Invasive species, environment and economy

Lately, invasive species have been one of the trending topics in the conservation of natural heritage. Not only thanks to the recent, and later modified, Royal Decree 630/2013, of August 2, which regulates the Spanish Catalogue of Invasive Exotic Species, but also because of the enormous environmental and economic damage they entail.

We could define a invasive species such as the plant, animal or microorganism that, once removed from its natural habitat, successfully establishes and develops, damaging ecosystems, the economy or human health in its new location. To put it another way and in the words of the specialists of the Atlas of Invasive Invasive Alloctone Plants in Spain:

“The introduction of living beings outside their natural distribution area represents, after the destruction of habitats, the second environmental problem in order of magnitude affecting the Biosphere on a global scale. Its impacts on the natural environment include the loss of biodiversity, changes and alterations in biogeochemical cycles, the homogenization of ecosystems and communities, and even the extinction of native species. On the latter, the introduction of exotic living beings has a negative impact through phenomena of competition, predation, genetic contamination, introduction of pathogens, etc.”

Argentinian parakeet
Source: Wikipedia

Apple snail
Source: Wikipedia

It's not a minor issue. Although the synanthropization, considered as the processes of transformation of flora, fauna and ecosystems as a whole, under human activity and influence, based on the principle of substitution, is as old as agriculture or domestication; it has accelerated tremendously in recent decades. Thanks to improved communications and changes in economic-productive models, mountain ranges, seas and rivers that previously represented insurmountable barriers for species no longer fulfill that function, putting them in direct contact with each other and leading biological invasions to reach dimensions of environmental catastrophe in many areas of the world.

Alicottonous flora by country
Source: Elorza et al. 2004

Form of introduction of allochthonous flora
Source: Elorza et al. 2004

In New Zealand, one of the regions with the highest number of endemic botanicals on the planet, the percentage of alien plants is 50%, and in South Africa, which due to its biogeographic peculiarities has its own geobotanic region, foreign plants account for 20%. In Europe, it has been estimated that there are 10,822 alien species from all groups, of which 10-12% could be potentially dangerous to biodiversity. Recent studies on the invasion of neophytic plants on the continent (introduced after 1500) concluded that the patterns of presence of these plant species match land uses, and that there is a positive relationship between human density and the degree of invasion. They also appreciated that the magnitude of the invasion is adjusted to the bioclimatic characteristics of the regions. Thus, the invasions are strongest in the temperate and low-lying areas of Central and Western Europe, and on the coast, river corridors and irrigated agricultural areas of the Mediterranean basin. While the mountainous and boreal areas of the continent showed lower presence rates. But you don't have to go far to recognize the problem. In Spain, it has been estimated that there are 937 invasive species implanted, 92 of them in the Canary Islands, which represents 12% of the flora existing in our country. And that's just talking about plants.

Degree of invasion of allochthonous plants in Europe. Red indicates maximum presence.
Sources: Chytry et al. 2008

The problem is so serious that the The European Union has developed a strategy transnational to address the problem. The philosophy is that prevention is better than cure. In 2008, it was estimated that the cost of controlling and repairing the damage caused by these species ranged from 9,800 to 12,700 million euros per year, a figure that, on the other hand, is considered underestimated since many countries have started to assess the costs recently.

The environmental and economic seriousness of biological invasions means that the problem transcends borders and becomes an international issue that requires collaboration between countries for the coordination of strategies, control of species trafficking and surveillance of communication routes. In the same way, individuals have a lot to contribute by avoiding, for example, the purchase of exotic companion species, applying responsible gardening where local species prevail, avoiding bringing foreign species from countries with less demanding regulations and, above all, raising awareness among the generations that precede them. It is up to us to put a stop to one of the most important environmental problems of the 21st century.