WINDBREAKS ENHANCE SEED DISPERSAL INTO AGRICULTURAL LANDSCAPES IN MONTEVERDE, COSTA RICA

Abstract

Planting windbreaks on degraded tropical lands may accelerate natural successional processes by attracting seed-dispersing animals and increasing the seed rain of forest plants. I examined the effects of planted windbreaks on seed deposition patterns in dairy farms in Monteverde, Costa Rica, by comparing annual seed rain patterns in windbreaks and adjacent pastures. I also examined the effects of windbreak connectivity and remnant trees on seed rain patterns. Traps placed in 19 windbreaks and in seven pastures collected more than 3 million seeds (of 199 species) during the year-long study. Windbreaks received significantly greater densities and species richness of seeds of tree and shrub species than pastures. Bird-dispersed seeds occurred in greater densities and species numbers in windbreaks than in pastures; in contrast, the seed rain of bat-dispersed seeds did not differ between windbreak and pasture habitats. Windbreak connectivity had no detectable effect on seed dispersal patterns, whereas the presence of remnant trees increased the number of tree species but not the density of tree seeds. This study suggests that windbreaks can dramatically increase the deposition of tree and shrub seeds within the agricultural landscape, and that the location of windbreaks within the landscape may be important in determining seed deposition patterns.