Productivity and botanical composition of communally-owned Mediterranean grasslands in the marginal farming areas of north Syria

Abstract

Herbage production in winter and spring, seed bank size in summer and soil fertility were measured in two transects across dry Mediterranean grasslands in north-west Syria. The transects were repeated in 1983/84 and 1984/85. Measurements were taken inside and outside wire cages that protected the quadrats from grazing. The results, which were analysed using regression and cluster analyses, showed severe soil degradation, with lime content reaching 50% on the steeper slopes, indicating erosion of top soil. The soil contained low amounts of both available phosphorus and total nitrogen. The total amount of herbage produced depended strongly on plant numbers, the relationship between herbage and numbers weakening with time. Total herbage production tended to be greatest where clay content was high. Herbs and legumes increased during the growing season, while grasses decreased. Seed banks, dominated by grasses, were highest on sandy soils. Grass and herb seed banks were transient, most seed germinating by February each year. In contrast the legume seed bank was extremely persistent, with less than 5% of the seed bank producing plants in either year. Protection from grazing had little effect on feed on offer in 1983/84, suggesting that sheep obtained little, if any, benefit from grazing during the growing period. The sheep did however, reduce seed set. We concluded that (1) both soil and vegetation were degraded, (2) the grassland will continue to deteriorate unless grazing is controlled, and (3) the grassland will respond to improved management. (C) 1996 Academic Press Limited