Repeated large-scale mechanical treatment of invasive Typha under increasing water levels promotes floating mat formation and wetland methane emissions
Repeated large-scale mechanical treatment of invasive Typha under increasing water levels promotes floating mat formation and wetland methane emissions
复制标题
在水位上升的情况下对入侵香蒲进行重复大规模机械处理会促进漂浮垫的形成和湿地甲烷排放
DOI：
10.1016/j.scitotenv.2021.147920
复制
发表时间：
2021
影响因子：
9.8
通讯作者：
Lawrence, Beth
中科院分区：
文献类型：
--
作者：
Johnson, Olivia;Panda, Abha;Lishawa, Shane;Lawrence, Beth
入侵物种管理通常旨在促进多样性和野生动物栖息地，但对管理技术如何影响湿地碳(C)动态知之甚少。由于湿地的碳吸收在很大程度上受到水位和高产植物的影响，因此水文极端和入侵物种的相互作用是理解和管理这些生态系统的基础。在劳伦斯五大湖水位迅速上升的一段时间里，我们测试了机械处理入侵植物香蒲×蓝宝石植物如何通过植物介导的湿地C指标。从2015年到2017年，我们实施了大规模的处理小区(0.36公顷)，包括收获(即露出水面，每季度移走两次生物量)、粉碎(即用履带式车辆在季节中期碾压一次生物量)和以香蒲为主的控制。处理的Typharew每年的生物量大约是未处理对照的一半，对照林分的Typha产量从500g/干质量增加到1500g/干质量m−2yr−1，水位在5年内上升(~10到75厘米)。采伐林分的甲烷(CH4)总通量是对照林的两倍，这种增加很可能是通过切割茎的运输实现的，因为粉碎不会改变总甲烷通量。2018年，在实施最终处理一年后，粉碎林分的地表水扩散CH4通量比对照林(使用水中溶解气体测量)更大，这可能是由于压平的生物质的厌氧分解所致。2019年处理的遗留影响很明显；漂浮类型只出现在收获和压碎的林分中，在更深的水域中出现的频率更高，与地表水扩散的CH4通量呈正相关。我们的研究表明，两种机械处理对典型结构和随之而来的湿地CH4排放具有不同的影响，这表明基于C的响应和在可变水条件下的多年监测对于准确评估管理如何影响生态功能是必要的。
Invasive species management typically aims to promote diversity and wildlife habitat, but little is known about how management techniques affect wetland carbon (C) dynamics. Since wetland C uptake is largely influenced by water levels and highly productive plants, the interplay of hydrologic extremes and invasive species is fundamental to understanding and managing these ecosystems. During a period of rapid water level rise in the Laurentian Great Lakes, we tested how mechanical treatment of invasive plantTypha × glaucashifts plant-mediated wetland C metrics. From 2015 to 2017, we implemented large-scale treatment plots (0.36-ha) of harvest (i.e., cut above water surface, removed biomass twice a season), crush (i.e., ran over biomass once mid-season with a tracked vehicle), andTypha-dominated controls. TreatedTypharegrew with approximately half as much biomass as unmanipulated controls each year, andTyphaproduction in control stands increased from 500 to 1500 g-dry mass m−2yr−1with rising water levels (~10 to 75 cm) across five years. Harvested stands had total in-situ methane (CH4) flux rates twice as high as in controls, and this increase was likely via transport through cut stems because crushing did not change total CH4flux. In 2018, one year after final treatment implementation, crushed stands had greater surface water diffusive CH4flux rates than controls (measured using dissolved gas in water), likely due to anaerobic decomposition of flattened biomass. Legacy effects of treatments were evident in 2019; floatingTyphamats were present only in harvested and crushed stands, with higher frequency in deeper water and a positive correlation with surface water diffusive CH4flux. Our study demonstrates that two mechanical treatments have differential effects onTyphastructure and consequent wetland CH4emissions, suggesting that C-based responses and multi-year monitoring in variable water conditions are necessary to accurately assess how management impacts ecological function.