The coypu: an intruder that swims with you

The coypu (Myocastor coypus) is an invasive alien species native to South America, introduced to Empordà in 2004, and which has grown exponentially. This semi-aquatic rodent has a significant negative impact on local ecosystems, especially in aquatic and agricultural areas. It affects rice crops and native vegetation. Since 2013, containment and control strategies have been implemented. Its eradication is complex. This case exemplifies the global problem of invasive species, which threaten biodiversity and ecological balance.

The coypu, invasive rodent on Pals beach

The coypu is a newcomer to our beaches! It's an invasive rodent native to South America. It has a significant negative impact on the aquatic and agricultural areas of Pals.

This exotic invasive species which has almost certainly come to stay. The first record of a coipú in Empordà was in 2004 at a golf course in Pals. Since then, its population has grown exponentially.

The coypu is a rodent of the Myocastoridae family. In fact, it is the only living member of its genus. In appearance it resembles a cross between a rat, a otter and a beaver. It can weigh up to 10 kg and measure over half a metre in length.

It can be easily recognized by its large orange incisors and its hairless, scaly tail. It has a long brown coat with a grey undercoat. Its body is adapted for semi-aquatic life. It has webbing between its toes, ideal for swimming and diving. Its eyes and nostrils are situated on the dorsal side, allowing it to see and smell while swimming.

The coypu inhabits areas with running or stagnant water that have abundant aquatic vegetation, as well as the banks and coastal wetlands. They build shallow burrows near the water, where they live in pairs or colonies. They are most active at night.

It has an herbivorous diet that mainly includes aquatic plants and riparian vegetation. It also eats roots, rhizomes, and wild and cultivated fruits, such as cereals and apples. It can also feed on bivalve molluscs. Their ability to adapt their diet is one reason they have managed to survive and thrive in different regions.

Reproduction

Coypus reproduce 2 or 3 times a year, giving birth to about 5-6 pups each time.. These are already able to swim while feeding on their mother, thanks to the lateral position of the mammary glands. The young can reproduce within their first year and have a lifespan of about 4-6 years. So, do the maths! How many offspring can a female have over her lifetime?

In our region, coypus have few natural predators, only foxes and some birds of prey.

Impact on biodiversity

This mammal is native to South America, and its name comes from the Mapuche word ‘kóypu’, meaning water trail, due to its swimming style. South American natives hunted it for food and to use its fur.

It has been introduced precisely in various parts of Europe and other regions of the world on breeding farms for its value in the fur industry. The fur of the coypu is dense and soft, which has made it highly prized for the creation of coats and other fur items.

The first route of entry into Europe, documented at the end of the 19th century. It was the result of intentional escapes or releases from fur farms established on the continent, which allowed them to live in the wild.

It is about of an invasive exotic species and is included on the list of the 100 most harmful invasive exotic species in Europe., according to the International Union for Conservation of Nature and Natural Resources (IUCN). Since 2013, both in Catalonia and in Spain, it has been declared an invasive species (Royal Decree 630/2013, of 2 August).

It is believed that the current population in Catalonia was established through the colonisation of specimens originating from France. A progressive increase in the population has been observed since 2013–2014. It is a species widely distributed in north-east Girona. From the Alt Empordà, specimens have spread through the river basins of the Muga, the Fluvià and the Ter. They have already reached the Ripollès, the Selva, the Pla de l'Estany, the Garrotxa, the Gironès and the Baix Empordà. It is estimated that in stretches of the Fluvià or the Muga we can find up to ten coypu per kilometre.

Exotic or invasive?

What is the difference between an exotic species and an invasive species?

Exotic or non-native species are those that are introduced into an environment where they do not naturally occur.

Those exotic species that manage to overcome the various stages of introduction, establishment and expansion in a new ecosystem are what we call invasive fauna or flora. Invasive species interfere with the natural dynamics of the new habitat. They trigger ecological changes that pose a threat to native biological diversity.

From the association we have done different things. Volunteering days for the removal of invasive exotic flora at Pals Beach.

Damage to rice

For some years now, this mammal has threatened the ecological balance, especially of aquatic ecosystems and riverbanks areas. It also has a significant negative impact on agriculture, affecting different types of crops, especially rice cultivation. Its excavation activity to build its galleries. It can also alter the banks of rivers and drainage channels in search of food. This causes instability on the banks, as well as affecting meadows and crops near the water, and degrading irrigation systems.

When feeding, coypus only consume the underground stems and young shoots of plants, leaving the rest untouched. This leads to the destruction of a large quantity of aquatic vegetation, resulting in a decline in native plant species. One of the most affected plants has been the flowering rush, an endangered species found only in the Empordà region. This plant It has been disappearing from the rice paddies of the Lower Ter. It also affects other animal species, as it reduces the area available for waterfowl to nest, as well as damaging fish spawning grounds.. Additionally, its rummaging through ground vegetation, though not for food, causes erosion along riverbanks, streams, and marshes.

Health

Finally, We must not forget the negative consequences for human health and that of other animals, as it can act as a reservoir and/or vector of infectious and parasitic diseases.. Some illnesses are leptospirosis, fasciolosis, hydatidosis, tuberculosis or septicaemia.

In light of this situation, the Department of Climate Action has established a strategy that includes a management plan for the containment and control of the coypu. It is therefore considered a priority to limit its expansion into the southern catchments and towards the river headwaters it currently occupies. It is also necessary to reduce population density to prevent damage to sensitive habitats.

Population Control

The only effective method we have to combat the spread of this species and minimise the damage it causes is the selective capture of the species by trapping or by firearm. This is carried out through capture and population-control campaigns. They are normally conducted by the Rural Agents Corps and other professionals.

The coypu has only been successfully eradicated from one location worldwide: Great Britain. Introduced to the islands in the early 20th century for its fur, coypus flourished, with populations reaching around 200,000 individuals. However, extensive eradication programs in the 1960s and 1970s, involving dedicated teams of professional trappers, successfully removed coypus from the wild by the late 1980s. This has led to the recovery of local wildlife and plant populations that were previously impacted by this invasive species. Ongoing monitoring efforts are now in place to prevent their reintroduction.

In the rest of Europe, despite the considerable efforts invested in countries such as France and Germany, eradication campaigns have not worked. Eradication is far more complex here than in the case of Great Britain, because we are not on an island. Moreover, its native population density rapidly recovers through immigration from adjacent areas.

Invasive species

The coypu is a fascinating animal that has found a place in the aquatic habitats of the Empordà. Unfortunately, it has not been welcomed here because of its impact on the invaded ecosystems. We must not forget that we are the quintessential invasive species.. We are responsible for the introduction of the coypu and other invaders such as the American mink, which displace native wildlife such as the hill.

The latter, similar to the coypu, arrived in our lands at the hands of the fur trade. It has already become a threat to ecosystems and other native species..

EXOCAT is a large database of exotic and invasive species present in Catalonia. At present there are around 1,700 exotic species, of which about 200 (12.1 per cent) are invasive. Smaller animals or plants can have an even greater impact on the local ecosystem. In fact, the vast majority of intruders are plants, such as the so-called pampas grass, present on Pals beach. Moreover, it is still present in many private gardens as an ornamental plant. 

Climate change

With climate change, we are accelerating the process of invasion by species that can be harmful to biodiversity. Moreover, the areas most disturbed by our activities are prone to attracting more species that lack predators. In contrast, ecosystems with high biodiversity are less susceptible to biological invasions.

Globally, a recent UN study reveals that humans have introduced over 37,000 species of exotic animals and plants into various regions around the world, with more than 3,500 of these species classified as invasive. According to the IUCN, biological invasions rank as the second most significant cause of species extinction, following habitat destruction.

Article creation date: 7/3/2024.

Header photo: Coipú. © Shivainc via Pixabay.

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