The effects of revegetation in the natural environment and perception of the people linked to Camero Viejo (Iberian System)

During the 20th century, Euro-Mediterranean mountains underwent a process of marginalization, with high rates of emigration, land abandonment, reduction of livestock census and poor use of pasture and forest products. Marginalization, with the abandonment of most of the fields and pastures, encouraged secondary succession processes that favored the expansion of shrubs and forests. Simultaneously, the administration encouraged the reforestation of large areas for economic purposes (the increase of wood and paper pulp production) and environmental objectives (the regulation of floods and prevention of soil erosion and degra- dation). As a result of these changes, Mediterranean mountain landscapes have been simplified and homogenized, fragmentation has been reduced and many of their cultural values are being degraded, a trend that also involves the loss of local knowledge on sustainable land management. The expansion of vegetation shows other negative effects, including an increase of fire risk, a reduction in water availability, the concentration of sediment sources in ancient agricultural terraces (which maintain the most fertile and deepest soils), loss of biodiversity and problems for the economic sustainability of the mountain, due to pasture degradation, and the loss of an attractive landscape. On the other hand, we must take into account that the impacts of land use changes in mountain areas occur not only at a local scale, but also at regional and global scales, as mountain ecosystems provide a range of goods and services to the society. The aim of this study is to investigate the diversity of opinions that people linked to Camero Viejo (Iberian Range) present about the major environmental changes since the mid-twentieth century: (i) vegetation cover dynamics, (ii) soil erosion, (iii) water yield and quality, (iv) fire risk, and (v) changes in wildlife and landscape. This perception will be related to current changes, quantified from land cover and land uses maps, information taken in the administration, and literature of the study area. The final objective is to find out which social groups have a closer or unrealistic perception; in that way, decision-makers could obtain more information to develop and implement new public policies

Comportamiento hidromorfológico de los microambientes de campos abandonados con lluvias intensas: experiencias en el Valle de Aisa (Pirineo Aragonés)

[Resumen] A partir de pruebas de simulación de lluvia se estudia la respuesta hidromorfológica de diferentes microambientes de campos abandonados en pendiente del Pirineo (valle de Aísa). Los resultados muestran pérdidas de suelo moderadas en los microambientes con buen cubrimiento vegetal, tanto si es de matorral como de herbáceas, y relativamente más elevadas en el enlosado de piedras. La disminución de la vegetación implica incrementos considerables en el coeficiente de escorrentía y en las pérdidas de suelo.[Abstract] Using a rainfall simulator the authors have studied the hydromorphological response of different micro-environments of abandoned sloping fields (Aísa Valley, Pyrenees). The results show moderate sediment losses in microenvironments with a good vegetable cover of shrub or meadows. The erosion is more important in fields with a stone pavement. The diminution of the vegetation involves considerable increments of the runoff coefficients and the erosion rates

Woody encroachment and soil carbon stocks in subalpine areas in the Central Spanish Pyrenees

Woody encroachment has been an ongoing process in the subalpine belt of Mediterranean mountains, after land abandonment, the disappearance of the transhumant system and the decrease of the livestock number. The main objectives of this study were: (i) to identify land use/land cover (LULC) changes from 1956 to 2015, and (ii) to investigate the effects of LULC changes in physical and chemical soil properties and soil organic carbon (SOC) and nitrogen (N) stocks. It is hypothesized that woody encroachment in the subalpine belt may lead to significant changes in soil properties, and will generate an increase in the SOC stocks. A land use gradient was identified in the subalpine belt of the Central Spanish Pyrenees: (i) subalpine grasslands, (ii) shrublands, (iii) young forests, and (iv) old forests. Mineral soil samples were collected every 10 cm, down to 40 cm, at three points per each LULC and a total of 48 samples were analyzed. The results showed that (i) woody encroachment has occurred from 1956 to 2015 due to the expansion of coniferous forests and shrublands (at the expense of grasslands), (ii) land cover and soil depth had significant effects on soil properties (except for pH), being larger in the uppermost 0–10 cm depth, (iii) SOC and N contents and stocks were higher in the grassland sites, and (iv) the woody encroachment process initially produced a decrease in the SOC stocks (shrublands), but no differences were observed considering the complete soil profile between grasslands and young and old forests. Further studies, describing SOC stabilization and quantifying above-ground carbon (shrub and tree biomass) are required

Tethyan versus Iberian extension during the Cretaceous period in the Eastern Iberian Peninsula: insights from magnetic fabrics

This work investigates how anisotropy of magnetic susceptibility (AMS) recorded the strain related to the Early Cretaceous extensional processes in synrift sediments of the Maestrat basin (eastern Spain). Forty-two sites, distributed throughout the Lower Cretaceous sequence with dominant gentle dips, were sampled. Minerals contributing to the AMS are mainly phyllosilicates. The parallelism between magnetic and sedimentary foliation seems to indicate that a primary (synsedimentary and early diagenetic) magnetic fabric was preserved at 84% of sites. Consequently, preferred orientations of magnetic lineations are interpreted to record the effect of extensional processes coeval with sedimentation and diagenesis during this period. At these 35 sites, two main magnetic lineation orientations are found, delimiting two large domains: a NE–SW orientation prevailing in the NW sector of the basin (parallel to the extension direction of the Iberian basin), and NW–SE to NNW–SSE orientations to the SE (parallel to the extension direction controlling the western Tethys margin). Directional variability demonstrates that the Maestrat basin is located at the boundary between two domains (Iberian and Tethyan) undergoing different plate-scale extensional processes. The subsequent Cenozoic tectonic inversion affected the synsedimentary magnetic fabrics at only a few sites at the borders of the basin, where compressive features are more developed