HR: 0800h
AN: B41A-0158    [Abstracts]
TI: Dry Season Rainfall Anomalies due to Deforestation in Northern Mesoamerica: Implications for Forest Sustainability
AU: * Welch, R M
EM: welch@nsstc.uah.edu
AF: Dept Atmospheric Science, University of Alabama-Huntsville, Huntsville, AL 35805 United States
AU: Ray, D K
EM: dkray@purdue.edu
AF: Dept Forestry and Nat. Resources, Purdue University, West Lafayette, IN 47907 United States
AU: Lawton, R O
EM: lawtonr@email.uah.edu
AF: Dept Biological Sciences, University of Alabama-Huntsville, Huntsville, AL 35899 United States
AU: Nair, U
EM: nair@nsstc.uah.edu
AF: Dept Atmospheric Science, University of Alabama-Huntsville, Huntsville, AL 35805 United States
AB: In the region stretching between Mexico and Panama, the proposed Mesoamerican Biological Corridor (MBC) is an ambitious effort to stem and turn back the erosion of biodiversity in one of the world's biologically richest regions by connecting large existing parks and reserves with new protected areas by means of an extensive network of biological corridors. The success of this effort will depend in part on the ability of the connecting corridors to provide adequate habitats permitting the sustainability of some populations and the migratory movements of others. Ideally these connecting corridors would contain the biological communities which were originally present. Currently, however, many of these connecting corridors do not contain their original forest, but are instead occupied by agricultural landscapes containing croplands, grasslands and degraded woodlands. The forest types in northern Mesoamerica generally are those that require dry season rainfall for their survival, and it is not clear whether current environmental and climatological conditions are sufficient to maintain existing forests and regenerate the pristine forests in the deforested patches. Hourly climatological rainfall rates have been averaged for the time period of 1961 to 1997 at 266 stations in Guatemala and adjacent areas. These climatological rainfall rates have been segregated for forested and deforested regions of each of the major Holdridge life zones. Dry season cloud frequency of occurrences derived from GOES satellite imagery then are. correlated with the March climalogical data in order to generate regression estimates of current local rainfall. Differences between estimated current rainfall and historical values define regions under increased dry season water stress. In general dry season rainfall in March is markedly lower in deforested areas than in forested areas of the same life zone for most of the Holdridge life zones. In some deforested areas within the Holdridge wet forest life zones, estimated March rainfall deficits are >25 mm. Dry season deforested habitats tend to have higher daytime temperatures, are less cloudy, have lower estimated soil moisture and lower values of Normalized Difference Vegetation Index (NDVI) than do forested habitats in the same life zone. The result is hotter and drier air over deforested regions, with lower values of cloud formation and precipitation. The data suggest that deforestation is locally intensifying the dry season and increasing the risk of fire, especially for the long corridor connecting regions. In addition, forest regeneration in some parts of the MBC may not result in second-growth forest that is characteristic of that life zone but rather in forest regeneration more typical of drier conditions. The extent to which this would influence the conservation utility of any given corridor depends upon the ecological requirements of the organisms concerned.
DE: 0426 Biosphere/atmosphere interactions (0315)
DE: 1631 Land/atmosphere interactions (1218, 1843, 3322)
DE: 1632 Land cover change
DE: 1640 Remote sensing (1855)
SC: Biogeosciences [B]
MN: Fall Meeting 2005