Document: JOH-3-83-3

Regeneration of slash-and-burn agricultural fields in relation to landscape structure in the Orange Walk District, Belize.

WEBBEKING, A.* ¹, J.A.KUPFER ² and S.B.FRANKLIN ¹

University of Memphis, Memphis, TN 38152 USA ¹
University of Arizona, Tucson, AZ 85721 USA ²

Abstract:
Due to demographic and economic pressures, the predominantly forested matrix that historically characterized many areas of slash-and-burn agriculture is being replaced by a matrix of younger forests at various stages of recovery. The more rapid turnover of plots and the altered spatial context of the fields and forests within the landscape may have ramifications for the long-term fate of tropical forests. For example, it could be hypothesized that the adjacency and diversity of seed sources for regeneration on fallow fields has been altered as a result of the changes in landscape structure, and this altered spatial context may subsequently influence the rate and trajectory of succession. We examined this hypothesis by collecting vegetation data from thirty-two milpas (slash-and-burn fields) that varied in their age (fallow > 3 years, fallow < 3 years, in use >3 years, in use < 3 years) and their distance to older forest (> 100 m or < 100 m). Species composition for both the woody and herbaceous strata were found to be significantly different between near and distant milpas. Further, Shannon's diversity index values for woody vegetation were greater in the milpas near old growth than distant milpas currently in use. One implication that could be drawn from these results is that regenerating fields marked by lower diversity may be less resilient and recover more slowly from cultivation because of greater soil leaching brought about by the less efficient uptake and cycling of soil resources (e.g., nitrogen).

Keywords: Disturbance, landscape, diversity, sustainability

This abstract is being presented at: 1:15 PM in session:
Oral Session #31: Agroecology.