PDF(Pubmed)
Abstract：
Community assembly is influenced by environmental niche processes as well as stochastic processes that can be spatially dependent (e.g. dispersal limitation) or independent (e.g. priority effects). Here, we sampled senesced tree leaves as unit habitats to investigate fungal community assembly at two spatial scales: (i) small neighborhoods of overlapping leaves from differing tree species and (ii) forest stands of differing ecosystem types. Among forest stands, ecosystem type explained the most variation in community composition. Among adjacent leaves within stands, variability in fungal composition was surprisingly high. Leaf type was more important in stands with high soil fertility and dominated by differing tree mycorrhizal types (sugar maple vs. basswood or red oak), whereas distance decay was more important in oak-dominated forest stands with low soil fertility. Abundance of functional groups was explained by environmental factors, but predictors of taxonomic composition within differing functional groups were highly variable. These results suggest that fungal community assembly processes are clearest for functional group abundances and large spatial scales. Understanding fungal community assembly at smaller spatial scales will benefit from further study focusing on differences in drivers for different ecosystems and functional groups, as well as the importance of spatially independent factors such as priority effects.
摘要：
社区聚集受到环境生态位过程以及空间依赖（例如分散限制）或独立（例如优先效应）的随机过程的影响。这里,我们采样了衰老的树叶作为单位栖息地，以调查两个空间尺度的真菌群落组装：i）来自不同树种的重叠树叶的小邻域，ii）不同生态系统类型的林分。在林分中，生态系统类型解释了群落组成的最大变化。在林分中相邻的叶子中，真菌组成的变异性惊人地高。在土壤肥力高的林分中，叶片类型更为重要，并且以不同的树木菌根类型为主（糖枫与basswood或红橡木)，而距离衰减在土壤肥力低的橡树为主的林分中更为重要。官能团的丰富是由环境因素解释的，但是不同功能组中分类组成的预测因子差异很大。这些结果表明，对于官能团丰度和大空间尺度，真菌群落组装过程最清晰。在较小的空间尺度上了解真菌群落组装将受益于进一步研究，重点关注不同生态系统和功能群的驱动因素差异。以及优先效应等空间独立因素的重要性。
