Soil Biodiversity and Response to Climate Change: A Regional Comparison of Cape Hallett and Taylor Valley, Antarctica

土壤生态系统沿着南极维多利亚陆地海岸，从南部（78-76 S）的麦克默多（MCM）干谷到北部的哈雷特角（72 S），跨越了生物多样性、气候和土壤资源遗产（如有机质、养分、盐）的大尺度梯度。整个地区遇到的条件的范围可以用来测试特定的假设来自土壤生物多样性和栖息地模型开发的MCM干河谷长期生态研究计划（LTER）的结果。这一“生境适宜性”模型描述了土壤生物群的分布、丰度和多样性，其基础是传统和当代土壤和气候特性的结合。目前的项目将把在麦克默多干谷开发的生境适宜性模型扩展到哈雷特角的大维多利亚陆地地区。深入了解生物多样性与（微生物、无脊椎动物）和生态系统功能（土壤呼吸和养分循环）在维多利亚陆地地区可能特别重要，因为它包括一系列生态系统，包括有机物接近最低检测限和没有无脊椎动物的生态系统，到那些有机质沉积量很高和食物网复杂的物种（2-3个营养类群，由4个无脊椎动物类群组成）。一项为期两年的实地和实验室研究将探讨土壤食物网和生态系统进程如何受到气候变化、遗产和当代土壤进程的影响。这项研究将开始区域化的结果和见解，从麦克默多LTER研究，并确定是否在生物多样性的变化沿着泰勒谷的土壤生境和景观梯度的范围内，发生类似的梯度在一个更丰富，更复杂的栖息地（如哈雷特角）。这项研究涉及国际合作，并将进一步推动多国在南极的研究。目前显然迫切需要了解土壤生物多样性和生态系统功能在所有生态系统中的关系，并确定影响南极地貌土壤生物多样性分布的因素。这里提出的研究动机强调了土壤及其生物区系在提供对社会重要的生态系统服务方面的价值（例如，土壤肥力）。这是一项艰巨的挑战，因为其他地方土壤食物网的分类复杂性限制了我们推断生物多样性的功能意义以及土壤群落对不同土壤条件和气候的反应的能力。这项研究将为在所有土壤中测试生物多样性理论做出重大贡献，因为扩展和测试基于地球上最简单土壤群落的土壤生物多样性概念模型将有助于了解复杂的温带生态系统。泰勒谷和哈利特角的微生物和无脊椎动物多样性与土壤有机质、水分和温度变化的相关研究将提供迄今为止最完整的土壤多样性定量评估之一。

Soil ecosystems along the Antarctic Victoria Land coast from the McMurdo (MCM) Dry Valleys in the south (78-76 S) to Cape Hallett (72S) in the north occur across broad scale gradients of biodiversity, climate, and soil resource legacies (e.g. organic matter, nutrients, salts) from previous climates. The range of conditions encountered across this region can be used to test specific hypotheses derived from a soil biodiversity and habitat model developed from the findings of the MCM Dry Valleys Long-term Ecological Research Program (LTER). This "habitat suitability" model describes the distribution, abundance and diversity of soil biota based upon a combination of legacy and contemporary soil and climate properties. This current project will extend the habitat suitability model developed in the McMurdo Dry Valleys to the greater Victoria Land region at Cape Hallett. Insights into the relationship between biodiversity (microbes, invertebrates) and ecosystem functioning (soil respiration and nutrient cycling) may be especially important in the Victoria Land region since it encompasses a range of ecosystems, including those with organic matter near minimum detection limits and no invertebrates, to those with very high organic matter deposits and complex food webs (2-3 trophic groups comprised of 4 invertebrate taxa). A two-year study of field and laboratory research will address how soil food webs and ecosystem processes are affected by changes in climate, legacy and contemporary soil processes. This research will begin the regionalization of results and insights from the McMurdo LTER study and determine whether the changes in biodiversity along the range of soil habitats and landscape gradients in Taylor Valley, occur similarly across gradients in a richer, more complex habitats (e.g. Cape Hallett). This study involves international collaborations and will further multi-national research in the Antarctic. There is a clear and immediate need to understand how soil biodiversity and ecosystem functioning are related in all ecosystems and to determine the factors influencing the distribution of soil biodiversity across the Antarctic landscape. The motivation for the research proposed here underscores the value of soils and their biota in providing ecosystem services important to society (e.g., soil fertility). This is a difficult challenge as the taxonomic complexity of soil food webs elsewhere limits our ability to draw inferences about the functional significance of biodiversity and the responses of soil communities to varying soil conditions and climate. This research will make a significant contribution to testing biodiversity theory in all soils, because extension of and testing this conceptual model of soil biodiversity based on the simplest soil communities on earth will contribute to knowledge of complex temperate ecosystems. These linked studies of microbial and invertebrate diversity in relation to soil organic matter, moisture, and temperature change at Taylor Valley and Cape Hallett will provide one of the most complete quantitative assessments of soil diversity to date.