Landscape dynamics and fire activity since 6740 cal yr BP in the Cantabrian region (La Molina peat bog, Puente Viesgo, Spain)

A lack of paleobotanic studies with adequate resolution and multiproxy approaches has limited proper discussion of vegetation dynamics in Cantabria and of the role of fires in the configuration of the plant landscape during the Holocene in the northwest part of the Iberian peninsula. The pollen diagram of La Molina peat bog in Puente Viesgo (43 ‹15 Œ38 N.3 ‹58 Œ37 W; ETRS89), located at 484 m.a.s.l., and the study of its sedimentary charcoals allowed the acquisition of a continuous and thorough fire sequence for the last 6 700 cal yr BP and an understanding of its relationship to the forest. The results show the importance of human influence on the incidence and characteristics of fire activity during the different phases studied: the Neolithic, Bronze Age, Iron Age, Roman period, and Middle Ages. A synergy seems to exist between dry climate periods (especially during Bond events 3 and 4) and a greater presence of biomass. As the Holocene advances, vegetation coverage clearly tends to decrease. This study provides key elements for understanding the role of fire activity in the forest dynamics of deciduous and evergreen Quercus, Corylus, Pinus, Fagus, and Alnus and demonstrates the strongly artificialized character of the present landscape

PRODUCCIÓN HERBÁCEA EN LOS BARBECHOS CEREALISTAS DEL N.O. DE MURCIA

Durante el invierno de 1987/88 se estudió la producción herbácea en los barbechos cerealistas del Campo de Caravaca (N.O. de Murcia, España) desde el punto de vista de su aprovechamiento ganadero. Para ello se eligieron cuatro parcelas donde se colocaron exclusiones en las que se realizaron cortes quincenales en una mitad (simulando el sobrepastoreo) y un solo corte al final del invierno en la otra. La producción en el primer caso varió de 644 a 1042 kg M.S./ha, y en el segundo 864 a 4476 kg M.S./ha. Al final de la experiencia se realizó un inventario florístico en las subparcelas B, estimando la cobertura de cada especi