Department of Ecology and Evolutionary Biology, University of Colorado, Boulder, CO 80309-0450, USA.
ISME J. 2013 Jun;7(6):1102-11. doi: 10.1038/ismej.2013.11. Epub 2013 Feb 14.
Although recent work has shown that both deterministic and stochastic processes are important in structuring microbial communities, the factors that affect the relative contributions of niche and neutral processes are poorly understood. The macrobiological literature indicates that ecological disturbances can influence assembly processes. Thus, we sampled bacterial communities at 4 and 16 weeks following a wildfire and used null deviation analysis to examine the role that time since disturbance has in community assembly. Fire dramatically altered bacterial community structure and diversity as well as soil chemistry for both time-points. Community structure shifted between 4 and 16 weeks for both burned and unburned communities. Community assembly in burned sites 4 weeks after fire was significantly more stochastic than in unburned sites. After 16 weeks, however, burned communities were significantly less stochastic than unburned communities. Thus, we propose a three-phase model featuring shifts in the relative importance of niche and neutral processes as a function of time since disturbance. Because neutral processes are characterized by a decoupling between environmental parameters and community structure, we hypothesize that a better understanding of community assembly may be important in determining where and when detailed studies of community composition are valuable for predicting ecosystem function.
尽管最近的研究表明，确定性和随机性过程在微生物群落结构中都很重要，但影响生态位和中性过程相对贡献的因素还了解甚少。宏生物学文献表明，生态干扰会影响组装过程。因此，我们在野火后 4 周和 16 周采样了细菌群落，并使用空偏离分析来研究干扰后时间对群落组装的作用。火灾极大地改变了细菌群落结构和多样性以及两个时间点的土壤化学性质。在燃烧和未燃烧的群落中，群落结构在 4 周到 16 周之间发生了变化。火灾后 4 周的燃烧点群落组装比未燃烧点更具随机性。然而，16 周后，燃烧点的群落比未燃烧点的群落更具非随机性。因此，我们提出了一个三阶段模型，该模型的特点是随着干扰后时间的推移，生态位和中性过程的相对重要性发生变化。由于中性过程的特点是环境参数和群落结构之间的解耦，我们假设更好地理解群落组装对于确定详细研究群落组成的价值以及何时何地对预测生态系统功能可能很重要。
