Evaluating the Ecological and Environmental Impact of Urbanization in the Greater Toronto Area through Multi-Temporal Remotely Sensed Data and Landscape Ecological Measures

Abstract

Urbanization is a critical factor affecting the ecological and environmental balance of the Greater Toronto Area (GTA), the most populous metropolitan area in Canada, in the past three decades. The purpose of this chapter is to examine the relationship between landscape change and population increase patterns as well as to evaluate ecological impacts of urbanization in the GTA. Multi-temporal remotely sensed data have been used to derive vegetation changes from 1992 to 2003. Land use change is derived from historical land use maps. Five landscape fragmentation indices are calculated for different periods using FRAGSTATS software. Population change is compared with land use and vegetation changes. The landscape fragmentation rate is then compared with the population growth rate. Our results show that the mean normalized difference vegetation index (NDVI) is negatively correlated with the percentage of the urban settlement land and population density at the census tract (CT) level. Changes in the percentage of urban land use show relatively weak correlations with the five fragmentation indices. It was found that shape and fractal dimension indices are better at characterizing the urbanization process than the indices of diversity, contagion, and percentage of like adjacencies.