Thursday, February 1, 2024
1...
min
Monk parakeets, catfish and pike, Asian hornets, even cats and rabbits. All these are invasive exotic species that must be controlled to ensure that their presence has a minimal impact on native habitats.
In a globalized world, the issue of invasive species is at the forefront. Whether they are animals or plants, viruses or bacteria, tackling the problem should be one of the priorities to prevent greater harm that tends to increase rapidly in a short period of time. There are many ways to control these populations.
For a species to be considered invasive, it must first have established itself in a place where it is not native. "This can happen for natural reasons, such as dispersion and by chance. On the other hand, what mostly happens is that humans are the underlying cause, whether voluntarily or involuntarily," says Fernando Valladares, a PhD in Biology, professor at the Rey Juan Carlos I University of Madrid (URJC), and scientist at the CSIC in the National Museum of Natural Sciences.
Upon arriving in a new location, not all species take hold. Those that are more adaptable and aggressive are able to overcome this first barrier and benefit from not having natural predators or other species it has coexisted with in its natural habitat and that fulfilled a certain regulatory function. "This leads to a demographic explosion with serious economic and ecological consequences," the biologist notes.
These consequences that the expert refers to are, for example, displacement. This is what happened when algae escaped from an aquarium in Monaco into the Mediterranean Sea. In a few years, it displaced many native algae and altered previous communities. The most extreme case is the eradication of other species, as has happened with Monk parakeets, which are highly established in Spain and also tend to cause damage to infrastructure such as cables and small electrical stations.
"It is very different when it is a boa traveling in a container on an airplane than when a species of fish is introduced, because fishermen find these fun. We see that with catfish and pike, a species of sport fish that arrive in rivers and marshes and destroy their biodiversity," the scientist explains. The same is true for Asian hornets that has been introduced onto Spanish shores: "It has killed the pollinating bees, and that is a serious danger." Although it depends on the species in question, negative effects tend to increase rapidly over time.
Based on early indications, prompt intervention could reduce the overall cost of invasive alien species, which stands at $423 billion. According to representatives from 143 states, and as stated by the Ministry for the Ecological Transition and Demographic Challenge, "invasive species are one of the main causes of biodiversity loss."
How to control invasive species
Legislative frameworks are already in place to try to avoid these problems, especially in island areas. The prime example of this is customs and border controls. Australia, Chile, and Hawaii are examples of states with strict protocols. On the other hand, there are also physical measures aimed at reducing plant or animal populations. These measures are usually the most harmless.
Another way to control and reduce the population of an invasive species is to introduce another species that will control them. "This also has to be done carefully." In Australia, foxes were introduced to control rabbits, but they also fed on other species and, in the end, they caused two problems," recalls Valladares. In contrast, one of the most common biological controls, which has been proven to have almost no side effects, are ladybugs that are distributed on many plants to reduce certain types of aphids and pests.
The situation is very different with the European rabbit, an invasive species in countries such as Chile, the United States, and Australia. A study by the Patagonia Ecosystem Research Center determined that rabbits can affect iconic native species, such as orchids, a type of plant that could see its survival threatened.
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