ECOSYSTEM‐SCALE IMPACTS OF DEFORESTATION AND LAND USE IN A HUMID TROPICAL REGION OF MEXICO

Deforestation of tropical evergreen forests is a major contributor to increasing levels of greenhouse gases in the atmosphere. However, large uncertainties currently exist concerning the quantities of C and other elements lost to the atmosphere due to the conversion of primary forests to pastures and agricultural lands. Elemental losses associated with land conversion in the heavily deforested Los Tuxtlas Region of Mexico were quantified. Total aboveground biomass (TAGB) as well as carbon and nutrient pools in aboveground vegetation and soils were measured along a land-use gradient that included primary forests as well as pastures and cornfields, which represent the dominant land-use types in the region. TAGB of primary forests in the Los Tuxtlas Region averaged 403 Mg/ha; pasture and cornfield sites averaged 24 and 23 Mg/ha, respectively. Approximately 80% of TAGB of forests was composed of trees >30 cm in diameter at breast height (dbh), while trees >70 cm dbh accounted for 44% of TAGB. Conversion of fo...

[1]  G. Robertson,et al.  Nutrient mobility in variable- and permanent-charge soils , 1988 .

[2]  A. Gómez-pompa.  Ecology of the vegetation of Veracruz. , 1978 .

[3]  Steven N. Ward,et al.  An application of synthetic seismicity in earthquake statistics - The Middle America Trench , 1992 .

[4]  F. Putz.  Liana biomass and leaf area of a «Tierra Firme» forest in the Rio Negro Basin, Venezuela , 1983 .

[5]  R. Detwiler,et al.  Land use change and the global carbon cycle: the role of tropical soils , 1986 .

[6]  D. Phillips,et al.  Resolution and error in measuring land-cover change: Effects on estimating net carbon release from Mexican terrestrial ecosystems , 1997 .

[7]  S. Hurlbert.  Pseudoreplication and the Design of Ecological Field Experiments , 1984 .

[8]  G. Baskerville.  Use of Logarithmic Regression in the Estimation of Plant Biomass , 1972 .

[9]  J. Meave,et al.  Floristic composition and structure of vegetation under isolated trees in neotropical pastures , 1992 .

[10]  R. K. Dixon,et al.  Global forest systems: An uncertain response to atmospheric pollutants and global climate change? , 1995 .

[11]  P. Fearnside,et al.  Carbon uptake by secondary forests in Brazilian Amazonia , 1996 .

[12]  Peter M. Vitousek,et al.  Changes in soil phosphorus fractions and ecosystem dynamics across a long chronosequence in Hawaii. , 1995 .

[13]  P. Crutzen,et al.  Biomass Burning in the Tropics: Impact on Atmospheric Chemistry and Biogeochemical Cycles , 1990, Science.

[14]  Van Wagner.  The Line Intersect Method in Forest Fuel Sampling , 1968 .

[15]  P. Sánchez,et al.  Soil fertility dynamics after clearing a tropical rainforest in Peru , 1983 .

[16]  J. Houghton.  Climate change 1994 : radiative forcing of climate change and an evaluation of the IPCC IS92 emission scenarios , 1995 .

[17]  Yoram J. Kaufman,et al.  Smoke and fire characteristics for cerrado and deforestation burns in Brazil: BASE-B experiment , 1992 .

[18]  Josefina Barajas-Morales.  Wood Specific Gravity in Species from Two Tropical Forests in Mexico , 1987 .

[19]  C. Uhl,et al.  Abandoned pastures in eastern Amazonia. I. Patterns of plant succession , 1988 .

[20]  E. Veldkamp.  Organic Carbon Turnover in Three Tropical Soils under Pasture after Deforestation , 1994 .

[21]  Common Regressions to Estimate Tree Biomass in Tropical Stands , 1978 .

[22]  P. Vitousek,et al.  Soil organic matter dynamics along gradients in temperature and land use on the Island of Hawaii , 1995 .

[23]  R. K. Dixon,et al.  Carbon Pools and Flux of Global Forest Ecosystems , 1994, Science.

[24]  J. Ovington,et al.  Biomass and chemical content of El Verde lower montane rain forest plants , 1970 .

[25]  G. Woodwell,et al.  Changes in the Carbon Content of Terrestrial Biota and Soils between 1860 and 1980: A Net Release of CO"2 to the Atmosphere , 1983 .

[26]  M. Duever,et al.  Mineral cycling in a tropical moist forest ecosystem , 1975 .

[27]  J. Levine.  Global biomass burning - Atmospheric, climatic, and biospheric implications , 1990 .

[28]  J. Kauffman,et al.  Interactions of Anthropogenic Activities, Fire, and Rain Forests in the Amazon Basin , 1990 .

[29]  A. Prasad,et al.  Geographical distributions of carbon in biomass and soils of tropical Asian forests , 1993 .

[30]  R. Dirzo,et al.  Rates of Deforestation in Los Tuxtlas, a Neotropical Area in Southeast Mexico , 1992 .

[31]  Robert L. Sanford,et al.  Nutrient Cycling in Moist Tropical Forest , 1986 .

[32]  Ariel E. Lugo,et al.  Biomass Estimation Methods for Tropical Forests with Applications to Forest Inventory Data , 1989, Forest Science.

[33]  J. Randerson,et al.  Terrestrial ecosystem production: A process model based on global satellite and surface data , 1993 .

[34]  P. Crutzen,et al.  Estimates of Annual and Regional Releases of CO2 and Other Trace Gases to the Atmosphere from Fires in the Tropics, Based on the FAO Statistics for the Period 1975–1980 , 1990 .

[35]  D. Ward,et al.  Dynamics associated with total aboveground biomass, C, nutrient pools, and biomass burning of primary forest and pasture in Rondônia, Brazil during SCAR‐B , 1998 .

[36]  Rodolfo Dirzo,et al.  CARBON EMISSIONS FROM MEXICAN FORESTS: CURRENT SITUATION AND LONG-TERM SCENARIOS , 1997 .

[37]  D. W. Nelson,et al.  Total Carbon, Organic Carbon, and Organic Matter 1 , 1982 .

[38]  E. Davidson,et al.  Belowground cycling of carbon in forests and pastures of eastern Amazonia , 1995 .

[39]  D. Ward,et al.  Fire in the Brazilian Amazon 2. Biomass, nutrient pools and losses in cattle pastures , 1998, Oecologia.

[40]  A. Page.  Methods of soil analysis. Part 2. Chemical and microbiological properties. , 1982 .

[41]  J. Sathaye,et al.  Carbon emissions and sequestration in forests: Case studies from seven developing countries , 1992 .