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Copyright of Cuadernos de Investigación Geográfica is the property of Universidad de la Rioja, Servicio de Publicaciones and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Los bancales configuran uno de los paisajes agrarios más característico de las regiones de montaña mediterránea. Sin embargo, cambios demográficos y socioeconómicos, ocurridos en la segunda mitad del siglo pasado, provocaron el abandono de las terrazas, con la consecuente desaparición de las labores de mantenimiento que requerían estas estructuras agrarias. Esto favoreció la activación de diversos procesos de erosión entre los que destacan el colapso de los muros de piedra y los pequeños desprendimientos que se activan en los saltos de las terrazas. En este trabajo se analizan estos movimientos en masa cuantificando sus dimensiones y frecuencia, y definiendo las variables que intervienen en su desencadenamiento en los altos valles del Leza, Jubera y Cidacos (Camero Viejo, Sistema Ibérico, España), donde los bancales llegaron a ocupar 13.274 hectáreas, es decir el 63% del espacio agrícola. Un total de 240 desprendimientos fueron contabilizados en las 53 terrazas analizadas, lo que supone un número medio de 4,5 desprendimientos por parcela y 33,1 m3 de material movilizado por 100 m de muro. En el estudio se comprueba que las causas más decisivas para la iniciación de desprendimientos están vinculadas a la capacidad de infiltración de los suelos y a la forma en que el agua circula por la ladera.

Copyright of Cuadernos de Investigación Geográfica is the property of Universidad de la Rioja, Servicio de Publicaciones and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Time compression was studied at the Aísa Valley Experimental Station to assess the effect of large rainfall events on suspended sediment load. The study was focused on the response of land under traditional and current land uses/land covers in Mediterranean mountain areas, including dense shrub cover, grazing meadow, abandoned field, cereal cultivation, fallow land and both active and abandoned shifting agriculture. The results confirm the importance of the largest rainfall events in explaining the geomorphological effects that occur during a small number of such events. Three groups of land uses were distinguished: (i) dense shrub cover and grazing meadow, which showed relatively little time compression; (ii) cereal cultivation, fallow land, and both active and abandoned shifting agriculture, which were characterized by a high degree of time compression and a major impact of the largest events; and (iii) the abandoned field, which was intermediate in response between the other two groups. The greater geomorpho-logical effects of the largest events in the plots at the Aísa Valley Experimental Station relative to those reported in studies in the USA, is a consequence of the Mediterranean climate charac-teristics, and in part because of scale effects. The contribution of the three largest events to total accumulated suspended sediment load ranged from 25.4 to 71.2% whereas for the five largest events it ranged from 35.4 to 76.9%. For each of the land uses the 25 largest events represented more than 80% (in some cases more than 90%) of the total suspended sediment load recorded since 1991.

Copyright of Cuadernos de Investigación Geográfica is the property of Universidad de la Rioja, Servicio de Publicaciones and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Time compression was studied at the Aísa Valley Experimental Station to assess the effect of large rainfall events on suspended sediment load. The study was focused on the response of land under traditional and current land uses/land covers in Mediterranean mountain areas, including dense shrub cover, grazing meadow, abandoned field, cereal cultivation, fallow land and both active and abandoned shifting agriculture. The results confirm the importance of the largest rainfall events in explaining the geomorphological effects that occur during a small number of such events. Three groups of land uses were distinguished: (i) dense shrub cover and grazing meadow, which showed relatively little time compression; (ii) cereal cultivation, fallow land, and both active and abandoned shifting agriculture, which were characterized by a high degree of time compression and a major impact of the largest events; and (iii) the abandoned field, which was intermediate in response between the other two groups. The greater geomorpho-logical effects of the largest events in the plots at the Aísa Valley Experimental Station relative to those reported in studies in the USA, is a consequence of the Mediterranean climate characteristics, and in part because of scale effects. The contribution of the three largest events to total accumulated suspended sediment load ranged from 25.4 to 71.2% whereas for the five largest events it ranged from 35.4 to 76.9%. For each of the land uses the 25 largest events represented more than 80% (in some cases more than 90%) of the total suspended sediment load recorded since 1991. [ABSTRACT FROM AUTHOR]

Copyright of Cuadernos de Investigación Geográfica is the property of Universidad de la Rioja, Servicio de Publicaciones and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)