Exploring Trade-offs Among Environmental Services to Support Landscape Planning
Modsim 2007: International Congress On Modelling and Simulation: Land, Water and Environmental Management: Integrated Systems For Sustainability
Spatial planning of land-use and human activities for natural resource management often involves many stakeholders, each with their own values and preferences, and complex biological processes. We present an exploratory approach named Landscape IMAGES, which can be employed to determine interactions among various environmental services. These services can represent productive, economic, cultural or ecological dimensions of (agro-)ecosystems in landscapes or small regions. The approach provides insight in the full range of possible futures without prioritizing preferences beforehand. Moreover, it offers room for discussion and perspective sharing, to inform decision making and to increase understanding and support of stakeholders. The methodology of Landscape IMAGES is illustrated with an example of the redesign of an agri-ecological zone in the Netherlands, where economical, ecological and culture-historical aspects were considered. The aim of research involvement was to support an NGO involved in landscape management with the evaluation of a sketch design landscape plan of adjustments to the hedgerow structure typical of the landscape. To offer insight in the quality of the landscape plan the following landscape characteristics and their interactions were explored: Ecological quality, with connectivity (largest connected sub-graph) of the hedgerow structure for dispersal of animal species as an indicator. Landscape identity, with indicators for variation, naturalness and historical configuration of the hedgerows. Landscape maintenance costs for farmers spent on removal, planting and recurrent maintenance of hedgerows. The resulting seven indicators reflect environmental services (or functions) of the landscape and served as objectives in a multi-objective decision problem. To solve this problem we used a heuristic technique: the evolutionary strategy of Differential Evolution. This technique yields a set of solutions, each representing a spatial configuration of hedgerows in the landscape, which determines the performance of environmental functions, and thus the quality of the solution. The solution set is randomly initialized and iteratively improved by generating a competitor for each solution in the set with evolutionary operators of mutation, uniform crossover and selection. The selection processes uses the Pareto optimality concept to rank solutions. A set of Pareto optimal solutions consists of solutions that are not dominated by other solutions, when all objectives are considered. By plotting the performances of the solution set interactions between the objectives were determined. By identifying in the solution space both the original landscape and the sketch design landscape plan it became clear that the decision rules employed by the NGO impacted positively on connectivity. However, the values of indicators of landscape identity were slightly reduced by the implemented redesign. The solutions indicated opportunities for improving these objectives simultaneously. By exploring trade-offs among objectives, the Landscape IMAGES modelling instrument aims to reveal the 'manoeuvring space' of decision makers on land use issues, thus contributing to solutions that do justice to interests of broad groups of stakeholders. This methodology is applicable to any design problem characterized by multiple scale spatial interactions.
Author(s): Groot, JCJ; Jellema, A; Rossing, WAH
Journal: Modsim 2007: International Congress On Modelling and Simulation: Land, Water and Environmental Management: Integrated Systems For Sustainability