| Integrated land-change science seeks to understand land dynamics and their various consequences through an examination of coupled human-environment systems. This synthesis approach is used to address the recent, four-fold spread of bracken fern (Pteridium aquilinum (L.) Kuhn) throughout the cultivated lands of the southern Yucatan in Mexico. By joining biophysical, socio-economic, and remote sensing-GIS evidence, some of the one-dimensional explanations for the advance and persistence of this invasive species are rejected in favor of those focused on the synergy between human and environmental dimensions of the problem.; The specific approach taken in this dissertation consists of documenting and analyzing the species' links to: (1) spatial-landscape conditions based on remote sensing and GIS analysis of the past and current distributions of land covers; (2) socio-economic conditions based on studies of land-use history and current land management practices based on household surveys; and (3) environmental conditions based on ecological transects and landscape ecology metrics. Once the pieces are understood they are linked as part of land-change models to explain and predict current bracken fern invasion and the probabilities of its spread within the region.; Bracken fern has become an important component of the coupled human-environment system of the southern Yucatan peninsular region. It increased nearly four-fold in the region from 1985 to 2001, associated directly with human disturbance, primarily agricultural activities. Once established, bracken fern's persistence is supported by fire, mostly incidental burns from the large amount of swidden fires set every year to clear farm and pasture lands. Its impacts include impediment of forest succession and farmland fallow, reduction in biotic diversity, and high labor costs to combat. While other factors are involved, bracken fern appears to become dominant in those disturbed parcels in which, for whatever reason, direct management ceases. In many cases, the decision to manage the invasive species or not is tied to household and ejido land pressures. This understanding of the invasion dynamics is facilitated by linking the three arms of integrated land-change science—biophysical, socio-economic, and remote sensing/GIS analysis—and would not necessarily follow from a more specialized study. |
