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，建立对河流环境影响的机制解释。接下来，我的计划将研究功能变化的河流生态系统发生的生态特征组成的变化的结果。目前基于分类学的方法来诊断退化的河流生态系统条件的原因是有问题的，因为它们是很好的联系到功能的措施。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的反应的机械联系（例如，沉积、营养物富集）。基于性状的方法有可能产生一致的指标，适用于广泛的空间尺度和关联的因果关系时，多种环境压力对生物群落的累积后果。 该提案采用基于特征的生物评估方法，为了解接触过量营养物和沉积物对河流中基于底栖特征的生物组合的相互影响建立基础。具体的研究目标是：（1）利用围隔生态系统实验，确定环境上现实的营养物-沉积物接触的相互作用效应，以确定其对底栖生物群落特征的单一和综合影响，（2）评估受改变河流营养物-沉积物状况的扰动影响的景观梯度上营养物和过量沉积物的综合影响。这项研究计划将：（1）通过评估加性效应、倍增效应和比较效应模型框架，确定营养富集和沉积对河流昆虫的影响;（2）通过操纵实验，研究营养在掩盖沉积效应方面可能发挥的作用;（3）沿着受密集农业和永久冻土退化影响的营养-沉积物压力梯度，沿着这些实验，检验预测结果。不同流域干扰（和不同生态区）的预测评估将测试该方法的普遍适用性。关键预测是：（1）河流昆虫将通过减小体型来应对非致死性压力;（2）沉积物的负面影响将通过轻度营养富集来缓和;（3）沉积将加剧过度营养富集的负面影响。这项工作将有助于移动监管，水质制度从简单的，单一的压力影响模型，从多个压力暴露的累积生态影响更现实的评估。HQP参与包括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职业所需的沟通，领导力和技术技能的广泛培训。

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.