2002 - Ecological restoration is the process of assisting the recovery of an ecosystem that has been degraded, damaged, or destroyed. 1996 - Ecological restoration is the process of assisting the recovery and management of ecological integrity. Ecological integrity includes a critical range of variability in biodiversity, ecological processes and structures, regional and historical context, and sustainable cultural practices. 1994 - Ecological restoration is the process of repairing damage caused by humans to the diversity and dynamics of indigenous ecosystems. 1990 - Ecological restoration is the process of intentionally altering a site to establish a defined, indigenous, historic ecosystem. The goal of the process is to emulate the structure, function, diversity, and dynamics of the specified ecosystem. I. ECOLOGICAL RESTORATION as defined by the Society for Ecological Restoration
1)Revegetation – process in which plants re-colonize a disturbed site. 2)Rehabilitation – visual improvements of a disturbed land…to look like it’s former self. 3)Reclamation – preparation and enhancement of degraded land to fulfill its former use or a new use. A. Past “restoration” projects have been categorized by the three R’s:
B. Ecological restoration differs from the 3 “Rs”: 1)Reestablish the function, components, structure and complexity of the site 2)Relies on human intervention 3)Create a self sustaining, persistent system
C. Role of ecological restoration in conservation (controversial): conservationists have been preoccupied with saving existing natural landscapes perception that restored landscapes are inferior to unmodified pristine areas perception that true restoration is not really feasible promise of restoration might undermine arguments for conserving existing wild lands* 1) Until Recently……….
2) Recent shift in interest toward Ecological Restoration due to: rehabilitation of areas disturbed by some forms of mining is now required creation/restoration of certain community types, primarily wetlands, is required to “mitigate” or offset destruction of other areas caused by development increased use of selected restoration procedures, especially use of native vegetation in many engineering applications growing interest in native vegetation for gardens and landscaping sheer scale and rate of destruction of natural landscapes everywhere has driven the need for the development of restoration approaches
A.Lack of Knowledge- some knowledge of original, “un-degraded” state is necessary extent of damage to hydrology, soil, & geomorphology degree of knowledge of original state degree of disturbance availability of biota for restoration resistance to invasion of non-native species genetic variability of biota productivity & nutrient retention Available reference sites II. Some Central Concerns of Restoration Ecology
B. Scale & Feasibility Implementation depends upon constraints, costs and design Political will is important Definition of goals and objectives is critical; they should ideally be more like a “motion picture” than a “snapshot” Central Concerns of Restoration Ecology cont.
Issues of Scale 4 general considerations are relevant to the size of a project: 1) large enough to minimize deleterious effects of boundary conditions/events on internal dynamics 2) size to permit managers to add, control, or eliminate disturbances to the system 3) size should permit various effects to be measured, to assess project success 4) project should be of affordable size
What can be done? 1.No Action – restoration too expensive, restoration won’t work, the ecosystem will recover on its own 2.Rehabilitation – replace ecosystem with another productive type 3.Partial restoration – restore some of the ecosystem functions, and a few dominant species 4.Complete restoration – restore the area to its original species composition, active program of site modification
Two general approaches - 1. Restore a site to its “natural” state (if that is known) 2. Create a condition with a series of traits that make it better than it was III. Restoration Processes
A. Soil Restoration 1)Direct replacement 2)Change rate of erosion –altering topography –changing landscape features 3)Increase capacity to receive and hold water 4)Divert water from the site 5)Change amount and or type of vegetation
Due to seasonal flooding, this area at mt. St. Helen’s is unable to recover, the soil cannot hold the nutrients necessary for vegetation.
Bioremediation – use of living microbes to remove toxic chemicals from the soil. Example: Winery had Petroleum Hydrocarbon concentrations in the soil that averaged 4,000 ppm - Soluble nutrients, vitamins, and minerals, in conjunction with hydrocarbon digesting microbes, were added monthly for 3 months using a water truck.
phytoremediation-- using plants to remove or degrade environmental pollutants from the soil
Experimental design used to create a new population of an endangered plant species, 20 plots (treatment or controls) designed in order to measure efficacy.
Usually only succeeds in previously forested areas Must pay attention to characteristics of canopy that will be restored
D. Wetland & River Restoration Input regulation to stop eutrophication Priority for wetlands drained within the last 20 years Should include surrounding area Restoring stream hydrology/ river flow critical
Wiers can deflect or accelerate flows Riffle habitat can be created & and gravel can be kept free of sediment
Five assumptions underlie current restoration practices: 1.Historical conditions can be re-created and extant ecosystems can be replaced. 2.The physical environment can be manipulated to support the desired plants and animals. 3.Inadequate substrate can be manipulated to sustain native biota. 4.The desired biota (plants & animals) will establish if selected plant species are introduced. 5.The ecosystem can sustain itself if the site is large enough for natural disturbance regimes.