Una estrategia silvopastoral para mitigar la degradación paisajística y socioeconómica en la montaña submediterránea: El desbroce de matorrales en Cameros Viejo (Sistema Ibérico)

The Spanish mountain has seen a historic cycle characterized by population loss and alienation of land from the mid-twentieth century, which has resulted in the abandonment of cultivated land and reduced stocking densities, resulting in the expansion of the bush through a process of plant succession. This process has positive environmental and landscape effects, but it has also negative effects, mainly increased vulnerability to the risk of fires (by increasing the fuel material), the loss of landscape diversity and grazing areas. The Government of the Autonomous Community of La Rioja has followed a strategy for a quarter of a century, to mitigate the negative effects of bushy. Since 1986,it had been launched a scrub plan to clear selected areas of to regenerate natural grasses, allowing lower the risk of genesis and spread of fires, at the same time offering pastoral areas to encourage extensive grazing (mainly cows), which is the main economic activity in the mountains of La Rioja. The study realized in this master thesis, analyzes the effects of clearings on fires, the landscape structure and the pastoral supply. For this, we chose as a study area three municipalities: San Román, Jalón de Cameros y Muro en Cameros, from Leza River Basin (Cameros Viejo). This study area covers 7184.92 ha, of which 879.79 ha were cleared between 2005 and 2012(time period studied). The clearings applied decreased the high risk of fire to 5.83% of the whole territory, while they increased the moderate risk to 6.28% on the same study area. The performance of the regional administration implies the fragmentation of the landscape, increasing the surface of the edges of the spots, a slight improvement in diversity and evenness and the decline of dominance. In addition, the mean average of shapes and the fractal dimension show that the landscape becomes more complex and irregular after the clearings.The soils of the cleared areas have a silty structure and an adequate level of fertility to make pasturelands. Four Taxonomic communities had been identified. After taking samples and calculating their Pastoral Value (through the phyto-sociological results), it had been estimated a spring fodder production with an average of 569.6 FU(Feed Unit) followed by an annual production of 1306.3 FU. Meanwhile, Chemical analyzes of the biomass reveal a spring fodder contribution of 748.69 FU , exceeding thus taxonomic estimation for 179.06 FU. For the same chemical analyzes realized, the pastureland can be classified as "first quality" with a substantial energy input, low lignification and good nutritional quality. Supporting that a stocking density of 1.01 LSU (large stock unit)in spring and 0.44 LSU annually and considering that the livestock number now is 1476 LSU, cleared fields allow to feed 60.2% of the livestock in spring and 26.2% over all the year, reducing the purchase of livestock feed from the outside. From the obtained results, it is considered that the Plan of clearings of the Government of La Rioja is a good strategy of land management, so that should be continued.