Dispersal of Spanish juniper Juniperus thurifera by birds and mammals in a fragmented landscape

摘要: Dispersal of Spanish juniper Juniperus thurifera was examined in a farming landscape central Spain to study the effects fragmentation on dispersal effectiveness different dispersers. and consequences for plant. The conducted two large forests (LF: 280 150 ha) representative unfragmented conditions, 18 small isolated fragments (0.1 -3 which were classified groups: 1) F1, forest remnants with both high cover cone production (N = 5): 2) F2, has caused heavy reduction junipers 13). Cone production, disperser abundances quantity by birds (Turdus thrushes) mammals (carnivores, rabbits sheep) estimated throughout years. thrushes measured three types trees representing decreasing attraction focus birds: cones (SJI). without (SJ2) holm oaks (HO). Cone greatly decreased from LF F1 F2 years, affecting dramatically. Thrush similar but lacked or very scarce Carnivores showed an even distribution whole area, herbivores relatively fragments, especially rabbits, lacking under 0.6 ha. Patterns seed deposition around activity SJ1 (83.1% had seed-packets thrush pellets) SJ2 (53.6%) HO (23.6%.). Both patterns density pellets roughly F1. only recorded one (SJ1) out 159 F2. supporting behaved as specialist feeders thus avoided patches devoid cones. Average densities reached 397.6 ha-1, surpassing at least 30 times quantitative (seed-packets ha-1) mammal Juniper seeds present faeces collected Overall, carnivores nearly 4 lower than LF, that 11 lower. This result is consistent availability and. together abundances, fits prediction (except rabbits) moved among according total food supplies. Overall, results seriously impaired loss their main dispersers (thrushes), recruitment became dependent upon low effectiveness, namely sheep.