Department of BioSciences, Rice University, 6100 Main Street, Houston, Texas, 77096, USA.
Department of Biology, Duke University, 130 Science Drive, Durham, North Carolina, 27708, USA.
Ecology. 2018 Feb;99(2):372-384. doi: 10.1002/ecy.2080. Epub 2017 Dec 20.
Evidence accumulates about the role of arbuscular mycorrhizal (AM) fungi in shaping plant communities, but little is known about the factors determining the biomass and coexistence of several types of AM fungi in a plant community. Here, using a consumer-resource framework that treats the relationship between plants and fungi as simultaneous, reciprocal exploitation, we investigated what patterns of dynamic preferential plant carbon allocation to empirically-defined fungal types (on-going partner choice) would be optimal for plants, and how these patterns depend on successional dynamics. We found that ruderal AM fungi can dominate under low steady-state nutrient availability, and competitor AM fungi can dominate at higher steady-state nutrient availability; these are conditions characteristic of early and late succession, respectively. We also found that dynamic preferential allocation alone can maintain a diversity of mutualists, suggesting that on-going partner choice is a new coexistence mechanism for mutualists. Our model can therefore explain both mutualist coexistence and successional strategy, providing a powerful tool to derive testable predictions.
有关丛枝菌根（AM）真菌在塑造植物群落中的作用的证据不断积累，但对于决定植物群落中几种 AM 真菌生物量和共存的因素知之甚少。在这里，我们使用消费者-资源框架，将植物和真菌之间的关系视为同时、互惠的利用，研究了植物向经验定义的真菌类型（正在进行的伙伴选择）进行动态优先碳分配的模式将如何最有利于植物，以及这些模式如何取决于演替动态。我们发现，在低稳态养分供应下，根茎 AM 真菌可以占主导地位，而在较高的稳态养分供应下，竞争 AM 真菌可以占主导地位；这些分别是早期和晚期演替的特征条件。我们还发现，仅通过动态优先分配就可以维持互惠共生体的多样性，这表明正在进行的伙伴选择是互惠共生体的一种新的共存机制。因此，我们的模型可以解释共生体的共存和演替策略，为得出可检验的预测提供了一个强大的工具。
