Study “An estimation of the Iberian wolf (Canis lupus signatus) population in the Nature Reserve Sierra de la Culebra (Zamora)”
Extensive knowledge of the distribution, temporary changes, and size of a species’ population, is one of the basic requirements to consider for its proper conservation.
Among the elementary factors that condition the dynamics of a wolf population are the availability of food, and the mortality rate provoked by man. Neither of these two factors are thoroughly known with regards to the population of the Iberian wolf, although several studies establish that a mortality rate higher than 28% will cause the decline of any wolf population. The impact of legal hunting, plus the uncontrolled poaching (34%) can heavily alter the age structure, which will put a population at risk. It is therefore vital in any Game Reserve that the aforementioned be thoroughly and responsibly investigated, as it is essential for the adequate management of the species.
The Plan for the Conservation and Management of the Wolf in Castile and León (Decree No. 28/2008, 3rd of April) considers the realisation of ten-yearly regional population censuses, in order to determine the evolution of the wolf, as well as improving the knowledge about the species.
The most recent demographic studies regarding the wolf population in the Reserve, date back to the end of the 1990s. Since then, six stable breeding areas are assumed to be in existence, with a steady and a continuous level of reproduction, counting a minimum of 21 specimens, and a maximum of 56. Traditionally, the Reserve is considered an area from where wolves move to other zones, where the species is not as numerous, which makes it essential for keeping the population in those areas on a healthy level.
With this worrying lack of adequate, up-to-date, and freely available information from the Reserve about a species that is part of our Natural Heritage, classified as “Almost Threatened” by the IUCN, and considered “of Community Interest”, we decided, in 2013, to start our own, independent estimation of the wolf population in the area, which would allow us to assess the decline said population has suffered in the past fifteen years.
As we expected, the results are discouraging. Instead of the officially estimated six stable breeding areas, we counted three with a secure reproduction, one with a probable reproduction, one with no evidence of reproduction, while the last one has disappeared completely.
According to information obtained after finalising our investigation, the missing pack was killed around six to seven years ago, presumably because it had attacked the livestock of the village of Villardeciervos. Today, after all those years, the non-recolonisation of the area is downright suspicious.
Article published in No. 347 of Quercus Magazine:
The Iberian wolf in the Sierra de la Culebra enjoys “first with salad”.
To see our work published in the specialized in observation, study and defense of nature magazine Quercus n. 357, you can download it here (in Spanish)