LTREB Renewal: High-amplitude midge fluctuations and the ecosystem dynamics of Lake Myvatn, Iceland

LTREB 更新：冰岛米湖的高振幅蠓波动和生态系统动态

• 批准号: 1556208
• 负责人: Anthony Ives
• 金额: $ 51.73万
• 依托单位: University of Wisconsin-Madison
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-03-15 至 2023-02-28
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1556208&HistoricalAwards=false
• 关键词: LTREB; Renewal; amplitude; midge; fluctuations

Dramatic 'outbreaks' of organisms - locusts, lemmings, insects - draw public attention to the natural world, in part because scientists do not completely understand the causes for these population surges. This study will investigate midges in Lake Mývatn, Iceland, and why their abundance fluctuates over 4 orders of magnitude in irregular cycles lasting 4-7 years. Adult midges that emerge from the lake die on shore. During high-midge years, the weight of midges that are deposited in the surrounding heathland is equivalent to 10 humpback whales, providing food for predators and scavengers, nutrients for plants, and the basis for local agriculture. By synthesizing results from field samples and experiments over several population cycles, this project promises new insights into fundamental scientific questions about the causes and consequences of population outbreaks. The project will engage graduate and undergraduate students who will work at Mývatn each summer, providing them exposure to extreme biology as well as to educational diversity, as they work in both the lake and on the shoreline under the tutelage of an interdisciplinary group of scientists. The public will learn more about midge outbreaks through an ongoing 'Smidge of Midge' blog.Ecosystems that show huge changes through time can reveal the ecological forces that stabilize or destabilize natural dynamics. This project involves both long-term data collection in aquatic and terrestrial systems and targeted experiments to test specific hypotheses. The aquatic data collection will build and expand on an existing database that dates back to the 1970s. The project has added weekly monitoring of many additional variables, including midge larvae density, benthic primary production, and pelagic nutrients. The collection of terrestrial data has continued with the monitoring of midge infall and arthropod communities along transects around the lake that were established in 2008. A suite of targeted experiments will address a wide range of research questions such as (i) the role that midges play as ecosystem engineers, changing benthic conditions to favor large-bodied epibenthic cladocerans over small-bodied infaunal species, (ii) the mutualistic effect that midge larvae have on algal growth, and (iii) the importance of midge adults for the flowering of carnivorous plants. These experimental projects are led by graduate students as part of their PhD theses, and by undergraduate interns as independent projects. This combination of aquatic and terrestrial experiments together with regular sampling will test hypotheses about how the lake and shoreline ecosystems are linked together. The research will examine whether the instability of the lake ecosystem could drive instability of the surrounding ecosystem on land.

蝗虫、旅鼠、昆虫等生物体的急剧“爆发”引起了公众对自然世界的关注，部分原因是科学家们并不完全了解这些人口激增的原因。这项研究将调查冰岛米湖的蠓，以及为什么它们的丰度在持续 4-7 年的不规则周期中波动超过 4 个数量级。从湖里出来的成年蠓会死在岸上。在高蠓年份，沉积在周围石南地的蠓重量相当于10头座头鲸，为捕食者和食腐动物提供食物，为植物提供营养，也是当地农业的基础。通过综合多个种群周期的现场样本和实验结果，该项目有望对有关种群爆发原因和后果的基本科学问题提供新的见解。该项目将吸引每年夏天在米湖工作的研究生和本科生，让他们在跨学科科学家小组的指导下在湖泊和海岸线工作，接触极端生物学和教育多样性。公众将通过正在进行的“小蠓”博客了解有关蠓爆发的更多信息。随着时间的推移显示出巨大变化的生态系统可以揭示稳定或破坏自然动态的生态力量。该项目涉及水生和陆地系统的长期数据收集以及测试特定假设的有针对性的实验。水生数据收集将在可追溯至 20 世纪 70 年代的现有数据库的基础上建立和扩展。该项目增加了对许多其他变量的每周监测，包括蠓幼虫密度、底栖初级生产力和中上层营养物质。陆地数据的收集继续进行，监测 2008 年建立的湖周围横断面沿线的蠓和节肢动物群落。一系列有针对性的实验将解决广泛的研究问题，例如 (i) 蠓作为生态系统工程师的作用，改变底栖条件以有利于大型表栖枝角动物而不是小型动物物种，(ii) 蠓与小体动物的互利效应 (iii) 幼虫对藻类生长的影响，以及 (iii) 蠓成虫对食肉植物开花的重要性。这些实验项目由研究生领导，作为其博士论文的一部分，并由本科生实习生领导，作为独立项目。这种水生和陆地实验与定期采样的结合将检验有关湖泊和海岸线生态系统如何联系在一起的假设。该研究将研究湖泊生态系统的不稳定是否会导致周围陆地生态系统的不稳定。