (the case of American Red Crayfish in Spain). Furthermore, some Invasive Species can change a whole ecosystem or a habitat; it is the case of Mussel Zebra (NOAA).
ECONOMY AND HUMAN ACTIVITY DAMAGES
- American Red Crayfish. Spanish Invasive Specie.
- Mussel Zebra.
A lot of this kind of species cause huge harm in human activities and thus in the economy of the region. Those Invasive Species could cause damages in forests, in fishing activities, they can affect water quality, in industrial process… Also it is important to mention that it is necessary to use chemical methods to eliminate those pests and it could be harmful for the environmental of the area. It is the case again of the Mussel Zebra that cause huge damages in pipes of water and is the reason of enormous inversion of the government that tries to solve the problem (NISIC).
HUMAN AND ENVIRONMENT HEALTH
Finally, some Exotic Invasive Species can transmit diseases that could affect to human, pets or wild species. It is relevant in mammals.
Who is responsable for managing Invasive Species?
Local governments have responsibility for nature conservation through land-use planning, development and of course the control of invasive species. In my opinion is cooperation between land managers, local communities, landholders, local government and international agencies that have to control the animal’s transportation and the entrance vectors that those species use.
State and territory governments have specific legislation relating to conservation of biodiversity and have responsibility for managing Invasive Species at local, regional and state levels.
Managing Invasore Species. Source: Invasive Species International.
Invasive Species in Spain. Source: Spanish Government.
References
- NOAA (National Oceanic and Atmospheric Administration).
- NISIC (National Invasive Species Information Center), United States Department of Agriculture.
- Environmental Department of Australia Government.
- GEIB (Grupo Especialista en Invasiones Biológicas).
- Department of Agriculture, Cattle Raising and Environment, Aragón Government.
- Vilà M., Bacher S., Hulme P., Kenis M., Kobelt M., Nentwig W., Sol D., Solarz W. 2006. Impactos ecológicos de las invasiones de plantas y vertebrados terrestres en Europa . Ecosistemas. 2006/2.
- Invasive Species International.
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10 Jan 2014
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