Erro: a Pyrenean river to be preserved
Erro: a Pyrenean river to be preserved
Pedro M. Leunda, researcher of the University of Navarra, has studied the environmental quality of this river where the lamprey, an endangered fish, lives.
The biologist Pedro M. Leunda has investigated the state of conservation of the Erro River, a Pyrenean tributary of the Ebro River in the Community of Navarre, at department of Zoology and Ecology of the University of Navarre.
According to the specialist, within the quality thresholds proposed by the legislation for salmon rivers,"the Erro River remains within the appropriate limits both in physicochemical parameters -temperature, dissolved oxygen, water conductivity, etc.- and in dissolved chemical compounds -metals and nutrients-".
The new doctor at Biology and Environment analyzed the state of the tributary through the sampling of 15 stretches depending on each season and over a period of two years. "The Erro River rises in Sorogain, at 1,125 m. altitude. It runs from north to south through the Erro Valley for 48 km to flow into the right bank of the Irati River. During its journey it crosses a territory with 1,300 inhabitants and most of the high and middle ground is covered with beech, oak, pine and boxwood forests, as well as pastures and meadows, while on the leave account dry crops and scrub abound".
From the data taken by researcher the good state of conservation of the tributary was also confirmed through the biotic indices: "These indices are based on the presence of macroinvertebrates, small organisms very sensitive to changes in the environment and that serve as the basis of the food chain of the rivers. Therefore, by measuring their status we know what the biological quality of the stream is like over a longer period of time, as it is not a one-off measurement."
8native species
Pedro M. Leunda, who works as a technician of management pesquera at business management Ambiental de Navarra, studied the composition of the fish community of the Erro River, where he found eight species native to the Iberian Peninsula: trout, piscardo, loach, madrilla, red-tailed barbel, Graells barbel, goby and lamprey. "The latter is listed as an endangered species on the red lists of Spain, Europe and the International Union for Conservation of Nature, so the fact that it is found in this river offers an opportunity for its conservation," he stresses.
The preservation status of the tributary - included in the SCI (Site of Community Interest) Sistema Fluvial de los Ríos Irati, Urrobi y Erro, proposed for the network Natura 2000 - "makes this river a good candidate to establish the conditions of reference letter for Pyrenean mountain rivers in the Water Directive framework , the European rule that serves as the basis for improving the ecological status of river ecosystems throughout Europe," adds the researcher.
Finally, in his work at the University of Navarra, the biologist examined the effect of two impacts, one permanent and the other temporary, on the conservation of the river, which affected riparian vegetation, size composition of fish species and the presence of some fish species in different ways.