Heavy precipitation events and subsequent high flows are occurring with greater frequency and intensity, which could have substantial implications for biomonitoring programs that typically evaluate changes in biological condition due to stressors at local and watershed scales. In this study we evaluated response and recovery of macroinvertebrate communities at nine reference quality streams located in multiple watersheds throughout Vermont to flooding from Tropical Storm (TS) Irene in 2011. At each site, the Vermont Department of Environmental Conservation (VT DEC) had collected macroinvertebrate data on an annual basis from 2009–2013. We compared the data collected in the days and weeks following TS Irene (2011) to samples collected for 2 years prior to the event (2009–2010) and 2 years after (2012–2013). While most metrics used in Vermont's biocriteria did not demonstrate a response to TS Irene, density showed a significant reduction in 2011 (across sites, percent change ranged from −24 to −91%; mean −66%). The percent change in density at each site was significantly correlated with the amount of localized rainfall during the storm (r_s = −0.79, p = .02) and was most evident at small to medium‐sized, high gradient streams. Reduced density caused several of these sites to fail to meet minimum criteria for biological integrity, though densities rebounded the following year. While the quick recovery indicated resiliency at these reference streams, the timing and magnitude of flood events may decrease the ability of biomonitoring programs to accurately evaluate the effect of watershed stressors.

中文翻译：

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极端高流量事件对佛蒙特州溪流中大型无脊椎动物群落的影响

强降水事件和随后的高流量正在以更高的频率和强度发生，这可能对生物监测计划产生重大影响，这些计划通常评估由于局部和流域尺度的压力源引起的生物状况变化。在这项研究中，我们评估了位于整个佛蒙特州多个流域的九个参考质量流中的大型无脊椎动物群落对 2011 年热带风暴 (TS) 艾琳洪水的响应和恢复。在每个地点，佛蒙特州环境保护部 (VT DEC) 都收集了2009-2013 年的大型无脊椎动物数据。我们将在 TS Irene（2011 年）之后的几天和几周内收集的数据与事件发生前 2 年（2009-2010 年）和事件后 2 年（2012-2013 年）收集的样本进行了比较。虽然佛蒙特州使用的大多数指标 s biocriteria 没有表现出对 TS Irene 的反应，密度在 2011 年显着降低（跨站点，百分比变化范围为 -24% 至 -91%；平均 -66%）。每个地点的密度变化百分比与暴风雨期间的局部降雨量显着相关（r _s = −0.79, p = .02) 并且在中小型高梯度流中最为明显。密度降低导致其中一些地点未能达到生物完整性的最低标准，尽管密度在第二年有所反弹。虽然快速恢复表明这些参考流具有恢复能力，但洪水事件的时间和规模可能会降低生物监测计划准确评估流域压力因素影响的能力。