Collaborative Research: RUI: how landscape fragmentation interferes with plant-pathogen interactions that maintain local plant diversity

合作研究：RUI：景观破碎化如何干扰维持当地植物多样性的植物-病原体相互作用

• 批准号: 1655893
• 负责人: Michelle Hersh
• 金额: $ 22.89万
• 依托单位: Sarah Lawrence College
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2017
• 资助国家: 美国
• 起止时间: 2017-04-01 至 2023-02-28
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1655893&HistoricalAwards=false
• 关键词: Collaborative; Research; RUI; how; landscape

Many natural areas are being broken up into smaller fragments due to land-use changes such as suburban sprawl. Compared with larger fragments, small fragments are often extreme environments because they can experience stresses like higher temperatures, more light, and lower soil moisture. This research looks at how plants living in different sized fragments are affected by their pathogens. Interactions between plants and their pathogens are important because although pathogens are best known for the damage they cause they can also help preserve biological diversity. This is because each plant species has its own unique group of pathogens that specialize on it, and slows growth or kills just the plants they infect. This can keep any single plant species from dominating in an area. However, not all pathogens can thrive in the extreme environments found in small patches. It may be that in small patches, different types of pathogens that slow growth or kill multiple plant species indiscriminately are more common. If this is the case, they could decrease plant diversity compared with large patches. By uncovering how plants and pathogens interact in different patch sizes this work will be relevant for understanding the biodiversity consequences of breaking up natural areas, and may affect management of natural landscapes. Both lead researchers for this project are early-career faculty at undergraduate colleges, and will incorporate undergraduate students into all aspects of this work, including community outreach.Three parallel studies will be conducted to assess how plant-pathogen interactions are altered by landscape fragmentation, focusing on fungal pathogens in particular. First, researchers will bury seeds of twelve plant species in patches of different sizes at the Kansas Fragmentation Site, allowing the seeds to be colonized by potential pathogens and testing to see if the seeds remain viable after a year of burial. This will determine if seed mortality due to fungal pathogens is most influenced by ecological factors that vary with patch size, such as plant host density, plant species richness, and microclimatic conditions (such as temperature and soil moisture). Second, the fungal community from these buried seeds will be characterized using both culture-based methods and culture-independent molecular tools. This will determine whether fungal community structure varies predictably with patch size, host identity, and host density. Finally, a combination of greenhouse and field experiments will test the hypothesis that negative feedbacks (when plants "culture" host-specific pathogens in the soil surrounding their roots) are strongest in the interiors of large patches, rather than on the edges of large patches or in small patches. It is predicted that thermally stressful environments on edges and small patches will favor generalist fungi, reducing the influence of diversity-maintaining feedbacks on smaller fragments. Collectively, these studies link individual plant-fungal interactions to observed landscape patterns in plant diversity.

由于土地使用的变化，如郊区的扩张，许多自然区域正在被分割成更小的碎片。与较大的碎片相比，小碎片通常是极端环境，因为它们可能会经历更高的温度，更多的光线和更低的土壤湿度等压力。这项研究着眼于生活在不同大小片段中的植物如何受到病原体的影响。植物和病原体之间的相互作用很重要，因为尽管病原体以其造成的损害而闻名，但它们也有助于保护生物多样性。这是因为每种植物都有自己独特的病原体群，专门针对它，并减缓生长或杀死它们感染的植物。这可以防止任何单一的植物物种在一个地区占主导地位。然而，并不是所有的病原体都能在小块土地上的极端环境中茁壮成长。可能是在小斑块中，不同类型的病原体减缓生长或不分青红皂白地杀死多种植物物种更为常见。如果是这种情况，与大斑块相比，它们可能会减少植物多样性。通过揭示植物和病原体如何在不同斑块大小中相互作用，这项工作将有助于了解破坏自然区域的生物多样性后果，并可能影响自然景观的管理。该项目的两位主要研究人员都是本科院校的早期教师，他们将把本科生纳入这项工作的各个方面，包括社区外展。将进行三项平行研究，以评估景观破碎化如何改变植物-病原体相互作用，特别是真菌病原体。首先，研究人员将把12种植物的种子埋在堪萨斯碎片遗址不同大小的补丁里，让种子被潜在的病原体定殖，并测试种子在埋了一年后是否还能存活。这将确定真菌病原体引起的种子死亡率是否受随斑块大小而变化的生态因素的影响最大，如植物宿主密度，植物物种丰富度和微气候条件（如温度和土壤湿度）。其次，将使用基于培养的方法和不依赖于培养的分子工具来表征来自这些埋藏的种子的真菌群落。这将决定真菌群落结构是否随斑块大小、宿主身份和宿主密度而变化。最后，温室和田间实验的组合将测试的假设，负反馈（当植物“文化”的主机特定的病原体在土壤中周围的根）是最强的大补丁的内部，而不是在大补丁的边缘或小补丁。据预测，热应激环境的边缘和小补丁将有利于多面手真菌，减少多样性维持反馈的影响较小的片段。总的来说，这些研究将个体植物-真菌相互作用与观察到的植物多样性景观格局联系起来。