Advances in Modelling Land Change and Estimating Ecosystem Function Across Ontario

土地利用和土地覆盖变化对生态系统功能的影响已经成为地方、省、国家和全球关注的一个关键问题。超过30%的地球表面已被人类活动改变，虽然自然干扰的改变程度尚不确定，但在面积大、人口相对较少的国家（如加拿大），这些干扰可能比人类活动产生更大的生态影响。由于驱动土地利用和土地覆盖变化的人类和自然活动是如此明显，土地利用和土地覆盖的变化与生态过程有着令人费解的联系，并常常指导生态系统功能的数量和质量。在加拿大，土地利用和土地覆盖变化的测量和监测是通过遥感实现的（例如，加拿大土地清查、年度作物清查）。遥感产品在量化历史土地利用和土地覆盖变化以及估算生态系统功能方面极为有用。然而，这些在国家评估中经常使用的估计通常采用自上而下的方法（例如，利益转移），无法解释由于气候条件或景观异质性（即场地特征）而导致的生态功能变化。**为了结合生物地球化学（如养分循环）、生物地球物理（如热通量、蒸发）和其他过程对生态系统功能的影响，科学家们使用了生态系统过程模型（如Century、Biome-BGC、CBM-CFS3）。这些模型解释了土壤、气候和其他驱动植被生长和其他生态过程的因素的异质性。然而，它们通常应用于粗尺度（例如，0.5度分辨率）。在这个决议中，他们对全国范围的生态状况提供了有用的估计，但结果与人类做出决策或制定政策的土地单位并不一致。此外，这些模型无法解决土地覆盖、土地管理以及景观破碎化等问题的变化。当代生态建模工作使用规定的土地覆盖数据，无法解释土地利用、土地覆盖或土地管理的动态变化。需要新的模型来整合土地利用和土地覆盖变化与生态系统过程的动态表示，以提高我们对土地利用和土地覆盖变化如何影响生态系统功能的理解和量化。**尽管全球土地项目、未来地球和美国国家科学基金会的自然/人类耦合系统计划呼吁改进将土地利用和土地覆盖变化与生态过程联系起来的研究和模型，但加拿大的国家土地利用和土地覆盖变化模型尚未存在。本研究项目采用自下而上的建模方法，为安大略省创建了一个土地利用和土地覆盖变化模型，该模型与生态系统过程模型相结合，明确目的是估计不同数量和模式的土地利用和土地覆盖对生态系统功能的影响，这些影响来自社会经济和政策情景。本研究的结果将：(1)提高对不同数量和类型的土地利用和土地覆盖与生态系统功能相关的相互作用、反馈和阈值的理解；(2)确定易受特定类型土地利用和土地覆盖影响的敏感生态区域；(3)在土地利用和土地覆盖变化与生态过程耦合的模型整合和概念问题方面提供方法上的进步。4)为建立全国土地利用和土地覆盖变化模型和生态系统功能评价方案提供了第一步。

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.