Collaborative Research: MSA: The influence of temperature and resource supply on community size spectra in streams

合作研究：MSA：温度和资源供应对溪流中群落大小谱的影响

• 批准号: 2106068
• 负责人: James Junker
• 金额: $ 3.96万
• 依托单位: Louisiana Universities Marine Corsortium
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-07-01 至 2024-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2106068&HistoricalAwards=false
• 关键词: Collaborative; Research; MSA; influence; temperature

Humans rely on properly functioning freshwater ecosystems (e.g., streams, lakes, wetlands) for food, recreation, and drinking water. A major challenge in ecology is to understand how freshwater ecosystems will change in response to environmental disruptions. However, past efforts at measuring this change across large spatial scales are complicated by at least two challenges: 1) different places have different species, which makes it hard to compare across species when it comes to ecosystem function, and 2) collecting ecological information is extremely labor intensive, which makes it difficult to study ecological communities over space and time. This project solves those problems using cutting-edge ecological approaches. First, to overcome the limitations of species turnover, this project will measure ecosystem structure and function using animal body size distributions known as size-spectra (e.g., the relative abundance of large to small organisms), which are thought to be conserved across ecosystems regardless of species composition. Size spectra are an indicator of how efficiently energy is transferred from one organism to another in a food chain. Second, this project overcomes logistical limitations by using data already collected and curated from the National Ecological Observatory Network (NEON). Using NEON data, the researchers will analyze a large collection of size-spectra in streams over a wide range of environmental conditions to determine how stream temperature and nutrients influence freshwater ecosystems. This project is in the national interest because it provides a critical test of how freshwater ecosystems might respond to future temperature scenarios at macroecological scales. The researchers will also develop software that makes analysis of body size distributions freely available to the public and easier for ecologists to study in the future. Over 50 years of research reveals a common pattern across ecosystems in which abundance (N) declines with increasing body mass (M). The shape of this relationship is described by a power law, N ~ M(exp b), known as the abundance size-spectrum, and the exponent b varies in relation to changes in energy flow through the food web. The value of b is almost always negative, suggesting a remarkably consistent ecological pattern. However, climate change is expected to alter size-spectra, based in part on shifts in body size with temperature. Despite a seemingly simple relationship of body size and temperature, experimental and field studies demonstrate disparate results for size spectra-temperature relationships, finding positive, negative, and neutral shifts in size-spectra across temperature regimes. These studies largely consist of limited samples across relatively small spatial scales, making it difficult to predict how size-spectra varies with temperature at larger scales such as continents. In addition, deviations from theoretical predictions of the b-temperature relationship may be resolved by accounting for variation in resource supply, but the effect of resource supply at large scales is also unknown. This project uses statistical modeling to determine the influence of stream temperature and resource supply on stream size spectra exponents across a broad environmental gradient represented by a national monitoring network.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.

人类依靠正常运转的淡水生态系统（例如溪流、湖泊、湿地）来获取食物、娱乐和饮用水。生态学的一个主要挑战是了解淡水生态系统将如何因环境破坏而发生变化。然而，过去在大空间尺度上测量这种变化的努力因至少两个挑战而变得复杂：1）不同的地方有不同的物种，这使得在生态系统功能方面很难进行跨物种的比较；2）收集生态信息劳动强度极大，这使得研究空间和时间上的生态群落变得困难。该项目使用尖端的生态方法解决这些问题。首先，为了克服物种更替的限制，该项目将使用称为尺寸谱（例如，大型生物体与小型生物体的相对丰度）的动物体型分布来测量生态系统结构和功能，这种分布被认为在生态系统中是保守的，无论的物种组成。尺寸谱是能量在食物链中从一种生物体转移到另一种生物体的效率的指标。其次，该项目通过使用从国家生态观测站网络（NEON）收集和整理的数据克服了后勤限制。研究人员将使用 NEON 数据分析各种环境条件下溪流中的大量尺寸光谱，以确定溪流温度和营养物质如何影响淡水生态系统。该项目符合国家利益，因为它提供了淡水生态系统如何在宏观生态尺度上应对未来温度情景的关键测试。研究人员还将开发软件，使公众可以免费获得体型分布的分析，以便生态学家将来更容易研究。 50 多年的研究揭示了整个生态系统的一个共同模式：丰度 (N) 随着体重 (M) 的增加而下降。这种关系的形状由幂律 N ~ M(exp b) 描述，称为丰度大小谱，指数 b 随食物网能量流的变化而变化。 b 的值几乎总是负数，表明生态模式非常一致。然而，气候变化预计会改变体型谱，部分原因是体型随温度的变化。尽管身体尺寸和温度之间的关系看似简单，但实验和现场研究表明尺寸谱与温度关系的结果不同，发现尺寸谱在不同温度范围内存在正、负和中性变化。这些研究主要由相对较小空间尺度上的有限样本组成，因此很难预测在大陆等较大尺度上尺寸光谱如何随温度变化。此外，b-温度关系理论预测的偏差可以通过考虑资源供应的变化来解决，但大规模资源供应的影响也是未知的。该项目使用统计模型来确定溪流温度和资源供应对以国家监测网络为代表的广泛环境梯度范围内溪流尺寸谱指数的影响。该奖项反映了 NSF 的法定使命，并通过使用基金会的评估进行评估，被认为值得支持。智力价值和更广泛的影响审查标准。