Quantifying spatiotemporal dynamics of agricultural landscapes usingremotely sensed data and landscape metrics

摘要

This study focuses on the spatiotemporal dynamics of agricultural lands anddifferences in rapidly developing urban and declining rural counties in Iowa, USAbetween 1984 and 2000. The study presents an analysis of land-cover maps derivedfrom Landsat TM and ETM+ satellite imagery and different landscape metrics usingFRAGSTATS and IDRISI software. The study provides evidence of both loss ofcroplands and change in fragmentation between 1984 and 2000. Fragmentation inagriculture-dominated areas increased with the development of urban centres anddiversification of land uses. Fragmentation of landscapes, including agricultural land,was found to be higher in the urbanized counties, but was stable or even declined overtime in these counties. In contrast, in the context of remote rural areas, agriculturallandscapes experienced rapid increase in fragmentation and farmland loss. The urban–rural gradient analysis used in this study showed that the highest fragmentationoccurred on the city edges. These findings suggest that farmland fragmentation is acomplex process associated with socio-economic trends at regional and local scales. Inaddition, socio-economic determinants of landscape fragmentation differ betweenareas with diverging development trajectories. Intensive cropland fragmentation inremote agricultural regions, detected by this research, should be further studied and itspossible effects on both agricultural productivity and biodiversity should be carefullyconsidered.