Bouncing Back: plant-associated soil microbes respond rapidly to prairie establishment

It is well established that soil microbial communities change in response to altered land use and land cover, but less is known about the timing of these changes. Understanding temporal patterns in recovering microbial communities is an important part of improving how we assess and manage reconstructed ecosystems. We assessed patterns of community-level microbial diversity and abundance in corn and prairie plots 2 to 4 years after establishment in agricultural fields, using phospholipid fatty acid biomarkers. Principal components analysis of the lipid biomarkers revealed differing composition between corn and prairie soil microbial communities. Despite no changes to the biomass of Gram-positive bacteria and actinomycetes, total biomass, arbuscular mycorrhizal fungi biomass, and Gram-negative bacteria biomass were significantly higher in restored prairie plots, approaching levels found in long-established prairies. These results indicate that plant-associated soil microbes in agricultural soils can shift in less than 2 years after establishment of perennial grasslands.

已有研究证实，土壤微生物群落会随土地利用方式与土地覆被的改变而发生变化，但学界对这类变化的发生时序仍知之甚少。解析恢复中微生物群落的时间动态模式，是优化重建生态系统评估与管理方法的重要一环。本研究采用磷脂脂肪酸生物标志物（phospholipid fatty acid biomarkers），对农田中定植2至4年后的玉米田与恢复草原样地内的群落级微生物多样性与丰度模式展开了分析。对脂质生物标志物的主成分分析（Principal components analysis）结果显示，玉米田与恢复草原的土壤微生物群落组成存在显著差异。尽管革兰氏阳性菌（Gram-positive bacteria）与放线菌（actinomycetes）的生物量未出现显著变化，但恢复草原样地的总微生物生物量、丛枝菌根真菌（arbuscular mycorrhizal fungi）生物量以及革兰氏阴性菌（Gram-negative bacteria）生物量均显著更高，且趋近于长期成熟草原的相应水平。上述研究结果表明，农田土壤中依附于植物的土壤微生物群落，可在多年生草原定植后不到2年的时间内发生结构转变。