Perlman - Practical Ecology for Planners, Developers and Citizens - Chapter 9 docx

Recall for a moment the imaginary transcontinental flight that we took at the beginning of Chapter 6. Viewing North America from the air quickly reveals that humans have changed the land dramatically across most of the continent; in fact, some regions have few or no remaining large blocks of intact habitat. Furthermore, the land is dotted, if not blanketed, with sites in various states of degradation, from intensively used agricultural lands to mining sites to urban brownfields. Many conservationists who once wrote off such human-influenced landscapes as lost causes now recognize the importance of trying to create healthier ecosystems from those that have been overused or abused. The process of improving and maintaining the health of ecosystems is the subject of this chapter. Just as there is no simple dichotomy between pristine and damaged ecosys- tems, there is no single process that turns a damaged area into one that is again ecologically intact. Conservationists have proposed various terms to describe the improvement of sites, but we will use just two: restoration and reclamation. Restoration means returning an ecosystem to its original condition or state, while reclamation focuses on the remediation of heavily damaged sites so that they can serve some useful purpose even if they are not brought all the way back to their original condition (see Figure 9-1). To illustrate these concepts, we present case studies of two sites that lie at very different points on the continuum: the cop- per mines of Butte, Montana, and the grasslands of Prairie Crossing, in Grayslake, Illinois. 9 Restoration and Management Reclaiming Land after Mining in Butte, Montana In Butte, Montana, underground and open-pit copper mines have disrupted much of the landscape. When we say “in Butte,” we do not mean near Butte or in the general region of Butte; these mines are right in the city (see Figure 9-2). Here, at the largest Superfund cleanup site in the United States, ecological restoration efforts are focused not on creating a close approximation of a pristine native habi- tat but on creating more livable neighborhoods in a city that has been ravaged by the effects of mining for more than a century. 1 Several distinct processes have led to Butte’s environmental problems, and each requires its own responses to return the landscape to a healthier state. Butte and mining have been synonymous since the late 1800s. Gold was dis- covered there in 1864, and silver soon after, but the really serious money came from one of the most base of metals: copper. Marcus Daly discovered copper here in 1882, and by 1884, 300 copper mines were operating on The Hill, as Butte is often called. 2 At least a few of Butte’s underground mines continued to operate until 1975, but a drastic change in technology to open-pit mining took place in 1955 when the Berkeley Pit opened. The Pit, like the underground mines, was in the city—but in this case, the Pit destroyed the city one neighborhood at a time to get at the copper ore below. By 1982, when mining in the Pit was finally shut down, the hole in the ground measured 1 mile by 1.5 miles (1.6 by 2.4 km), and it was over a quarter-mile (0.4 km) deep. 3 The different types of mines created different environmental problems. The old underground mines, some of which went down nearly a mile (1.6 km), brought up huge amounts of ore full of various heavy metals.While most of the ore went by train to a nearby smelter, a great deal of material stayed in and around Butte, polluting the ground with these metals. The Pit, however, was an- other story. When mining ceased in 1982, workers shut off the giant pumps that had kept the Pit and adjoining mine shafts free of water. Groundwater began seeping into the Pit and surface water ran in as well, adding about 6 million gal- lons (22 million L) per day to the Pit and causing the water level to rise approx- imately two feet (0.6 m) per month. 4 However, the liquid flowing into the Pit is not really water—at least, it is nothing you could use for drinking or washing. Because the surrounding rock contains sulfur compounds, the liquid is really a 170 APPLICATIONS Figure 9-1. Ecosystems range in condition from pristine to heavily damaged. The processes of reclama- tion and restoration move ecosys- tems toward the pristine end of the continuum. sulfuric acid solution full of heavy metals. Hydrologists have calculated that when the acid in the Pit reaches a level of 5,410 feet (1,650 m) above sea level, it will begin to flow outward and contaminate the underground aquifer. This situa- tion, unlike the issue of contaminated tailings from older mines, is continually getting worse and is expected to reach a critical state in about 2020, when the Pit’s acidic water begins its migration outward. In short, Butte has two major problems that need to be addressed: the heavy metals of the mine tailings that lie on the ground near the old underground mines and the metals and acid of the water in the Berkeley Pit. The challenge for restorationists working in Butte is twofold: first, to sharply reduce the threat to human and ecological health of toxic compounds in the soil and water, and, sec- ond, to return the formerly mined areas to land that is once again viable—either for natural vegetation or for limited human use. Restoring Grasslands in Grayslake, Illinois In Grayslake, Illinois, an hour’s train ride northwest of Chicago, a group of neigh- bors in 1987 purchased a 677-acre (274 ha) tract of farmland that had been slated for a massive development. Instead of the 2,400 condominium units originally Restoration and Management 171 Figure 9-2. In Butte, Montana, copper mining has taken place for over a century. Here, a headframe, which stood over the top of a mine shaft, still stands in a Butte neighborhood. planned, this group proposed a smaller development called Prairie Crossing, which would showcase emerging principles of ecologically based planning and design. A major component of this plan was to transform large portions of the site—which at the time consisted of soybean fields—into restored prairies, wet- lands, wet prairies, and savannas. 5 In the reclamation of mine sites in Butte, any reasonable use of the land would be a large improvement over the existing barren piles of tailings.At Prairie Crossing, however, the developers and ecologists restoring the site had specific targets in mind for their restoration activities. They wanted to re-create high- quality examples of the type of prairie and savanna ecosystems that existed in northeastern Illinois before it became so heavily agricultural. To do so, they needed to address several challenges inherent in converting a heavily managed ecosystem into one containing the native species, structure, and processes for- merly present on the site. First, decades of intensive farming had altered the soil profile and introduced chemical fertilizers, pesticides, and herbicides, creating a hostile environment for many native species. Second, because viable seeds for most prairie species were no longer present in the soil, the restorers needed to find sources of seeds or seedlings from other locations and successfully estab- lish them in the restoration area. Finally, healthy prairies are highly dependent on frequent fires, but the restored grasslands at Prairie Crossing would be situ- ated in the midst of a 362-house development, raising obvious management issues. To address these challenges, the Prairie Crossing developers needed eco- logical information that could guide the restoration efforts, they needed access to native plant species, and they needed expertise to implement the project. The Restoration Process As the examples of Butte and Prairie Crossing illustrate, restoration and recla- mation efforts span a wide range of goals, scales, and contexts. However, several common themes run through most restoration projects, and a common sequence of steps is often used to advance such projects. In this subsection, we focus on the process of restoration rather than on its detailed mechanics.The information pro- vided here is intended to help planners and designers assess when and how restoration might play a part in their projects, understand and critique restora- tion plans and designs that are presented to them, and work with restoration ecologists or engineers with whom they may collaborate on projects. Ecologists Richard Hobbs and David Norton have developed a five-step methodology for guiding restoration projects, which we use here to structure our discussion. The process consists of the following stages: (1) identifying and ad- dressing the processes leading to degradation in the first place, (2) defining 172 APPLICATIONS restoration goals, (3) developing strategies, (4) implementing these strategies, and (5) monitoring the restoration and assessing success. 6 Step 1: Identify and Address Processes Leading to Degradation As the descriptions of mining in Butte and agriculture at Prairie Crossing demonstrate, the causes of ecological degradation are many and varied—but in all cases, restorationists must determine why a site has become degraded. If one does not properly recognize and address both the initial causes of degradation and any later problems that might have occurred, it is unlikely that restoration efforts will be successful. In both settings described above, the causes of degra- dation were obvious. Sometimes, however, the causes of ecological degradation are harder to determine; all we can see at first are the effects, and we must find the source so we can act. Restorationists may have to perform ecological detec- tive work, such as trying to find the pollution source that is causing a lake to eu- trophy (to become oversupplied with nutrients, a condition that can eventually lead to a loss of oxygen). Although the original causes of degradation in Butte (the continual dump- ing of heavy metal–laden material on the surface) stopped once underground mining stopped, the area required significant cleanup. In areas where mine tail- ings were piled on the ground, restorationists had to remove the noxious mate- rial or cover it; in either case, they would have to bring in new topsoil and plant appropriate vegetation. At Prairie Crossing, initial soil testing revealed that years of agricultural practices had led to elevated nutrient levels, while certain non- native weeds associated with farms were abundant. In some cases, the source of degradation is not an added component—such as toxic mine tailings or exotic species—but, rather, something missing from the ecosystem. This was the case in Prairie Crossing, where native grassland species and fire—a critical ecosystem process—were both missing from the landscape. Those restoring the site had to find seed sources and incorporate fire back into the ecosystem, without which it would be impossible to recover a prairie or sa- vanna landscape. Thus, causes of degradation can include both “missing pieces” (e.g., species, ecological processes, or soils) and “unwelcome additions” (e.g., ex- cess nutrients, pollutants, or unwanted species), and restorationists should look for both. Step 2: Define Realistic Goals and Measures of Success Goal setting is a critical stage in any restoration project—and one that can be exceedingly contentious. Perhaps the single most important word in the title above is the adjective realistic. However, what is “realistic” for one group of restora- Restoration and Management 173 tionists may be far beyond another group’s wildest dreams—and since restora- tion requires money, time, and effort, goal setting will have an immense impact on the overall price, time sequence, and likelihood of a project’s success. If, in an attempt to be realistic, one initially sets low goals, these expectations may put an upper limit on how effective the restoration can be. On the other hand, overly ambitious goals can lead to a project that spreads its resources too thin, resulting in less success than might have been achieved with more realistic goals. The physical, chemical, and biological properties of an ecosystem represent three separate, though interrelated, sets of possible goals for reclamation and restoration. Physical properties include soils, topography, hydrology, and other environmental conditions. Chemical properties include measures of ecosystem functioning, such as carbon uptake by plants and nutrient cycling. Biological properties include the types, abundances, and distribution of species present as well as their interactions. These sets of properties are closely interconnected and can be generally thought of as a ladder: it is usually impossible to restore the bio- logical or chemical properties of an ecosystem as long as the physical environment remains heavily degraded.Thus, restoration projects often begin with physical ma- nipulations, such as smoothing out mining trenches or reestablishing natural hy- drologic flows to a wetland. When setting goals, restorationists need to consider how and to what extent they will address all three sets of characteristics. Butte and Prairie Crossing offer two very different examples of the relative emphasis that restorationists might place on physical, chemical, and biological restoration goals in different situations. In Butte, several factors influenced the development of the reclamation and restoration plan for the old mine sites. First was the sheer size of the problem. The mine sites cover several square miles, most of which contain heavy metal–laden soils. In addition, the giant, open Berkeley Pit is almost two square miles (5 square km), and surrounding areas are also dam- aged. Second, while the toxic metals found in these soils posed a threat to human and environmental health, the threat was not of the highest magnitude, since these metals are far less toxic than, say, mercury or dioxin.Third, the mine yards were virtually devoid of vegetation and their soils mostly could not support plant growth. Finally, the sheer volume of soils—1.6 million cubic yards (1.3 million cubic meters)—and the problem of disposal made it impracticable simply to re- move them. 7 With these considerations in mind, it became clear that the project’s principal goal should be to reduce to safe levels the amount of heavy metals reaching the people of Butte and the surrounding environment rather than to create a perfectly clean area. This “waste in place” approach could not have been considered if the project goal was to reestablish a pristine ecosystem. At Prairie Crossing, the overall vision of the developers and their consulting ecologist Steven Apfelbaum, of Applied Ecological Services, was to restore many 174 APPLICATIONS of the native prairie, savanna, and wetland communities that had been present prior to the early 1800s, but the specific restoration goal was much more nuanced (see Figures 9-3 through 9-5). First,Apfelbaum and his colleagues had to use clues such as nearby prairie remnants and historical records to determine what kinds of plant communities once inhabited the area. After they had a sense of the his- torical plant communities, they needed to decide whether the site could still sup- Restoration and Management 175 Figure 9-3. Restored prairie at Prairie Crossing on land that used to be soybean fields. (Photo courtesy of Steven Apfelbaum.) Figure 9-4. Some homeowners in Prairie Crossing have elected to plant their yards with native prairie species. (Photo courtesy of Steven Apfelbaum.) port these communities or whether it had changed too much in the intervening years. Based on observed gradients in environmental conditions (mainly soil and moisture), they created a “plant species palette” for different parts of the site that reflected preexisting conditions as well as a realistic assessment of current land suitability. Finally, the restorationists considered whether to try to introduce the full range of native plants and animals that once existed at the site or a more lim- ited suite of species. They determined that not only would it be cost prohibitive to introduce all species initially but that it may also be futile, since some species colonize a prairie only after it has existed for decades. In addition, because Prairie Crossing is part of the 3,000-acre (1,200 ha) Liberty Prairie Reserve and is lo- cated near the Des Plaines River habitat corridor, it was deemed unnecessary to introduce animals that could disperse to the site from nearby natural areas. 8 The example of Prairie Crossing illustrates not only that it is not always pos- sible or desirable to re-create exactly the historical ecological conditions on a site, but also that sound alternatives providing much of the structure, function, and biodiversity of the original ecosystem can often be formulated if adequate eco- logical research and planning is conducted. Regardless of the form the goals take, restorationists must make sure to specify their goals clearly ahead of time to give themselves a benchmark by which to measure their efforts. 176 APPLICATIONS Figure 9-5. Restored wetlands at Prairie Crossing not only create habitat for native species but also contribute to the development’s natural stormwater management sys- tem, which uses native wetland and upland vegetation to filter stormwater. (Photo courtesy of Steven Apfelbaum.) Steps 3 and 4: Develop and Implement the Restoration Plan Developing and then implementing a restoration plan are technically two separate steps, but because they are based on the same concepts, we discuss them together here. Since the 1980s, the field of restoration ecology has expanded greatly as conservationists have recognized the need to restore damaged ecosys- tems and as laws have been enacted to require such restoration. Early on, prac- titioners mostly improvised, generating new approaches and technologies with each new project. Now, however, a growing body of knowledge about restoration techniques exists, and land use professionals have hundreds of experts whom they can consult as well as numerous off-the-shelf restoration “products” they can incorporate into projects. Much effort has gone into developing restoration methods for specific ecosystem types—rivers, estuaries, grasslands, forests—and a wide variety of technical and semitechnical books are available on the subject. 9 Table 9-1 presents a range of restoration techniques that may be appropriate in projects with different challenges, goals, and constraints. The restoration efforts at Butte and Prairie Crossing illustrate how restora- tionists combine different types of interventions to achieve a particular set of goals. For example, the restoration plan for Butte called for initial actions to im- prove the physical environment, such as moving especially highly contaminated soils to sites where they are less likely to affect the city’s people and ecosystems, building concrete ditches to channel polluted stormwater into sedimentation ponds and away from Silver Bow Creek, and recontouring contaminated areas to reduce erosion and runoff before covering them with crushed limestone and eighteen inches (46 cm) of topsoil. Once these extensive physical alterations were complete, the biological restoration—which consisted of seeding with native plant species—was relatively straightforward (see Figure 9-6). At Prairie Crossing, relatively few alterations to the site’s physical and chemi- cal properties were required, although restorationists needed to address the ele- vated nutrient levels that had resulted from years of agricultural fertilizer use.To do this, they planted cover crops that rapidly absorbed many of the nutrients, cre- ating a lower nutrient environment suitable for the prairie species. Most of the interventions at Prairie Crossing were targeted toward changing the site’s species composition. In a few locations where infestations of farm weeds would have im- peded the establishment of prairie species, herbicides were used to reduce compe- tition from the non-native weeds. In most areas, however, prairie plants were simply introduced and allowed to grow. Given the relatively large area being restored, seeding was chosen over seedling planting as the method for reintroducing the prairie plant species. Restoration and Management 177 Table 9-1. Examples of Restoration Techniques to Meet Different Restoration Goals Ecosystem Component Being Restored Restoration Goal Sample Intervention Techniques Physical properties Remove toxic contaminants Mechanically remove soil in soils Implement bioremediation (the use of plants or microbes that absorb or break down toxins) Reestablish aspects of natural Mechanically move earth slope and topography Stabilize slopes using “geotextiles” or soil-stabilizing plant species Reestablish natural soil profile Import topsoil or organic matter Plant fast-growing species to add organic matter Reestablish natural stream Mechanically remove dams or channel and bank structure channelization structures Place woody debris in stream channel and bank using machines or human power Chemical properties Reestablish natural nutrient Plant fast-growing species to regime (on land) absorb excess nutrients, then harvest them to remove nutrients from the site Plant nitrogen-fixing species or use manure or fertilizers to add nutrients Reestablish natural nutrient Harvest lake weeds regime (in water) Dredge nutrient-rich sediments Improve riparian nutrient and Plant various species with deep sediment filtering properties roots and ground-covering foliage Alter hydrology to create oxygen- rich or oxygen-poor soil zones Biological properties Reintroduce native plant species Seed by machine or hand Plant seedlings or nursery specimens Reintroduce native animal Move animals from other species populations Introduce animals from captive breeding programs Reintroduce soil biota to Inoculate soil with native soil improve functioning insects, bacteria, and fungi Maintain or establish a Conduct prescribed burning particular successional state Cut or mow vegetation Eliminate invasive exotic species Conduct prescribed burning Physically remove exotic species using machines or human labor Apply herbicides or pesticides Introduce biological control agents, such as predatory insects, bacteria, or viruses [...]... 197 2 Under pressure from local citizens, the city adopted a restoration and management plan in 197 5 and replanted portions of the site with grasses, shrubs, and trees By the late 198 0s, succession had resulted in vegetational communities that provided habitat for 175 bird species, mammals including fox and beaver, and numerous reptiles, amphibians, fish, and invertebrates.10 Land Management Almost everywhere... managing land—a homeowner managing his quarter-acre yard for grass and flowers, a farmer managing her fields for corn or tomatoes, or a provincial park superintendent managing her park for recreation and wildlife habitat Conservationists usually manage land to improve or maintain its habitat value for desired native species and to introduce, promote, or maintain various natural ecological processes and functions... to guard against such natural hazards as fires and floods In this section, we focus primarily on managing land for biodiversity and other ecological values, but it is worth remembering that land management almost always has implications for both humans and ecosystems and that humans can benefit significantly from ecologically based land management efforts For example, riparian management to preserve streamside... natural ecological processes and functions Planners, designers, and developers may have numerous occasions to manage land or contribute to land management decisions For example, they may be involved in Restoration and Management preparing a master plan for a public park, establishing the terms by which common open space in a subdivision will be used and maintained, or formulating a plan or regulatory program... are removed and limited restoration work is undertaken For example, the 264-acre (107 ha) Tifft Nature Preserve in Buffalo, New York, was a municipal and 1 79 180 A P P L I C AT I O N S Figure 9- 7 According to the reclamation plan, revegetated areas in Butte must have at least 35 percent of the ground covered by an agreed-upon list of native plant species industrial waste site as recently as 197 2 Under... managing sand barrens communities on Martha’s Vineyard off the coast of Massachusetts, for example, ecologists use fire and clearing (tree and shrub cutting) to change forests to more open ecosystem types, such as savannas, shrublands, and grasslands Once lands have become more open, ecologists mow, use grazing animals, and set prescribed fires to maintain these open areas.12 Each of these management methods... Americans who helped shape the open nature of the Martha’s Vineyard landscape by setting fires and girdling trees These open areas are necessary for the survival of rare community types, such as grasslands, heathlands, and scrub oak–heath shrublands They also support several rare plant species, such as the sandplain gerardia, Nantucket shadbush, and bushy rockrose, as well as numerous rare moth species.13 183... processes cannot be allowed free rein, land managers may either have to temper their impacts or introduce them under carefully controlled conditions In fire- and flood-prone ecosystems, the tendency over much of the last century was to prevent disturbance wherever possible—to put out every fire and build ever-higher levees and dams But we are now learning that efforts to eliminate all disturbance may be...Restoration and Management Figure 9- 6 Reclamation efforts in Butte have transformed old mine tailings sites from bare, metal-laden earth, as seen on the right, to sites covered with native grasses, as on the left Step 5: Monitor the Restoration and Assess Success The monitoring process should begin at the start of a restoration project with the collection of baseline ecological data that will allow for valid... disturbance and successional processes by asking the questions shown in Box 9- 1 maintaining natural disturbance processes Allowing natural disturbance processes to follow their course with minimal human interference is usually the best way to ensure that organisms and ecosystems continue to experience the types and frequency of disturbance that they 181 182 A P P L I C AT I O N S Box 9- 1 Understanding Ecological . in the soil and water, and, sec- ond, to return the formerly mined areas to land that is once again viable—either for natural vegetation or for limited human use. Restoring Grasslands in Grayslake,. mechanics.The information pro- vided here is intended to help planners and designers assess when and how restoration might play a part in their projects, understand and critique restora- tion plans and designs. are removed and limited restoration work is undertaken. For example, the 264-acre (107 ha) Tifft Nature Preserve in Buffalo, New York, was a municipal and Restoration and Management 1 79 Figure 9- 6 . Reclamation