Some ecological effects of feral sheep on Santa Cruz island, California, USA

摘要: Abstract Long-term overgrazing by feral sheep has resulted in moderate to severe ecological impacts about one-half of Santa Cruz Island. Feral were generalist herbivores, consuming a variety plants according availability and phenology. Insular endemic species particular preferred, reared on their hind legs reach leaves shrubs. Effects grassland community included reduced herbaceous cover, increased bare ground, altered structure, decreased litter, erosion. Sheep browsing impacted shrubs altering growth form preventing regeneration, completely defoliating lower-growing Trailing denuded 7% some areas. Sheep-caused modifications one plant associated with dramatic decrease density, richness, diversity birds, including several insular taxa. These results, along those other recent studies, demonstrate that cause serious unacceptable damage sensitive ecosystems.