Cairns, M.A., P.K. Haggerty, R. Alvarez, B.H.J. De Jong, and I. Olmsted. 2000. Tropical Mexico's recent land-use change: a region's contribution to the global carbon cycle. Ecological Applications 10(5):1426-1441.
We applied modeled biomass density estimates to changes in land use/land cover (LU/LC) statistics for the intensively impacted and highly fragmented landscape of tropical Mexico to estimate the flux of carbon (C) between terrestrial ecosystems and the atmosphere between 1977 and 1992. Biomass densities were assigned to hybrid LU/LC classes on vegetation maps produced by Mexican governmental organizations and, by differencing areas and biomass C pools, net C flux was calculated in the eight-state tropical region of southeast Mexico. These states, representing tropical Mexico, experienced a mean annual deforestation rate of nearly 559,000 ha/yr, or 1.9%, between 1977 and 1992. The total area of closed forests decreased by 26%, open/fragmented forests decreased by 31%, and agroecosystem areas increased by 64%. Total mean biomass densities ranged from a high of 265 Mg/ha in the Veracruz state tall/medium tropical evergreen forest class to a low of 12 Mg/ha in the cultivated land class (several states). We estimate that a total of 280 Tg C were released from the terrestrial biosphere during the 15-yr period covered by our study, equal to nearly 20% of the region's 1977 biomass C pool. The study region, while comprising just 24% of Mexico's surface area, contributed 36% of the net national C emissions from LU/LC change.