Presentation on theme: "Ecological restoration refers to the rehabilitation, reclamation, re-creation and recovery of degraded lands. These efforts may be conducted on either."— Presentation transcript:
Ecological restoration refers to the rehabilitation, reclamation, re-creation and recovery of degraded lands. These efforts may be conducted on either a small- scale (e.g. tree planting) or may involve major human and technical efforts (e.g. re-creation of wetlands, acid lake neutralization). Restoration can be claimed to begin with Aldo Leopold’s restoration of oak openings and prairie at the University of Wisconsin Arboretum. The 4 r’s above indicate different possibilities and end points of the process Ecological Restoration
If no action is taken, the ecosystem might moderately improve or might get somewhat worse. If only a few ecosystem processes or species are ‘restored’, but the system remains far from its pristine state, the effect is called enhancement. If the ecosystem is significantly improved but remains quite distinct from its pre-degradation condition, the effect is called rehabilitation. This is frequently the objective in areas that have been strip mined (e.g. oil sands in Alberta). Reclamation stabilizes land and restores sufficient soil to revegetate the land, without attempting to restore the condition before mining. Replacement builds a new community that meets some set of conservation objectives, but is unlike the one degraded. Constructed wetlands around the Great Lakes fit into this category. Finally, restoration rebuilds an ecosystem little different than the pristine ecosystem that was degraded. This approach represents what is done to the physical environment and to plants in restoration. For animals there are translocation and reintroduction (using captive-bred animals).
All this suggests that with sufficient economic support, virtually any ecosystem could be restored. However, it is inappropriate to assume that true restoration is always or even frequently possible However, sometimes real progress is made: The dry forest in northeastern Guanacaste, Costa Rica, has been actively under restoration. 1980 2000
One of the important keys to restoration of Guanacaste dry forest has been fire suppression. With fires (accidental and intentional) large areas were maintained as pasture. Dry forest trees were able to grow once more once fire was suppressed. In other systems, like prairie grasslands, fire is a tool used to maintain and restore areas. Some fires happen accidentally, and others are carefully controlled for management and/or restoration. An accidental fire during the 1970s in what is now the Ojibway Prairie Preserve shows you how rapidly the plant community recovers.
spring, two years ago, just before the fire 4 weeks after the fire 2 weeks after the fire 10 weeks after the fire Ojibway Prairie Preserve
When a restoration project is to be implemented, what are the important considerations?
The flow chart is useful in determining what is possible biologically and physically, but there are steps not included in the flow chart: Site assessment – what was there, and what is there now? What is the ownership and other legal restraints on restoration? What can be learned from other similar ecosystems in the region? Setting the goals – true restoration is rarely even approachable; what are realistic goals for a project? Funding limits, stakeholder interests, and physical constraints examined in the flowchart all interact in determining realistic goals.
Designing the project – design needs to take into account subjects you’ve seen in this course: genetics, population biology, demography, community ecology, species (or trophic level) interactions, weather, and conditions of the physical environment. Simple steps may have far reaching consequences. The dry forest of Guanacaste required only re-establishment of a natural fire regime and facilitation of seed dispersal from forest remnants. In another example from the text, restoration of vernal pools in California was achieved by using topsoil retained from development to re-inoculate pools with natural microbial flora and fauna.
Implementing the project – what is done to reach the restoration goals? Hydraulic shovels, bulldozers, and other heavy machinery can be used to move earth or modify the landscape. exp: Detroit River bank close to downtown. The objective is to restore a ‘natural’ riverbank for both aesthetic and biological (fish habitat) reasons. In other cases, e.g. restoring prairies, much of the work is done with hand tools (shovels, hoes,…)
How is the success of a restoration program evaluated? One such method for objectively determining the success of a restoration program is through a measure called the 'Index of Biological Integrity'. This index feeds information from a suite of indicators. For aquatic systems these might include: fish species richness, presence of indicator taxa (e.g. those (in)tolerant of low oxygen concentration), incidence of abnormalities, disease etc. IBI values for different times can be plotted to determine whether progress has been made following implementation of remedial action plans (RAPs). On the Great Lakes, 43 sites have been identified where water quality is deemed degraded. For each of these Area of Concern (AOC) sites (e.g. Detroit River, Hamilton Harbour, Wheatley Harbour), RAPs are designed to identify and resolve problems impairing water quality.
Cultural Eutrophication and its attendant water quality problems (e.g. anoxia) is one of the leading reasons why we have Areas Of Concern on the Great Lakes (others are due mainly to industrial activities and their waste products). Lake Erie faced a problem as a result of nutrient inflow, mainly from the Detroit River and untreated sewage. The western basin of the lake experienced a slow increase in nutrient loading until about 1940. The loading shot up from sewage and agricultural fertilizer inflows until the mid-1960's; human population in the watershed increased from 3.8 to 11 million between 1910 and 1960 (Sweeney 1993). By the mid 1960's, people were greatly concerned by surface mats of the cyanobacterium Aphanizomenon flos aquae and low oxygen levels in the west and central basins.
Anoxia caused massive invertebrate and fish die-offs. Mats of the nuisance alga Cladophora glomerata washed ashore with the dead fish. Beaches were closed to swimmers and drinking water was tainted. All of this was due mainly to increased phosphorus levels in the lake – from 7.5 µg/L in 1948 to 36 µg/L in 1962. Public outrage finally forced joint US-Canada efforts (creation of the International Joint Commission) to reduce inflows of phosphorus to the lake. The major sources were municipal inflows from Detroit and Toledo.
Overall inflow declined from 14,000 and 1,500 tonnes of phosphorus per year in 1972 (USA and Canadian contributions, respectively) to ~1800 and <200 tonnes per year in 1990 (Dolan 1993). These values were below the guidelines set for improvement of water quality. Water quality improved dramatically, but we have seen backsliding in the past decade in part due to diffuse input (runoff from fields) and in part due to recirculation of nutrients by invasive zebra mussels Closed: western Open: central Ludsin et al. 2001.
When we move from the large scale projects to attempts to conserve individual species, different problems arise. A number of 'species restoration' projects have been quite successful. For example, the California condor, peregrine falcon, and Whooping crane have all increased in breeding programs so that individuals are being released into the wild. However, re-introductions have sometimes been politically controversial, and in other cases scientific questions have been raised…
Re-introduction requires careful consideration of genetic consequences. What are the concerns? 1.Captive-bred plants (or animals) may have been subjected to much different selection pressures than natural ones. When placed in the wild, they may not tolerate new, natural selection pressures; when their genes are mixed into wild populations, they may weaken adaptations of wild populations. 2.There may be outbreeding depression when captive- bred and wild populations reproduce. 3.Breeding between groups may “break up coadapted gene complexes”.
4. Depending on relative numbers of natural and captive-bred, reintroduced organisms, genetic diversity and effective population size may be negatively affected. Here’s a theoretical N for small (40) and large (400) natural populations with reintroduction from a captive population:
5. One reason for introducing fairly large numbers of captive-bred individuals is maintenance of genetic diversity. Successful introductions tend to be large or to cause rapid increase in total population size.
Animal re-introductions have a slightly different set of problems when compared to plants. Animals that attract sufficient interest and support for this expensive approach are typically charismatic species, and frequently top predators. As a result, they are significant concerns for human populations in areas of re-introduction. Think of the black-footed ferret and the Florida panther. Because they are key species, the IUCN (1995) developed guidelines (steps) for animal re- introduction:
1.Examine feasibility. That means ensuring that species biology is suitable, there is a suitable source of animals for the project, and that whatever threats drove the population to endangerment or extirpation are not still present. 2.Make sure there is suitable habitat for re- introduction within the historic range of the species, and that protected status can be provided for the re-introduced population. 3.Evaluate the genetics (similarity to natural population, genetic diversity) of potentially re- introductions.
4.This is the political reality! – valuate support and opposition to reintroduction, and that both long- term economic and political support is available. 5.Design the reintroduction to ensure potential for long-term adaptive management. Since there have been only a few re-introduction programs, more about what makes such projects successful needs to be known. The design should permit experimental tests of methodology. 6.Make sure that, if necessary in adaptive management, intervention is possible.
Why Protect and Restore? In part, because it is required by legislation. Your text covers American legislation, here we’ll review the Canadian Acts: Canada Water Act – An Act to provide for the management of the water resources of Canada, including research and the planning and implementation of programs relating to the conservation, development and utilization of water resources. This is the act that prohibits pollution in Federal waters, including waste disposal.
Canada Wildlife Act (1985) – The provisions of this Act respecting wildlife apply to (a) any animal, plant or other organism belonging to a species that is wild by nature or that is not easily distinguishable from such a species; and (b) the habitat of any such animal, plant or other organism. It includes wildlife conservation and wildlife research. The Minister of Environment establishes advisory committees to determine status and actions regarding rare and endangered species. Actions are generally limited to ‘public lands’ and marine areas.
Canadian Environmental Protection Act (1999) – An Act respecting pollution prevention and the protection of the environment and human health in order to contribute to sustainable development. In this act the government acknowledges the need to integrate environmental, economic and social factors in making decisions. With regard to pollution, the ‘watchword’ is “virtual elimination of persistent and bioaccumulative toxic substances” and management if their release into the environment cannot be prevented”. The precautionary principle is embedded in the act.
There are many components to the Environmental Protection Act. This is where the rules for strip mine (and oil sands) reclamation and restoration are. Regulations on PCBs, import and export of hazardous materials, ozone-reducing substances (CFCs), paper mill effluents (mostly mercurial compounds), and phosphorus release from sewage treatment are among a much larger number of component parts of the act.
Migratory Birds Convention Act (1994) – No person shall, without lawful excuse, (a) be in possession of a migratory bird or nest; or (b) buy, sell, exchange or give a migratory bird or nest or make it the subject of a commerce. Additionally, it’s illegal for vessels to foul nests, birds, or their habitats. It’s not clear whether anyone has been charged after spills.
Species At Risk Act (2002) – An Act respecting the protection of wildlife species at risk in Canada. The Government of Canada has ratified the United Nations Convention on the Conservation of Biological Diversity. This act provides legal protection for species at risk and complements existing legislation. A committee set up by the Minister of Environment, the Committee on the Status of Endangered Wildlife in Canada (COSEWIC) advises the minister about species that are in need of legal protection and/or recovery. The act also recognizes shortcomings in designing conservation plans:
1.knowledge of wildlife species and ecosystems is critical to their conservation, and 2.the habitat of species at risk is key to their conservation. Wild Animal and Plant Protection and Regulation of International and Interprovincial Trade Act ( 1992) – This is the act that legislates Canada’s acceptance of the terms of the CITES treaty.
References Dolan, D.M. 1993. Point source loadings of phosphorus to Lake Erie: 1986-1990. Journal of Great Lakes Research 19:212-223. Gore, J.A., Jr. and F.D. Shields. Jr. 1995. Can large rivers be restored? Bioscience 45:142-153. Ludsin, S. A. M. W. Kershner, K. A. Blocksom, R. L. Knight, and R. A. Stein. 2001. Life after death in Lake Erie: Nutrient controls drive fish species richness, rehabilitation. Ecological Applications 11:731-746. Makarewicz, J.C. 1993. Phytoplankton biomass and species composition in Lake Erie, 1970 to 1987. Journal of Great Lakes Research 19:258-274. Nicholls, K.H., G.J. Hopkins, and S.J. Standke. 1999. Reduced chlorophyll to phosphorus ratios in nearshore Great Lakes waters coincide with the establishment of dreissenid mussels. Canadian Journal of Fisheries and Aquatic Sciences 56:153-161. Sweeney, R.A. 1993. 'Dead' sea of North America? - Lake Erie in the 1960s and 1970s. Journal of Great Lakes Research 19:198-199.