Type 5 Streams and Small Wetlands Literature Review

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What are options for protecting Type 5 stream functions within the scope of the riparian management strategy?

Statements within this literature review are based on the reported findings from various published sources. Due to differences in sample design, methodology, geographical location, site characteristics, data analysis and interpretation, these statements may or may not agree with the results of other published reports. Despite contradictory results, one cannot say the findings of one author are more or less valid than another, due to the wide range of site characterists. Readers are urged to consider how and where information was collected when interpreting the value of the following conclusions. Headwater stream science is, in many ways, a relatively new field. Early observations and case studies may or may not represent widespread relationships.

Click on the citation following each statement to view the annotated bibliography

Organize statements by:

  • Terrestrial invertebrates play a vital role in aquatic food supplies, therefore adequate retention of riparian zones is an important consideration for streamside management. (Allan et al. 2003).


  • Timber harvesting signicantly increases marsh temperatures. However, timber harvesting did not affect spring temperatures. (Black 2001).


  • Even when buffers are in place, stream microclimate gradients can be affected up to 180m away from harvest activities. (Brosofske et al. 1997).


  • Microclimatic change have been shown to occur in small streams, even when the harvest unit is far away from the stream but within the same watershed. (Brosofske et al. 1997).


  • Harvesting practices that include the installation of buffer zones, can still affect nearstream habitat by increasing temperatures and decreasing humidity levels. (Brosofske et al. 1997).


  • Slash left in first order streams restricts the movement of coarse sediment. The author suggests that leaving slash in first order channels is beneficial because it reduces the risk of large sediment transportation (generated from harvest areas) to downstream channels. (Commandeur et al. 1997).


  • Broader buffer widths (greater than 30m) resulted in similar litterfall rates, as in the control sites. The author found a linear association between litterfall, and buffer width. However there was no strong correlation due to the small sample size. (Grady 2001).


  • Buffer windthrow increased large woody debris (LWD) recruitment into the stream channel by an average of 33%. (Grizzel and Wolff 998).


  • The buffered streams warmed faster, but remained cooler than the controls. The author speculates that the warm air generated from the clearcut area was drifting through the riparian buffer strip, increasing air temperature. (Hagan 2000).


  • Mature shrub species, such as vine maple and huckleberry, should be treated as legacies, and therefore protected during thinning operations because they provide a large seed bank for regeneration, and are a critical food source for wildlife. (Harrington et al. 2002).


  • Leave tree islands should also be "no-entry" zones to prevent ground disturbance, and to reduce the expansion of invasive species. (Harrington et al. 2002).


  • Post treatment response can be assessed more accurately if pretreatment data is used in the analyses. (Harrington et al. 2002).


  • This author's simple and inexpensive "sunpath" technique gave superior results for predicting height growth, in comparison to more specialized equipment and/or software. (Harrington et al. 2002).


  • The authors state that their model compares the relationship of the size of large woody debris relative to stream size, and also has a lower rate of error than a similar model used by the Washington Department of Natural Resources. (Hyatt et al. 2004).


  • The un-buffered stream did not exhibit a change in temperature because the logging debris covered and shaded the stream. (Jackson et al. 2001).


  • The headwater streams that were buffered protected the streambanks from instablity, resulting in no bank failure, or erosion. However, these buffers did experience significant blowdown. (Jackson et al. 2001).


  • When small streams are buffered, Dicamptodon tenebrosus behaves similarly to those found in uncut areas. This study found that without a buffer, this species ability to find food and to reproduce, is limited by its reduced range of movement. (Johnston and Frid 2002).


  • 100m buffers protect ambient temperatures, humidity, light intensity, and soil moisture. (Kelsey and West 2001).


  • 150-185m buffers protect interior buffers from windthrow. (Kelsey and West 2001).


  • 10m buffers (without the threat of windthrow) are adequate for protecting amphibians and other wildlife associated with early seral forests. (Kelsey and West 2001).


  • Some options for protecting buffers from windthrow include: topping trees on the outter edge--while retaining 6-8m of trunk for snags and future woody debris recruitment, and/or whorl-pruning trees to break up wind currents. (Kelsey and West 2001).


  • Careful manuevering of skidders and logging equipment, can greatly decrease the amount of stream sediment loading. The operator should follow topographical contours, and stay out of muddy wet areas (including stream banks). However, this study found that in the diameter selection harvest, where 50% of the canopy was removed and equipment was used right up to the streambank, no statistical increases in sediment were found. (Kreutzweiser et al. 2001).


  • The basin size for the perennial initiation point (PIP) sites ranged from 2 to 4096 acres, and the spatially intermittent initiation point (SIIP) ranged from 2 to 346 acres. The 52 acre default basin size overpredicts the PIP sites by an average of 744 feet. When PIP, and SIIP data is combined, it overpredicts by 514 feet. (Liquori 2001).


  • There are four main classes of perennial initiation point (PIP), and spatially intermittent initiation point (SIIP) sites. They are as follows: mainstem, confluent, variable source, and stationary. This study found a wide range in variablity between these four groupings. (Liquori 2001).


  • Heavy road traffic can increase sediment yields by 1,000 times the sediment generated from abandoned roads, or 130 times that of a road only used by light vehicles. Sediment discharge from road use, can be averted by gating roads and abandoning them after timber harvest. (MacDonald and Ritland 1989).


  • Roads and skid trail placement should not disrupt the pre-existing drainage network. Skid trails should especially not be in close proximity to the stream channel. (MacDonald and Ritland 1989).


  • Instream large woody debris plays an integral role in sediment storage in headwater streams. Functional woody debris acts as a buffering process to downstream sediment loading. (MacDonald and Ritland 1989).


  • Variable retention (ie. riparian thinning) of buffers is one way to satisfy both ecological and economical interests. (MacDonald et al. 2003).


  • Aspect and topographical features are important factors to consider when making management decisions because they greatly influence temperature. For example, south facing aspects are warmer and dryer than north facing aspects. Furthermore, deeply incised channels may recieve enough shading from their corresponding slopes to regulate temperatures. (MacDonald et al. 2003).


  • The authors conclude that after 11-15 years, partial harvesting only has a small effect on stream temperature, chemistry, and turbidity. (Murray et al. 2000).


  • Habitat recovery options: Protection--preserve intact and functional riparian zones by restricting anthropogenic activities that would alter the site. Passive restoration--eliminate human activities and let area re-generate naturally. Active restoration--using management activities to speed up regeneration (ie. planting native vegetation). Rehabilitation--reestablish riparian ecosystems to function optimally despite irreversible damage (ie. hydro dams). Substitution--enhancing and increasing selected riparian functions or mitigation to improve or create habitat off site. (Naiman et al. 2000).


  • FEMAT cites studies that indicate buffers between 30-185m wide are effective for wildlife protection. (O'Laughlin and Belt 1995).


  • Buffers should be wider on steep slopes, and in areas were ground infiltration is slow. (O'Laughlin and Belt 1995).


  • Leave trees can help in retaining biodiversity, especially of lichens and bryophytes. (Olson et al. 2000).


  • This paper provides practical resolutions to management decisions that need to consider a variety of forest uses including commercial, recreational, and endangered species habitat. (Olson et al. 2002).


  • Narrow buffer treatments did not maintain the pre-harvest bird communities, however wide buffers did maintain most of the pre-harvest communities two years after treatment. (Pearson and Manuwal 2001).


  • Rhyacotriton kezeri (Columbia Torrent) species prefer high gradient streams with basalt bedrocks, rather than low gradient streams with marine sediments. Therefore, harvesting near high gradient streams is more likely to negatively affect R. kezeri, than logging near low gradient streams. (Russell et al. 2004).


  • Conservation of riparian and upland habitats is important for more mobile species that utilize resources in both zones. (Sabo et al. 2005)


  • Forestry management designed to establish and/or protect overstory canopies and large woody debris, will positively benefit amphibian species. By modifying management procedures, riparian obligate species can thrive in buffer zones and patch reserve areas. (Sheridan and Olson 2003).


  • Adequate riparian buffers will ensure long term recruitment of woody debris, which is important for creating a diversified habitat within the stream channel. (Swanson and Fredriksen 1982).


  • Excessive sediment loading can be avoided by predeterming erosion-prone sites; by calculating the erosion rate of management activities; by theorizing downstream effects of debris flows; and by planning mitigation activities to offset increased sediment inputs. (Swanson et al. 1987).


  • For differentiating between Type 4 and 5 streams, within the Skagit basin, a 21 acre default would be more accurate than a 54 acre default. (Veldhuisen 2000).


  • This study suggests that in the Skagit basin, a 3 acre default should be considered for streams with glacial-lacustrine sediment deposits. (Veldhuisen 2000).


  • Habitat connectivity between streams and within a watershed is important for maintaining Ascaphus truei dispersal and gene flow. (Wahbe et al. 2004).


  • Maintaining detritus loading to small streams is integral for the conservation of diversified food webs. (Wallace et al. 1997).


  • This study suggests that a "patch retention management strategy" could greatly reduce extirpation by leaving suitable habitat remnants. (Whitman and Hagan 2000).



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