De Jong, B. H. J.; Michael A. Cairns, N. Ramirez-Marcial, S. Ochoa-Gaona, J. Mendoza-Vega, P.K. Haggerty, M. Gonzalez-Espinosa, and I. March-Mifsut. 1999. Land-use change and carbon flux between the 1970s and 1990s in the central highlands of Chiapas, Mexico. >Environmental Management 23(3)375-38
We present results of a study in an intensively impacted and highly fragmented landscape in which we apply field-measured carbon (C) density values to land use/land cover (LU/LC) statistics to estimate the flux of C between terrestrial ecosystems and the atmosphere from the 1970s and 1990s. Carbon densities were assigned to common LU/LC classes on vegetation maps produced by Mexican governmental organizations and, by differencing areas and C pools, net C flux was calculated from the central highlands of Chiapas, Mexico during a 16 year period. The total area of closed forests was reduced by half while degraded and fragmented forests expanded 56% and cultivated land and pasture areas increased by 8% and 30%, respectively. Total mean C densities ranged from a high of 504 MgC ha-1 in the oak and evergreen cloud forests class to a low of 147 MgC ha-1 in the pasture class. The differences in total C densities among the various LU/LC classes were due to changes in biomass while soil organic matter C remained similar. We estimate that a total of 19.99 TgC were released to the atmosphere during the period of time covered by our study, equal to approximately 34% of the 1975 vegetation C pool. The Chiapas highlands, while comprising just 0.3% of Mexico's surface area, contributed greater than 3% of the net national C emissions.