Land change and sustainability science calls for increased attention to the vulnerability and resilience of coupled human-environment systems to various stresses and perturbations tied to increased human demands in the face of climate change. Seasonal tropical forest biomes require special attention because of the amount of deforestation taking place in them. Since 1997, a large, interdisciplinary project has been developing data and analysis to understand the human and biophysical dynamics of deforestation, and to model and project land changes in the southern Yucatan, which includes the Calakmul Biosphere Reserve. The understanding gained is being used to develop insights about the vulnerability and resilience of coupled land uses and land covers in the region, ultimately building towards a full-blown vulnerability study. The project seeks to identify some of the critical factors linked to sustained human disturbance and increasing aridity (climate change) on the land systems. It will complete extant work on an extremely detailed forest-land cover classification and its accuracy assessment, and it will bring help make that work current into 2004, via ASTER imagery. The project will establish an AVHRR archive that will ultimately address the question: Have Normalized Difference Vegetation Index (NDVI) measurements decreased among the extant mature forests, and is this linked to increased aridity? The study will also use existing data and modest levels of new data to compare the litter between mature forests and successional forest and examine the impact of land history on biomass accumulation. A carbon stock estimate for the region will be generated using extant tree measurements as well as litter and soil carbon data. Several biodiversity data sets (transect captures) will be completed in order to address the question of biodiversity loss linked to habitat change from deforestation. Finally, a survey of farmer's responses to the recent hurricane Isidore will be completed to determine how differently endowed households respond to hurricane disturbances.
The Southern Yucatan Peninsular Region (SYPR) project on which this study builds has laid out one of the most comprehensive assessments of land change undertaken anywhere, linking biophysical and human subsystem dynamics into several different kinds of models that explain and project land change. In this sense, it provides methodological and analytical advances for emerging land-change science by linking the natural, social, and spatial sciences. Land-change science now moves toward questions of system response to perturbations and stresses, such as climate change. The SYPR project has the capacity to take a leadership role in this effort as well. This research will begin the transition of the project to questions of vulnerability, resilience, and sustainability of land systems in one of the most important seasonal tropical forests remaining in the Americas. It begins to provide the answers to the question: How will forest types and land-uses respond to a more occupied, frequently used (cut and burned) landscape that is subject to climate change? The answers are important for the many people who call the region home as well as to the Calakmul Biosphere Reserve situated in the center of the region and pivotal the Mesoamerican Biological Corridor. Research results will have more general utility for scholars and practitioners working in many other parts of the world, too.
