Development of Functional Trait Measures for Assessing Stream Ecosystem State

我的长期目标是开发和应用新的环境评估方法，以建立对河流环境影响的机械解释。接下来，我的节目将研究由于生态特征组成的变化而发生的河流生态系统的功能变化。目前以分类学为基础的诊断河流生态系统状况退化原因的方法存在问题，因为它们与功能措施的联系很差。相反，基于生态特征的信息有可能提供生物对特定环境干扰(例如，沉积、营养丰富)的反应的机械性联系。当多种环境应激源对生物群落产生累积影响时，基于特征的方法有可能为在广泛的空间尺度上的应用提供一致的度量标准，并将因果关系联系起来。*该提案使用基于特征的生物评估方法，为开发暴露于过量营养物质和沉积物对基于河流底栖特征的组合的交互影响的知识奠定基础。具体的研究目标是：(1)利用中观实验确定环境上现实的营养-沉积物暴露的相互影响，以确定它们对底栖群落特征发生的单一和综合影响，以及(2)评估营养物质和过量沉积物在受干扰影响的景观梯度上的综合影响，这些干扰改变了河流的营养-沉积物状况。这项研究计划将：(1)通过评估加性、乘性和比较效应模型框架，建立营养丰富和沉积对河流昆虫的影响；(2)通过操纵性实验，检验营养物质可能在掩盖沉积物效应中所起的作用；以及(3)沿着受集约化农业和永久冻土退化影响的营养-沉积物压力源梯度测试这些实验的预测。对不同分水岭干扰(和不同生态区)的预测评估将检验该方法的普遍适用性。关键的预测是：(1)河流昆虫将通过减小个体尺寸来应对非致命性压力；(2)沉积物的负面影响将被温和的营养丰富所缓和；以及(3)沉积将加剧过度营养丰富的负面影响。这项工作将有助于将监管、水质制度从简单的单一应激源影响模型转移到更现实的多应激源暴露累积生态影响评估。HQP项目包括2名博士、4名硕士和5名本科生，他们将接受在学术、政府和私营部门成功就业所需的沟通、领导力和技术技能方面的广泛培训。

My long term objectives develop and apply novel environmental assessment approaches to establish mechanistic explanations of environmental impacts on rivers. Next, my program will examine functional changes to river ecosystems that occur as a result of shifts in ecological trait composition. Current taxonomically-based methods for diagnosing the cause of degraded river ecosystem conditions are problematic as they are poorly linked to functional measures. In contrast, ecological traits-based information has the potential to provide mechanistic linkages of biotic responses to specific environmental disturbances (e.g., sedimentation, nutrient enrichment). Traits-based approaches have the potential to produce consistent metrics for application across broad spatial scales and associate cause and effect when multiple environmental stressors have cumulative consequences on biological communities.******The proposal uses traits-based bioassessment approaches to create the building blocks for developing knowledge of the interactive effects that exposure to excess nutrients and sediments have on benthic traits-based assemblages in rivers. Specific research objectives are to: (1) use mesocosm experiments to establish the interactive effects of environmentally realistic nutrient-sediment exposures to identify their single and combined effects on the occurrence of benthic community traits, and (2) evaluate the combined effects of nutrients and excess sediments across landscape gradients affected by disturbances that modify riverine nutrient-sediment regimes. This research program will: (1) establish the effects of nutrient enrichment and sedimentation on riverine insects by assessing additive, multiplicative and comparative effects model frameworks; (2) examine the role nutrients may have in masking the sediment effects through manipulative experiments; and (3) test predictions from these experiments along nutrient-sediment stressor gradients affected by intense agriculture and permafrost degradation. Assessment of predictions across distinct watershed disturbances (and different ecozones) will test the general applicability of the method. Key predictions are: (1) river insects will respond to non-lethal stress through decreased body size; (2) negative sediment effects will be moderated by mild nutrient enrichment; and (3) sedimentation will worsen the negative effects of excessive nutrient enrichment. This work will help move regulatory, water quality regimes from simplistic, single stressor effects models to more realistic evaluations of cumulative ecological effects from multiple stressor exposure. HQP engagement includes 2 PhD, 4 MSc, and 5 undergraduate students who will receive extensive training in the communication, leadership and technical skills required for successful careers in the academic, government and private sectors.********