Mycorrhizas as mediators of plant population dynamics and community assembly

菌根真菌与植物形成共生关系，提供营养和病原体保护，以换取植物来源的碳。因此，菌根可以通过改变植物生长和改变土壤生物群如何影响同种幼苗的招募来调节植物种群动态（植物-土壤反馈；PSFs）。这些影响可以在植物群落中级联，影响它们的结构和功能。然而，菌根生长响应和psf也高度依赖于环境，尽管它们很重要，但我们缺乏一个预测它们对植物群落影响的框架。植物性状越来越多地被用于了解植物群落的聚集，并且通常与菌根反应和psf相关。因此，它们可以用来提高我们对菌根对植物群落的影响的理解和预测能力。我的研究项目侧重于利用植物性状开发菌根响应和psf的预测模型，并将这些模型整合到更大的基于性状的入侵和群落动态模型中。我的短期目标是1)确定菌根改变植物群落聚集的机制，2)量化菌根对psf时间动态的影响。为了确定菌根对群落组装的影响，我将通过实验操纵植物和真菌沿水梯度的组成。通过建立基于生态位和性状的植物和真菌群落组装模型，我可以量化菌根对植物和真菌群落组装和共变的影响。为了探索PSF的时间动态，我将使用两个可估计人口年龄的系统：草原入侵和森林更新。在这两个系统中，我将测量不同菌根依赖（草地）或菌根类型（森林）的物种在不同年龄级之间的PSF。在草原上，这些数据将与实地调查和竞争实验相结合，以确定PSF如何随着时间的推移改变入侵影响。在森林中，他们将与幼苗的实地调查相结合，以测试PSF是否驱动同种距离依赖的时间变化，并与多分类单元下一代测序相结合，以确定驱动这些变化的土壤生物群。拟议的研究有可能影响应用生态学和基础生态学。通过量化入侵影响如何随时间变化，本研究将有助于制定这些入侵者的管理和恢复计划。此外，量化森林中年龄相关的补充可以帮助优化采伐时间，最大限度地提高林分更替率。更广泛地说，将植物性状与菌根对植物种群和群落的影响机制联系起来，为建立植物群落组装的预测模型奠定了基础，这是群落生态学的主要目标。

Mycorrhizal fungi form symbiotic associations with plants, providing nutrients and pathogen protection in exchange for plant-derived carbon. As such, mycorrhizas can regulate plant population dynamics through changes in plant growth and by modifying how soil biota affect the recruitment of conspecific seedlings (plant-soil feedbacks; PSFs). These effects can cascade across plant communities, influencing their structure and function. However, mycorrhizal growth responses and PSFs are also highly context dependent, and despite their importance, we lack a predictive framework for their effects on plant communities. Plant traits are increasingly being used to understand plant community assembly, and are often correlated with mycorrhizal responses and PSFs. As such, they could be used to improve our understanding of, and ability to predict, mycorrhizal effects on plant communities. My research program focuses on developing predictive models of mycorrhizal responses and PSFs using plant traits, and integrating these models into larger trait-based models of invasion and community dynamics. My short-term objectives are to 1) identify the mechanisms by which mycorrhizas alter plant community assembly, and 2) to quantify the influence of mycorrhizas on the temporal dynamics of PSFs.To determine mycorrhiza effects on community assembly, I will experimentally manipulate the composition of plants and fungi along a water gradient. By developing niche and trait based models of plant and fungal community assembly, I can quantify mycorrhiza effects on community assembly and covariation between plant and fungal communities. To explore the temporal dynamics of PSF, I will use two systems where population age is estimable: invasion in grasslands and forest regeneration. In both systems, I will measure PSF among different age-classes for species differing in mycorrhizal dependency (grasslands) or mycorrhizal type (forests). In grasslands, these data will be combined with field surveys and competition experiments to determine how PSF alters invasion impacts over time. In forests, they will be combined with field surveys of seedlings to test whether PSF drives temporal shifts in conspecific distance dependence, and with multi-taxon next generation sequencing to identify the soil biota driving these changes.The proposed research has the potential to impact both applied and fundamental ecology. By quantifying how invasion impacts change over time, this research will aid the development of management and restoration plans for these invaders. Additionally, quantifying age dependent recruitment in forests can help optimize harvest times to maximize stand replacement. More broadly, mechanistically linking plant traits to mycorrhiza effects on plant populations and communities lays the groundwork for predictive models of plant community assembly a primary goal in community ecology.