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'Living fence' species as forest regeneration foci in abandoned pastures in Honduras.
Zahawi, Rakan*,1, Augspurger, Carol1, 1 University of Illinois, Urbana, IL
ABSTRACT- Forest regeneration from seeds or transplanted seedlings is greatly impeded by grasses in abandoned tropical pastures. Use of woody cuttings to quickly establish an incipient "forest" may accelerate their succession. Two native tree species, commonly used as "living fences" throughout tropical America, were evaluated for their ability to establish in pastures and serve as forest "regeneration foci" in Pico Bonito National Park, Honduras. Applying island biogeography theory, "artificial islands" of three sizes (4, 16, 64 m2) were created by planting 2m tall cuttings of Gliricidia sepium (Fabaceae) and Bursera simaruba (Burseraceae), each in monoculture in three pastures. To evaluate regeneration processes and compare them to the surrounding pasture, data were collected on seed rain and seedling establishment. Additionally, a bird survey was initiated to evaluate the attractiveness of islands to seed dispersers. Results show that G. sepium has higher establishment rates (>90%) as compared to B. simaruba (30-50%) at all sites and develops a canopy cover faster. Seed rain for key early successional species, such as Cecropia sp. and Trema micrantha, is greater in islands as compared to pasture. Bird visitations and seedling establishment are also greater in artificial islands as compared to pasture, further demonstrating their ability to serve as regeneration foci. Given the problems associated with restoring abandoned pastures to a forested habitat, the use of woody cuttings presents a simple, possibly universally applicable, non-labor intensive alternative for facilitating succession in these areas.
KEY WORDS: pasture, restoration, living fences, tropics