Cumulative effects in a riverscape across scales: thresholds of disturbance in ecosystem integrity

跨尺度河流景观的累积效应：生态系统完整性干扰的阈值

• 批准号: 463575-2014
• 负责人: Richardson, John
• 金额: $ 14.05万
• 依托单位: University of British Columbia
• 依托单位国家: 加拿大
• 项目类别: Strategic Projects - Group
• 财政年份: 2015
• 资助国家: 加拿大
• 起止时间: 2015-01-01 至 2016-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=577081
• 关键词: Cumulative; effects; riverscape; across; scales

Ecosystems are being lost incrementally to development (urbanisation, agriculture, forestry, etc.) across the landscape. Habitat loss is especially obvious for the small tributary streams that provide the water, nutrients and materials to sustain habitats, water supply and ecosystem services downstream. Although we know that tributaries are cumulatively altered in many stream networks, we are not yet able to predict downstream consequences on water quality, biodiversity, and ecosystem services. And we know very little about how such losses impact conservation of habitats critical to headwater species themselves. Agencies that protect our natural environments struggle with ways to conserve stream ecosystems, both in the headwaters and to protect downstream environments. Assessment of cumulative effects from multiple stressors on large streams is problematic for many reasons, but especially including the very large scaling issues, dilution effects, lag times, and non-additive and non-linear effects. Cumulative effects also occur at the scale of habitat loss across a landscape for headwater specialists. Headwater streams provide an excellent place to begin to combine empirical and modelling studies to understand the impacts of cumulative effects and how best to predict and measure the contribution of losses of headwater streams to downstream conditions. Our proposal includes four objectives. 1. Using two unique datasets, and additional data to be collected, we will study the spatial and temporal patterns of the community structure of headwaters and larger streams in nested catchment designs. This will also use landscape context, e.g., the degree of alteration of neighbouring headwaters, as an environmental gradient affecting persistence of local headwater communities. We will also add measures of select ecosystem functions to the field studies. 2. We will use detailed, process-based models to generate predictions of how changes might scale across catchment sizes as one progresses downstream. 3. We will use data to test the model predictions downstream at nested scales through fluvial networks. 4. We will develop GIS-based decision tools to assist evaluation of risks associated with the loss of headwater streams.

生态系统正在因发展而逐渐丧失（城市化、农业、林业等）穿越整个世界生境的丧失对于提供水、养分和物质以维持下游生境、供水和生态系统服务的小型支流尤其明显。虽然我们知道，在许多河流网络中，支流的变化是累积的，但我们还无法预测对水质、生物多样性和生态系统服务的下游影响。我们对这种损失如何影响对源头物种本身至关重要的栖息地的保护知之甚少。保护我们自然环境的机构努力寻找保护河流生态系统的方法，无论是在源头还是保护下游环境。由于许多原因，评估来自多个压力源对大型流的累积效应是有问题的，但特别是包括非常大的缩放问题、稀释效应、滞后时间以及非加性和非线性效应。对于水源专家来说，在整个景观中栖息地丧失的规模也会产生累积效应。源头流提供了一个很好的地方开始联合收割机结合经验和建模研究，以了解累积效应的影响，以及如何最好地预测和衡量损失的源头流下游条件的贡献。我们的建议包括四个目标。1.利用两个独特的数据集，以及将要收集的其他数据，我们将研究 嵌套汇流设计。这也将使用景观背景，例如，邻近水源的改变程度，作为影响当地水源社区持久性的环境梯度。我们还将在实地研究中增加选定生态系统功能的措施。2.我们将使用详细的，基于过程的模型，以生成预测的变化可能如何跨流域规模作为一个进展下游。3.我们将使用数据来测试模型预测下游嵌套尺度通过河流网络。4.我们将开发基于地理信息系统的决策工具，以协助评估与源头河流损失相关的风险。