Data collection for fresh-water regions of The Ecosystem Health Monitoring Program (EHMP), in southeast Queensland, Australia, involves the sampling of over 130 sites among 19 catchments twice per year and has been ongoing for over ten years. The sampling design was derived following an exhaustive process of indicator and site selection to develop a composite indicator that represented aquatic ecosystem health. After 13 years of implementation, there was an interest in identifying redundancies in sampling to reduce sampling costs without making a substantial impact on the integrity of the program and its capacity to report on ecosystem health. This paper focuses on identifying a subset of sites and times that could be removed from sampling with a minimal impact on the subsequent ecosystem health scores. Herein, Mixed models are employed to assess a variance structure from which optimality criteria are utilized to identify the scheme. Integer programs are then used to ensure specific practical constraints are observed.

澳大利亚昆士兰州东南部生态系统健康监测计划（EHMP）淡水地区的数据收集工作涉及每年两次对19个流域的130多个站点进行采样，并且这项工作已经进行了十多年。抽样设计是在详尽的指标和选址过程之后得出的，以开发出代表水生生态系统健康的综合指标。在实施了13年之后，人们有兴趣确定采样的冗余度，以减少采样成本，而又不会对该计划的完整性及其报告生态系统健康的能力产生重大影响。本文的重点是确定可以从采样中删除的站点和时间的子集，并且对后续生态系统健康评分的影响最小。在此处，使用混合模型来评估方差结构，从中使用最优性标准来识别方案。然后使用整数程序来确保遵守特定的实际约束。