文摘
Landsat images covering the St. Lawrence Lowlands (30,000 km2) and Appalachians (33,000 km2) ecoregions of southern Qu¨¦bec, Canada, have been classified for the years 1993 and 2001 to (1) quantify land use/land cover (LULC) changes and changes to agricultural landscapes and (2) relate LULC changes to changes of farm-related descriptors of economic and farming activities. Over 25 LULC classes were identified on each classification which were merged into 5 LULC classes (anthropogenic, annual crop, perennial crop, forest, water/wetlands) used to delineate a gradient of five types of agricultural landscapes. Transition matrices reveal a shift in major agricultural classes in the St. Lawrence Lowlands where perennial crops have been converted into annual crops. Furthermore, suburban sprawl was observed adjacent to major cities whereas overall forest cover was reduced. Changes in agricultural land classes were few in the agroforested landscapes of the Appalachian ecoregion. Landscapes dominated by intensive agriculture expanded onto adjacent regions previously under extensive agriculture. Most farm-related variables extracted from agriculture censuses showed an increase, reflecting an intensification of agriculture in both ecoregions though no clear association with LULC changes were revealed. Increase in annual crops may be related to intensive corn production associated with pig farming. Differences in landscape changes between the two ecoregions may be related to proximal causal factors such as soil topography and suitability for high-quality crops. Our analysis will provide baseline information to implement a monitoring program of habitat dynamics in this vast region.
