Identified the 108 exotic species of animals and plants most at risk of invading ecosystems and not considered as such by the State


A scientific team with members from 31 research institutions, including IMEDEA researcher Anna Traveset, has pinpointed 108 non-established exotic animal and plant species in Spain most likely to invade ecosystems and significantly impact the environment over the next decade

The team assessed 933 species with the horizon scanning methodology, leading to a priority list of 108 species, 47 of which represent a very high and 61 a high risk of invading ecosystems.

Many of these species have a long history of invasiveness across countries, are prevalent in the pet trade and present in neighbouring countries. The list includes the common house gecko (Hemidactylus frenatus) and the Chinese pond turtle (Mauremys reevesii).


Photo: Mauremys reevesii. Font: Wikipedia


A worrying absence of species in the Spanish catalogue of Invasive Alien Species.

Most of the species identified in this study (84.3%) are not currently included in the Spanish Catalogue of Invasive Alien Species. Therefore, the authors of the research recommend that a more detailed risk analysis of these species be carried out and, if the high risk of invasion is confirmed, that they be incorporated into the catalogue or the List of Alien Species likely to compete with native wildlife, and alter genetic purity or ecological balance.


According to Traveset, ‘this study provides an updated list of potentially invasive species and will be extremely useful in prioritising efforts and resources to curb their presence in Spain. The present work covers a wider range of terrestrial and aquatic organisms in comparison with other horizon scans in Spain. It lays the foundations for more comprehensive risk analysis methods to improve management and raise efficiency for early warning signs. All of this will enable us to quickly tackle the arrival of invasive alien species’.


The presence of invasive alien species (IAS) is one of the main causes of biodiversity loss around the globe and has a high social and economic impact. According to studies on the subject, the most effective way to control their spread is to prevent their arrival.


Examples of high-risk invasive alien species

- Nile tilapia (Oreochromis niloticus). A cichlid fish native to North Africa and the Levant, widely used in aquaculture. It has been introduced in more than 50 countries and has an impact on water quality and ecosystems..

- Japanese beetle (Popillia japonica). A beetle native to northwest Asia and present in several European countries. It has a long history of invasiveness and can severely damage plants, especially by feeding on them in meadows, forests and crops.

- Burrowing nematode (Radopholus similis). A plant-parasitic nematode worm that feeds on roots and rhizomes, thus destroying their absorption zone. It is currently found in several EU countries (i.e. Belgium, France, Germany, Italy, the Netherlands, Poland and Slovenia). If we fail to take the necessary measures, it could enter Spain before long.

- Bohemian knotweed (Reynoutria × bohemica). This hybrid terrestrial plant is a cross between R. japonica and R. sachalinensis. Being difficult to control, it can establish itself in a wide range of habitats. It has recently been found in the United States and several European countries.

- Halophila stipulacea. A tropical marine seagrass that entered the Mediterranean through the Suez Canal. Due to its high environmental tolerance, it has managed to colonise the eastern and central Mediterranean coastline, reaching as far as Sicily to date.




"Identification of potential invasive alien species in Spain through horizon scanning"

Carlos Cano-Barbacil a, Martina Carrete b, Pilar Castro-Díez c, Miguel Delibes-Mateos d, Josep A. Jaques e, Marta López-Darias f, Manuel Nogales f, Joan Pino g h, Macarena Ros i, Anna Traveset j, Xavier Turon k, Montserrat Vilà l m, María Altamirano n, Inés Álvarez o, Andrés Arias p, Dani Boix a, Carlos Cabido q, Eva Cacabelos r, Fernando Cobo s, Joaquín Cruz e…Emili García-Berthou.