Fish habitat rehabilitation using wood in the world

Abstract

To provide river managers and researchers with practical knowledge about fish rehabilitation, various studies of fish habitat rehabilitation that used wood were reviewed. The review focuses on fish responses, wood installation methods, and geomorphic features of the rehabilitation sites. Most studies were conducted in moderately sized (small and medium) streams with relatively high bed gradients and aimed to improve the habitats of salmonid species. In this stream type, structures spanning the full (log dam) and partial (log deflector) width of the river were most common, and wood structures that created pools and covers were successful in improving fish habitat. Some projects were conducted in moderately sized lowgradient streams, in which wooden devices used to create instream cover were effective for fish assemblages. There were few studies in other aquatic ecosystems. However, well-designed large wood structures, known as engineered log jams, were used in rehabilitation projects for large rivers. In slack-water or lentic systems such as sidechannels, estuaries, and reservoirs, small and large wood structures that created cover were used to improve habitat for many fish species. For successful fish habitat rehabilitation projects, the hydrogeomorphic conditions of rehabilitation sites should be carefully examined to avoid physical failure of wood structures. Although artificial wood structures can be used to improve fish habitat in various aquatic ecosystems, they should be considered to be a complementary or interim habitat enhancement technique. The recovery of natural dynamic processes at the watershed scale is the ultimate target of restoration programs.

Wood placement in river restoration: fact, fiction, and future direction

“…holding and cover for hiding Nagayama and Nakamura 2010). Greater wood abundance increases the overall number of pools (Beechie and Sibley 1997;Montgomery et al 1995), pool area (Beechie and Sibley 1997), and residual pool depth (Collins et al 2002) and can change the overall channel morphology from plane bed to forced-pool riffle channels (Buffington and Montgomery 1999;Montgomery et al 1996).…”

“…In the Columbia River Basin of the Pacific Northwest, the focus of a large habitat restoration program, at least 2000 wood placement projects have been implemented since 1980 (National Oceanic and Atmospheric Administration (NOAA), unpublished data). Wood placement has also become commonplace in Europe, Japan, Australia, and other parts of the world (Brooks 2006;Nagayama and Nakamura 2010;Reich et al 2003).…”

Effects of configuration of instream wood on autumn and winter habitat use by fish in a large remeandering reach

“…Therefore, we need to develop installation methods and configurations of log jams that can serve to maintain fish habitats, and we need to recognize that engineered log jams can be used as a tool for interim habitat rehabilitation. Moreover, in rivers where physical conditions are unstable and sediment production is abundant, a greater consideration of the hydrogeomorphic conditions will be needed for success in rehabilitation projects (Shields et al, 2006;Nagayama & Nakamura, 2010).…”

“…Instream large wood plays an important role in shaping the distribution and composition of fish assemblages (Dolloff & Warren, 2003;Zalewski et al, 2003), as shown by many previous studies on the habitat of salmon in small streams (Zalewski et al, 2003;Nagayama & Nakamura, 2010). In contrast, there are few studies on other fish species, particularly in large rivers where the channel width is greater than the length of wood pieces (Murphy et al, 1989;Nagayama & Nakamura, 2010).…”

“…In contrast, there are few studies on other fish species, particularly in large rivers where the channel width is greater than the length of wood pieces (Murphy et al, 1989;Nagayama & Nakamura, 2010). Moreover, few studies have examined the effect of the configuration of the wood structures on local habitat use by fish, although the relationship between fish and wood abundance has been well examined (e.g., Inoue & Nakano, 1998;Horan et al, 2000;Rosenfeld et al, 2000).…”