Microbial Ecology Program, The University of Montana, Missoula, MT, USA Biology Department, Boise State University, Boise, ID, USA Geology Department, The University of Montana, Missoula, MT, USA.
Ecol Lett. 2005 Nov;8(11):1201-10. doi: 10.1111/j.1461-0248.2005.00821.x.
We used a 93-year-old mine waste contamination gradient in alluvial soil to explore the relationship between ecosystem level functioning and community structure in a chronically stressed ecosystem. The sensitivity of broad functional parameters (in situ soil respiration, microbial biomass, above and below ground plant biomass) and microbial diversity [phospholipid fatty acid (PLFA) abundance and richness] were compared. Functional responses were linear with respect to contaminants while thresholds were detected in the community structural response to contamination along the gradient. For example, in situ soil respiration was negatively and linearly correlated to contamination concentration (R = -0.783, P < 0.01), but changes in microbial community structure only became evident where contaminant concentrations were greater than 28 times above background levels. Our results suggest that functional redundancy does not prevent depression of ecosystem function in the long-term.
我们利用一个 93 年历史的矿山废弃物污染梯度的冲积土壤，来探索在一个长期受压力的生态系统中，生态系统功能和群落结构之间的关系。我们比较了广泛的功能参数（原位土壤呼吸、微生物生物量、地上和地下植物生物量）和微生物多样性（磷脂脂肪酸（PLFA）丰度和丰富度）的敏感性。功能响应与污染物呈线性关系，而在群落结构对梯度中污染的响应中则检测到了阈值。例如，原位土壤呼吸与污染物浓度呈负相关（R = -0.783，P < 0.01），但是微生物群落结构的变化只有在污染物浓度超过背景水平 28 倍以上时才变得明显。我们的研究结果表明，功能冗余并不能阻止生态系统功能在长期内的下降。
