MSB-FRA: The influence of biological diversity on land-atmosphere exchange in forests: confronting theory with data

生物多样性对人类福祉和维持健康环境至关重要。如果没有生活在各种环境中的一系列物种，生命所依赖的水、养分和生物量的循环将受到严重损害。尽管如此，准确理解多样性如何影响特定的环境过程是具有挑战性的。虽然有一些理论描述了植物物种多样性对环境过程的影响，但它们还没有完全阐明。我们主要在草地和其他以小型植物为主的系统中进行了测试，在这些系统中，可以通过种植和除草来控制多样性。森林是一个挑战，因为树木的大小和寿命使进行可操纵的多样性实验变得困难，因为自然多样性梯度也因气候而异，使结果难以解释。鉴于森林对许多环境过程的重要性以及森林多样性正在下降的程度，克服这一障碍至关重要。该奖项将研究在小型生态系统中得到广泛验证的生物多样性和环境过程理论是否也适用于北美森林的宏观过程。通过整合森林与大气之间的碳、水和能量交换数据、森林多样性遥感和野外测量，将使美国森林多样性的发展以及碳和水与陆地-大气交换的关系成为可能。它将量化森林在地球系统中的重要作用和森林多样性下降的程度。该奖项将涉及项目所有阶段的本科生和研究生，并通过在多个层面上为普通公民、教师和学生带来新的遥感方法的额外活动。这将通过讲习班和发展可由教师采用并在课堂上使用的重点活动来实现。参与该项目的本科生将参加新罕布什尔大学？美国大学生研究会议（URC）是全国最大的大学生研究活动之一。了解多样性如何影响特定的生态系统和地球系统在单个生物群系中的功能是非常困难的，被认为是生态学的重大挑战之一。考虑到世界上有许多物种已经灭绝或受到栖息地丧失、害虫和病原体、采伐、来自非本地物种的竞争、污染和气候变化的威胁，应对这一挑战非常重要。该奖项将考察美国森林树木多样性对二氧化碳吸收、水分从土壤向大气转移的影响，以及这些过程在应对气候变化时的稳定性。该奖将检验下列具体假设：(A)北美森林的生物多样性对初级生产有积极影响，对蒸散有消极影响，导致水利用效率的提高。(B)与多样性低的森林相比，多样性高的森林不太容易受到极端事件的影响，碳和水通量随气候波动的时间变异性也较小。这些假设将通过汇集几个独特的数据来源来解决，这些数据来源以前没有被用来解决这个问题。首先，将要使用的研究地点配备了仪器塔，可以详细测量森林冠层上方的二氧化碳和水蒸气，以及一系列气候和生态变量。其次，将使用先进的遥感仪器来测量树冠的多样性，这是仅靠实地调查无法做到的。这些数据将来自无人机系统以及国家生态观测站的仪器。通过这些数据集的独特性质和先进的数据分析方法，结果将用于在广泛的地理范围内量化重要过程中多样性的具体特征。

Biological diversity is important to human well-being and to the maintenance of a healthy environment. Without an array of species inhabiting a range of environments, the cycles of water, nutrients and biomass on which life depends would be severely compromised. Despite this, understanding exactly how diversity influences specific environmental processes is challenging. Although there are theories describing the influence of plant species diversity on environmental processes, they?ve primarily been tested in grasslands and other systems dominated by small plants, where diversity can be manipulated through planting and weeding. Forests present a challenge because the size and lifespans of trees make it difficult to conduct manipulative diversity experiments and because natural diversity gradients also vary in climate, making results difficult to interpret. Overcoming this hurdle is critical given the importance of forests to many environmental processes and the degree to which forest diversity is declining. This award will examine whether theories of biological diversity and environmental processes that have been largely tested in small-statured ecosystems also apply to macro-scale processes over North American forests. By integrating data on carbon, water, and energy exchanges between forests and the atmosphere, remote sensing of forest diversity, and field measurements, will enable the development of forest diversity for the US and the relationship to land-atmosphere exchange of carbon and water. It will quantify the important role of forests in the Earth system and the degree to which forest diversity is declining. The award will involve undergraduate and graduate students in all phases of the project, and through additional activities that bring new methods of remote sensing to private citizens, teachers and students at multiple levels. This will be accomplished through workshops and through development of focused activities that can be adopted by teachers and used in the classroom. The undergraduates working on the project will participate in the University of New Hampshire?s Undergraduate Research Conference (URC), one of the largest undergraduate research events in the country. Understanding how diversity influences specific ecosystem and earth system functions within individual biomes is extremely difficult and is considered one of the grand challenges in ecology. Meeting this challenge is important given the number of species worldwide that have already gone extinct or have been threatened by habitat loss, pests and pathogens, harvesting, competition from non-native species, pollution, and climate change. This award will examine the effects of tree diversity in forests across the U.S. on the uptake of CO2, the transfer of water from soils to the atmosphere, and on the stability of these processes in response to climate variability. The award will test the following specific hypotheses:(A) Biological diversity in North American forests has a positive effect on primary production and a negative effect on evapotranspiration, leading to increased water use efficiency. (B) Forests with high levels of diversity are less susceptible to extreme events and exhibit less temporal variability in carbon and water fluxes in response to climate fluctuations than low-diversity forests. These hypotheses will be addressed by bringing together several unique sources of data that have not previously been used to address this question. First, the research sites to be used are equipped with instrumented towers that make detailed measurements of CO2 and water vapor above the forest canopy, as well as a range of climate and ecological variables. Second, advanced remote sensing instruments will be used to measure tree canopy diversity in ways that field surveys alone cannot. These data will come from unmanned aerial systems as well as instruments that are part of the National Ecological Observatory. Through the unique nature of these data sets and advanced methods of data analysis, results will be used to quantify the specific signature of diversity on important processes at a broad geographic scale.