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Ecological restoration is the process of
assisting the recovery of an ecosystem Society for Ecological Restoration, www.ser.org
Ecological restoration is an intentional activity that initiates or accelerates the recovery of an ecosystem with respect to its health, integrity and sustainability. Frequently, the ecosystem that requires restoration has been degraded, damaged, transformed or entirely destroyed as the direct or indirect result of human activities, such as the intentional or unintentional introduction of invasive species. In some cases, impacts to ecosystems have been caused or aggravated by natural agencies such as wildfire, floods, storms, or volcanic eruption, to the point at which the ecosystem cannot recover its pre-disturbance state or its historic developmental trajectory. Restoration attempts to return an ecosystem to its historic trajectory. Historic conditions are therefore the ideal starting point for restoration design. The restored ecosystem will not necessarily recover its former state, since contemporary constraints and conditions may cause it to develop along an altered trajectory. The historic trajectory of a severely impacted ecosystem may be difficult or impossible to determine with accuracy. Nevertheless, the general direction and boundaries of that trajectory can be established through a combination of knowledge of the damaged ecosystem's pre-existing structure, composition and functioning, studies on comparable intact ecosystems, information about regional environmental conditions, and analysis of other ecological, cultural and historical reference information. These combined sources allow the historic trajectory or reference conditions |
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to be charted from baseline
ecological data and predictive models, and its emulation in the restoration
process should aid in piloting the ecosystem towards improved health and
integrity. In the simplest circumstances, restoration consists of removing or modifying a specific disturbance, thereby allowing ecological processes to bring about an independent recovery. For example, removing a dam allows the return of an historical flooding regime. In more complex circumstances, restoration may also require the deliberate reintroduction of native species that have been lost, and the elimination or control of harmful, invasive exotic species to the greatest practicable extent. Often, ecosystem degradation or transformation has multiple, protracted sources, and the historical constituents of an ecosystem are substantially lost. Sometimes the developmental trajectory of a degraded ecosystem is blocked altogether, and its recovery through natural processes appears to be delayed indefinitely. In all of these cases, however, ecological restoration aims to initiate or facilitate the resumption of those processes that will return the ecosystem to its intended trajectory. When the desired trajectory is realized, the ecosystem under manipulation may no longer require external assistance to ensure its future health and integrity, in which case restoration can be considered complete. Nevertheless, the restored ecosystem often requires continuing management to counteract the invasion of opportunist species, the impacts of various human activities, climate change, and other unforeseeable events. In this respect, a restored ecosystem is no different from an undamaged ecosystem of the same kind, and both are likely to require some level of ecosystem management. Although ecosystem restoration and ecosystem management form a continuum and often employ similar sorts of intervention, ecological restoration aims at assisting or initiating recovery, whereas ecosystem management is intended to guarantee the continued well-being of the restored ecosystem thereafter. Clearly, managing and controlling invasive plants is a restoration action in and of itself. We can also look at restoration as a Management Tool or a means of controlling or managing invasive plants. Either way, restoration plays an important role in Adaptive Management. Where and when it gets considered in the process depends on how it is used or viewed. Consider the following issues related to restoration of managed lands: Plant Material used in Restoration One concept that deserves further consideration is the idea of restoring an area by means of deliberately reintroducing native species that have been lost or removed. This is a concept that many land managers will be familiar with especially as it relates to addressing areas that have been impacted by activities that leave damaged or disturbed bare ground (well-site development, road building, facility construction, insect or disease outbreaks, fire, etc.). Depending on the site conditions, goals for restoration and resources available, plant material in the form of a seed mix or nursery stock can be used to restore a site. Before purchasing plant material or planting, take into account the following best management practices from the Lady Bird Johnson Wildflower Center:
SELECTING A SUITABLE SUPPLIER It is an ideal situation if the expertise, equipment, and staff are available to produce propagated native plant material or native seed on site for the restoration project. However, this is usually not feasible. Often a suitable supplier must be chosen to perform the work. Native plant material is available from retail or wholesale nurseries or specialized growers. Native seed is available from commercial seed suppliers. Some nurseries, growers, and seed collectors may specialize in native plants and some may only include them as part of their business. Choosing a supplier who specializes in native plants and seeds is desirable, but is not always an option. TIMING is extremely important in this phase of project planning. It is virtually impossible for suppliers to keep a giant inventory of native plants and seeds on hand at all times. Suppliers try to anticipate needs for variety and quantity of native plants and seeds, but it is difficult. Also, it can take several years to grow plant material or collect seed for a specific project. This is very important to remember as you are searching for a supplier that can help you acquire the plants or seeds that you need. PLANT MATERIAL SUPPLIERS Select nurseries or plant growers that have experience working in your ecoregion and carry plant materials or can collect plant materials from the area in which you are doing the project (within the same ecoregion). The supplier should have staff knowledgeable about local native flora. If specific plants are to be grown for the restoration project, interview the grower about their knowledge of propagating all planned species. Ask them to send catalogs and/or price lists if available. Find out where and how the plants they are selling have been grown. Plants may have been grown in a very different part of the country and would thus not be well-suited for the restoration site. Make sure plant material has never been dug in the wild and removed from its natural habitat. Unfortunately, this practice does occur and has negative far-reaching effects on natural systems and native plant populations. Nursery owners and growers should assure the customer that all plants have been "nursery propagated." This means that staff have collected only seeds or cuttings from the wild, and have not removed whole plants from the wild. You should also ask the supplier for information about the original location of the parent plant material so you can determine how locally adapted the plants might be. Good native plant nurseries will have this type of information on record. If plants have been salvaged, ask the staff person where and how they were salvaged. Ethical salvage occurs when plants are removed before some type of construction or destruction takes place and always with the landowners' permission. Plan to visit the nurseries. Nursery grounds should be clean and orderly. Survey plant material for general vigor and health. Note the presence or absence of weeds on the grounds or in container plants. Some weeds are acceptable, since it is extremely difficult to control weeds in nurseries. Many nursery operators are trying to reduce their pesticide use and may therefore be weeding everything by hand, which is time-consuming. Note how well equipment on site is maintained and cared for (e.g. tractors, greenhouse systems, irrigation systems, etc.). Nurseries and growers may advertise membership in professional trade organizations such as the American Association of Nurserymen, International Society of Arboriculture, or their state Nursery and Landscape Association. Although these trade memberships are not required for operation, they show that the owners care about keeping abreast of current issues, regulations, technology, product improvement, etc. in the nursery trade. SEED SUPPLIERS Many of the considerations for choosing plant material suppliers also apply to choosing seed suppliers. Again, try to choose a seed supplier that operates in the same geographic ecoregion as the restoration site, as that supplier is most likely to have native seed suitable for that area. There are companies which specialize in native seed collection and processing, and these individuals can have a wealth of knowledge about native plants and seeds. Ask them to send catalogs and/or price lists if available. UNDERSTADING THE IMPORTANCE OF GENETICS There has been a growing awareness recently of the importance of plant genetics in restoration projects. Genetic variation within plant species can influence their long-term chances of survival and growth. Sometimes specialized ecotypes within a species develop that are adapted to specific local environmental conditions. An ecotype is a certain population of plants within a species that, due to different genetics, has a different form (height, leaf size, etc.), flowering time, or hardiness that is adapted to certain environmental conditions. Plant ecotypes are not different species because they can still interbreed. Taking plant species that are of one ecotype and moving them to an area with environmental conditions different than the ones that the plant is adapted to, such as different freezing stresses or different moisture levels, can result in poor growth or death. These types of genetic concerns have been recognized for quite a while in the forestry industry. Tree seed zones have been developed for specific tree species based on an understanding of their genetic variation across the landscape. Seeds are only planted in the same tree seed zone they were collected from, in order to increase the plants' chances of survival and adaptability. However, it is only recently that some scientists have begun to examine the genetic variation of herbaceous or shrub species across the landscape. Consequently there is very little information available yet about what might be the appropriate distance to relocate native plant species. In addition to concerns about the ability of the planted species in restoration projects to survive and adapt, some people are concerned that the introduction of new genetic material in an area can damage local populations of native species. The thought is that new genetic material could result in the weakening of local populations' ability to survive and adapt to environmental pressures. This particular concern is still being debated. However it is clear that without a better understanding of the genetic variation of the species, it is a safer option to avoid as much as possible introducing non-adapted genetic material that may have unanticipated detrimental effects. Depending on the genetics, there may be very different strategies for the appropriate places to collect propagation material for specific species. A general rule to follow is, if information is not available on the plant species' genetic variation, try to use local genetic sources for plant material whenever possible. There is no universal agreement as yet on the exact guidelines for "local" sources, however some factors to consider include whether the plant sources' genetic origin:
Because this is a fairly new concern in the restoration field it may be difficult to get plants that are from as local a genetic source as you would like. However, a broad guideline to follow is to ensure that they are at least from the same ecoregion. There are a few different ecoregion classifications of the United States that have been developed. One popular classification is Bailey's ecoregions, a product of a cooperative effort of a number of different federal resource agencies and The Nature Conservancy. These regions are areas that have been defined as having similar natural communities, geology, and climate. The DCNR - Bureau of Forestry has a policy in place that addresses genetic diversity issues as they relate to vegetation introductions on state forest land. See "Recommendations for the Management of Natural Genetic Diversity on Pennsylvania State Forest Lands" Sources of Plant Material for Pennsylvania For a list of seed and plant material suppliers in Pennsylvania and nearby states, see "Pennsylvania Native Plant Suppliers". This list is taken from the Pennsylvania Native Plant Society website at http://www.pawildflower.org > Links > Native Plant Sources. A few additional suppliers in Pennsylvania were added to the list on the website. The National Park Service Ecosystem Restoration Program is sponsoring an initial effort in California and the northeastern United States to develop a database of restoration techniques related to exotic plant invasions. They are currently accepting information from practitioners who have implemented restoration projects and are particularly interested in techniques that are being used to restore native plant communities after weed control and what the success of these programs have been. NPS intends to collect and organize this information so that it is accessible to land managers. This information will be made available at the following website: http://www.nrel.colostate.edu/~jsunderl/. Contact Jennifer Sunderland at this website for more information. If you are interested in learning more about ecological restoration, restoration planning or implementing a restoration project, visit the resources identified below and begin with The SER International Primer on Ecological Restoration (http://www.ser.org > Reading > The SER International Primer on Ecological Restoration). SER is the leading authority on the restoration of natural lands and if viewed as an important resource for land management practitioners.
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