Collaborative Research: Nutritional Landscapes of Arctic Caribou: Observations, Experiments, and Models Provide Process-Level Understanding of Forage Traits and Trajectories

陆地北极系统是气候、植被、食草动物和人类之间复杂相互作用的结果，必须一起研究才能了解它们的功能特征。虽然低温和短暂的生长季节限制了植物的生长，但有足够的植物生物量来支持阿拉斯加原住民赖以生存的迁徙驯鹿群。食物网底层植物的任何变化都可能对食草动物和人类消费者及其相互作用产生连锁反应。今天，北极系统正处于变化之中，导致新的植被组合，植物组织的营养价值发生变化，并最终改变了迁徙驯鹿和依赖它们的人类的饮食。该项目将北极中部驯鹿群的营养景观作为一个统一的概念进行研究，将营养景观描述为驯鹿可用蛋白质（CAP）和驯鹿可用能量（CAE），综合饲料数量措施，反映生物量，物种组成，植物C和N含量，消化率和次级化合物。核心目标是了解整个冻土带CAP和CAE量的时空模式的驱动因素;驯鹿对这种营养景观的利用;在可能的气候情景和长期实验下，CAP和CAE量在未来将如何不同，以及驯鹿和土著社区之间的相互作用。这项研究的更广泛影响涉及阿拉斯加利益相关者的几个群体，包括：Nuiqsut北坡社区的收割者，全球驯鹿社区和多个教育阶段的学生。该项目将在Nuiqsut，#8232;嵌入一名团队成员与猎人，并为#8232;高中学生制作一部关于驯鹿-阿拉斯加土著互动的教育科学纪录片。该组织计划雇用与阿拉斯加土著科学和工程项目有关的乡村学生和本科生，以协助图里克湖的实验工作和植被收集。这项研究对来自环北极牧场监测#8232;和评估网络的生态学家具有重要意义&，该网络致力&于#8232;美国、加拿大和斯堪的纳维亚半岛的驯鹿保护和可持续管理，他们将利用这些数据来考虑一系列气候变化情景如何影响驯鹿群的繁殖力和种群动态。这个项目的智力价值源于五个元素的融合，以了解北极
系统功能和对气候变化的响应：（1）对植物物种、土壤和植物C和N、消化率和次级化合物进行生态规模评估&，用于计算CAP（kg m-2）和CAE（kJ m-2）的量;（2）分析驯鹿觅食与全年营养景观的关系有多密切;（3）分析&来自现有长期冬-夏气候变化实验的样本#8232;，以提供关于#8232&;CAP和CAE在未来如何不同的数据;（4）预测未来营养景观和
驯鹿觅食相互作用;以及（5）观察阿拉斯加土著猎人的收获和&决定其空间和时间模式的系统属性。这些项目的组成部分将使一个重要的食草动物，驯鹿，如何与正在迅速变化的景观相互作用的综合理解。这项研究：（1）检查北极系统从初级生产到次级消费者和#8232;气候变化对多个营养水平的影响;（2）通过检查#8232;最丰富的大型草食动物及其食物来源而广泛应用，这两者都分布在整个#8232;北极;（3）整合实验，观察和建模方法来了解生态系统和气候变化。综合观察、实验数据和建模来描述当前和预测未来的营养景观，旨在提供对北极系统功能的机械理解，并改变对气候-植被-驯鹿-生计猎人相互作用的理解。

Terrestrial Arctic systems are the result of complex interactions between climate, vegetation, herbivores, and humans that must be studied together to understand their functional
traits. While low temperatures and short-growing seasons limit plant growth, enough plant biomass exists to support herds of migratory caribou, on which Alaska Natives depend. Any changes in the plants at the base of the food web can have cascading consequences for herbivores and human consumers and their interactions. Today, the Arctic system is in the midst of change resulting in new vegetation assemblages, changes in the nutritive value of plant tissues, and ultimately in the diets of migratory caribou and the humans that depend on them. This project examines the nutritional landscape of the Central Arctic Caribou Herd as a unifying concept, describing the nutritional landscape as caribou available protein (CAP) and caribou available energy
(CAE), integrative forage quantity measures that reflect biomass, species composition, plant
C and N content, digestibility, and secondary compounds. The core objectives are gaining understanding of the drivers of spatial and temporal patterns in the amounts of CAP and CAE across the tundra; caribou use of this nutritional landscape; how the amounts of CAP and CAE will differ in the future under likely climate scenarios and long-term experiments, and the interactions between caribou and Native communities. The broader impacts of this study involve several groups of Alaskan stakeholders, including: harvesters of the North Slope community of Nuiqsut, the worldwide caribou community, and students at multiple stages of education. The project will embed a team member with hunters in Nuiqsut,
and develop an educational scientific documentary on the caribou - Alaska Native interactions for
high school students. The group plans to employ village students and undergraduates affiliated with the Alaska Native Science
and Engineering Program to assist with experimental work and vegetation collection at Toolik Lake. This research is significant to ecologists from the Circumarctic Rangifer Monitoring
and Assessment Network, dedicated
to caribou conservation and sustainable management in the US, Canada, and Scandinavia, who will use the data to consider how a suite of climate change scenarios affect herd fecundity and population dynamics. The intellectual merit of this project stems from the merging of five elements to understand Arctic
System function and response to climate change: (1) A landscape-scale assessment of plant species, soil and plant C and N, digestibility, and secondary compounds that will be used
to calculate the amounts of CAP (kg m-2) and CAE (kJ m-2); (2) analysis of how closely caribou foraging is tied to the nutritional landscape throughout the year; (3) analysis of samples
from an existing long-term winter - summer climate change experiment to provide data on how
CAP and CAE will differ in the future; (4) prediction of future nutritional landscapes and
caribou foraging interactions; and (5) observations of Alaska Native hunter harvesting and attributes
of the system that determine their spatial and temporal patterns. These project components will enable an integrative understanding of how an important herbivore, caribou, interact with a landscape that is rapidly changing. This research: (1) examines the Arctic System from primary production to secondary consumers and the
influence of climate change across multiple trophic levels; (2) applies broadly by examining
the most abundant large herbivore and its food sources, both of which are distributed throughout
the Arctic; and (3) integrates experimental, observational, and modeling approaches to understanding ecological systems and climate change. The integration of observation, experimental data
and modeling to describe current and forecast future nutritional landscapes is intended to provide a
mechanistic understanding of Arctic System function and transform the understanding
of climate-vegetation-caribou-subsistence hunter interactions.