Influence of riparian shade on stream thermal regime (New Forest 2010)

River temperature is a key parameter of water quality. Most bio-chemical processes and physical characteristics of a water body are functions of temperature. Aquatic organisms including fish are polikothermic and respond to the entire temperature regime; the absolute value, seasonal and diel ranges, rate of change and the timing and duration of extreme thermal events. Salmonids are cold water species with high metabolic rates and oxygen demand, they thrive in temperatures below 20oC and have an upper thermal limit of 24 - 28oC. In recent summers water temperatures in excess of 25oC have been recorded in streams across the New Forest. High water temperature is associated with low flow, reduced oxygen level and increased ammonia concentration. Fish are able to move to cooler water but the stress caused by crowding and potential exposure to diseases can led to fish deaths. The shade cast by riparian vegetation has a significant influence on river habitat quality and with climate change predicted to lead to warmer, drier summers the role of riparian shade may become important across England and Wales to protect vulnerable species from the threat of high water temperatures.
Objectives (1) to monitor stream water temperature in shaded and unshaded sections of three streams in the New Forest and (2) investigate the relationship between water temperature and riparian shade levels.
Additional resource: Broadmeadow, S., Jones. J.G., Langford, T.E.L., Shaw, P.J. and Nisbet, T., (2010). The influence of riparian shade on lowland stream water temperatures in Southern England and their viability for Brown Trout. River Research and Applications DOI: 10.1002/rra.1354 Jan (2010). Attribution statement: If you use this data you wish to cite Broadmeadow, S., Jones. J.G., Langford, T.E.L., Shaw, P.J. and Nisbet, T., (2010). The influence of riparian shade on lowland stream water temperatures in Southern England and their viability for Brown Trout. River Research and Applications DOI: 10.1002/rra.1354 Jan (2010).

水温是水质的关键参数。水体中绝大多数的生化过程及其物理特性均为温度的函数。水生生物，包括鱼类，均为多温性生物，对整个温度范围作出响应；包括绝对值、季节性及昼夜变化范围、变化速率，以及极端热事件的时机和持续时间。鲑科鱼类为冷水物种，具有高代谢率和氧气需求，它们在低于20°C的温度下繁衍生息，其最高温度极限为24至28°C。近年来，在新森林的溪流中记录了超过25°C的水温。高温与低流量、氧气水平下降和氨浓度增加相关。鱼类能够迁移至较冷的水域，但拥挤造成的压力以及可能暴露于疾病的风险可能导致鱼类死亡。河岸植被所投射的阴影对河流栖息地质量具有显著影响；随着气候变化预计将导致英格兰和威尔士夏季变得更加炎热和干燥，河岸阴影的作用可能成为保护易受威胁物种免受高温威胁的关键。研究目标包括：（1）监测新森林三条溪流的有遮蔽和无遮蔽区域的溪流水温；（2）研究水温与河岸遮蔽程度之间的关系。附加资源：Broadmeadow, S.，Jones. J.G.，Langford, T.E.L.，Shaw, P.J.和Nisbet, T.（2010）。《英格兰南部低地溪流水温受河岸遮蔽的影响及其对棕鳟的适宜性》。《河流研究与应用》DOI：10.1002/rra.1354，2010年1月。归属声明：如果您使用此数据，您希望引用Broadmeadow, S.，Jones. J.G.，Langford, T.E.L.，Shaw, P.J.和Nisbet, T.（2010）。《英格兰南部低地溪流水温受河岸遮蔽的影响及其对棕鳟的适宜性》。《河流研究与应用》DOI：10.1002/rra.1354，2010年1月。