THE DISPERSAL OF A DRY-FRUITED SHRUB BY RED DEER IN A MEDITERRANEAN ECOSYSTEM

Seed dispersal of dry-fruited shrubs has received little attention in Mediterranean areas despite their frequency in the vegetation and the consideration given to the dispersal. of fleshy-fruited shrubs in the area. Red deer faeces has recently been found to contain large numbers of seeds from one of the most common shrubs of this group, gum cistus Cistus ladanifer, although its importance in the reproduction of the species is unknown. This study examines the role of the red deer as an effective disperser of C. ladanifer. For this purpose, we quantify i) the C. ladanifer seed content in red deer dung over a year, ill the s eed shadow generated by the red deer with their faeces during the same period, and iii) the ability of the clung-borne seeds to germinate an d establish as seedlings under held conditions within five years follo wing excretion. The results reveal an extremely high seed content of t he species in red deer dung (up to 80.5 +/- 41.9 germinable seeds g(-1 )), which is virtually confined to the slimmer (July-August), when we estimate that a red deer defecates up to 24 000 seeds of the species p er day. Furthermore. red deer mainly deposit gum cistus seeds amongst plant formations lacking the species: over the year, red deer excrete <2600 seeds m(-2) in C. ladanifer-dominated scrub and 7400-8800 seeds m(-2) in other plant formations. Under natural conditions, the dung-bo rne seeds have a more staggered among-pears germination pattern than f ree seeds in the soil. Though no seedling survived its first summer dr ought, the survival of seedlings sprouted from dung was. significantly longer than that of control seedlings in the first and third years af ter deposition, and indistinguishable from it the second, fourth and f ifth years. This is the first quantification of the importance of red deer to C. ladanifer dispersal and establishment, and suggests that en dozoochory by mammalian herbivores can be very valuable for dry-fruite d shrubs in the Mediterranean region.