Interactive Effects of Disturbance Frequency and Species Composition on Ecosystem Functioning of Intermittent Streams: a Test of Future Climate Change Scenarios

对美国大平原地区全球气候变化的预测包括干旱持续时间的增加和洪水的严重程度。这些气候变化将伴随着由于人类对景观的改造而引起的水生生物丰度和分布的变化。在大平原的水生研究表明，洪水和干旱对草原河流生态系统的状况有很强的影响。然而，气候事件的变化将与水生生物多样性的变化相结合，这些变化的组合将如何影响草原河流生态系统目前尚不清楚。拟议的实验将模拟气候事件的变化和主要水生生物（如鱼类和居住在溪流中的昆虫）的丰富程度。利用野外实验和控制实验溪流设施的观察结果，将描述洪水、干旱和草原溪流中水生生物多样性的影响。这些实验将测量在不同气候变化情景下的光合作用产量和河流捕获营养物质的能力。了解草原河流的动态对于保护和管理这些重要的生态栖息地至关重要。此外，在健康的情况下，这些溪流会过滤周围景观中的营养物质，并对水质产生强烈影响。拟议的研究与康扎草原长期生态研究（LTER）站点的总体主题一致，并将允许对整个草原生态系统的气候变化后果进行广泛评估。与康扎草原生物站的实验溪流设施相关的研究也将通过让游客直接观察溪流生物来促进公众教育。通过与堪萨斯州立大学学生本科研究机会计划和目前资助的NSF-REU现场活动的合作，将促进来自代表性不足群体的学生的招募。

Predictions of global climate change in the Great Plains region of the U.S. include an increase in the duration of droughts and the severity of floods. These climatic changes will be accompanied by shifts in the abundance and distribution of aquatic organisms that are caused by human modifications to the landscape. Aquatic research in the Great Plains has indicated a strong influence of flooding and drought on the condition of prairie stream ecosystems. However, changes in climatic events will be coupled with changes in aquatic biodiversity, and how the combination of these changes will influence prairie stream ecosystems is currently unknown. The proposed experiments will simulate both changes in climatic events and the abundance of dominant aquatic organisms such as fish and stream-dwelling insects. Using observations from field experiments and from a controlled experimental stream facility, the effects of floods, drought, and the diversity of aquatic life in prairie streams will be characterized. The experiments will measure the amount of photosynthetic production and the ability of streams to capture nutrients under different climate change scenarios. Understanding dynamics of prairie streams is essential for the conservation and management of these ecologically important habitats. Moreover, when healthy, these streams filter nutrients from the surrounding landscape and can have strong influences on water quality. The proposed research is consistent with the general theme of the Konza Prairie Long-term Ecological Research (LTER) site and will allow broad assessment of the consequences of climate change on an entire prairie ecosystem. Research associated with the experimental stream facility at the Konza Prairie Biological Station also will facilitate public education by allowing visitors to directly observe stream organisms. Recruitment of students from underrepresented groups will be facilitated through cooperation with the Kansas State University Student Undergraduate Research Opportunity Program and the currently funded NSF-REU site activities.