PARENT SESSION
Oral Session #61: Arid Lands Restoration.
Presiding: S. Loftin
Wednesday, August 7. 1:00 PM to 4:45 PM. Mohave Meeting Room, TCC.
A conceptual framework and experimental approach for the restoration of tropical deciduous forest in Mexico.
BURGOS, ANA*,1, MAASS, JOSE1, 1 Instituto de Ecología, Universidad Nacional Autónoma de México, Morelia, Michoacán, México
ABSTRACT- Currently, only 27% of the original distribution of tropical deciduous forest (TDF) in Mexico remains conserved. To deal with the problem of TDF restoration in the Chamela Region (19°N,105°W), we used an ecosystem management approach. Four steps were undertaken 1)Description of system initial conditions, including characterization of the transformation processes at different scales; 2)Identification of conceptual aspects for decision-making, including forces that drive TDF succession; 3) Experimental manipulation; and 4) Evaluation. In the experimental phase, we focused on the evaluation of the hydrological aptitude of the sites, seed availability, and the performance of five species of native trees. The experimental layout consisted of 24 plots distributed on three independent slopes with pasture and two with intact TDF as controls. According to 28 in-depth interviews with local inhabitants, woody elements appear fast in the system after abandonment (first 1-2 years), however, the established tree species (mostly thorny individuals of Mimosa and Acacia spp) maintains a mono-dominant canopy cover, which persists for at least twenty years.The experimental results suggest poor native seed availability, as well as impaired physical site conditions for seed establishment. Upper soil water availability was higher in pasture than in intact forest. Seedlings of native trees showed a survival >50% even under direct sun exposure with a severe drought occurring during the study period. Slope aspect was determinant in survival rates.
KEY WORDS: ecosystem management principles, successional forces, thorny vegetation, Western Mexico