Restoration of riparian vegetation along large rivers is complicated by the patchiness of the habitat and by conflicts with the societal need to control flooding. The Sacramento River Project, led by The Nature Conservancy in northern California, is testing whether it is possible to restore native forest along a large river without removing flood control. We conducted a post-hoc analysis of monitoring data collected by the project on 1-4-year old plantings of 10 native trees and shrubs at five sites. Two questions of general interest were: Can one identify types of species or sites that are especially suitable for restoration in such riparian habitats? To what degree must sites be treated as mosaics of patches, with different types of patches that are suited to different species? Plant performance as measured by height was better in species of Salicaceae or in species planted as cuttings than in species of other families or in species planted as seedings or seeds. Three within-site factors, land form, soil depth to a buried layer of sand or gravel, and soil texture, affected the growth of several species, indicating that sites do need to be treated as patchy. However, there was little evidence that different species performed better on different types of patches. Instead, areas with deep or fine soils seemed to be favorable for a number of species. Results suggest that it is feasible to re-establish native trees and shrubs along large, regulated rivers, at least at certain sites for an initial period of several years with the aid of weed control and irrigation. Shallowly buried layers or lenses of gravel or sand are a hidden, fine-scale factor that can reduce plant growth on river terraces.

Anderson, B. W. and R. D. Ohmart (1985). Riparian Revegetation as A Mitigating Process in Stream and River Restoration. The restoration of rivers and streams : theories and experience. J. A. Gore. Boston, Butterworth Publishers: 41-80

Apple, L. L., B. H. Smith, et al. (1985). The Use of Beavers for Riparian-Aquatic Habitat Restoration of Cold Desert Gully-Cut Stream Systems in Southwestern Wyoming Usa. INVESTIGATIONS ON BEAVERS. G. PILLERI. BERNE, SWITZERLAND, BRAIN ANATOMY INSTITUTE: BERNE, SWITZERLAND. 4: 123-130

Bell, G. (1997). Ecology and management of Arundo donax, and approaches to riparian habitat restoration in Southern California. Plant Invasions: Studies from North America and Europe. Leiden, The Netherlands, Blackhuys Publishers: 103-113 (http://teamarundo.org/ecology_impacts/arundo_ecology.html).

Carothers, S. W., G. S. Mills, et al. (1990). The Creation and Restoration of Riparian Habitat in Southwestern Arid and Semi-Arid Regions Usa. Wetland Creation and Restoration: The Status of the Science. J. A. Kusler and M. E. Kentula. Washington, D.C, Island Press: 351-366

Chambers, J. C. and J. C. Korfmacher (2001). "Relationships between stream incision, riparian vegetation dynamics, and restoration potential in Great Basin watersheds." Ecological Society of America Annual Meeting Abstracts 86: 68-69

Cleverly, J. R., J. R. Thibault, et al. (2001). "Middle Rio Grande riparian evapotranspiration, water balance, and restoration in space and time." Ecological Society of America Annual Meeting Abstracts 86: 72

Cornish, P. S. and S. Burgin (2005). "Residual Effects of Glyphosate Herbicide in Ecological Restoration." Restoration Ecology 13(4): 695 (http://www.blackwell-synergy.com/doi/abs/10.1111/j.1526-100X.2005.00088.x).

This study assesses the risks in ecological restoration arising from transplanting into soil containing glyphosate residues. Four Australian restoration species were grown for 60 days in nonadsorbing media treated continuously with glyphosate to establish threshold concentrations for damage. Visual signs of injury were observed in three species, and severe effects on root growth in all species, at solution concentrations as low as 18 mg/L. Only the perennial grass Themeda sp. died at this concentration, with other species surviving at concentrations in the range 36–360 mg/L, beyond which all plants died. Fourteen days exposure followed by removal of glyphosate from root media produced similar effects. Field and glasshouse experiments with the relatively tolerant tree species Angophora costata showed that application rates in the range 10–50 L/ha of herbicide product (360 g/L) would be needed to sustain damage to young plants transplanted into soil typical of local restoration sites. The volume of spray delivered using a hand-operated sprayer varied between operators by 5- and 10-fold to complete the same tasks, at the high end presenting a potential risk to the most tolerant species under field conditions, even when spray concentrations follow label instructions. For all but the most sensitive species, the risk of glyphosate residues in ecological restoration should be minimized by training operators of unregulated applicators to deliver controlled volumes of herbicide when spot spraying prior to transplanting.

Duran, N. L., K. A. Urick, et al. (2001). "Effects of aldicarb and atrazine on the microbial community structure and denitrification potential in soils from a riparian buffer restoration site." Abstracts of the General Meeting of the American Society for Microbiology 101: 643

Riparian buffers are vegetative areas along aquatic habitats that help minimize the movement of soils and reduce the nutrient loadings (nitrogen and phosphorus) into rivers and streams. In order to use riparian buffers as management tools, it is necessary to evaluate their nitrate removal capacity and the effects that anthropogenic chemicals may have in this process. Therefore, this study was conducted to investigate the effects of aldicarb (a pesticide) and atrazine (a herbicide) on the microbial community structure and denitrification potential of a riparian buffer restoration site using molecular biology techniques. Oligonucleotide primers specific for the nirK and nirS nitrite reductase genes were used to detect the denitrifying bacteria present in microcosms amended with aldicarb or atrazine via touchdown PCR. Sample DNA from all treatments revealed amplification of the nirK and nirS genes. However, the atrazine-treatments demonstrated weak band patterns visible only after reamplification. In addition, phospholipid fatty acid (PLFA) analyses revealed a shift in the microbial community structure and early stages of membrane toxicity were also observed as a result of atrazine exposure. Further characterization of the riparian restoration site indicated that the streambed zone had the highest microbial biomass content, heightened levels of toxicity, increased levels of Gram-positive and Gram-negative/anaerobic bacteria, and lower levels of actinomycetes and sulfur reducers as compared to the pasture area and vegetative riparian zone. The results of this study indicate that the presence of anthropogenic chemicals can impact the microbial communities and reduce the nitrate attenuation effectiveness of riparian buffers.

Fennessy, M. S. and J. K. Cronk (1997). "The effectiveness and restoration potential of riparian ecotones for the management of nonpoint source pollution, particularly nitrate." Critical Reviews in Environmental Science and Technology 27(4): 285-317

Friedman, J. M., M. L. Scott, et al. (1995). "Restoration of riparian forest using irrigation, artificial disturbance, and natural seedfall." Environmental Management 19(4): 547-557

In interior western North America, many riparian forests dominated by cottonwood and willow are failing to reproduce downstream of dams. We tested the hypothesis that establishment is now prevented by absence of the bare, moist substrate formerly provided by floods and channel movement. Along Boulder Creek, a dammed stream in the Colorado plains, we tested the effects of disturbance (sod removal), irrigation, and addition of seed on the establishment of seedlings of plains cottonwood (Populus deltoides subsp. monilifera) and peachleaf willow (Salix amygdaloides). In unirrigated, undisturbed plots, mean cottonwood density was 0.03 seedlings/m-2. Irrigation or disturbance alone produced mean cottonwood densities of 0.39 and 0.75 seedlings/m-2. Plots that were both irrigated and disturbed produced a mean cottonwood density of 10.3 seedlings/m-2. The effects of irrigation and disturbance on cottonwood establishment were significant (P lt 0.005); added seed had no significant effect (P = 0.78). The few cottonwood seedlings in unirrigated plots were in low positions susceptible to scour by future moderate flows. We conclude that cottonwood establishment along Boulder Creek is limited by the scarcity of bare, moist sites safe from future scour. Establishment of peachleaf willow was significantly affected only by disturbance; daily sprinkler irrigation did not provide sufficient moisture to increase survival of this species. Our results demonstrate the feasibility of restoring plains cottonwood forests using natural seedfall, even where only widely scattered adult trees are present. Because use of natural seedfall conserves the genetic makeup of the local population, this method may be preferable to the use of imported cuttings.

Gaffney, K. A. "Post eradication restoration protocols." from http://www.crpinc.org/eco/restoration.html#restore.

Goodwin, C. N., C. P. Hawkins, et al. (1997). "Riparian restoration in the Western United States: Overview and perspective." Restoration Ecology 5(4 SUPPL): 4-14

This historical and conceptual overview of riparian ecosystem restoration discusses how riparian ecosystems have been defined, describes the hydrologic, geomorphic, and biotic processes that create and maintain riparian ecosystems of the western USA, identifies the main types of anthropogenic disturbances occurring in these ecosystems, and provides an overview of restoration methods for each disturbance type. We suggest that riparian ecosystems consist of two zones: Zone I occupies the active floodplain and is frequently inundated and Zone II extends from the active floodplain to the valley wall. Successful restoration depends on understanding the physical and biological processes that influence natural riparian ecosystems and the types of disturbance that have degraded riparian areas. Thus we recommend adopting a process-based approach for riparian restoration. Disturbances to riparian ecosystems in the western USA result from streamflow modifications by dams, reservoirs, and diversions; stream channelization; direct modification of the riparian ecosystem; and watershed disturbances. Four topics should be addressed to advance the state of science for restoration of riparian ecosystems: (1) interdisciplinary approaches, (2) a unified framework, (3) a better understanding of fundamental riparian ecosystem processes, and (4) restoration potential more closely related to disturbance type. Three issues should be considered regarding the cause of the degraded environment: (1) the location of the causative disturbance with respect to the degraded riparian area, (2) whether the disturbance is ongoing or can be eliminated, and (3) whether or not recovery will occur naturally if the disturbance is removed.

Griggs, T., D. Peterson, et al. (1997). "Riparian forest restoration along the Sacramento River, California." Bulletin of the Ecological Society of America 78(4 SUPPL): 99

Harris, R. and C. Olson (1997). "Two-stage system for prioritizing riparian restoration at the stream reach and community scales." Restoration Ecology 5(4 SUPPL): 34-42

This paper describes a two-stage system for prioritizing stream reaches and riparian communities along a given river for protection or restoration. The system uses associations between geomorphology and riparian vegetation at stream reach and community scales as a basis for defining reference conditions. First-stage reach classification involves collecting and analyzing data from topographic maps and aerial photographs. These data, along with judgment-based criteria for ranking reaches relative to reference conditions, are used to classify stream reaches as suitable for protection, recommended for mitigation or restoration within existing site-specific regulatory procedures, or requiring further analysis to evaluate community-scale restoration needs. Second-stage field sampling is conducted on the reaches needing further analysis to determine the riparian communities present, the associations between communities and floodplain landforms, and reference community conditions. This stage requires collection of field data on geomorphic conditions, plant species composition, and plant community structure. Cluster analysis or a comparable technique is used to classify plant communities associated with floodplain landforms and identify reference conditions for each landform. Community structure and species composition are compared to reference conditions to define restoration possibilities at the community scale. The combined results from stream reach and community scale analysis provide a strategy for protecting and restoring riparian resources for a whole river. Implementation requires further site-specific information on hydrology, geomorphology, and other factors.

Harris, R. R. (1999). "Defining reference conditions for restoration of riparian plant communities: Examples from California, USA." Environmental Management 24(1): 55-63

Currently, there is an emphasis on restoration of riparian vegetation in the western United States. Deciding on what and where to restore requires an understanding of relationships between riparian plant communities and their environments along with establishment of targets, or reference conditions, for restoration. Several methods, including off-site data and historical analysis have been used for establishing restoration reference conditions. In this paper, criteria are proposed for interpreting reference community composition and structure from the results of multivariate cluster analysis. The approach is illustrated with data from streams in the California Sierra Nevada, Central Valley, and southern coastal region to derive descriptions of reference communities for stream reaches and floodplain landforms. Cluster analysis results can be used to quantify the areas of both degraded and reference communities within a flood-plain, thereby facilitating restoration cost estimation.

Hawkins, C. P., K. L. Bartz, et al. (1997). "Vulnerability of riparian vegetation to catastrophic flooding: Implications for riparian restoration." Restoration Ecology 5(4 SUPPL): 75-84

In this study, we examined the site-specific effects of a large episodic flood on the riparian vegetation within the floodplain of the San Luis Rey River in southern California. Using multispectral airborne videography, we quantified percent cover of riparian vegetation, cultivated agricultural land, urban surfaces, upland vegetation, bare soil, and water within 22 sections of floodplain, both before and after a large flood (January 13, 1993). We also quantified the amount of these cover types within bands of the watershed 1 km wide X 5 km long directly upstream of each floodplain site. The amount of riparian vegetation destroyed by the flood within each section varied from nearly zero to almost 40% of pre-flood coverage. The magnitude of loss in riparian vegetation was most strongly related to the amount of riparian vegetation initially present in the floodplain and the amount of urban surfaces in the nearby watershed. These results suggest that riparian vegetation within the San Luis Rey River floodplain is generally at high risk of destruction from large floods, and that this risk is exaggerated in areas with high urban development. We infer from these results that sites near existing large areas of intact riparian vegetation and away from urban development will have the highest potential for successful long-term restoration.

Hulse, D. W. and S. V. Gregory (2001). Alternative futures as an integrative framework for riparian restoration of large rivers. Applying ecological principles to land management V. H. Dale and R. A. Haeuber. New York, Springer: 194-212

Hunter, J. C., K. B. Willett, et al. (1999). "Prospects for preservation and restoration of riparian forests in the Sacramento Valley, California, USA." Environmental Management 24(1): 65-75

This GIS-based study analyzes the distribution and management of woody riparian vegetation in California's Sacramento Valley and discusses the prospects for its conservation. Although forests were the predominant floodplain vegetation prior to extensive settlement, only 3.3% of floodplain was covered by forest in the late 1980s. This remaining forest was fragmented into 2607 patches with an average area of 3.1 ha. Only 180 patches were > 10 ha, with three patches > 100 ha. Despite over two decades of conservation efforts, these forests are essentially unpreserved: Only 14.5% of extant forests are in public ownership or on land managed primarily for biological conservation. Some privately owned forests represent opportunities for preservation, but owing to their small size and scattered distribution, reforestation would be necessary to obtain a high cover of forest over large areas. Additionally, high property values, existing land uses, and regulated hydrology constrain conservationefforts. As a consequence of these constraints, and current distribution and ownership patterns, preservation or restoration of substantial areas of riparian forest would be extremely expensive and would divert conservation resources from other habitats in this rapidly developing state. Therefore, efforts to conserve these forests should satisfy two criteria: (1) that the specific goals are attainable with available funding and existing human uses, and (2) funding the effort will result in more effective regional conservation than would funding the conservation of other habitats.

Jensen, S. E. and W. S. Platts (1990). Restoration of Degraded Riverine-Riparian Habitat in the Great Basin and Snake River Regions Usa. Wetland Creation and Restoration: The Status of the Science. J. A. Kusler and M. E. Kentula. Washington, D.C, Island Press: 367-404

Jorgensen, E. E., T. J. Canfield, et al. (2000). "Restored riparian buffers as tools for ecosystem restoration in the MAIA; processes, endpoints, and measures of success for water, soil, flora, and fauna." Environmental Monitoring and Assessment 63(1): 199-210

Riparian buffer restorations are used as management tools to produce favorable water quality impacts, moreover among the many benefits riparian buffers may provide, their application as instruments for water quality restoration rests on a relatively firm foundation of research. However, the extent to which buffers can restore riparian ecosystems; their functionality and species composition, are essentially unknown. In light of the foregoing, two broad areas of research are indicated. First, data are needed to document the relative effectiveness of riparian buffers that differ according to width, length, and plant species composition. These questions, of managing buffer dimension and species composition for functionality, are of central importance even when attenuation of nutrient and sediment loads alone are considered. Second, where ecosystem restoration is the goal, effects to in-stream and terrestrial riparian biota need to be considered. Relatedly, the effects of the restoration on the landscape need to be considered. Particularly, at what rate do the effects of the riparian buffer on in-stream water quality, biota, and habitat diminish downstream from restored sites? Answers to these important questions are needed, for streams and watersheds of different size and for areas of differing soil type within watersheds. U.S. EPA-NRMRL has initiated a research project that will document the potential for buffers to restore riparian ecosystems; focusing on water quality effects, but also, importantly, documenting effects on biota. While substantial riparian buffer management initiatives are already underway, the extent of landscapes that influence riparian ecosystems in the eastern United States is large; leaving ample opportunity for this suggested research to provide improved buffer designs in the future. The ultimate goal of research projects developed under this paradigm of ecosystem restoration is to develop data that are needed to implement riparian buffer restorations in the mid-Atlantic and elsewhere, especially the eastern United States.

Kentula, M. E. (1997). "A comparison of approaches to prioritizing sites for riparian restoration." Restoration Ecology 5(4 SUPPL): 69-74

This study compares the results of Olson and Harris (1997) and Russell et al. (1997) in their work to prioritize sites for riparian restoration in the San Luis Rey River watershed. Olson and Harris defined reaches of the mainstem and evaluated the relative potential for restoration and protection based on cover of natural vegetation, land use, and connectivity. Then they used data on geomorphic conditions, plant species composition, and community structure to prescribe strategies for restoration. Russell et al. used a modeling approach within a geographic information system to combine data on wetness and land use/land cover to identify areas with potential for protection and restoration. They prioritized the areas based on patch size and proximity to extant riparian habitat. The mainstem and associated floodplain defined by Olson and Harris was more than twice the size of the area defined by Russell et al., because Olson and Harris considered the entire valley floor, whereas Russell et al. used a wetness index to identify saturated zones within the floodplain. For seven of the twelve management units delineated along the mainstem, the two studies agreed on a strategy of restoration or protection. They differed on two. No comparison could be made of the three units for which Olson and Harris used project review, a unique category. Agreement of the results is due to the similarity of criteria used to identify and rank sites for protection and restoration; disagreement is due primarily to the level of resolution of the data. Both approaches have potential for use in watershed-level planning. The predictive power of the two approaches may be maximized when they are used in a complementary fashion.

Kershner, J. L. (1997). "Setting riparian/aquatic restoration objectives within a watershed context." Restoration Ecology 5(4 SUPPL): 15-24

Declines in native plant and animal communities have prompted new interest in the restoration of aquatic and riparian ecosystems. Past restoration activities typically have been site specific, with little thought to processes operating at larger scales. A watershed analysis process developed in the Pacific Northwest identifies four operating scales useful in developing restoration priorities: region, basin, watershed, and specific site. Watershed analysis provides a template for restoration practitioners to use in prioritizing restoration activities. The template identifies seven key steps necessary to understand and develop restoration priorities: (1) characterization, (2) identification of key issues and questions, (3) documentation of current conditions, (4) description of reference conditions, (5) identification of objectives, (6) summary of conditions and determination of causes, and (7) recommendations. When a similar process was used in the Uinta Mountains, Utah, and in the Siuslaw National Forest, Oregon, specialists were able to identify key habitat conditions and habitat forming processes and then to establish restoration priorities and implement the appropriate activities. Watershed analysis provides a valuable set of tools for identifying restoration activities and is currently being used throughout the Pacific Northwest to develop management strategies and restoration priorities. Although the analysis requires significant time, money, and personnel, experience suggests that watershed analysis provides valuable direction for managing aquatic and riparian resources.

Landers, D. H. (1997). "Riparian restoration: Current status and the reach to the future." Restoration Ecology 5(4 SUPPL): 113-121

Nine articles in the special issue of Restoration Ecology addressing the subject of site selection for riparian restoration activities were critically examined for this review. The approaches described make significant and original contributions to the field of riparian restoration. All are interdisciplinary to some extent, often combining the fields of hydrology, geomorphology, and biology in the design of restorations. A common component among the articles is that they take a broad view, if not a watershed view, of restoration site selection. The approaches can be generally described as top-down strategic approaches to siting restorations, as opposed to the more methods- and site-driven bottom-up, or tactical, approach. All the articles recognize the importance of developing endpoints related to the ecological function of riparian ecosystems. They succeed in their quest for these indicators of ecological function to varying degrees. The most common indicator used in these papers is riparian vegetation. Several additional elements of scientific investigation, if successfully pursued, could provide vital information and advance our understanding of riparian restoration: developing interdisciplinary approaches more fully, defining endpoints and reference conditions; implementing multiple scale approaches; viewing restorations as experimental ecosystem manipulations; developing a philosophy regarding exotic species; incorporating geographic information systems more often; and integrating science, society, and politics. The foundation provided by the contributions in this issue should provide a strong basis for the rapid advancement of future research in the area of riparian restoration.

Leidy, R. (1998). Historical Distribution and Current Status of Stream Fishes of the San Francisco Estuary: Opportunities for Protection and Restoration of Native Fish Assemblages. State of the Estuary Conference. San Francisco Estuary Project, San Francisco

Luken, J. O. and J. W. Thieret (1997). Assessment and management of plant invasions. New York, Springer

Martin, D. W. and J. C. Chambers (1997). "Effects of potential restoration techniques on soil moisture, rooting depth, and rooting activity in central Nevada riparian meadows." Bulletin of the Ecological Society of America 78(4 SUPPL): 281

Meals, D. W. (2001). "Water quality response to riparian restoration in an agricultural watershed in Vermont, USA." Water Science and Technology 43(5): 175-182

Achievement of management goals for Lake Champlain (Vermont/New York, USA and Quebec, Canada) will require reduction of agricultural phosphorus loads, the dominant nonpoint source in the Basin. Cost-effective phosphorus reduction strategies need reliable treatment techniques beyond basic cropland and waste management practices. The Lake Champlain Basin Agricultural Watersheds National Monitoring Program (NMP) Project evaluates the effectiveness of livestock exclusion, streambank protection, and riparian restoration practices in reducing concentrations and loads of nutrients, sediment, and bacteria in surface waters. Treatment and control watersheds in northwestern Vermont have been monitored since 1994 according to a paired-watershed design. Monitoring consists of continuous stream discharge recording, flow-proportional sampling for total P, total Kjeldahl N, and total suspended solids, grab sampling for indicator bacterial, and land use/agricultural monitoring. Strong statistical calibration between the control and treatment watersheds has been achieved. Installation of riparian fencing, protected stream crossings, and streambank bioengineering was completed in 1997. Early post-treatment data suggest significant reduction in P concentrations and loads and in bacteria counts in the treated watershed. Monitoring is scheduled to continue through 2000.

Miller, C. (1997). Ecological restoration in riparian ecotones: A way forward for conservation. Proceedings of a Workshop on Scientific Issues in Ecological Restoration. M. C. Smale and C. D. Meurk. Landcare Research, P. O. Box 40, Lincoln, New Zealand 1997., Manaaki Whenua Press: 15-17

Mitchell, J. J., Giessow, and J. Giessow (2001). Role of the Santa Margarita and San Luis Rey Watersheds Weed Management Area in watershed-based exotic plant control and restoration in northern San Diego County. Proceedings, California Exotic Pest Plant Council Symposiums: Achievements and Challenges in Wildland Weed Management. M. Kelly. Berkeley, CA, California Exotic Pest Plant Council 6: 86 (http://www.cal-ipc.org/symposia/archive/index.php#2002).

Molles, M. C., C. S. Crawford, et al. (1997). "Managed floods. Restoration of riparian forest ecosystem structure and function along the Rio Grande." Bulletin of the Ecological Society of America 78(4 SUPPL): 24

Morrison, M. L., T. Tennant, et al. (1994). "Laying the foundation for a comprehensive program of restoration for wildlife habitat in a riparian floodplain." Environmental Management 18(6): 939-955

We analyzed the past and current distribution and abundance of vegetation and wildlife to develop a wildlife habitat restoration plan for the Sweetwater Regional Park, San Diego County, California. Overall, there has been a substantial loss of native amphibians and reptiles, including four amphibians, three lizards, and 11 snake species. The small-mammal community was depauperate and dominated by the exotic house mouse (Mus musculus) and the native western harvest mouse (Peithrodontomys megalotis). It appeared that either house mice are exerting a negative influence on most native species or that they are responding positively to habitat degradation. There has apparently been a net loss of 13 mammal species, including nine insectivores and rodents, a rabbit and three large mammals. Willow (Salix) cover and density and cottonwoods (Populus fremontii) had the highest number of positive correlations with bird abundance. There has been an overall net loss of 12 breeding bird species; this includes an absolute loss of 18 species and a gain of six species. A restoration plan is described that provides for creation and maintenance of willow riparian, riparian woodland, and coastal sage scrub vegetation types; guides for separation of human activities and wildlife habitats; and management of feral and exotic species of plants and animals.

Newhouser, M., C. Cornwall, et al. (1999). Controlling Arundo in Your Watershed: A Guide for Organizations. Sonoma CA, Sonoma Ecology Center and California State University, Sacramento, Media Services (http://teamarundo.org/education/org_guide.pdf).

This is a primer for organizations that wish to start an Arundo eradication program in their watershed. These include nonprofits, government agencies, and Resource Conservation Districts, as well as restoration companies working with such organizations. Groups working to control and eliminate other non-native invasive species from riparian areas can also use this guide. Contents: Working with landowners, addressing landowner concerns, negotiating an eradication agreement, working with volunteers and other stakeholders, eradication techniques, prevention and public outreach, Arundo identification, additional resources, landowner agreement. Also includes a sample landowner-contractor agreement.

Olson, C. and R. Harris (1997). "Applying a two-stage system to prioritize riparian restoration at the San Luis Rey River, San Diego County, California." Restoration Ecology 5(4 SUPPL): 43-55

A two-stage system for selecting stream reaches and riparian communities for restoration was applied to the 80-km San Luis Rey River below the Lake Henshaw dam in southern California. In the first stage, data from topographic quadrangles and aerial photographs were analyzed to define and classify reaches. These analyses concluded that (1) 28 km of the river and adjacent floodplain were suitable for second-stage evaluation of restoration needs and (2) 32 km met criteria for reference conditions at the stream reach scale and should be protected from further impacts. The remaining 20 km of the river and floodplain were considered unsuitable for restoration to reach-scale reference conditions; individual sites may be restored under existing regulatory review. Second-stage field sampling provided data on vegetation and floodplain landforms and substrate from more than 3000 plots within the 28 km of river and 1120 ha of floodplain selected for further study. Classification of floristic samples stratified by landform/substrate class indicated six primary riparian communities on the floodplain, some associated with particular floodplain landform/substrate classes and others ubiquitous. Reference conditions for these communities were interpreted from the data. There were two major departures from reference conditions: tree-dominated communities were less extensive than historic levels and exotic plants had significantly invaded some landforms and communities, displacing natural communities. General goals would include restoration of tree communities and removal of exotics, with further consideration of site-specific objectives. The results included estimates of the areas by community type requiring restoration. The approach was developed for streams in the semi-arid western United States, but it may be adapted for use elsewhere.

O'Neill, M. P., J. C. Schmidt, et al. (1997). "Identifying sites for riparian wetland restoration: Application of a model to the Upper Arkansas River basin." Restoration Ecology 5(4 SUPPL): 85-102

We present a conceptual model for identifying restoration sites for riparian wetlands and discuss its application to reaches within the Upper Arkansas River basin in Colorado. The model utilizes a Geographic Information System (GIS) to analyze a variety of spatial data useful in characterizing geomorphology, hydrology, and vegetation of riparian wetland sites. The model focuses on three basic properties of riparian wetland sites: relative soil moisture, disturbance regime, and vegetative characteristics. A relative wetness index is used to define nominal soil moisture classes within the watershed. These classes generally coincide with uplands (low), channel margins (moderate), and channels or open water (high). Vegetative conditions are characterized using color infrared aerial photographs. Land cover types are grouped into five major land cover classes: riparian, moist herbaceous, bare ground, upland, and open water. Disturbance regime is characterized by a reach-based index of specific power (omega). Preliminary results indicate that reaches within the Upper Arkansas River basin can be classified as high energy (omega greater than or equal to8 W/m2) or low energy (omega less than or equal to 3W/m2), using discharge estimates that reflect the 10-year flood event. Field surveys of channel and floodplain conditions show that high-energy reaches (omega greater than or equal to 8 W/m2) are characterized by sites where the channel occupies a large proportion of the valley bottom. By contrast, low-energy reaches (omega less than or equal to 3 W/m2) are characterized by meandering channels with wide alluvial valleys. Restoration potential is evaluated as a combination of nominal scores from wetness, land cover, and disturbance indices. Application of these methods to field sites within the Upper Arkansas River basin identifies a wide range of riparian wetland sites for preservation or restoration. Potential sites within identified reaches are prioritized using size and proximity criteria.

Opperman, J. J. and A. M. Merenlender (2000). "Deer herbivory as an ecological constraint to restoration of degraded riparian corridors." Restoration Ecology 8(1): 41-47

Ungulate herbivory can impact riparian vegetation in several ways, such as by reducing vigor or reproductive output of mature plants, and through increased mortality of seedlings and saplings. Much work has focused on the effects of livestock grazing within riparian corridors, while few studies have addressed the influence of native ungulate herbivory on riparian vegetation. This study investigated the effect of deer herbivory on riparian regeneration along three streams with degraded riparian corridors in Mendocino County, California. We utilized existing stream restoration efforts by private landowners and natural resource agencies to compare six deer exclosures with six upstream control plots. Livestock were excluded from both exclosure and control plots. Three of the deer exclosures had been in place for 15 years, one for 6 years, and two for 4 years. The abundance and size distribution of woody riparian plant species such as Salix exigua, S. laevigata, S. lasiolepis, Alnus rhombifolia, and Fraxinus latifolia were quantified for each exclosure and control plot. The mean density of saplings in deer exclosures was 0.49 plus-minus 0.15/m2, while the mean density of saplings in control plots was 0.05 plus-minus 0.02/m2. Within exclosures, 35% of saplings were less than 1 m and 65% were greater than 1 m; within control plots, 97% of saplings were less than 1 m in height. The fact that little regeneration had occurred in control plots suggests that deer herbivory can substantially reduce the rate of recovery of woody riparian species within degraded riparian corridors. Exclusionary fencing has demonstrated promising results for riparian restoration in a region with intense deer herbivory.

Osborne, L. L. and D. A. Kovacic (1993). "Riparian vegetated buffer strips in water-quality restoration and stream management." Freshwater Biology 29(2): 243-258

Quinn, L. and J. Holt (2003). Invasibility of Experimental Riparian Communities by Arundo donax. Proceedings of the California Invasive Plant Council Symposium: Planning Weed Management for Ecosystem Recovery. C. Pirosko. Berkeley, CA, California Invasive Plant Council. 7: 60 (http://www.cal-ipc.org/symposia/archive/index.php#2002).

Invasibility of experimental riparian communities by Arundo donax

Quinn, Lauren and Jodie Holt Department of Botany and Plant Sciences, University of California, Riverside <lquinn@citrus.ucr.edu>

As invasive plants enter new areas, they necessarily interact with resident plant communities. Several researchers have found a link between the functional diversity of a resident plant community and its invasibility. This study investigates the role of functional diversity in experimentally constructed riparian communities in regulating invasibility by Arundo donax L. Two experiments, differing only in planting density, were conducted simultaneously in an agricultural field at the University of California, Riverside. Three native riparian species (Salix goodingii, Baccharis salicifolia, and Scirpus americanus) representing three putative functional groups, were planted six to a plot in all combinations (seven community treatments). These communities were allowed to establish for 14 months before A. donax rhizomes were introduced into half of the plots in each experiment. A. donax was expected to invade more readily into single-species low-density plots and less readily into three-species high-density plots. Shoot emergence timing and shoot height for A. donax were monitored until senescence. In the first season, A. donax shoot emergence timing was not different when the two experiments were compared. Number of days to shoot emergence was significantly different among community treatments (p=0.008), and was greatest in single- or two-species plots containing B. salicifolia. Shoot growth rate was significantly greater (p=0.04) in the low-density experiment than in the high-density experiment, and was lower in single- or two-species plots containing B. salicifolia than in all other plot types. A. donax shoots emerged quickly and grew rapidly in "diverse" plots containing all three species. These data suggest that the establishment of A. donax is influenced by community composition, and that diverse communities may be more invasible than some simpler ones. The poor performance of A. donax in plots containing B. salicifolia may provide support for use of this species in riparian restoration following A. donax removal.

Russell, G. D., C. P. Hawkins, et al. (1997). "The role of GIS in selecting sites for riparian restoration based on hydrology and land use." Restoration Ecology 5(4 SUPPL): 56-68 (http://www.blackwell-synergy.com/links/doi/10.1111%2Fj.1526-100X.1997.00056.x).

Successful long-term wetland restoration efforts require consideration of hydrology and surrounding land use during the site selection process. This article describes an approach to initial site selection in the San Luis Rey River watershed in southern California that uses watershed-level information on basin topography and land cover to rank the potential suitability of all sites within a watershed for either preservation or restoration. This approach requires the use of a geographic information system (GIS) to map relative wetness and land cover within a watershed. Relative potential wetness values were derived from U.S. Geological Survey (USGS) 30-m digital elevation models by calculating the flow that would potentially accumulate at all 30-m X 30-m pixels within the watershed. Land cover was derived from a Landsat scene covering the 1500 km2 study area. We ranked sites (contiguous groups of pixels > 1 ha with similar land cover) in terms of their potential for restoration or preservation based on their wetness values (low, medium, and high), size, and proximity to existing riparian vegetation. Sites with medium or high wetness values and extant vegetation were identified as potential preservation sites. Agricultural or barren sites with medium to high wetness were identified as potential restoration sites. Approximately 5500 ha (3.67% of the total watershed) were prioritized for preservation or restoration.

Smith, E. B., M. S. Silbert, et al. (1997). "Integrated ecological restoration of a high-elevation riparian forest in northern Arizona." Bulletin of the Ecological Society of America 78(4 SUPPL): 187

Stevens, M. L. (1997). "The effects of traditional California Indian management practices on the autecology of white root (Carex barbarae); implications for riparian woodland restoration." Bulletin of the Ecological Society of America 78(4 SUPPL): 191

Stromberg, J. C. (2001). "Restoration of riparian vegetation in the south-western United States: Importance of flow regimes and fluvial dynamism." Journal of Arid Environments 49(1): 17-34

Riparian ecosystems in the south-western United States have undergone extensive physical and biological changes, due, in part, to alteration of natural flow regimes and suppression of fluvial processes. Many riparian ecosystem restoration projects are achieving success because they recognize the importance of restoring the hydrologic regime. In other words, these projects are restoring flows of water and sediment in sufficient quantities and with appropriate temporal and spatial patterns. Other projects have proceeded without recognition of the need to incorporate environmental stream flow requirements into management plans. To increase success rate of riparian ecosystem restoration, this paper describes some changes that have occurred within riparian ecosystems of the southwestern United States, reviews the role of stream flow regimes in structuring riparian plant communities, and assesses various ways in which riparian plant communities can be restored by naturalizing ecological processes.

Sweeney, B. W., S. J. Czapka, et al. (2002). "Riparian forest restoration: Increasing success by reducing plant competition and herbivory." Restoration Ecology 10(2): 392-400

The reestablishment of riparian forest is often viewed as "best management practice" for restoring stream ecosystems to a quasi-natural state and preventing non-point source contaminants from entering them. We experimentally assessed seedling survivorship and growth of Quercus palustris (pin oak), Q. rubra (red oak), Q. alba (white oak), Betula nigra (river birch), and Acer rubrum (red maple) in response to root-stock type (bare root vs. containerized), herbivore protection (tree shelters), and weed control (herbicide, mowing, tree mats) over a 4-year period at two riparian sites near the Chester River in Maryland, U.S.A. We started with tree-stocking densities of 988/ha (400/ac) in the experimental plots and considered 50% survivorship (i.e., a density of 494/ha (200/ac) at crown closure) to be an "acceptable or minimum" target for riparian restoration. Results after four growing seasons show no significant difference in survivorship and growth between bare-root and containerized seedlings when averaged across all species and treatments. Overall survivorship and growth was significantly higher for sheltered versus unsheltered seedlings (49% and 77.6 cm vs. 12.1% and 3.6 cm, respectively) when averaged across all species and weed control treatments. Each of the five test species exhibited significantly higher 4-year growth with shelter protection when averaged across all other treatments, and all species but river birch had significantly higher survivorship in shelters during the period. Seedlings protected from weeds by herbicide exhibited significantly higher survivorship and growth than seedlings in all other weed-control treatments when averaged across all species and shelter treatments. The highest 4-year levels of survivorship/growth, when averaged across all species, was associated with seedlings protected by shelters and herbicide (88.8%/125.7 cm) and by shelters and weed mats (57.5%/73.5 cm). Thus, only plots where seedlings were assisted by a combination of tree shelters and either herbicide or tree mats exhibited an "acceptable or minimum" rate of survivorship (i.e., >50%) for riparian forest restoration in the region. Moreover, the combined growth and survivorship data suggest that crown closure over most small streams in need of restoration in the region can be achieved most rapidly (i.e., 15 years or less) by protecting seedlings with tree shelters and controlling competing vegetation with herbicides.

Tucker, G. F., B. A. Schrader, et al. (1992). "Restoration Ecology of Coastal Oregon Riparian Areas an Applied Approach." Bulletin of the Ecological Society of America 73(2 SUPPL): 369

Washitani, I. (2001). "Plant conservation ecology for management and restoration of riparian habitats of lowland Japan." Population Ecology 43(3): 189-195

Conservation ecology is a new paradigm of ecology that aims at scientific contributions to maintaining earth's biodiversity and is committed to ecosystem management indispensable to intergenerational long-term sustainability. Population ecology plays a central role in conservation ecology. Persistence of the metapopulation rather than that of each local population should be pursued in species conservation management. Biological interactions essential to reproduction and soil seed bank components of the population should be investigated and applied to planning for the conservation of a plant population. Gravelly floodplains and moist tall grasslands are among typical riparian habitats containing many threatened plants in Japan. These riparian habitats are now subjected not only to heavy fragmentation but also to intensive invasion of highly competitive alien (nonnative) plants. Extreme habitat isolation may result in reproductive failure or fertility selection in a plant population without pollinators, as exemplified by a nature reserve population of Primula sieboldii. Biological invasions, which are facilitated by extensive changes in the river environment including decreased seasonal flooding, abandonment of traditional vegetation management, eutrophication, and extensive clearing of the land for recreational use, threaten endemic riparian species. To preserve safe sites and growing conditions for threatened plants such as Aster kantoensis, active management to suppress the dominance of alien invader plants is necessary. Population management and habitat restoration should be based on sound information on the population ecology of both threatened and alien invader plants, designed as an ecological experiment to clarify effective ways for management.

Willard, D. E., V. M. Finn, et al. (1990). Creation and Restoration of Riparian Wetlands in the Agricultural Midwest. Wetland Creation and Restoration: The Status of the Science. J. A. Kusler and M. E. Kentula. Washington, D.C., Island Press: 327-350

Williams, K. S. (1994). "Terrestrial arthropods as indicators of riparian habitat restoration in southern California." Bulletin of the Ecological Society of America 75(2 PART 2): 249-250

Wissmar, R. C. and R. L. Beschta (1998). "Restoration and management of riparian ecosystems: A catchment perspective." Freshwater Biology 40(3): 571-585

1. We propose that strategies for the management of riparian ecosystems should incorporate concepts of landscape ecology and contemporary principles of restoration and conservation. A detailed understanding of the temporal and spatial dynamics of the catchment landscape (e.g. changes in the connectivity and functions of channel, riparian and terrestrial components) is critical. 2. This perspective is based upon previous definitions of riparian ecosystems, consideration of functional attributes at different spatial scales and retrospective analyses of anthropogenic influences on river catchments. 3. Restoration strategies must derive from a concise definition of the processes to be restored and conserved, recognition of social values and commitments, quantification of ecological circumstances and the quality of background information and determination of alternatives. 4. The basic components of an effective restoration project include: clear objectives (ecological and physical), baseline data and historical information (e.g. the hydrogeomorphic setting and the disturbance regime), a project design that recognizes functional attributes of biotic refugia, a comparison of plans and outcomes with reference ecosystems; a commitment to long-term planning, implementation and monitoring and, finally, a willingness to learn from both successes and failures. 5. Particularly important is a thorough understanding of past natural disturbances and human-induced changes on riparian functions and attributes, obtained by a historical reconstruction of the catchment.

Xu, F.-L., S. Tao, et al. (1999). "The restoration of riparian wetlands and macrophytes in Lake Chao, an eutrophic Chinese lake: Possibilities and effects." Hydrobiologia(405): 169-178

Experiments with replanting macrophytes in Lake Chao showed that the water quality inside an Alternathera philoxeroides Griseb. and a Phragmites australis community were better than outside. Transparency was significantly higher and the content of N and P decreased inside the communities, as did the rate of sedimentation of organic suspended matter in the Phragmites australis community. Modeling revealed that macrophyte restoration could decrease phytoplaniton biomass, increase fish biomass, exergy, structural exergy, zooplankton/phytoplankton ratio and transparency (Xu et al., 1999b). It is concluded that macrophyte restoration can purify lake water, regulate lake biological structure and control eutrophication.

Zalewski, M., B. Bis, et al. (1998). "The importance of the riparian ecotone and river hydraulics for sustainable basin-scale restoration scenarios." Aquatic Conservation 8(2): 287-307

1. The effect of riparian ecotone functional complexity and stream hydraulics on an upland river ecosystem has been analysed. 2. The amount of nutrients retained by bottom sediment was lowest on a sandy substrate (range: 26-104 mg m-2 P-PO4) and highest in wetland bays (range: 558-5368 mg m-2 P-PO4). A stream bed covered by Berula erecta had about three times higher retentive nutrient capacity (x = 584 mg m-2 day-1) than did a sandy substrate x = 205 mg m-2 day-1). 3. The amount of allochthonous organic matter (CPOM) deposited on the stream bed decreased with current velocity. The trophic potential of CPOM, measured as total protein, was significantly correlated with the amount of deposited CPOM (r = 0.863; p < 0.00001) and depended on stream order. 4. Both invertebrate and fish biomass in the upland river were significantly correlated with calcium/bicarbonate (benthos: r = 0.858; p < 0.006; fish: r = 0.918; p < 0.001). 5. Fish biomass, diversity and species richness were highest in pools, lower in riffles and lowest in the run/transition zone. 6. Macroinvertebrate biomass was highest at an intermediate riparian ecotone complexity with an adequate supply of organic matter and incident light. Fish biomass followed the same trend, being lowest in heavily shaded areas and in open channels without riparian vegetation (range: 1-4.5 g m-2), but highest in ecotones of intermediate complexity (range: 1.6-92.8 g m-2). The ,cascading effect' of invertebrate density depletion, which was inversely related to fish biomass, was observed seasonally. 7. The above results indicate that riparian ecotone structure and the heterogeneity of the stream channel may regulate biodiversity, productivity and nutrient retention in the fluvial corridor. These quantitative data help to create alternative scenarios for sustainable river basin management.

Zembal, R. a. S. H. (2000). "Environmental Assessment of the Santa Ana Watershed Program."

The Santa Ana River (SAR) watershed encompasses about 3,200 square miles, comprising the largest river system in coastal southern California (Figure 1). Human development and activities in the watershed have greatly reduced the floodplain and associated habitats and deleteriously affected the river's natural function and processes.

The purpose of the Santa Ana River Watershed Program is to gradually restore as much of the natural function of the river as possible, thereby maximizing the natural resources supported by this river system. This report describes the current Santa Ana River Watershed Program in 2000-2002, which focused on the control of invasive weeds especially Arundo donax (giant reed) and Tamarix (saltcedar) as well as the restoration of wetland habitat, management of endangered species, and public