Lester Rebecca E, Boulton Andrew J
School of Applied Sciences and Engineering, Monash University, Gippsland Campus, Churchill, VIC 3842, Australia.
Environ Manage. 2008 Aug;42(2):310-26. doi: 10.1007/s00267-008-9151-1. Epub 2008 Jun 17.
Worldwide, the ecological condition of streams and rivers has been impaired by agricultural practices such as broadscale modification of catchments, high nutrient and sediment inputs, loss of riparian vegetation, and altered hydrology. Typical responses include channel incision, excessive sedimentation, declining water quality, and loss of in-stream habitat complexity and biodiversity. We review these impacts, focusing on the potential benefits and limitations of wood reintroduction as a transitional rehabilitation technique in these agricultural landscapes using Australian examples. In streams, wood plays key roles in shaping velocity and sedimentation profiles, forming pools, and strengthening banks. In the simplified channels typical of many agricultural streams, wood provides habitat for fauna, substrate for biofilms, and refuge from predators and flow extremes, and enhances in-stream diversity of fish and macroinvertebrates.Most previous restoration studies involving wood reintroduction have been in forested landscapes, but some results might be extrapolated to agricultural streams. In these studies, wood enhanced diversity of fish and macroinvertebrates, increased storage of organic material and sediment, and improved bed and bank stability. Failure to meet restoration objectives appeared most likely where channel incision was severe and in highly degraded environments. Methods for wood reintroduction have logistical advantages over many other restoration techniques, being relatively low cost and low maintenance. Wood reintroduction is a viable transitional restoration technique for agricultural landscapes likely to rapidly improve stream condition if sources of colonists are viable and water quality is suitable.
在全球范围内，溪流和河流的生态状况因农业活动而受损，这些活动包括集水区的大规模改造、高养分和沉积物输入、河岸植被丧失以及水文状况改变。典型的影响包括河道下切、过度淤积、水质下降以及河内生境复杂性和生物多样性丧失。我们回顾这些影响，以澳大利亚的实例为重点，探讨在这些农业景观中重新引入木材作为一种过渡性恢复技术的潜在益处和局限性。在溪流中，木材在塑造流速和沉积剖面、形成水潭以及加固河岸方面发挥着关键作用。在许多农业溪流典型的简化河道中，木材为动物提供栖息地，为生物膜提供基质，为躲避捕食者和极端水流提供庇护所，并增加溪流中鱼类和大型无脊椎动物的多样性。此前大多数涉及重新引入木材的恢复研究都在森林景观中进行，但一些结果可能适用于农业溪流。在这些研究中，木材增加了鱼类和大型无脊椎动物的多样性，增加了有机物质和沉积物的储存，并改善了河床和河岸的稳定性。在河道下切严重和环境高度退化的地方，最有可能无法实现恢复目标。与许多其他恢复技术相比，重新引入木材的方法在后勤方面具有优势，成本相对较低且维护需求少。如果有可行的木材来源且水质适宜，重新引入木材是一种可行的过渡性恢复技术，有望迅速改善农业景观中的溪流状况。
