Category Archives: Invasive species in Spain

Invasive species are non-native plants and animals that are introduced into a new environment, where they can cause harm to the local ecosystem, economy, and human health. There are many invasive species in Spain that pose a threat to the natural environment and biodiversity.

Some of the most notable invasive species in Spain include the American mink, the Asian tiger mosquito, the giant hogweed, the red-eared slider turtle, and the zebra mussel. These species can outcompete native species for resources, alter the natural balance of ecosystems, and spread diseases.

Invasive species also have economic impacts, as they can damage crops, fisheries, and infrastructure. Spain has implemented several measures to control and manage invasive species, including the development of early warning systems, rapid response plans, and public awareness campaigns. The management is an ongoing challenge for Spain and requires the cooperation of scientists, policymakers, and the public to protect the country’s natural resources and biodiversity.

How Invasive Catfish Impact the Ebro River Ecosystem

In the serene waters of Spain’s Ebro River, a growing menace lurks beneath the surface – invasive catfish. This article delves into the profound effects of these unwelcome guests and how invasive catfish impact the Ebro river ecosystem.

The Catfish Invasion

The invasion of catfish in the Ebro River is a story that began decades ago. In the early 1970s, these formidable creatures, known scientifically as Silurus glanis, were introduced into the Mequinenza reservoir by fishermen seeking a new catch. Their origin traces back to the Danube and Volga rivers in central Europe. These native habitats provided the catfish with ample space to grow and thrive, reaching staggering sizes. Reports from the 18th and 19th centuries describe specimens weighing up to a colossal 375 kilograms and measuring up to 3 meters in length.

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Hornets in Spain

Hornets are often considered pests, as they aggressively guard their nesting sites when threatened and their stings can be more dangerous than those of bees. There are now four types of hornet in Spain with three being introduced, considered invasive and a threat to endemic wildlife. (A fifth is often mentioned in the press but the Asian giant hornet (Vespa Mandarina) is NOT present in Spain).

  • Hornets (insects in the genus Vespa) are the largest in the wasp family and some species can reach up to 6 cm in length. There are around 22 species of Vespa in the world and most only occur in the tropics of Asia.
  • Like other social wasps, hornets build communal nests by chewing wood to make a papery pulp. Each nest has one queen, which lays eggs and is attended by workers that, while genetically female, cannot lay fertile eggs. Male hornets are docile and do not have stings.
  • Most species make exposed nests in trees and shrubs, but some build their nests underground or in other cavities.
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Zebra mussel – Dreissena polymorpha – Mejillón cebra

The Zebra mussel – Dreissena polymorpha – Mejillón cebra is a species of freshwater mussel native to the freshwater lakes of Eastern Europe and Western Asia. It gets its name from the distinctive striped pattern on its shell, which resembles the stripes on a zebra.

Zebra mussels are small, fingernail-sized mollusks that have become invasive species in many parts of the world. They have also become a significant concern in Spain, were first detected in Spanish waters in the mid-2000s and have since spread to various regions across the country and is present in over 60 reservoirs along with canal systems and irrigation channels. The consequences of these “blockages” range from the inability of a hydroelectric plant to generate power to the inability to irrigate fields when mussels invade irrigation reservoirs.

Zebra mussels filter large amounts of water, which can alter the natural balance of aquatic ecosystems and negatively impact native species. Their accumulation on submerged structures like pipes, dams, and water intake systems can also lead to clogging and increased maintenance costs for infrastructure.

Introduction of Zebra mussel – Dreissena polymorpha – Mejillón cebra into Spain?
Zebra mussel - Dreissena polymorpha - Mejillón cebra

The introduction of zebra mussels in Spain is believed to have occurred through the transportation of contaminated boats or equipment, particularly in water bodies connected to international shipping routes. (They may have arrived in the water inside a boat’s engine or in larval form as live bait for fishing) Once established, zebra mussels have the ability to reproduce rapidly and colonize new areas, leading to their widespread distribution. It is one of the most concerning invasive exotic species due to its almost unstoppable expansion, with a million eggs laid each year, causing environmental and huge economic damage.

Efforts to control and manage zebra mussels in Spain include monitoring their spread, implementing measures to prevent further introductions, and developing strategies for their removal. These efforts involve collaborations between government agencies, researchers, and stakeholders to mitigate the impacts of this invasive species.

Part of their successful expansion in Spain is that they require water temperatures of 13 to 14 degrees Celsius for reproduction, which occurs “two or three months a year” in their place of origin but can happen “six or seven months” here in the warmer climate of the iberian peninsular.

In less than 20 years, zebra mussels have gone from being present in just one reservoir to the entire national territory and the challenge now lies in containing their expansion. Complete eradication of the Zebra mussel – Dreissena polymorpha – Mejillón cebra is doubtful.

See a full list of invasive species in Spain here:

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Invasive species – The red eared terrapin

  • Spanish: Galápago de Florida, Tortuga de orejas rojas
  • Scientific: Trachemys scripta elegans
  • English: Red eared terrapin

An invasive species, the red-eared terrapin (Trachemys scripta elegans), also known as the red-eared slider, red-eared slider turtle, red-eared turtle, slider turtle, and water slider turtle, is a semiaquatic terrapin belonging to the family Emydidae.

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