Three kinds of ants—fire, crazy, and Pharaoh—along with a goldfish, an ocean tree, red louse, and the entire mongoose and meerkat family (except one European Pharaoh) are part of Spain’s catalog of invasive alien species. This is a fact that bans possession, transport, and trade of these organisms in many contexts.
These species are labeled invasive due to their distinct ecological impacts. In some cases, such as the ants, entries in the catalog appear before or soon after detection, driven by prevention efforts and coordinated by Life’s management teams. The Invasaqua project of the Iberian Society of Ichthyology, supported by Frederic Casals, contributes photographs and documentation to this effort.
According to Casals, a professor in the Department of Animal Sciences at the University of Lleida, the fire ant, the crazy ant, or the Pharaoh ant typically arrive as stowaways via wood shipments or horticultural trade. Their appearance on the charts is often a consequence of heightened surveillance and risk assessment.
1. Red palm aphid
Described as a giant louse, this pest measures seven to eight centimeters in length and has persisted in Spain for decades, causing extensive damage to palm trees across numerous regions.
2. Mioporo
This tree has found use in landscaping and public works for years. Casals emphasizes the need for careful management of species used in public projects because coordination can sometimes be lacking, allowing unintended introductions.
3. Mongooses and meerkats
Another current issue linked to pet trade involves the sheer number of animal samples circulated as pets. Some animal groups argue that pet ownership has become excessive in certain areas, as seen with raccoon populations in Madrid.
Mongooses and meerkats may be kept as pets, but as they mature and experience stress, owners may release them. Such releases risk disrupting local biodiversity and triggering unpredictable ecological effects.
Similarly, the raccoon is described as an opportunistic feeder that consumes reptiles, amphibians, and insects, while also displaying relatively aggressive behavior toward humans. Expected releases of mongooses and meerkats are likely to have direct consequences for native species when they escape or are abandoned.
4. Ants
Certain ant species are considered potentially invasive because their future impact remains uncertain. For example, while the fire ant is known for its painful sting, predicting a direct human health impact remains challenging, and risks vary by context.
Some nonnative species that have persisted for years may gradually begin to affect the environment. Changes in climate or land use can create conditions for new ecological pressures and interactions that alter local ecosystems.
5. Aquarium fish
This type of fish, commonly kept in home aquariums, has been introduced to the Vallvidrera reservoir in Barcelona, part of the Sierra de Collserola Natural Park. Draining the reservoir may be required not only to address this species but also other invaders such as carp.
In the nearby wetlands of Barcelona, some people have released fish, turtles, or other pets. Such releases are seen in many aquatic systems when owners abandon or no longer want their pets.
Paramisgurnus dabryanus is recognized by its large, blunt snout. While not necessarily more dangerous than other invaders, its inclusion in the official catalog stems from the site where it was first promoted. The reservoir area is deemed critical for protecting native amphibian populations, with Nature Park managers periodically draining the reservoir to control invasive species that prey on eggs, tadpoles, and adult amphibians.
The main challenge cited by an expert is the ease of internet commerce, which enables the purchase of unregulated fish species despite legal restrictions. While this particular species has been controlled, Casals notes that many tropical fish require vigilance due to fluctuations in water levels, which can drive those animals to burrow into mud and survive adverse periods.