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

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

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

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.1Several 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.2At 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.4However, 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

Figure 9-1 Ecosystems range in

condition from pristine to heavily

damaged The processes of

reclama-tion and restorareclama-tion 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

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 restorarestora-tion 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

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 degradegra-dation 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

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.7With 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

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-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

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

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