The Restorative Ecology of Big Green Country

by Grant A. Mincy

Welcome to Big Green Country

Just across the Gay Street Bridge from downtown Knoxville there lies 1000 acres of urban wilderness. Complete with herbaceous cover and woody species, karst, wetlands, rivers and bluffs the area has become a safe haven for urban biodiversity. Furthermore, the Knoxville Urban Wilderness provides recreational opportunities for native Knoxvillians and visitors to the city. The urban wilderness system is much more than just a diversity hot spot (of sorts) and place of recreation, however, as it has motivated many Knoxvillians to think about, and conserve, urban biodiversity. The system has introduced many to the very concept of urban ecology and the ecosystem services such an area provides the general population. In addition to the benefits provided for the human population, the wilderness area also assists the fitness of all biotic populations by providing needed habitat. In this essay I explore concepts important to urban ecology, the establishment of the Knoxville Urban Wilderness, the ecosystem services it provides and the ancillary benefits it awards biodiversity.

Urban Ecology – Not an Oxymoron

When most folks think of ecosystems they probably envision natural wilderness landscapes. This need not always be the case, however, as urban landscapes are in and of themselves ecosystems. Urban landscapes may even be home to large forest tracts and aquatic systems that provide habitat for many different species. Urban ecology is a biological science in its own right as it not only deals with human beings living in neighborhoods, towns and cities (coupled with the environmental problems of such living standards such as air, water and soil pollution, the extraction of potable water, etc) but also with other organisms, how they relate to the urban landscape and what habitats are available to them (Rebele 1994). Urban ecologists are concerned with the distribution and species richness of plants and animals in urban landscapes and even seek to organize urban systems based on the individual organisms, populations and communities present (Rebele 1994).

Ecosystems are evolving landscapes that direct the development of species (Tansley 1935). With this in mind, any system or landscape can be examined at the compositional level of the populations that form them – this includes species richness, diversity, productivity, stability, resilience, and energetics (Tansley 1935). The ecology of an urban area is just as complex as a natural area, complete with various communities composed of different individual organisms that interact with one another (Rebele 1994). Even a single city park can be divided into various different types of communities such as lawns, meadows, woodlands, and aquatic habitats that all interact with one another (Rebele 1994).

Urban ecosystems are of course rather different from natural areas, however, and offer their own acute problems to biodiversity. Urban landscapes, as a product of human activity, greatly impact the migration, dispersal and extinction of species (D’Antonio and Vitousek 1992). Urban systems eliminate natural bio-geographical barriers so it is very common to find species co-existing together that have no common evolutionary history. This has allowed for incredible competition among species, both native and those introduced by humans (Rebele 1994). Many exotics are able to disperse through urban areas and establish themselves, sometimes to the detriment of native populations (Rebele 1994). Environmental changes in urban spaces are rather dramatic which makes it hard for natives to survive. Exotics, however, have no natural predators and are able to establish themselves and fill the niche left behind by natives (Pouyat et al. 2007). For this reason it is important to encourage landscapes suitable for natives.

There are of course other activities in urban landscapes that impact biodiversity. Construction and urban development destroys habitat and can eliminate local populations (Rebele 1994). Use of groundwater, eutrophication from nutrient loading of local aquatic systems, waste dispersal and a host of other activities normal to cities can also have negative impacts on local biota (Sukopp 1981).

Particularly interesting about urban ecosystems are changes in species composition over time. Succession is fairly well understood in natural systems but it becomes rather complicated in the city. This is because the urban experience alters the biological interactions among species. Biological norms such as competition, predation, mutualism (symbiosis) and how these interactions react to one another are all altered by urban systems and increased human influence (Rebele 1994). Anthropogenic activity can exacerbate challenges facing species richness and diversity, ecosystem complexity, stability and equilibrium. Depending on the challenges facing a biological community, even the productivity of urban ecosystems can vary from low to incredibly high depending on environmental parameters (Rebele 1994). Urban ecosystems are very complex!

The unique features of urban ecosystems and how the biological community organizes around them offer incredible insights to just how ecology actually works.

The Knoxville Urban Wilderness System

Two miles from Knoxville’s urban center there is a large patch of interconnected wilderness areas that offer recreational activities for all trail enthusiast and valuable (now protected) habitat for a number of plant and animal species (LPF 2013). The south-side of this wilderness system is defined by 35 miles worth of surface trails that connect city parks and natural areas with public and private lands. The south side of this system is home to many Knoxville favorites including Ijams Nature Center, Forks of the River Wildlife Management Area, William Hastie Natural Area and Marie Myers Park – all connected by trail-heads (LPF 2013). The topography of the area is highly variable and offers outdoors enthusiasts terrain that is easy, moderate or difficult to traverse (LPF 2013).

In all, the Knoxville Urban Wilderness (KUW) is estimated to be over 1000 acres. The project is championed by the Legacy Parks Foundation and is the result of partnerships among Ijams Nature Center, the Appalachian Mountain Bike Club, Tennessee Wildlife Resources Agency and both the City and County of Knoxville (LPF 2013). Still being established, this urban wilderness will connect 10 parks, boast over 30 miles or trail, three civil war forts (Fort Stanley, Fort Higley and Fort Dickerson), historic sites (the River Bluff and Loghaven) and diverse ecological systems and recreation activities (LPF 2013).

The KUW offers an exciting new direction for Knoxville: Urban Adventure. The project is so popular, in fact, it was featured in the September 2012 issue of the San Francisco based Backpacker magazine where it was described as a “playground of ravines and creeks and temperate rainforests… a model collaboration between government, business and disparate user groups.”

High praise indeed, especially for those who labored over the project – physically and mentally. Many Knoxvillians dedicated time to the wilderness project, offering their labor to build trails and bridges. Others donated their money, property and even their legal advice to see the project through. Perhaps the local who worked the hardest on the project, however, is Carol Evans of Legacy Parks. With her help, partners were able to come together to get the project underway – and she was also able to establish a “conservation culture” in Knoxville. By working with trail runners, hikers, bikers, officials, business owners and many others she helped foster a community that utilizes, values and wishes to protect the wilderness corridor. For this reason she sought to make the dense, undeveloped woodlands public property (Metro Pulse 2013).

Construction of the urban trail system itself was no easy task. Volunteer labor built the trail system, most of which came from the Appalachian Mountain Bike Club. The initial labor was mostly conducted by hand but some machines such as a mini excavators and chain saws were used (Knoxville News Sentinel 2013). The system was built to meet the standards of the International Mountain Bicycling Association. Construction was rather quick, before many residents even knew the project was underway. Funding for the project came largely from private donors, with only about 1/3 of the funds coming from the public trust (Knoxville News Sentinel 2013). Knoxville Mayor Madeline Rogero, a staunch supporter of the project, continually notes the impressive volunteer labor put into establishing the wilderness project:

The Appalachian Biking Club put hundreds and hundreds of hours—and quite a few cases of beer—into building trails all of us can enjoy.

Knowing how it all came together, with all the partners and volunteer labor is only one part of the story. It is also important to note how the project was even possible.  Knoxville has a rather large urban sprawl problem.

As far as escaping Knoxville’s notorious urban sprawl woes, it is the incredible topography of the area that saved the sections of forest from roads and shopping malls (Metro Pulse 2013). Knoxville has been expanding, rather unsuitability, for more than two centuries. The South Knoxville corridor, however, was protected from development by its steep topography, karst and ravines. These features created difficulty for development (Metro Pulse 2013). In fact, South Knoxville has still not developed residentially and commercially as most of the rest of the city (Metro Pulse 2013). Furthermore, other sections were exploited for resources such as marble, but were later abandoned and left alone for natural succession to begin (Metro Pulse 2013). This allowed for large forest tracts to remain intact or re-establish, meaning just a couple of miles from the hustle and bustle of the urban center there is 1000 acres of wilderness.

The KUW will only expand in 2014. Connections to House Mountain are in the works as well as improving access to the Upper Holston River to encourage recreation for more Knoxvillians. There are also large-scale projects being investigated that could potentially link several wildlife refuges along the Tennessee River, including the soon to be state park Seven Islands Wildlife Refuge.

A Sense of Place – The Human Dimensions of Urban Biodiversity

The most unique feature of urban ecosystems is that humans have absolute dominance over the landscape – the landscape is manufactured by us to support our needs. Human dimensions of natural resource management in urban systems become challenging. People care about where they live and hope for the best for their communities. This makes the work of the urban ecologists incredibly important. Feeding off of these human dimensions and sense of place connections, a healthy urban ecology can foster desire to protect local biodiversity. Through different mediums, the urban ecological movement can help people become aware of (and thus more concerned about) both their cultural and their natural heritage. This will naturally lead to a populace that is more concerned about conservation – the urban population will care more about the natural world and be motivated to protect it. This is an important point because there currently exists a dilemma between urbanization and conservation.

Over 50% of the human population now lives in cities and as populations expand so too does urbanization. This creates an incredible challenge to species conservation as the total size of urban spaces in the United States now exceeds the total size of areas protected for conservation (McKinney 2002). It is important then for markets to develop that encourage biodiversity conservation. The best way to do this, in my opinion, is through the “greening” of our communities – people naturally like green spaces, the days of sprawl for the benefit of developers are limited. Good riddance too, as homogenization of urban systems through the establishment of exotics and urban adapters is becoming a problem (McKinney 2008).

Not all is lost in urban systems, however, as they offer exciting opportunities for restoration ecologist and conservationists. Urban landscapes are very large and thus are very important for local, regional and even global biodiversity (Dearborn and Clark 2009). To protect species richness and urban diversity many urban planners are looking into establishing large blocks of protected habitats coupled with ecologically responsible development in surrounding areas (Dearborn and Clark 2009).

The idea of establishing large blocks of protected habitat is emerging in urban environments today, largely in the form of greenways and natural parks. Some cities are taking this idea a step further and developing urban wilderness. This is no easy feat as most often cities do not have large enough habitat blocks to sustain natural populations of plants and animals (Dearborn and Clark 2009). Places like Portland, Oregon and right here in Knoxville, Tennessee, then, have a unique opportunity to become leaders in habitat preservation and sustainable development. Especially prudent to these cities is that they can be at the forefront of protecting urban bio-diversity and development of ways to allow better ecological protection in the future.

Just how can the KUW ensure better species protection in the future? The answer is to simply keep doing what it already does – provide an incredible space for environmental recreation and education. When urban spaces are set aside for these activities the visitor experience becomes incredibly important for biodiversity (Dearborn and Clark 2009). The KUW is already equipped with all the weapons it needs to be an effective force for conservation: Great visitor access (including a short distance, possibly even a walk from the urban center) a growing public transportation system, educational programs offered by Ijams Nature Center, Legacy Parks and other sponsors and 1000 acres of “observable nature” and the space itself is incredibly charismatic (Dearborn and Clark 2009).

The features of the urban wilderness have already proven to provide opportunities for citizen recreation, citizen science, restoration ecology (ongoing projects at Ijams Nature Center) and increased environmental monitoring. In an area where many people live and work, the urban wilderness provides a venue for ecological volunteerism (Dearborn and Clark 2009) and thus creates a place connection to not just the urban center, but to its surrounding ecology. This connection to place and environmental education will naturally foster more concern and regard for biodiversity outside of the limits of the city as well. This is an incredibly important point because cities are where political and economic powers are concentrated (Dearborn and Clark 2009). This makes cities the places where public policy is developed which, in many ways, decides the fate of urban biodiversity. The more policy makers and members of the public that have access too and positive experience with biodiversity can create a positive feedback loop for species conservation and restoration (Dearborn and Clark 2009).

Ecosystem Services and the Ancillary Benefits of the Knoxville Urban Wilderness

Creating even more ecological considerations in the urban environment are the ecosystem services created by the KUW. Ecosystem services are for human beings – the more an urban populace realizes the economic and social benefits of natural areas the more return investment ecological systems will receive from human populations. The KUW is unique as it is located in an area where the urban population is already incredibly high.

The KUW is already host to valuable ecosystems that are providing ancillary benefits to Knoxvillians. Wetlands in the wilderness are improving urban hydrology, absorbing containments and are also mitigating flood hazards (Pankratz et al. 2007). The increased vegetation of the KUW can also reduce the heat island effect during the hot summer months – the more green space, the more comfortable we will all be (DeNardo et al. 2005). These green areas are also enhancing local biodiversity for plants and woodland species plus beetles, birds, spiders and other species that colonize the area (Brenneisen 2006). These insects and birds may also help as pollinators supporting another growing industry in Knoxville: Urban agriculture. With the growing local food scene in the Scruffy City, there is enormous potential for more small-scale farms like Beardsley that provide local food to eateries – stationary and mobile.

Another incredible ecosystem service for Knoxvillians is the regulation of air quality – which is notoriously bad during the summer months. In the United States, urban trees annually remove 711,000 tons of air pollutants – an economic value of nearly $3.8 billion (Nowak et al. 2006). The KUW is instrumental in providing a cost-effective way to reduce pollution in the city. Another service of urban trees, often overlooked, is their capacity for carbon sequestration. The more trees there are in an urban area the more carbon is sequestered. This is particularly important in the age of climate change – especially interesting is the fact that urban trees may have a larger effect on climate regulation than trees in wild landscapes (Akbari 2002).

Perhaps the most pertinent ecosystem service provided by the KUW is how it can improve the health and well-being of folks right here in Knoxville. We will of course physically benefit from air quality regulation – but we will also be encouraged to get out and play more. This get out and play mantra already surrounds the KUW. Folks regularly bike, hike, kayak, paddle, trail run (and much more) in the wilderness enhancing us both physically and mentally. There are many psychological benefits to having a green escape here in the city. Fuller et al, (2007) show something particularly amazing about urban green scapes – pyschological and emotional benefits awarded to the human population from urban wildernesses actually increases with the amount of biodiversity in the ecosystem, as measured by species richness of plants, birds and butterflies. The ability of the public to notice and benefit from what species richness and biodiversity provide exemplifies the importance of the KUW.

The KUW has already become an influential part of the City of Knoxville. Because of its presence, future development must be mindful of the Human Dimensions of urban green space – providing ancillary benefits for humans and other species.

The New Hotspot – Biodiversity in the Urban Forest

How does the urban wilderness support biodiversity? Urban ecosystems have usually been examined in how they negatively impact species diversity – this is not the case in urban wilderness, however. The KUW of course provides 1000 acres of natural habitat to a variety of species in Knoxville. The spatial heterogeneity, complex structure and function, and diverse specie composition of vegetation greatly helps the fitness of other living biological organisms such as mammals and birds (Tilgham 1987). The KUW just existing enhances biodiversity in the city. For birds alone there are great benefits of the wilderness area: Trees and shrubs provide viable habitat, they provide nesting structures, places to feed and regulate human behavior (no James White Parkway extension due to the urban wilderness, for example). Similar benefits are provided to a host of other species living within South Knoxville. A feed back loop exists here too – enhancement of biodiversity as a result of the KUW has increased the quality of life for Knoxvillians and this alone will indirectly facilitate the preservation of biodiversity in urban centers and natural ecosystems. In short, urban wilderness is essential for promoting and preserving biodiversity in the urban forest.

 The KUW is rather expansive – plans to grow the wilderness area will only help increase species richness and overall biodiversity within city limits. Equally important – as environmental education grows, natural areas outside of the city may benefit as well. The KUW is an incredible asset to the Scruffy City, in terms of recreation and biodiversity.

 Literature Cited:

Akbari, H. (2002). Shade Trees Reduce Building Energy Use and CO2 Emissions From Power Plants. Environmental Pollution, vol., 116, S119 -S126

Brenneisen, S. (2006) Space for Urban Wildlife: Designing Green Roofs as Habitat in Switzerland. Urban Habitats, vol. 4, 27-36.

D’Antonio, CM & P. Vitousek (1992). Biological Invasions by Exotic Grasses, the Grass/Fire Cycle and Global Change. Ann. Rev. Ecol. Syst. vol. 23, 63-87

Dearborn, Donald C. & Salit Kark (2009). Motivations for Conserving Urban Biodiversity. Conservation Biology.

Denardo, J.C., A. R. Jarrett, H. B. Manbeck. D. J. Beattie & R. D. Berghage (2005). Storm Water Mitigation and Surface Temperature Reduction by Green Roofs. Transactions of the ASAE vol. 48, 1491-1496.

Fuller, R. A., K. N. Irvine, P. Devine-Wright, P. H. Warren and K. J. Gaston (2007). Psychological Benefits of Green Space Increase with Biodiversity. Biology Letters, vol.3, 390-394.

Knoxville News Sentinel (2013) Knoxvilles Urban Wilderness.

Legacy Parks Foundation. (2013) Knoxville’s Urban Wilderness. Projects, http://www.legacyparks.org/projects.html

McKinney, M. L. (2002) Urbanization, Biodiversity and Conservation. BioScience vol. 52 883-890

McKinney, M. L. (2008) Effects of Urbanization on Species Richness: A Review of Plants and Animals. Urban Ecosystems vol. 11, 161-176

Neely, Jack (2013). Urban Wilderness Adventurer: Legacy Parks Carol Evans Reimagines Knoxville as an Outdoors Wonderland. Metro Pulse.

Nowak, D. J., D. E. Crane, and J. C. Stevens (2006). Air Pollution Removal by Urban Trees and Shrubs in the United States. Urban Forestry and Urban Greening, vol. 4, 115-123.

Pankratz, S., T. Young, H. Cuevas-Arellano, R. Kumar, R. F. Ambrose & I. H. Suffet (2007). The Ecological Value of Constructed Wetlands for Treating Urban Runoff. Water Science and Technology vol. 55, 63-69

Pouyat, R. V., D. E. Pataki. K. T. Belt, P. M. Groffman, J. Hom, and L. E. Band (2007). Effects of Urban Land Use Change on Biogeochemical Cycles. 45 – 48 in Terrestrial Ecosystems in a Changing World. Springer, Berlin.

Rebele, Franz. (1994) Urban Ecology and Special Features of Urban Ecosystems. Global Ecology and Biogeography Letters, vol. 4 173-187

Sukopp, H. (1981). Translated: Grundwasserabsenkungen. 239 – 272. Berlin, West.

Tansley, A. G. (1935). The Use and Abuse of Vegetational Concepts and Terms. Ecology, vol. 16, 284-307

Tilghman, N.G. (1987). Characteristics of Urban Woodlands Affecting Breeding Bird Diversity and Abundance. Landscape and Urban Planning vol. 14, 481 – 495

Related articles

• Ecological Urbanism: Cities and other creatures (urbannature13.wordpress.com)
• Environmental movement – inside and outside… (jinshinjyutsuheleneiliste.wordpress.com)
• Boston’s Evolving Urban Wilds (dirt.asla.org)