BRC-BIO: Alpine Hotspots: Nutrient patches facilitate upslope expansion of tropical alpine communities undergoing rapid climate change

长期以来，冰川前缘环境一直是理解在新的可用栖息地建立生态群落的自然实验室。由于土壤养分的限制，高山生态系统中植物的初始定植往往有很长的滞后时间。然而，可能有强大的动植物促进机制在起作用，当地草食动物的公共粪便沉积创造了营养热点，并推动了更快的植物建立。该项目将确定营养热点如何改善极端非生物条件，加速高山景观的初级演替，促进先锋社区的发展，并将植物和其他生物向上扩展到冰川前场。这项研究将为一所以本科为主的机构中处于多个职业阶段的学生提供强有力的研究、专业培训和指导。两名硕士研究生、6-12名本科生、一名获得学士学位后的研究技术员和至少一名秘鲁当地学生将通过该项目接受培训，使下一代气候变化生物学家具备应对这一领域日益增长的挑战的技能。揭示生态群落将如何与快速气候变化保持同步的未探索过程将使未来的实验和预测性建模工作成为可能，这将为迫切需要的冰川消退新暴露的土地的管理提供信息。动植物促进可能是一种比目前在全球新暴露的冰川退化土地上认识到的更普遍的初级演替机制。缺乏对动物促进的潜在重要作用的理解，削弱了我们预测冰川在快速气候变化下的生物多样性、组合和生态系统功能将如何发展的能力。这项建议的目标是了解动物造成的营养热点在生态系统演替方面的后果。这项研究将有助于在大量野外数据的支持下，建立冰川前场生态系统发展最早阶段的新概念模型，并指导未来的预测和实验工作。一种基于实地的多尺度方法将揭示热点如何改变冰川社区的发展。具体目标是：1)确定热点对冰川前场土壤养分、微生物生物量和植物特征的斑块级别的影响；2)确定景观级别的热点对冰川消退130年的时间序列中植物和微生物群落组合的影响；以及3)定义热点和非热点位置的动物活动和养分沉积的模式。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，认为值得支持。

Glacier forefield environments have long acted as natural laboratories for understanding the establishment of ecological communities in newly available habitat. There is often a long lag in the initial colonization of plants in alpine ecosystems because of limited soil nutrients. However, there may be strong animal-plant facilitation mechanisms at play, where communal dung deposition by native herbivores creates nutrient hotspots and fuels more rapid plant establishment. The project will define how nutrient hotspots ameliorate extreme abiotic conditions and accelerate primary succession in high-mountain landscapes, facilitating the development of pioneer communities and upslope expansion of plants and other organisms into glacier forefields. The research will provide strong research and professional training and mentoring for students at multiple career stages at a primarily undergraduate institution. Two Master’s students, 6–12 undergraduates, a post-baccalaureate research technician, and at least one local Peruvian student will receive training through this project, equipping the next generation of climate change biologists with skills to address growing challenges in this field. Revealing unexplored processes underlying how ecological communities will keep pace with rapid climate change will enable future experimental and predictive modeling work, which can inform urgently-needed stewardship of lands newly exposed by retreating ice.Animal-plant facilitation might be a more ubiquitous mechanism of primary succession than currently recognized in newly-exposed deglaciating lands worldwide. The lack of understanding of the potentially significant role of animal-mediated facilitation impairs our ability to predict how glacier forefield biodiversity, assemblages, and ecosystem function will develop under rapid climate change. The goal of this proposal is to understand the consequences of nutrient hotspots created by animals in terms of ecosystem succession. This research will help to create a new conceptual model of the earliest stages of ecosystem development in glacier forefields supported by extensive field data, and guide future predictive and experimental work. A multi-scale, field-based approach will reveal how hotspots alter glacier forefield community development. The specific aims are to: 1) define patch-level impacts of hotspots on soil nutrients, microbial biomass, and plant characteristics in glacier forefields; 2) determine landscape-level hotspot effects on plant and microbial community assembly across a 130-year chronosequence of glacier retreat; and 3) define patterns of animal activity and nutrient deposition at hotspots and non-hotspot locations.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.