The Iberian Peninsula is being invaded and not by a war between humans, but for 1,200 non-native species that have settled on our land. A phenomenon that represents a great threat to native fauna and flora and that now requires international cooperation to protect ecosystems and especially the animals and plants that are native to our peninsula.
The study. According to a study published in Diversity and Distributions, the number of exotic species established on the peninsula now exceeds 1,200, including plants, insects, mollusks, crustaceans and vertebrates introduced intentionally or by accident.
The protagonists in this case are Spain, Portugal and Andorra, which are the first affected by this silent invasion. The team, led by Ismael Soto and with participation, has documented 1,273 species that currently maintain themselves independently by feeding and reproducing.
The data. In the results of the research it has been seen that at first it has been seen that the species that are invading us come mainly from the Palearctic region (Europe, temperate Asia and northern Africa) followed by the American species. But not everything is animals, as you might think, but 75% of the invaders correspond to vascular plants and insects.
Although the big question here is: how did they get in here? The answer lies in the gardens and nurseries that, together with mechanisms linked to international transportation, participate with ornamental plant trade that are not original to the peninsula.
Where. This is not something that is similar throughout the geography of the peninsula. Mainly, exotic species are concentrated in coastal areas and large cities, and that is why we see a large number of these in Andalusia, Catalonia or the Valencian Community. Something that is also related to the number of ports that exist as they are a great gateway for international trade in these invasive species.
What damage do they cause? When the species arrive on the peninsula, they have a detrimental effect on our ecosystem, and that is why they generate so much alarm around them. Among the effects we find are:
- Ecosystem modification which can cause the local extermination of native species.
- Transmission of diseases to natural habitats that change their structure.
- Alteration of food webs and displacement of native species due to direct competition. For example, we can find a predatory species that ends up with a native species as its ideal prey.
Examples. There are some species that are undoubtedly perfect examples of this. One of them is the american red crab (Procambarus clarkii) that was introduced into our habitat in 1973 and that today is responsible for great ecological damage, since it has caused the disappearance of native aquatic species, which also triggers socioeconomic problems.
Another case is the bullhead (Silurus glanis), whose voracity and expansion as a fishing trophy have made it the dominant predator in several rivers and reservoirs, threatening the survival of other aquatic species.
The ants. Although they seem to be going their own way, the reality is that exotic ants like Argentina (Linepithema humile) It has expanded through cities and coasts, causing large effects on ecosystems and generating high control costs.
Floors. Most of the invasive species we have in this case are not animals, but plants. One of the classic examples is the fern Azolla filiculoides what is capable of consuming all the oxygen in the water and suffocate the native aquatic species that will use this oxygen. Another example is the water hyacinth which It is among the 100 most invasive species in the world for its impact on lagoons and aquatic ecosystems.
What can be done? The prevention and control of exotic species requires continuous monitoring, restoration of degraded habitats and effective policies based on science and citizen participation. Sectors such as aquaculture, recreational fishing, the pet trade and horticulture are critical points where preventive measures can make a difference.
The authors insist on the urgency of strengthening international collaboration and applying shared strategies between the scientific community, environmental managers and civil society. Only in this way will it be possible to face one of the greatest threats to Iberian biodiversity, protect endemic species and maintain ecological balance in this hot spot of European biodiversity.
Images | Joshua Ralph Ivan Bandura
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