EFFECT OF SHEEP GRAZING ON THE DEMOGRAPHY OF ANTHYLLIS-VULNERARIA IN SOUTHERN FRANCE

(1) The demography of Anthyllis vulneraria was studied under three contrasting sheep-grazing regimes (controlled, free and ungrazed) for 26 months, monitoring survival, fecundity, seedling appearance and the seed bank. (2) Free grazing and controlled grazing compared with no grazing strongly affected seed output but had no effect on the survival of juveniles and vegetative adults. Vegetative plants provide an important population reserve of dormant buds. (3) Grazing diminished fecundity by reducing plant resources; this effect was greater when grazing was unrestricted. Under controlled grazing, the reduction in fecundity was correlated with an increase in the survival of individuals, relative to free grazing and no grazing. (4) The population dynamics of A. vulneraria are more dependant on reproductive characteristics than on factors influencing survival.