Department of Biology, Western University, 1151 Richmond Street N., London, ON N6A 5B7, Canada.
School of Environment and Sustainability, 329 Kirk Hall, 117 Science Place, Saskatoon, SK S7N 5C8, Canada.
Conserv Biol. 2018 Jun;32(3):694-705. doi: 10.1111/cobi.13084. Epub 2018 Apr 16.
Mitigation and offset programs designed to compensate for ecosystem function losses due to development must balance losses from affected ecosystems with gains in restored ecosystems. Aggregation rules applied to ecosystem functions to assess site equivalence are based on implicit assumptions about the substitutability of functions among sites and can profoundly influence the distribution of restored ecosystem functions on the landscape. We investigated the consequences of rules applied to the aggregation of ecosystem functions for wetland offsets in the Beaverhill watershed in Alberta, Canada. We considered the fate of 3 ecosystem functions: hydrology, water purification, and biodiversity. We set up an affect-and-offset algorithm to simulate the effect of aggregation rules on ecosystem function for wetland offsets. Cobenefits and trade-offs among functions and the constraints posed by the quantity and quality of restorable sites resulted in a redistribution of functions between affected and offset wetlands. Hydrology and water purification functions were positively correlated with one another and negatively correlated with biodiversity function. Weighted-average rules did not replace functions in proportion to their weights. Rules prioritizing biodiversity function led to more monofunctional wetlands and landscapes. The minimum rule, for which the wetland score was equal to the worst performing function, promoted multifunctional wetlands and landscapes. The maximum rule, for which the wetland score was equal to the best performing function, promoted monofunctional wetlands and multifunctional landscapes. Because of implicit trade-offs among ecosystem functions, no-net-loss objectives for multiple functions should be constructed within a landscape context. Based on our results, we suggest criteria for the design of aggregation rules for no net loss of ecosystem functions within a landscape context include the concepts of substitutability, cobenefits and trade-offs, landscape constraints, heterogeneity, and the precautionary principle.
为弥补因开发而导致的生态系统功能丧失而设计的缓解和补偿计划，必须平衡受影响生态系统的损失与恢复生态系统的收益。用于评估站点等效性的生态系统功能聚合规则基于功能在站点之间可替代性的隐含假设，并且可以深刻影响恢复生态系统功能在景观上的分布。我们研究了应用于生态系统功能聚合的规则对加拿大艾伯塔省 Beaverhill 流域湿地补偿的影响。我们考虑了 3 种生态系统功能的命运：水文学、水净化和生物多样性。我们建立了一个影响-补偿算法来模拟聚合规则对湿地补偿的生态系统功能的影响。功能之间的共同效益和权衡以及可恢复性站点的数量和质量的限制导致受影响湿地和补偿湿地之间的功能重新分配。水文学和水净化功能彼此正相关，与生物多样性功能负相关。加权平均值规则没有按其权重成比例地替换功能。优先考虑生物多样性功能的规则导致更单一功能的湿地和景观。最低规则，湿地得分等于表现最差的功能，促进了多功能湿地和景观。最高规则，湿地得分等于表现最好的功能，促进了单一功能的湿地和多功能的景观。由于生态系统功能之间存在隐含的权衡，因此应在景观背景下构建多个功能的无净损失目标。基于我们的结果，我们提出了在景观背景下构建无净损失生态系统功能聚合规则的设计标准，包括替代、共同效益和权衡、景观约束、异质性和预防原则的概念。
