Dispersal of Neotropical tree seeds by cattle as a tool for ecoagricultural restoration

Cattle often move among forests, fallows and open areas, consume fruit of trees and shrubs, and excrete viable seed. However their role as seed dispersers has rarely been examined systematically. We characterize woody species previously reported as cattle-dispersed, present preliminary field data documenting the extent of seed dispersal by cattle in Chiapas, and describe innovative management of this phenomenon by ranchers. The ecological and agronomic literature mentions defecation by cattle of viable seed of 24 woody species globally: 16 Fabaceae, two Rosaceae, and one each of Boraginaceae, Caprifoliaceae, Myrtaceae, Rutaceae, Sterculiaceae and Tiliaceae. Fruits of species reported as cattle-dispersed are diverse, but are frequently dry, indehiscent, and brown-black. They typically have hard seeds, averaging 7.0 mm in diameter and 83 mg. Interviews with ranchers in lowland Chiapas, supported by observations of germination from droppings in pastures and in the greenhouse, identify cattle-dispersed species of Cactaceae, Fabaceae, Malpigiaceae, Myrtaceae, Moraceae, Sterculiaceae and Sapotaceae. These species cover a broad range of ecosystems but are most numerous in tropical dry forest. Our findings suggest that the number and diversity of woody, cattle-dispersed species are greater than previously reported. Under some circumstances, seed dispersal by cattle may exert considerable influence on patterns of secondary succession. Management of this phenomenon may provide efficient means for establishment of trees for silvopastoral systems and ecological restoration. Ranchers in the Central Valleys of Chiapas exploit cattle-dispersed trees as fodder and even purposefully use cattle to plant tree seeds.