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Biodiversity in the rivers of Andorra

river in the andorran forest

The Andorran ecosystems concentrates a natural treasure that is impressive not only for its visual beauty, but also for its enormous biodiversity of fauna and flora, giving birth to more than 180 types of habitats throughout the Principality.


The territory has an average altitude of 2000 m which varies greatly with areas ranging from the lowest at 838 metres to the highest at 2942 metres.

 Winding mountain ranges give rise to mirrors of crystalline water which are home to specimens such as the Pyrenean newt (Calotriton asper) in the Estany de Juclà, vast meadows or forests full of floral life with varieties such as the blue lily (Iris latifolia) in the Sorteny Natural Park, ont the parish of Ordino, or extensive rivers that run through the Andorran territory with the native trout (Salmo trutta fario) as one of the best known specimens, form part of an environment in constant interaction and harmony.

But the natural diversity of an ecosystem is not only limited to the environment itself, as it functions as a system whose parts play an essential role in the collective equilibrium.

The waters that flow through its rivers come from pure sources such as rainfall or winter snowfall, which through snowmelt provide a natural supply to lakes and wetlands, thus forming true international biological corridors.


Because of this biological cycle, an immense quantity of nutrients is generated, which is used by all the environments that surround the stream along its course, such as riverside vegetation, for example.

The latter plays a significant role in river health by enabling important ecological connectivity between species, acting as natural filters that help purify water, providing habitat and acting as a corridor for migration.

On top of that, they provide shade and shelter to several varieties of animals such as otters (Lutrinae), amphibians such as the tótil (Alytes obstetricians), the red frog ( Frog temporaria) or the common toad (Bufo bufo), the salamander (Salamandra salamandra), and birds such as the black kite (Milvus migrans) whose frequent habitat is located in watercourses, lakes and ponds.


A short stretch of lowland river may contain 10 different habitats such as ponds, rapids, slides (deeper, slower flowing water), backwaters, aquatic vegetation beds, submerged tree roots, exposed sediments, river banks, riparian vegetation and floodplains.


Despite this highly valued environment, it is important to consider factors that negatively alter ecosystems and unbalance the equilibrium to an often critical point, even to the risk of endangering the very existence of species. Some of these factors, such as climate change, urban growth, often in or near vulnerable areas, excessive agricultural activity, or the uncontrolled tourist industry, cause disturbances to the environment with immediate and direct repercussions on the living beings that inhabit them.

Another aspect that can have a negative impact on the local fauna and flora is the introduction of invasive or exotic species, which in some cases end up dominating and depleting local specimens.


An example of this is the Barb roig (Phoxinus phoxinus), a variety of fish introduced into the country's ponds as bait which, because of its great proliferation, has led to a significant decrease in local life such as the Pyrenean newt or the aquatic Isòet (Isoetes Lacustris), a plant adapted to high mountain waters.

Even though the negative consequences are difficult to reverse, it is not impossible to re-establish natural harmony in the damaged habitats with solutions that regulate and minimise human activity. In the specific case of Andorra and its rivers, there are different regulations that promote the protection of the aquatic environment through fishing restrictions set each year by official bulletins, as well as the controlled production of trout in the fish farm located in Les Salines, in the parish of Ordino. With the aim of reinforcing the population in the different water courses. Other measures carried out by the Andorran government include specific legislation on building permits, which is focused on the planning of spaces and land for sustainable urban growth, as well as an increasingly strong commitment to sustainable tourism and environmental education.

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