Scale Implications in Studies of Landcover Change

Abstract

Historical land-cover patterns may have a significant impact on ecosystem function today. To make inferences about the impacts of past land-cover, it is necessary to reconstruct historical patterns visually using data sources ranging from archival information to satellite data. We are exploring different approaches to mapping historical land-cover patterns and their impact on thematic and spatial errors. Our research is focused on three areas in the Frontenac Arch Biosphere (FAB), where we can map land-cover patterns from colonial periods to the present using a variety of data sources. Due to the long temporal scale of our work, we are using data sources collected at different spatial and thematic scales. The data sources include: settlement survey data, census, archival, aerial photos, and satellite imagery. To create maps comparing land-use patterns across time, all of these data sources need to be converted to a common scale.Settlement survey data were converted to maps by classifying colonial concession maps into different land-cover types based on surveyor notes. Air photos (1920, 1940, 1960, and 1980) were digitized at a scale of 1:5000 using the same land classes as were used for the colonial period mapping. Satellite data were used to map land-cover in 2008. We are quantifying errors associated with aggregating and disaggregating data in order to create maps at common spatial resolution.Results from our work will provide estimates of land-cover change over a 200 year period and will include estimates or errors associated with changing the spatial scale of various land-cover sources.