Data from: A before-and-after assessment of patch-burn grazing and riparian fencing along headwater streams

1. Fire and grazing are common in grasslands worldwide to maintain grass cover and cattle production. The effects of fire, cattle grazing, and riparian fencing efficacy on prairie stream ecology are not well characterized at catchment scales.
2. We examined alterations to stream water quality and biology from patch-burn grazing in tallgrass prairie during a five-year, replicated, catchment scale experiment that used a Before–After Control–Impact (BACI) design and was analysed by mixed-effects models. Treatments included two patch-burned control catchments (fire but no grazers) and patch-burn grazing in two riparian fenced and two unfenced catchments. We assessed the effectiveness of riparian fencing for mitigating potential water quality impacts by monitoring water quality and use of riparian by cattle via Global Positioning System.
3. Riparian fences effectively excluded cattle, while in unfenced pastures cattle aggregated along streams 10–20% of the grazing season.
4. After initiation of patch-burn grazing, we detected large increases in some nutrients, Escherichia coli, algal biomass, primary productivity, and community respiration in all catchments with patch-burn grazing. Some water quality variables, such as E. coli concentrations, recovered quickly which indicated resiliency.
5. Riparian fencing moderately reduced the impacts to stream variables, indicating either overland flow or subsurface flow allowed nutrients and bacteria to enter the streams.
6. Synthesis and applications. Patch-burn grazing is a measurable disturbance that can alter the ecological condition of streams. Riparian fencing lessened the degree of impact, yet some water quality variables still exceeded regional reference conditions. Managers will need to assess the costs of riparian fencing compared to the moderate benefits that fencing provides to water quality.

1. 火与放牧是全球草原生态系统中维持草地覆盖、保障肉牛生产的常规管理措施。目前，火、肉牛放牧以及河岸围栏效能（riparian fencing efficacy）对草原溪流生态学的影响特征，在集水区（catchment）尺度下尚未得到充分刻画。
2. 本研究依托一项为期5年、采用重复集水区尺度设计的野外控制实验，针对高草草原（tallgrass prairie）中的斑块火烧放牧（patch-burn grazing）对溪流水质与生物群落的改变效应展开探究。该实验采用前后对照影响（Before–After Control–Impact, BACI）设计，并通过混合效应模型（mixed-effects models）开展数据分析。实验处理组包含2个仅实施火烧但无放牧的斑块火烧对照集水区，以及2个设置河岸围栏、2个未设置河岸围栏的斑块火烧放牧集水区。本研究通过监测水质以及利用全球定位系统（Global Positioning System, GPS）追踪肉牛对河岸带的利用情况，评估河岸围栏缓解潜在水质负面影响的有效性。
3. 河岸围栏可有效阻隔肉牛进入河岸带，而在未设置围栏的放牧区，肉牛在放牧季内有10%~20%的时间会聚集在溪流周边区域。
4. 斑块火烧放牧实施后，所有采用该处理的集水区内，部分营养盐、大肠杆菌（Escherichia coli, E. coli）、藻类生物量、初级生产力以及群落呼吸水平均出现显著升高。部分水质指标（如大肠杆菌浓度）可快速恢复，这表明溪流生态系统具备一定的恢复力。
5. 河岸围栏可适度降低斑块火烧放牧对溪流相关生态指标的负面影响，这表明营养盐与细菌可通过地表径流（overland flow）或地下径流（subsurface flow）进入溪流。
6. 综合与应用。斑块火烧放牧属于可量化的人为干扰类型，可改变溪流的生态状态。河岸围栏虽可减轻放牧带来的负面影响，但部分水质指标仍超出区域参照标准（regional reference conditions）。管理者需权衡河岸围栏的建设成本与该措施对水质带来的适度效益，以制定合理的管理决策。