Land-use and land-cover effects on soil microbial community abundance and composition in headwater riparian wetlands
Land-use and land-cover effects on soil microbial community abundance and composition in headwater riparian wetlands
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DOI：
10.1016/j.soilbio.2016.02.021
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发表时间：
2016-06
影响因子：
9.7
通讯作者：
Jessica B. Moon;D. Wardrop;Mary Ann V. Bruns;R. Michael Miller;K. Naithani
中科院分区：
文献类型：
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作者：
Jessica B. Moon;D. Wardrop;Mary Ann V. Bruns;R. Michael Miller;K. Naithani
河源河岸湿地面积相对较小，但功能显著，是景观中微生物活动的热点。尽管他们的角色作为生物地球化学的驱动程序，很少有人知道如何在源头河岸湿地微生物群落受到周围的土地利用和土地覆盖（LULC）。本研究的主要目的是确定湿地土壤微生物丰度和群落组成是否以及如何作为景观指标的函数通过现场土壤特性介导而变化。42个土壤样品，从宾夕法尼亚州中部的山脊和山谷地区的8个源头河岸湿地收集，用于磷脂脂肪酸（PLFA）分析土壤微生物群落。这些样品用于创建微生物栖息地模型，描述土壤性质和微生物测量之间的地块水平关系（即，微生物生物标志物丰度、比率和组成）。土壤有机质（SOM）含量是微生物生物标志物丰度和真菌/细菌比例的强预测因子，而土壤pH值是微生物组成的强预测因子（即，单个脂肪酸的相对丰度）和潜在的微生物应激指数（即，Cy 19：0 α/18：1ω 7 c和Cy 17：0/16：1ω 7 c比率）。土壤质地，土壤水分，凋落物总氮较小，但显着的影响，在这些经验的微生物栖息地模型。微生物栖息地模型，随后被用来估计微生物的措施，一个更大的区域河源河岸湿地数据集（n = 87），土壤属性的信息进行了编译。站点平均微生物测量与湿地海拔高度相关，并与景观评估区的景观组成指标相关（即，125 664平方米）。湿地海拔解释了高的土壤微生物丰度的措施，介导的SOM含量，在水源河岸湿地的森林景观的变化。然而，湿地海拔混淆景观组成，在森林-农业混合景观的源头河岸湿地。水文，地貌和植被的变化可以用来解释整个湿地海拔和周围景观组成的变化SOM的变化。微生物组成的措施，包括cy 19：0/18：1ω 7 c的比例和主成分（PC）轴来自23个单独的PLFA生物标志物的景观开发强度（LDI）指数，和中耕作物，牧草和草地面积的百分比呈负相关，并与森林面积的百分比呈正相关。cy 17：0/16：1ω 7 c比值与土地退化指数、草地和牧草面积百分比呈正相关，与森林和湿地面积百分比呈负相关。沿着PC轴的差异与真菌群落的相对丰度相关性最明显;森林景观中的水源河岸湿地具有显著较高的腐殖真菌生物标志物的相对丰度，而混合景观中的水源河岸湿地具有显著较高的丛枝菌根真菌生物标志物的相对丰度。这项研究突出了简单的景观指标，描述湿地的位置和景观组成，用于预测在区域尺度上的土壤变异性和相关的微生物群落组成和生物量之间的差异河源河岸湿地的效用。
Headwater riparian wetlands are relatively small in size but functionally significant as expected hot spots of microbial activity in the landscape. Despite their roles as biogeochemical drivers, little is known about how microbial communities in headwater riparian wetlands are affected by surrounding land-uses and land-covers (LULCs). The primary objective of this study was to determine if and how wetland soil microbial abundance and community composition varied as a function of landscape metrics as mediated through on-site edaphic properties. Forty-two soil samples, collected from eight headwater riparian wetlands in the Ridge and Valley Region of central Pennsylvania, were used for phospholipid fatty acid (PLFA) profiling of soil microbial communities. These samples were used to create microbial habitat models describing plot-level relationships between edaphic properties and microbial measures (i.e., microbial biomarker abundances, ratios and composition). Soil organic matter (SOM) content was a strong predictor of microbial biomarker abundances and fungi/bacteria ratios, while soil pH was a strong predictor of microbial composition (i.e., relative abundance of individual fatty acids) and potential microbial stress indices (i.e., cy19:0a/18:1ω7c and cy17:0/16:1ω7c ratios). Soil texture, soil moisture, and litter total nitrogen had smaller, but significant effects in these empirical microbial habitat models. Microbial habitat models were subsequently used to estimate microbial measures for a larger regional headwater riparian wetland dataset (n = 87), where edaphic property information was compiled. Site-average microbial measures were correlated with wetland elevation, and with landscape composition metrics in a landscape assessment area (i.e., 125,664 m2). Wetland elevation explained high among-site variability in microbial abundance measures, as mediated through SOM content, in headwater riparian wetlands in forested landscapes. However, wetland elevation was confounded by landscape composition, for headwater riparian wetland in mixed forested-agricultural landscapes. Hydrology, geomorphology, and changes in vegetation could be used to explain SOM variation across wetland elevation and variability in surrounding landscape composition. Microbial composition measures, including the cy19:0/18:1ω7c ratio and principal component (PC) axes derived from 23 individual PLFA biomarkers were negatively related to the Landscape Development Intensity (LDI) index, and the percent area of row crops, pastures and grasslands, and positively related to the percent area of forest. The cy17:0/16:1ω7c ratio was positively related to the LDI index, and the percent area of pasture and grasslands, and negatively related to the percent area of forest and wetland elevation. Differences along PC axes were most clearly related to the relative abundances of fungal communities; headwater riparian wetland in forested landscapes had significantly higher relative abundances of saprophytic fungi biomarkers, while headwater riparian wetland in mixed landscapes had significantly higher relative abundances of the arbuscular mycorrhizal fungi biomarker. This study highlights the utility of simple landscape metrics, which describe wetland position and landscape composition, for predicting differences in edaphic variability and associated microbial community composition and biomass among headwater riparian wetlands at a regional scale.