Advances in Modelling Land Change and Estimating Ecosystem Function Across Ontario

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The effects of land-use and land-cover change on how ecosystems function has become a critical issue of local, provincial, national, and global concern. Over 30% of the Earth’s surface has been altered by human activities and while the extent of alteration by natural disturbances is uncertain, these disturbances may have greater ecological impacts than human activities in countries with large areas and relatively small populations (e.g., Canada). Because human and natural activities driving land-use and land-cover change are so pronounced, land-use and land-cover change is inexplicably linked to ecological processes and often guides the quantity and quality of ecosystem function. In Canada, measurement and monitoring of land-use and land-cover change is achieved using remote sensing (e.g., Canada Land Inventory, Annual Crop Inventory). Remote sensing products are extremely useful in terms of quantifying historical land-use and land-cover change and deriving estimates of ecosystem function. However, these estimates, which are often used in national assessments, typically use top-down approaches (e.g., benefits transfer) that fail to account for changes in ecological function due to climate conditions or landscape heterogeneity (i.e., site characteristics). To incorporate biogeochemical (e.g., nutrient cycling), biogeophysical (e.g., heat flux, evaporation), and other process effects on ecosystem function, scientists use ecosystem process models (e.g., Century, Biome-BGC, CBM-CFS3). These models account for heterogeneity in soil, climate, and other factors that drive vegetation growth and other ecological processes. However, they are typically applied at coarse scales (e.g., 0.5 degree resolution). At this resolution they offer useful estimates of national scale ecological conditions, but results do not coincide with land units at which humans make decisions or at which policy is made. Furthermore, these models are ill equipped to address changes in land cover, land management, and among other issues, landscape fragmentation. Contemporary ecological modeling efforts use prescribed land-cover data and are unable to account for dynamic changes in land use, land cover, or land management. New models are needed to integrate a dynamic representation of land-use and land-cover change and ecosystem process to improve our understanding and quantification of how land-use and land-cover change affects ecosystem function. Despite calls to improve research and models that link land-use and land-cover change with ecological processes by the Global Land Project, Future Earth, and the United States National Science Foundation’s Coupled Natural/Human Systems program, a national land-use and land-cover change model for Canada has yet to exist. This research program uses a bottom-up modeling approach to create a land-use and land-cover change model for Ontario that integrates with ecosystem process models for the explicit purpose of estimating the effects of different quantities and patterns of land use and land cover derived from socio-economic and policy scenarios on ecosystem function. Results from this research will 1) garner an improved understanding of the interactions, feedbacks, and thresholds associated with ecosystem function due to different quantity and patterns of land use and land cover, 2) identify sensitive ecological areas vulnerable to specific patterns of land use and land cover, 3) provide methodological advancements in terms of model integration and conceptual issues in coupling land-use and land-cover change with ecological processes, and 4) provide the first step towards a national land-use and land-cover change model and ecosystem function assessment program.