Riparian Restoration

CHAPTER 5: RESTORATION TECHNIQUES (CONTINUED)

Planting Specifics

Workers should—

• Plant woody species rooted stock and transplants with their crowns 0.5 to 2 inches above the soil surface. Build a water retention basin around each plant. On a slope build a crescent basin, leaving the uphill side open. The berm of soil on the downhill side will capture runoff. Fill the basin with water. Tamp the soil to squeeze out air bubbles and add more soil, if necessary. Be sure the crowns are exposed. See figure 78.

Figure 78—A water retention basin will catch
water to help keep soil moist.

• Plant herbaceous plants with their crowns even with the ground level.
  
  
• Consult with specialists on planting times and irrigation needs.

Pests

The following methods are used to combat pests. (See appendix D.) Workers should—

• Overplant a bit and lose a few plants to browsing and gophers. (Do not do this if there is an overpopulation of animals, deer for instance.)
  
  
• Install a plastic or cardboard weed mat at the base of plants to lessen weed competition.
  
  
• Install a chicken-wire basket around plant roots to protect against rodents. Be sure baskets are large enough to avoid restricting roots. Be sure the soil has a high enough mineral and water content to rust the cages (ask the soil scientist), or they will end up girdling the roots and the plants will die. Do not use stainless steel wire. (If an area floods near planting time, rodents may not be a worry for a while. Flooding kills some rodent populations.)
  
  
• Use wire cages to protect individual plants from browsing, if possible. Use planting collars to protect seeds, seedlings, and cuttings during the first year of growth.
  
  
• Use 4-foot plant collars or tubes on trees and shrubs if browsing and rodents are a problem. Tubes are made of translucent material or mesh.
  
  
• Install raptor perches and/or barn owl boxes, if these birds are native to the site, to encourage the presence of rodent-eating birds.

Mulch

Mulch holds moisture in the soil, helps prevent wind and rain erosion and rain compaction of soil, and helps control weeds. Workers should mulch up to 2 inches deep. Seed size may dictate mulch thickness. A larger seed, such as an oak, benefits from thick mulch. The mulch hides the seeds from birds and squirrels, so more seeds germinate. A thin layer of mulch would promote the germination of a different type of seed at the expense of the oak, for instance (Dunmore 2000).

Mulch can be clean, weed-free rice straw; clean, shredded hardwood from the forest; or leaf litter and humus (duff) from adjacent sites. Leaf litter may be the best mulch because it is native to the site and contains native seeds. Some of these seeds will germinate and provide more plants in the restoration site. Humus provides organic matter to promote plant growth and soil regeneration. Bark chips are not recommended because they decompose slowly, robbing nitrogen from the soil, and they have a tendency to float away and do not knit together (LaFayette and others 2001).

In high mountain projects, scarification and adding organic matter and compost before planting and seeding did result in higher success rates than just scarification or scarification and organic matter. Test plots showed that mulch resulted in greater canopy development and a smaller increase in height (Cole and Spildie 2000).

Irrigation

In many parts of the United States where rain is plentiful or the ground water is high, irrigation may not be necessary. When irrigation is necessary, workers should use sprinklers and avoid drip systems; drip tubing is quickly eaten by wildlife. They can pump water from an adjacent channel or lake using a portable generator, or use a water truck. In general, workers should water during the dry months of the first year after installation.

Water until the soil is deeply saturated to enhance deep root growth and survivability. A Yosemite National Park publication had two examples: One site was irrigated for a 24-hour period once per month; another was irrigated for 8 hours twice a month. Both had similar survival rates despite extremely porous, sandy-to-cobbled soils (Tucker 1998). These sites were watered during the dry months for the first year after installation. It is important to check the saturation level on the site; one watering per month may be too little and the soils may be different, dictating a different watering profile. Workers should consult a soil scientist, local botanist, landscape architect, native-plant society, or nursery about irrigation frequency and duration.

Recently, staff at Yosemite revised its irrigation ideas. If a restoration site is in full sun and precipitation has been limited for 1 month, plants are irrigated using the above saturation method. July, August, and September are the dry months. If the cuttings are in the shade, they receive no irrigation. Cuttings are planted using the waterjet stinger, so it is assumed that their roots will be at the dry-season water level. The irrigation is to ensure survival when there is little precipitation (Fritzke 2001).

Management

Most project success comes from good management. Genesis of projects can also come from good managers who notice problems and seek solutions.

Studies sponsored by the Carhart National Wilderness Training Center have shown the following management strategies to be successful:

• Minimize visitor impacts by controlling distribution and location of visitor use (Cole as quoted in Alexander and Fairbridge 1999).
  
  
• Tell visitors what fees are used for; this has produced positive responses.
  
  
• Close and restore campsites. This strategy is seen as active management and has strong visitor support (Cole 1997). A closed site may take 10 years or longer to restore (Cole 2000c). Many factors affect recovery time, including climate, soil conditions, and inherent resiliency of an ecosystem.
  
  
• Involve the public through education and information. “Educating our visitors [and potential wildland visitors] about proper behavior on public lands and communicating effectively with them will be the foundation for making them partners in management, not passive recipients of authoritarian regulation and control.” (Lucas 1986) The nonprofit organization, Leave No Trace, Inc. (LNT), has a partnership with the USDA Forest Service and has developed many information packets. LNT will also assist, at no cost, in developing new information sheets (National Outdoor 1996).
  
  
• To be effective, recreation management depends on simultaneous consideration of both social and physical-biological goals. Management of recreation impacts is largely management of people’s perceptions, behaviors, and needs (Cole as quoted in Alexander and Fairbridge 1999).
  
  
• Intensified site management to protect natural resources is a good strategy. “The ultimate goal of the programs would be to minimize the areal [of, relating to, or involving the area] extent of physical impacts by channeling traffic and rehabilitating some portion of existing damaged sites. Certain trails, day-use areas, and campsites would be designated for use, while others would be closed off and restored. Visitors would be asked to use open trails and to stay off closed trails and areas.” (Cole 1997)

Adaptive Management

Once the site is restored, adaptive management ensures the integrity of the site. Adaptive managers use original project objectives. They must be measurable. These monitoring objectives, which support the natural processes of the restoration site, are used as management guides. For example, if a section of the site is being misused, the management makes changes to address this misuse and to ensure the continued health of the riparian ecosystem. In other words, management techniques are changed or adapted to continue to meet the project objectives.

In some cases an objective may seem unachievable, making it easy to dismiss it and dash off a new objective, which is not good management. To dismiss an objective, a manager needs to describe what method was used to determine that the objective could not be met. In other words, the manager should document the decision using scientific evidence. When new objectives are forged, the manager should describe how they will be measured, a timeline for attainment, and a method for discerning when they are not achievable.

Monitoring and Maintenance

Monitoring and maintenance are intertwined; monitoring may lead to maintenance and vice versa. Both are critical for project success.

Monitoring

Monitoring is a way to ascertain a project’s success. Workers should monitor a project for at least 5 years to see that growth is occurring. It is important to monitor the vegetation’s growth and its functions. Workers might ask, for example, how animals are using the area or whether erosion has lessened. They might also monitor appropriate and inappropriate uses by visitors, site managers, maintenance crews, and other personnel.

The project objectives, which are really performance objectives, can serve as monitoring objectives. Two examples of such objectives are—

• Native vegetation will increase in density by 50 percent, as one indicator of riparian functional and structural characteristics, in 5 years. When the 50 percent density level is achieved, the site should continue to be monitored to ensure that native plant density does not dip below 50 percent.
  
  
• Resident bird species will increase by 20 percent in 3 years.

Riparian ecosystems are subject to flooding, so plant growth may not be steady, and drought, flooding, wind, normal streambank erosion, sediment deposition, and so on will affect plant growth and survival. Note whether the riparian structure and function are returning and whether the vegetation is becoming a self-perpetuating riparian plant community. A selfperpetuating riparian plant community equates to restoration. To compare what is happening on the restoration site to the reference site, use the same sampling techniques to gather information on both sites.

Photographs can help monitoring efforts by showing changes over time. Workers should establish set photo points to use before restoration, immediately after restoration installation, and at set intervals into the future. They can use survey or global positioning system (GPS) coordinates to site photo points accurately to consistently photograph the same area from the same point; this makes comparison possible. If the photo point changes, it is difficult to track the same spot’s progress. If workers pound a rebar or survey marker into the ground below ground surface as a reference point, they can use a metal detector to locate it later.

Workers should also monitor the project by doing the following:

• Note which plants are doing well and which did not survive.
  
  
• Observe whether a correlation exists between the growth rate of certain cuttings and the “mother” plants. Keep track of where seeds, cuttings, and plants were harvested.
  
  
• Determine whether the installation is functioning as designed.
  
  
• Note which areas are maturing more rapidly than others and why.
  
  
• Note which seeds germinate in various locations.
  
  
• Determine which native plants have returned to the site through natural succession.
  
  
• Observe what has sprouted in the second season. Some plants may have died after the first year and some plants may have just come alive.
  
  
• Note which areas are experiencing difficulty and why. This may be natural for a small area that has a different soil type, for instance.
  
  
• Observe whether streambanks and lakeshores are stabilizing or are washing away and why.
  
  
• Note if something is occurring that is a surprise.
  
  
• Determine which planting techniques are succeeding and which are not.
  
  
• Observe whether an increased number of shrews, deer mice, voles, gophers, and earthworms are present in the soil. (Their presence is good.)
  
  
• Note what wildlife is using the area and for what purposes.
  
  
• Observe whether macroinvertebrate levels have changed. If they have, determine whether the change is for better or worse.
  
  
• Note whether the water temperature is changing.
  
  
• Note whether the soil moisture is changing. If it is, determine whether the change corresponds to a certain decompaction method used.

Monitoring for use

Adaptive management cannot take place unless the restored site is monitored. Monitoring can catch a problem before it is out of control, and adaptive management enables managers to change management to address problems.

Indicators, which are characteristics that change in response to use, are part of monitoring/managing objectives. Loss of woody debris in and around campsites and bare mineral soil both indicate that structure and function may be threatened. Absence of expected wildlife might also be an indicator (Elzinga and others 1998).

“Visitors will use the hardened beach path 90 percent of the time” is a project management objective. Managers can monitor this by looking for social trail development and trampled vegetation. (Social trails need to be blocked immediately upon discovery, vegetation replanted, and further use discouraged.) If visitors are not using the hardened path, managers need to find out why and take action. They might ask if the path is in the wrong place, or if it is a matter of visitor education.

Managers should monitor for the following:

• Are individuals—
  • Staying on the trails?
  • Taking shortcuts?
  • Trampling vegetation?
  • Cutting down vegetation?
  • Trampling banks?
    
    
• Is the site overcrowded?
  
  
• Are inappropriate uses occurring; if so, what are they?
  
  
• Has the area been trampled, grazed, or driven over?
  
  
• What is working as planned; what is not working as planned?

It is important to determine whether campsite dimensions are expanding by using “Campsite Monitoring Instructions” in appendix F.

Maintenance

Maintenance of a newly installed project is absolutely necessary during the first few years after installation or until the vegetation becomes established. Site maintenance is critical to giving the project every chance to be effective over a long period. Project partners may be willing to assist in maintenance. Workers should—

• Repair fences, replant and reseed as necessary, and remove weeds and excessive debris that may shade and compete with cuttings and new plants.
  
  
• If a flood occurs days after installation, not an uncommon occurrence, replant and rebuild structures as necessary.
  
  
• Inspect the project every other week for the first 3 months after installation, then once per month for the next 6 months, and every 2 months for at least 2 years. Inspect after heavy precipitation, flooding, snowmelt, drought, or an occurrence that is out of the ordinary.
  
  
• Check for damage from the following:
  • flooding
  • wildlife
  • grazing
  • a fetch
  • boat wakes
  • trampling
  • drought
  • high precipitation

Table 1 is a sample monitoring form. Use it or your own version to fit your projects. Be sure that monitoring and maintenance are part of each project.

Appendix G contains techniques for establishing plants in an ecosystem.

Appendix H includes publications and internet sites.

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