The effect of grazing on phenology and biomass allocation in Quercus coccifera (L.)

摘要

The spatial arrangement of above-ground tissues, the biomass allocation patterns, the root structure and the temporal variations in biomass were examined in grazed and ungrazed Quercus coccifera shrubs. Grazed shrubs exhibited lower values of individual leaf area and weight, and a higher number of leaves per shoot. This means that a grazed shrub's photosynthetic area is divided into more numerous, although smaller, units. In grazed shrubs, 60 % of the total biomass was invested in below-ground parts, while in ungrazed shrubs, the highest proportion of the biomass (50 %) was allocated to woody tissues. The root structure of Q. coccifera shrubs was characterized by high biomass allocation to coarse roots (65 %) and low allocation to fine ones (7 %). The allocation to coarse roots was significantly increased in grazed shrubs. The temporal variations in above- and below-ground biomass appeared to be grazing independent. Above- and below-ground plant biomass increase during the period from late spring to September, the most severe period for the Mediterranean ecosystem. The intrinsic features of Q. coccifera, coupled with features induced by grazing, probably favor its dominance in areas degraded by grazing. (C) Elsevier, Paris. [References: 36]