| dc.description.abstract |
"The overall objective of this research is to understand more fully the processes and potential impacts of land cover change and future climate change on both managed and natural terrestrial ecosystems. These changes in land cover are due to human impacts such as deforestation and reforestation (Honduras and Mexico), and also are due to climate change impacts as modeled for 2050 (Midwestern United States).
"The potential impacts of future climate change, for the 2050s, across the Midwestern United States, are for decreased maize yields across the southern portions of the study area, and increased yields across the northern areas. The high summer maximum temperatures inhibit maize growth above temperatures of 35 C, which become more frequent across southern areas of the study region. In addition, increases in climate variability result in decreases in maize yields. In addition, CO2 fertilization for maize, a C4 crop, is limited. For forested regions, potential climate change under a doubled CO2 climate results in an overall shift in forest composition from a transitional oak-hickory and beech-maple composition to a predominantly oak-hickory forest. In addition northern conifers and northern deciduous species were almost completely extirpated from the study region.
"Land cover changes, specifically of forest cover, across the study region of western Honduras and eastern Guatemala, show an overall trend of deforestation between 1987 and 1996. However, at the smaller study area scale of La Campa, reforestation is the dominant trend. These differences relate to a ban on logging within the community, land tenure and agricultural intensification processes currently occurring in the region. Research on changes in land cover using different techniques, specifically thermal band analysis, for Yucatan, Mexico, reveals an improved method of analysis. Using discriminant analysis, it was found that land cover was significantly related to surface temperatures, and as such this provides for a potential method for determining land cover. In addition, the data derived for the land cover analysis can also be used for climate modeling of terrestrial ecosystems, and to link the terrestrial and atmospheric components of the Earth system." |
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