Collaborative Research: Asynchrony in the timing of goose-vegetation interactions: implications for biogeochemical cycling in wet sedge tundra

陆地高纬度生态系统正在经历急剧的温度上升，降水量的变化，以及营养相互作用的重要影响的生长季节的推进。迁徙动物与它们所依赖的能量、营养和养育后代的牧草的物候之间的时间关系的脱钩是这些变化最明显的后果之一。此外，高纬度地区的食草动物很可能介导对气候变化的生物地球化学反应，从而大大改变生态系统的功能。然而，鲜为人知的是，如何在草食动物-植被相互作用的同步变化将影响地球化学cycles.This项目将在阿拉斯加州西部的育空-Kuskokwim（Y-K）三角洲，那里有强有力的证据表明，气候变化正在推动植物的物候和鹅迁移的时间之间的进化联系的时间脱钩。研究的紧迫性在于：世界上一些最迅速的气候变化正在阿拉斯加进行，使迁徙的鹅和它们影响的生态系统过程容易受到新条件的影响，随着生长季节的快速推进，迁徙的鹅饲养生态学大大滞后，威胁着土著社区不可替代的生存资源。总体研究目标是量化生长季节的推进和植被-鹅的相互作用改变了Y-K三角洲C和N循环的幅度和模式。两个具体的问题将解决一个实验：如何与鹅到达时间的植物生长的时间相互作用，以改变夏季长的幅度的植物生产，叶面化学，和N的可用性;和，如何与鹅到达时间的植物生长的时间相互作用，以改变夏季长的幅度的净生态系统CO2交换，总生态系统光合作用，生态系统呼吸？SAVANNA-YK是一个生态地球化学模型，认为放牧是Y-K三角洲植被和痕量气体过程的关键控制因素，将用于预测这些生态系统过程和植物-草食动物相互作用将如何继续变化，从而改变未来几年生态系统过程和景观动态的性质。对候鸟及其主要食物在生态系统地球化学循环中的物候解耦的关注是第一次。更具体地说，这项研究是第一个调查如何与植物物候相互作用的食草动物的时间，以影响生态地球化学循环相比，其他程序，重点是存在或不存在食草动物和/或食草动物密度对这些周期的影响;这项研究是第一次采取实验方法来解决阿拉斯加西部亚热带地区营养不匹配的问题，同时将这些发现与针对北方湿莎草系统的预测生态系统模型相结合。这种结合使得能够调查气候变化对食草动物-植被相互作用的影响如何在未来几年影响大的空间尺度;这项研究的重点是对迁徙鹅至关重要的植物物种，而其他关注气候变化影响的北方研究则集中在冻原植物物种上，这些植物对候鸟觅食生态并不重要。活动首先，将利用国家物候学网络的协议建立一个公民科学观测站。整个Y-K三角洲的学生将记录鹅的到达时间和草和木本植物的关键物候事件。第二，将招募贝瑟尔地区高中的学生协助实地研究，并有机会开发小型项目。研究人员将每年春天访问村庄教室，介绍该项目，气候变化和植物-动物相互作用;分享研究领域以前和正在进行的研究成果;并招募感兴趣的学生。第三，通过阿拉斯加本土科学和工程计划（ANSEP）的阿拉斯加本土本科生将被招募为现场和实验室技术人员;这些学生也可以开发自己的项目。第四，虚拟科学将与当地教师一起开发博客，播客和教学视频，这些视频可以分发到整个阿拉斯加西部和其他地区的远程教室。第五，目标和结果将传达给土著组织机构，这些组织机构有来自每个主要村庄的代表，为研究提供知识和支持，并为依靠鹅为生的家庭提供教育渠道。最后，一名博士后研究员，一名研究生和几名本科生将获得新的培训，指导，并有机会在项目活动中合作，并在科学会议上展示他们的发现。

Terrestrial high-latitude ecosystems are experiencing dramatic increases in temperature, changes in precipitation, and advancement of the growing season with important implications for trophic interactions. Uncoupling of the temporal relationships between migratory animals and the phenology of the forage they rely on for energy, nutrition, and rearing of young is one of the most glaring consequences of these changes. Furthermore, herbivores in high latitudes are likely to mediate biogeochemical responses to climate change substantially altering ecosystem function. However, little is known about how changes in the synchrony of herbivore-vegetation interactions will influence biogeochemical cycles.This project will be conducted on the Yukon-Kuskokwim (Y-K) Delta in western Alaska, where there is strong evidence that climate change is driving temporal decoupling of the evolved linkage between the phenology of plants and the timing of goose migration. There is an urgency to the research because: some of the most rapid climate changes in the world are underway in Alaska, leaving migratory geese and the ecosystem processes they influence vulnerable to new conditions, and with the rapid advancement of the growing season, migratory goose feeding ecology is lagging substantially, threatening an irreplaceable subsistence resource for Native communities.The overall research objective is to quantify how an advancing growing season and changes in the synchrony of vegetation-goose interactions alter the magnitudes and patterns of C and N cycling in the Y- K Delta. Two specific questions will be addressed with an experiment: How does the timing of plant growth interact with goose arrival time to alter summer-long magnitudes of plant production, foliar chemistry, and N availability; and, How does the timing of plant growth interact with goose arrival time to alter summer-long magnitudes of net ecosystem CO2 exchange, gross ecosystem photosynthesis, and ecosystem respiration? SAVANNA-YK, a biogeochemical model that considers grazing a critical control on vegetation and trace gas processes in the Y-K Delta, will be used to predict how these ecosystem processes and plant-herbivore interactions will continue to change, altering the nature of ecosystem processes and landscape dynamics in years to come.The intellectual merit of the research is three-fold: The focus on phenologic decoupling of migratory birds and their primary forage on ecosystem biogeochemical cycles is the first of its kind. More specifically, the research is the first to investigate how the timing of herbivory interacts with plant phenology to affect biogeochemical cycles compared to other programs that have focused on the presence or absence of herbivores and/or on herbivore density effects on these cycles; The research is the first to take an experimental approach to the issue of trophic mismatch in the western Alaskan sub-Arctic while integrating these findings with forecasting ecosystem models tailored to wet sedge systems of the north. This combination allows investigation into how climate change effects on herbivore-vegetation interactions will influence large spatial scales in years to come; and The research focuses on plant species that are critical to migratory geese, while other northern studies focusing on climate change effects have focused on tundra plant species that are not critical to migratory bird foraging ecology.The broader impacts of the research will be realized throughh several activities. First, a citizen- science observatory will be established using protocols of the National Phenology Network. Students throughout the Y-K delta will record goose arrival times and key phenological events in grasses and woody plants. Second, students from Bethel Regional High School will be recruited to assist in the field research and be given the opportunity to develop small projects. Researchers will visit village classrooms each spring to introduce the project, climate change, and plant-animal interactions; share results of previous and ongoing research in the study area; and recruit interested students. Third, Native Alaskan undergraduate students through the Alaska Native Science and Engineering Program (ANSEP) will be recruited as field and laboratory technicians; these students may also develop their own projects. Fourth, Virtual Science will be used with local teachers to develop blogs, pod-casts, and instructional videos that can be distributed to remote classrooms throughout western Alaska and beyond. Fifth, objectives and results will be communicated to Native organizational bodies, which have representatives from each major village, to build knowledge and support for the research, and provide educational outlets for families who rely on geese for subsistence. Finally, one post-doctoral researcher, one graduate student, and several undergraduates will be provided new training, mentoring, and an opportunity to collaborate on project activities and present their findings at scientific meetings.