Riparian Areas Functions and Strategies for Management (2002) / Chapter Skim
Currently Skimming:
5. Management of Riparian Areas
5. Management of Riparian Areas
Pages 299-424
The Chapter Skim interface presents what we've algorithmically identified as the most significant single chunk of text within every page in the chapter.
Select key terms on the right to highlight them within pages of the chapter.
From page 299... ...
For example, the experimental flood of the Colorado River in the southwestern United States in the spring of 1996 focused worldwide attention on alternative methods for managing and restoring river and riparian ecosystems (Collier et al., 1997~. Reinstating flooding and overbank flows on a river where flow regulation has been in place for decades is now seen as a potential means for partially restoring fluvial geomorphology and riverine habitats for threatened and endangered species in this human-impacted landscape.
|
From page 300... ...
Intact riparian areas represent valuable reference sites for understanding the goals and the efficacy of various restoration approaches and other management efforts. In some cases they are important sources of genetic material for the reintroduction of native biota into areas in need of restoration.
|
From page 301... ...
A fundamental goal of riparian restoration is to facilitate selfsustaining occurrences of natural processes and linkages among the terrestrial, riparian, and aquatic ecosystems. Ecological restoration of riparian areas results in the reestablishment of functional linkages between organisms and their environment, even though these
|
From page 302... ...
For example, riparian areas in forests and rangeland areas throughout the western United States represent likely candidates for ecological restoration if the adverse effects of historical or ongoing land uses can be significantly reduced, controlled, or eliminated. Success is more likely where fundamental disturbance regimes continue to occur relatively unhindered by human influence.
|
From page 303... ...
For example, the reintroduction of an extirpated plant species into a degraded riparian area is likely to fail if the underlying causes of extirpation have not been addressed. Focusing on those human influences that affect multiple ecological processes is more likely to attain greater restoration of riparian habitat and species of interest.
|
From page 304... ...
An extended network of intermittent and ephemeral streams has become established in many agricultural areas where they did not previously exist; many of these streams could support riparian plant communities. Reclamation Reclamation has traditionally been defined as the process of adapting natural resources to serve utilitarian human purposes (NRC, 1992~.
|
From page 305... ...
For example, where levees may be needed along a river to protect human developments, mitigation might require the levees to be set back some distance from the channel edge to retain some riparian functions of the streamside vegetation and to maintain hydrologic connectivity of the near-channel floodplains and side channels. Where rip-rap is to be employed along a streambank, mitigation might require that measures be taken to ensure that riparian plants can become established and survive along the structure.
|
From page 306... ...
Naturalization Naturalization, an alternative to ecological restoration, attempts to accommodate watershed-scale human influences in environmental designs of channels by establishing stable, self-sustaining geomorphologic systems with abundant and diverse ecological communities that are fundamentally different from those that existed before. The concept of naturalization was developed for specific application to agricultural streams that have been significantly modified, often by deepening and straightening previously existing channels (Rhoads and Herricks, 1996~.
|
From page 307... ...
Management that might be used to achieve naturalization includes not only vegetated riparian buffers (discussed later) , but also off-channel wetlands, side-slope reduction of streambanks, increased stream sinuosity, and other practices that provide improved ecological and water-quality benefits (Petersen et al., 1992~.
|
From page 310... ...
(As of yet there has been little monitoring or research to document the ecological changes that are occurring as a result of these improved riparian management practices.) After passive restoration is implemented, a riparian area may remain in an ecological condition that is significantly different from that of a comparable reference site, particularly if its inherent capacity to recover has been severely influenced or lost.
|
From page 311... ...
Although some of these factors can be addressed via active restoration, others can be sufficiently severe in their magnitude, persistence, and spatial extent that full ecological restoration may not be technologically or economically feasible. Nonetheless, restoration can still achieve ecological improvement of a system so that specific ecosystem features (e.g., water quality)
|
From page 312... ...
Short-term versus Long-term Restoration Goals In nearly all restoration efforts, one is typically faced with trying to balance short- and long-term goals. For example, former riparian plant communities may have experienced a loss in species diversity and cover because of grazing or conversion to agricultural crops.
|
From page 313... ...
Although the incremental impact to summertime stream temperatures is likely to be small if a single landowner were to harvest the riparian forest or convert it to another use (e.g., grazing, agriculture) , the cumulative effect on water quality can be considerable if multiple landowners temporarily or permanently remove their riparian forests.
|
From page 314... ...
The extent to which the public's need or desire to maintain and protect public resources (e.g., water quality, fish and wildlife habitat) outweighs landowners' rights to manage and alter riparian systems continues to be a hotly contested issue.
|
From page 315... ...
Eliminating exotic vegetation in riparian areas and reestablishing native plant communities is another approach to riparian restoration that can sometimes lead to conflicts between interest groups. For example, controversy marks recent proposals for biological control of exotic saltcedar in riparian areas of the western United States.
|
From page 316... ...
(NRC, 1999~. Although instigated in the early part of the twentieth century, watershed management has found renewed support in the last 15 years for primarily water quality and ecological reasons (Adler, 1995~.
|
From page 317... ...
Rather, such things as improvement of water quality and protection of a fishery have been the motivating factors (Kenney et al., 2000~. Yet it is precisely because of their important role in achieving many distinct objectives, such as healthy fish and wildlife habitat or floodplain management, that protection and restoration of riparian areas should be approached on a watershed scale, even though this may increase the complexity and timeline of the project.
|
From page 318... ...
Rapid assessment methods for evaluating ecosystems have undergone dramatic development in the past three decades. Of particular relevance for riparian areas are methods that were developed for assessing wetlands, to which there has been considerable attention as a consequence of government regulatory programs.
|
From page 319... ...
Most assessment methods discussed below use classification to identify what portion of the landscape is being evaluated and whether the riparian component needs to be further subdivided into more relatively homogeneous areas (although classification is not emphasized in the description of any particu
|
From page 320... ...
This would be consistent with a restoration approach that uses relatively unaltered riparian areas as targets for restoration (NRC, 2001~. Reference Sites Reference sites ideally represent relatively large and intact riparian systems that are self-sustaining and have not been markedly influenced by anthropogenic impacts.
|
From page 321... ...
Conversely, where unaltered sites are infrequent, small, or fragmented, one may have to rely on historical data and descriptions or on information gathered at similar sites outside the geographical region of interest. Even less-than-ideal reference sites can provide important information on species composition and structure of plant communities, frequency of inundation, and other characteristics.
|
From page 323... ...
MANAGEMENT OF RIPARIAN AREAS 323 _ spoor FOR STIR ~ Sin Sin OTTO ONTO ~ TODD 0~0 S~04 O3X ~0 ~ P ma_ .S.~ SS)
|
From page 324... ...
Both contribute to a system of reference sites in ways that would be lacking if only unaltered sites were utilized. Information Needs for Riparian Restoration History of Resource Development.
|
From page 325... ...
For many floodplains, an understanding of subsurface hydrology and geologic stratigraphy is also critical (Jones and Mulholland, 2000; Woessner, 2000~. In some cases reestablishing the hydrologic regime will not be sufficient to restore degraded riparian areas, necessitating a better understanding of the links between flow regime, sediment dynamics, and vegetative growth.
|
From page 326... ...
Understanding not only the functions that specific species and groups of species perform, but also the hydrologic and edaphic requirements for their successful establishment and growth (e.g., Kovalchik, 1987; Law et al., 2000) , is fundamental to any restoration project targeting riparian plant communities.
|
From page 327... ...
The Hydrogeologic Equivalence concept recognizes that landscapes have developed and maintained different frequency distributions of wetlands and riparian areas with particular "hydrogeologic settings." Such settings may represent desirable endpoints for ecological restoration at a watershed scale. These Hydrogeologic settings reflect not only regional climate, but also surface relief, slope, hydrologic properties of soil, and underlying stratigraphy.
|
From page 328... ...
From a practical perspective, npanan restoration efforts would be most successful if they use these hydrogeologic settings as guides for deciding what kinds of restoration should occur and where on the landscape they should take place. Still uncertain is how progressive changes in land use constrain the capacity of a watershed to maintain the original distribution of hydrogeologic types.
|
From page 329... ...
(1992) for the Pearl River Basin in Mississippi and Louisiana and for mostly riverine wetlands in Illinois.
|
From page 330... ...
Water quality standards ~ ~ · Advancedidendfication ~'~S Watershed or Subwatershed Scale · Advanced identification · Goal setting · Mitigation siting FIGURE 5-6 Applying synoptic assessments at various spatial scales. SOURCE: Liebowitz et al.
|
From page 331... ...
is based on the premise that wetlands have an array of functions that can be classed in one of three major categories: hydrologic, water quality, and habitat. Within each of these categories, more specific functions can be identified.
|
From page 332... ...
Finally, the method uses literature reviews and best professional judgment, rather than reference sites, as the primary sources of information for model development. Reference-based Assessments The most powerful assessment methods are dependent, to some degree, on knowing the background or reference conditions within a region.
|
From page 333... ...
Three rapid assessment techniques are presented and compared below: Proper Functioning Condition, which was developed explicitly for riparian areas, and the Hydrogeomorphic Approach and the Index of Biological Integrity, which can be adapted for use in riparian areas. Proper Functioning Condition The Bureau of Land Management (BLM)
|
From page 334... ...
334 RIPARIAN AREAS Functional-At-Risk: This category includes riparian-wetland areas that are in functioning condition, but existing soil, water, and/or vegetation attributes make them susceptible to degradation. Nonfunctional: Riparian-wetland areas are nonfunctional when they clearly are not providing adequate vegetation, landform, or large wood to dissipate stream energy associated with high flows and thus are not reducing erosion, improving water quality, etc., as listed above.
|
From page 335... ...
If the alterations and stressors that make a site "nonfunctional" are corrected, it is assumed that the site will achieve a rating of "functional-at-risk" or higher as vegetation establishment and growth take place over time. The goal of riparian management is always to achieve proper functioning condition, "because any rating below this would not be sustainable" (Prichard et al., 1998~.
|
From page 336... ...
If the local assessment team is not familiar with sites in good ecological condition and their characteristic plant communities, its capability to assess the status of a stream is likely to be diminished. Finally, because only the site conditions on a PFC rating form are addressed, the spatial context and connectivity of a given riparian area relative to a watershed setting are not explicitly recognized.
|
From page 337... ...
Functional indices may be multiplied by surface area in order to compare two or more sites that differ in condition and size. HGM relies on the development of a guidebook that contains a literature review, an identification of functions, data on variables from reference sites within the biogeographic region of interest, and "models" that relate variables to functions (Smith et al., 1995~.
|
From page 338... ...
Much more data are collected from reference sites than are incorporated in the final assessment tool; the final method used in the field is pared down to include only measurements that are sensitive to activities that alter or degrade the functioning of sites. This background work makes it possible to conduct simple assessments in a matter of hours.
|
From page 339... ...
-~ ~ 1 -i ¢ o ~ ~ o ~ ~ n ~ Cow 0~ ~ ~ O 1 ~ ,' 4t $~ ~l ;¢ t l!
|
From page 340... ...
Measures of biological integrity, such as species richness or trophic composition, are used to compare sample site characteristics to that of reference sites or conditions that are minimally influenced by human activities. For example, the Index of Biological Integrity (IBI)
|
From page 341... ...
Although other indices of biological integrity have been developed (see Box 5-5) , IBI is the most frequently used and thus is the focus of this section.
|
From page 342... ...
Although IBI was developed for measuring benthic populations in streams, theoretically any biological integrity index can be adapted to riparian areas in one of two ways. One is based on the assumption that riparian area condition and upstream land uses are reflected in a typical analysis of benthic invertebrates or fish.
|
From page 343... ...
. Intolerant taxa richness would be the number of species that are sensitive to degradation of water quality in the broadest sense.
|
From page 344... ...
For biological integrity assessments, a greater degree of expertise is required for specific taxonomic groups of plants, animals, or both. As in all assessments, experience is a valuable asset in assuring consistency and accuracy.
|
From page 345... ...
In the HGM guidebooks prepared for wetlands, important components are species composition of vegetation, the presence of non-native species, and groups of indicator species sensitive to alteration. For biological integrity methods developed for wetlands, metrics can be developed for hydrophytic plants, much like the Floristic Quality Assessment Index described in Box 5-5.
|
From page 346... ...
346 RIPARIAN AREAS TABLE 5-1 Comparison of Environmental Assessment Methods that Are Either Used in Riparian-Wetland-Aquatic Areas or Could Be Modified for These Areas Attributes Proper Functioning Condition Hydrogeo, Primary purpose for developing Restore and maintain riparian-wetland systems Assess im on BLM lands mitigati 404 prc Primarily applied to which systems Riparian-wetland ecosystems on BLM lands, mostly in the arid West Developed associal environ Use of reference Reference is embedded in the professional Must be d judgment of the multidisciplinary team conduce are the Use of classification to partition No explicit approach to classification is provided; Classifica natural variation assessment team is responsible for recognizing relative regional conditions for reference compar Use of indicators Hydrologic Physical factors are central to evaluating condition Geomorphic setting and related Physical factors are central to evaluating condition attributes Plant and animal species composition Species composition of vegetation partly indicates whether physical factors are effective Physical plant community structure Vigor and type (shrub, herbaceous) of vegetation indicates whether physical factors are supportive of "proper functioning condition" Highly de sources function Essential evaluate Plants, es]
|
From page 347... ...
. ~gnlzlng Classification is fundamental to developing relatively homogeneous standards for comparison For wetlands, uses the HGM classification approach condition condition indicates getation lition" Highly dependent on identifying water sources and flows necessary for evaluating functions Essential both for classification and evaluating condition Plants, especially, used to indicate alteration; non-native species can be used to indicate degraded conditions Essential for evaluating condition Seldom used; instead, biotic indicators are central to method Not required except for the classification step Biological data are central to the assessment, especially aquatic animals; vegetation indicators are undergoing development Not required lucted; Substantial effort required for field data collection, establishing reference standards, and developing guidebook Requires office preparation (maps, photos, etc.)
|
From page 348... ...
As with the choice of assessment methods for riparian conditions, the policy framework should be scaled to the types of questions being asked. For example, reference-based assessments tend to assign low scores to urban riparian areas in degraded conditions.
|
From page 349... ...
MANAGEMENT OF RIPARIAN AREAS 349 Hydrogeomorphic Approach Indices of Biological Integrity ,; easy be Allows detailed restoration planning because of information from the reference system; a simple assessment is rapid The basic IBI approach has been around for 20 years, allowing many of the problems to be resolved; background literature is available assessors es Has a high front-end cost for developing regional guidebooks Has been incompletely developed in wetlands where vegetation is the principal biotic variable ~ of fly stain, area Once a reference system is developed for a riparian class, assessment determines current condition of a site, and can project losses or gains due to alterations or restorations, respectively Once multimetric or predictive models are developed for a riparian class, assessment places the site within a continuum of alteration by human activities address the need for making decisions that are supported by the public. To better integrate public participation in decision-making on riparian resources, education is required about the condition of riparian areas and implications for social wellbeing (i.e., "quality of life," internalizing environmental costs, etc.~.
|
From page 350... ...
In 2A production function is a mathematical description of the relationship between specified inputs, in the present case riparian ecosystem services (water quality, habitat, etc.) and outputs from the production process (cleaner water, fish and wildlife, etc.)
|
From page 351... ...
The current version should be refined to increase its capacity to link physical conditions with water quality, instream biota, plant community structure and composition, and terrestrial animal communities. The approach should become more quantitative and rely more on regional reference sites rather than on the exclusive judgment of a team of local experts.
|
From page 352... ...
Some of these strategies will be more passive, some more active, and others a blend of both passive and active approaches. In all examples, successful restoration appears to be based on extensive local knowledge of hydrology and ecology including the range of natural variability, disturbance regimes, soils and landforms, and vegetation; on understanding the history of resource development; and on identifying reference sites.
|
From page 353... ...
Many water resources developments have caused concurrent degradation in water quality and fish and wildlife habitats as well as dwindling amounts of riparian areas along lake shores, streambanks, and floodplains. In the opinion of this committee, repairing the hydrology of the system is the most important element of riparian restoration.
|
From page 354... ...
This section discusses how long-term restoration of riparian areas might be achieved if components of the natural hydrologic regime, sediment dynamics, and hydrologic connectivity between rivers and their floodplains were reestablished. Restoring more natural flooding regimes and sediment dynamics in the nation's rivers is likely to be a major theme for environmental science in the twenty-first century (Poff et al., 1997~.
|
From page 355... ...
Prescribed flooding has the potential to become a management tool similar to the use of prescribed burns in managing forests and grasslands. Given the current level of water resources infrastructure, dammed rivers will probably never have flow releases that fully replicate pre-dam flow regimes, and upstream portions of dammed rivers may never be restored.
|
From page 356... ...
Thus, establishing a flow regime downstream of reservoirs that mimics some of the high-flow dynamics of the original river system could serve as a major restoration tool and is important for successfully maintaining gallery forests associated with these river systems. Similarly, experimental high-flow
|
From page 357... ...
Other prominent examples have occurred on the Upper Colorado River and the Napa River. Recent decisions regarding the management of dams on the upper Missouri River reflect changing attitudes toward incorporating environmental considerations into dam operations (NRC, 2002~.
|
From page 358... ...
358 RIPARIAN AREAS opinion calls for operation of the dams to create higher spring flows and lower summer flows compared with flows under past management. The purpose of increased spring flows is to provide reproductive cues for the federally endangered palled sturgeon and other species, and to build sandbars that would be used by nesting terns and plovers during the time of exposure of the bars in summer.
|
From page 359... ...
This is especially true when restoring a river's natural flow regime by manipulating dam operations to create variable flows or by removing dams altogether. Either strategy could change rates of sediment transport and deposition in ways that affect the size, morphology, and disturbance frequency of sediment patches that are suitable for establishment of riparian plants (Friedman et al., 1996; Scott et al., 1996)
|
From page 360... ...
However, where the ecological and social values associated with reestablishing periodic flooding (e.g., increased detention storage of flood waters, increased riparian functions, improved habitat and food web support for aquatic organisms and wildlife) are high and the economic costs are low, breaching or creating gaps in levees and dikes may be a relatively straightforward approach to reclaiming significant amounts of historical riparian area.
|
From page 361... ...
When these roadways and bridges are scheduled for updating, reconstruction, or other improvements, reconnecting former floodplains and side channels should be considered and implemented wherever possible. Streambank Stabilization Bank stabilization, utilizing a variety of structural approaches, has been undertaken along many streams and rivers throughout the United States.
|
From page 362... ...
Although it is unlikely that many streambank stabilization projects in heavily developed areas are likely to be dismantled in order to improve riparian functions, there is a real need to "soften" the impact of these structures. Particularly important would be their modification to allow and encourage the establishment of native riparian plants.
|
From page 363... ...
Unless changes are made to return the hydrologic regime to a more natural state, other geomorphic and structural restoration activities are likely to fail. The temporal dynamics of the flow regime are fundamental to the structure of riparian plant communities and the functions they perform.
|
From page 364... ...
Impediments to changing dam operations include both legal and socioeconomic factors. Future structural development on floodplains should occur as far away from streams, rivers, and other waterbodies as possible to help reduce its impacts on riparian areas, and existing human uses of floodplains should be modified where possible to allow periodic flooding of riparian areas.
|
From page 365... ...
Communities and municipalities can, for example, use the area between a river and its 100-year floodplain boundary to delineate those areas where significant structural development would not be allowed and where existing structures might be removed when opportunities avail themselves. Vegetation Management Because of the fundamental importance of vegetation to the ecological functioning of riparian areas, where such vegetation has been degraded or removed, its recovery is a necessary part of any restoration effort.
|
From page 366... ...
On these lands, riparian forests may recover if future tree harvesting is simply excluded from riparian areas. This approach assumes that native riparian plants remained as part of the post-harvest vegetation composition and were not replaced by a single forest species or by exotic species.
|
From page 367... ...
Figure 5-9 also illustrates that where forested riparian buffers are of sufficient width to provide high levels of large wood and shade protection, functions related to bank stability and litter inputs are also generally satisfied.
|
From page 368... ...
These include not only the management of riparian forests for specific species and commercial timber products, but also the enhancement or active restoration of riparian functions. Active restoration may be particularly needed on industrial forestlands and land under other nonfederal ownership where previous management actions have greatly altered the composition and structure of native riparian forests.
|
From page 369... ...
According to this paradigm, the initial step for integrating functional objectives into silvicultural practice is to delineate the ecological boundaries of a riparian management area. The second step is to prescribe site-specific silvicultural practices that protect or enhance riparian functions along the riparian ecotone while meeting other management objectives; this prescription would outline the silvicultural system designed for the management area as well as a method for monitoring results over time.
|
From page 370... ...
(B) The riparian forest is harvested along a gradient.
|
From page 371... ...
of riparian buffers and their application throughout a drainage basin (e.g., on intermittent streams, non fish-bearing perennial streams, fish-bearing perennial streams) are likely to vary depending upon ownership and management goals.
|
From page 372... ...
Conclusion on Large Wood Introducing large wood into streams draining forested watersheds can be an important short-term practice for assisting the recovery of instream habitats, particularly where large wood has been depleted by historical land uses and the remaining riparian forests are unable to provide sufficient large wood for many decades. Even in such situations, the restoration of riparian forests to provide for long-term large wood recruitment must remain a high priority.
|
From page 373... ...
{When used as a management tool for water quality protection, riparian areas are referred to as "buffers," "buffer zones," or "riparian buffers" in this report.
|
From page 374... ...
Three principal types of buffers are being promoted in the United States for water quality protection: grassed filter strips, the multi-species riparian buffer system, and the three-zone riparian forest buffer. Grassed filter strips are the simplest type of buffer, defined by the NRCS as a strip of herbaceous vegetation situated between cropland, grazing land, or disturbed land (including forest land)
|
From page 375... ...
This zone should be designed and maintained so that it converts entering concentrated flow into sheet flow in order to improve the effectiveness of the adjacent managed forest zone in trapping pollutants (Dillaha et al., 1989~. Under shallow, sheet flow conditions, the runoff control zone will account for most of the sediment trapping in the three-zone buffer.
|
From page 376... ...
376 RIPARIAN AREAS The undisturbed forest zone is situated immediately next to the stream and consists of unmanaged native trees and shrubs. Harvesting of trees and shrubs in this zone generally requires special permission.
|
From page 377... ...
The unmanaged forest zone is typically 15- to 30-ft wide, but a minimum width equal to mature tree height may be a more effective width for
|
From page 379... ...
To reduce pollutant loadings to receiving waters from tile drains, riparian buffers must include constructed wetlands or similar systems to treat tile effluents, as discussed in Box 5-11. Managing for Success.
|
From page 380... ...
380 o at o so at Cal at o Cq Cq an .= ad ad Cal ¢ ca o .= C)
|
From page 381... ...
Areas where flows concentrate have shorter detention times, and pollutant-removal mechanisms in these areas can be overwhelmed. Unfortunately, the majority of overland flow and a significant portion of the shallow subsurface flow from contributing upland areas naturally concentrates before reaching the
|
From page 382... ...
can force overland flow to flow across rather than parallel to the riparian area. The runoff control zone of riparian buffers should be maintained by grading out rills, gullies, and excessive sediment deposits to encourage shallow sheet flow.
|
From page 383... ...
What type of vegetation should be used for each of the subzones, and how will the vegetation composition affect pollutant/nutrient sequestration and habitat values? How can riparian buffer zones be managed to maximize long-term nutrient/pollutant removal?
|
From page 384... ...
Some are located in riparian areas, but most are situated upslope of riparian areas and are designed to keep sediment, agricultural chemicals, and organic matter in the field where they are viewed as valuable natural resources rather than pollutants. Many in the agricultural conservation community prefer to focus on infield BMPs and view riparian buffer zones as a BMP of last resort for water-quality protection.
|
From page 385... ...
Conclusions and Recommendations on Riparian Buffers for Water Quality Protection Engineered and constructed buffer zones are a valuable conservation practice with many important water-quality functions. Under proper conditions, these buffers are highly effective in removing a variety of pollutants from overland and shallow subsurface flow.
|
From page 386... ...
Of the strategies listed above, exclusion is by far the most effective means of restoring riparian areas damaged by cattle. The efficacy of each method depends in part on the site potential, the area's grazing history and state of depletion, and the management goals and timeframes for achieving those goals.
|
From page 387... ...
Finally, while potential benefits of exclusionary fencing are significant, some can be difficult to quantify, making it hard to balance them against the costs of construction and maintenance, lost forage, and possible negative impacts to wildlife and recreational users. In part for these reasons, several western researchers have urged more research into innovative grazing management strategies that would not require fencing and permanent exclusion of livestock (Olson and Armour, 1979; Platts and Wagstaff,1984~.
|
From page 388... ...
Grazing management may bring about positive changes in the former, but not in the latter; thus, a short-term (less than 5-year)
|
From page 389... ...
MANAGEMENT OF RIPARIAN AREAS 389 study could misinterpret the overall effectiveness of the new management system. Livestock manager commitment is crucial, as improper implementation or lack of enforcement will reduce the effectiveness of any grazing management strategy (Platte and Nelson, 1985b; Clary and Webster, 1990; GAO, 1990; Ehrhart and Hansen, 1997~.
|
From page 390... ...
Many researchers have recommended that more attention be given to developing grazing systems designed to improve and maintain riparian conditions. For example, Platts and Nelson (1985c)
|
From page 391... ...
Stocking Intensity. Stocking rate, or grazing intensity, refers to the density of animals on a given area, and is usually described as light, moderate, or heavy.3 The failure of many studies to document stocking rates or to define terms such as heavy and moderate stocking makes it difficult to evaluate claims that reduced stocking intensity can improve riparian conditions.
|
From page 392... ...
Effective use of this indicator requires frequent monitoring and the ability to remove cattle quickly when conditions so require. Although no standards have been established, EPA recommended to BLM that a resource management plan for an area in Colorado limit autumn utilization of streamside vegetation to 30 percent with 4-6 inches of stubble remaining at the end of the grazing season, and it recommended that the plan require stubble heights greater than 6 inches in critical fishery habitats (EPA, 1992~.
|
From page 393... ...
Improvements, e.g., in vegetation conditions, soil and water quality, and/or streambank stability, will depend in part on site conditions and potential. Further research is needed concerning effective grazing management strategies in both the interior/arid West and more mesic areas of the country.
|
From page 394... ...
. Given the multiple factors that must be considered when managing riparian buffers as habitat for plants and animals, it is no surprise that no single management prescription can optimize diversity in all situations.
|
From page 395... ...
(2000~. Increasingly, such information on widths, combined with data on reference sites, can be used by resource managers in their design of leave areas or engineered buffer strips, although the wide disparity in desired riparian widths associated with various taxa presents an ongoing challenge.
|
From page 397... ...
Thus, efforts have been made to increase habitat diversity with the planting of trees and shrubs to create a more varied agricultural field edge. Identifying native species for this purpose through the use of reference sites can be a formidable task where agricultural practices have so altered soil characteristics that they are no longer suitable for some native vegetation.
|
From page 398... ...
This is particularly evident in developed landscapes where often the only remaining natural or semi-natural land exists along floodplains, or in agricultural landscapes where buffer zones planted for waterquality protection also serve a wildlife habitat function (Forman and Baudry, 1984; Barrett and Bohlen, l991~. Such riparian remnants frequently include wetlands where anthropogenic alterations have been limited.
|
From page 399... ...
Conclusions and Recommendations on Riparian Buffers for Habitat Riparian areas both natural reserves and managed buffer zones provide some of society's best opportunities for restoring habitat connectivity on the landscape. Identification, mapping, and assessment of these areas are needed.
|
From page 400... ...
Current silvicultural and agricultural management approaches do not adequately address the habitat values of riparian areas. Most forestry buffers, fenced riparian enclosures, and agricultural buffers have the protection of water quality (or sometimes fisheries)
|
From page 401... ...
Durable areas should also be sought out as locations for placement of recreational facilities (Cole, 1993~. Placement should also consider the inevitable negative edge effects on surrounding natural areas and should seek to mitigate these with buffer zones or screening.
|
From page 402... ...
Wilderness areas often have setbacks from waterbodies for camping or horse use to protect the riparian area and aquatic ecosystem; these range from 20 to 200 feet (Cole et al., 1987~. In some areas, certain activities may need to be excluded entirely if ecological restoration is the goal.
|
From page 403... ...
In most cases, all or many of these components are lacking in recreational management plans. The goal of managing recreational activities in riparian areas is to perpetuate natural functions (e.g., water quality, wildlife habitat, etc.)
|
From page 404... ...
Higher education needs to envision riparian science as a truly interdisciplinary field that includes a solid grounding in hydrology, limnology, ecology, conservation biology, experimental design, mapping (GIS) , and statistics (Noss, 1997~.
|
From page 405... ...
Natural resources managers and regulators form another crucial audience in need of information on riparian functions as well as up-to-date findings on alternative management strategies. Although it might be assumed that these professionals are adequately prepared to address the challenges associated with riparian areas and their management, the rapidly increasing information base of the last 25 years (see Chapter 1)
|
From page 406... ...
Educational efforts may easily break down when users perceive them as simply threats to grazing privileges or available wood fiber. Riparian education will have to address a blend of socioeconomic and ecological issues that go beyond the questions scientists usually research issues that are often neglected by those making management decisions.
|
From page 407... ...
Riparian areas provide essential life functions such as maintaining streamflows, cycling nutrients, filtering chemicals and other pollutants, trapping and redistributing sediments, absorbing and detaining floodwaters, maintaining fish and wildlife habitats, and supporting the food web for a wide range of biota. The protection of healthy riparian areas and the restoration of degraded riparian areas relate directly to at least five national policy objectives: protection of water quality, protection of wetlands, protection of threatened and endangered species, reduction of flood damage, and beneficial management of federal public lands.
|
From page 408... ...
For many sites, substantial time, on the order of years to decades, will be required for a full sequence of high and low flows to occur, for riparian vegetation to establish and plant communities to fully function, for channels to adjust, for water quality to improve, and so on. Restoring riparian areas to fully functional condition may not be possible in those cases where permanent modifications to the hydrologic regime have been made.
|
From page 409... ...
However, where upslope management practices significantly alter the magnitude and timing of overland flow, the production of sediment, and the quality of water arriving at a downslope nparian area, then simply focusing on the nparian system may be inadequate for achieving restoration goals. In such situations, upslope practices that are contributing to nparian degradation must be addressed in order for long-term success to be achieved.
|
From page 410... ...
1999. Survey of livestock influences on stream and riparian ecosystems in the western United States.
|
From page 411... ...
Pp. 393-397 In: Riparian ecosystems and their management: reconciling conflicting uses.
|
From page 412... ...
1989. Vegetative filter strips for nonpoint source pollution control.
|
From page 413... ...
1997. Riparian restoration in the western United States: overview and perspective.
|
From page 414... ...
1991. Riparian zone management model for optimized water quality, biomass and wildlife species diversity.
|
From page 415... ...
1983. Effects of late season cattle grazing on riparian plant communities.
|
From page 416... ...
1995. Water quality functions of riparian forest buffer systems in the Chesapeake Bay Watershed.
|
From page 417... ...
1997. Guidelines for managing cattle grazing in riparian areas to protect water quality: review of research and best management practices policy.
|
From page 418... ...
Pp. 233-254 In: Riparian management in forests of the continental Eastern United States.
|
From page 419... ...
1999. The benefits of watershed management: water quality and supply.
|
From page 420... ...
2000. Riparian forest buffer practices.
|
From page 421... ...
1997. Off-stream water sources for grazing cattle as a stream bank stabilization and water quality BMP.
|
From page 422... ...
2000c. NRCS Conservation Practice Standard Riparian Forest Buffer Code 391.
|
From page 423... ...
1991. Riparian forest buffers function and design for protection and enhancement of water resources.
|
From page 424... ...
424 Wue~ner, G
|
Key Terms
This material may be derived from roughly machine-read images, and so is provided only to facilitate research.
More
information on Chapter Skim is available.