Effects of Multiple Resource Additions on Community and Ecosystem Processes: NutNet NPP Quadrat Sampling at the Sevilleta National Wildlife Refuge, New Mexico

Two of the most pervasive human impacts on ecosystems are alteration of global nutrient budgets and changes in the abundance and identity of consumers. Fossil fuel combustion and agricultural fertilization have doubled and quintupled, respectively, global pools of nitrogen and phosphorus relative to pre-industrial levels. In spite of the global impacts of these human activities, there have been no globally coordinated experiments to quantify the general impacts on ecological systems. This experiment seeks to determine how nutrient availability controls plant biomass, diversity, and species composition in a desert grassland. This has important implications for understanding how future atmospheric deposition of nutrients (N, S, Ca, K) might affect community and ecosystem-level responses. This study is part of a larger coordinated research network that includes more than 40 grassland sites around the world. By using a standardized experimental setup that is consistent across all study sites, we are addressing the questions of whether diversity and productivity are co-limited by multiple nutrients and if so, whether these trends are predictable on a global scale.人类活动对生态系统的两类最普遍干扰，分别为全球养分收支的改变，以及消费者群落的丰度与物种组成变化。化石燃料燃烧与农业施肥分别使全球氮、磷储存库相较工业化前水平增至原有规模的2倍与5倍。尽管这些人类活动已产生全球性影响，但目前尚无全球性协同实验来量化其对生态系统的一般性影响。本实验旨在探明养分有效性如何调控荒漠草原的植物生物量、物种多样性与群落组成。该研究结果对于理解未来大气养分沉降（N, S, Ca, K）如何影响群落与生态系统尺度的响应具有重要意义。本研究隶属于一个覆盖全球40余个草原样地的大型协同研究网络。通过采用所有研究站点统一的标准化实验方案，本研究旨在解答两个核心问题：一是物种多样性与生产力是否受到多种养分的共同限制；二是若存在此种限制，该规律是否可在全球尺度上进行预测。