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[Spanish] La Nutria en Córdoba, situación tras el IV sondeo nacional

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Arvícola, 2017, 8: 53-69.

Summary: The study describes the evolution of otter populations in the province of Córdoba on the basis of the few available historical sources and the national Otter surveys organized every 10 years since 1984. Data from the fourth national enquiry – period 2014-2015 – show the best results to date, with 92.5 of the 10×10 UTM squares sampled positive, i.e. with species detection. The situation is analyzed by ecological sector. We can affirm that the otter is today a common species in the province of Cordoba, in particular in the Sierra Morena, which constitutes its historical bastion, and the river Guadalquivir, colonized since the years 90. A colonization of the rivers of La Campiña and Las Subbéticas has taken place over the past two decades.
Otter (Lutra lutra), a mammal in Andalusia. Photo: Enrique Calzado Rivillas.

The otter (Lutra lutra), one of the most attractive mammals in all of Europe.

RECOVERY OF THE OTTER IN CORDOBA

Figure 1 represents the results of the IV national otter (Lutra lutra) survey in the province of Cordoba carried out during the period 2014-2015. A total of 147 grids were sampled, of which 136 were positive (92.5%).
The otter appears in the province as a common species in the 19th century, in particular in the streams of the Sierra and Guadalquivir (Ramírez de las Casas-Deza, 1867; Martínez and Reguera, 1881). The information available is insufficient to describe the distribution of the mustelid at the end of the 20th century.

Figure 1: Results of the IV national Otter survey in the province of Cordoba carried out during the period 2014-2015 (OPEN circle – white: positive locality; CLOSE circle – red: non-positive locality).

RECOVERY OF THE OTTER IN CORDOBA

Sierra Morena, Alto Guadiato, Los Pedroches

In 2014-15, the panorama is similar to that of the previous survey, the otter being present throughout the area. The grids appear positive without laborious sampling. The joint analysis of the situation makes it possible to state with a high probability that the few negative or unvisited squares are home to the species.

Rivière Guadalquivir

In 2004-06, the III national survey revealed the use of the entire Guadalquivir river as habitat by mustelids. During this period, direct sightings of otters became more and more frequent in the city (Hermoso de Mendoza & Prunier, 2011). In 2014-2015, the situation is similar to that of the previous period.

La Campiña

In 2014-2015, the species colonized the minor tributaries of Genil and Guadajoz and the Zoñar lagoon where it was not present in the period 2004-06. Numerous indices have demonstrated the consolidated presence of the species during this survey IV. The temporary nature and the degradation of the rivers of La Campiña limit the presence of the species and its main rivers.

La Subbética

In 2014-2015, the species was detected in a large part of the region’s waterways, except on the saline streams, which are numerous in this region, and places that are not very conducive to the presence of otters and their potential prey.

RECOLONIZATION OF THE IBERIAN PENINSULA

The reasons for the recolonization of the Iberian Peninsula by otters – and other parts of Europe – are not precisely known (López-Martín & Jiménez, 2008), although the availability of abundant and easy to find prey. catching like the Louisiana crayfish (Procambarus clarkii) played an important role.
The otter is a generalist predator, with some preference for fish. In this latest survey a very high abundance of Louisiana crayfish was observed in the diet coinciding with the study by Clavero et al. (2008).
The crayfish is thus the food par excellence of the otter in rivers where fish are scarce. When the contamination exceeds the tolerance limits of the crayfish, the otter disappears.
Otter (Lutra lutra), a mammal in Andalusia. Photo: Enrique Calzado Rivillas.

CONCLUSION

Otters are very attractive animals to observe and study. We are fortunate to have an easily visible population in the city of Cordoba. It is a charismatic species that can be used to promote environmental education and to raise awareness about the state of conservation of rivers, generally very deficient in Andalusia.

It should be noted that agricultural intensification continues its course in Andalusia, that the Andalusian rivers are almost all transformed and that the populations of native fish are very seriously threatened. Therefore, the recovery of the otter population is great news but cannot mask the existing problems.

MORE INFORMATIONS ON THE WEB

Arvícola

Otter fact sheet

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