When you look out your window at home, do you see native habitat and animals? Or do you see a landscape filled with fescue lawns, Bradford pear, Chinese privet, and grackles?
We exist in a time when the power of the human species to affect the environment has become so vast that the unofficial term “Anthropocene” is used to describe an unofficial current geologic epoch dominated by human activity. The characteristics of the Anthropocene include (1) the “sixth extinction,” (2) climate change caused by an exponential increase in carbon dioxide emissions, and (3) massive amounts of pollution resulting in environmental degradation.
Animal population decline and species extinction are occurring at an increasing rate and ought to be a serious concern. A recent Pulitzer-Prize-winning book estimates that “a quarter of all mammals, a fifth of all reptiles, and a sixth of all birds are headed toward oblivion” and notes that these losses can be observed as close to us as our own backyards. Elizabeth Kolbert, The Sixth Extinction: An Unnatural History 17-18 (Holt 2014). Extinction is not reserved to these animal classes, of course; it is affecting all orders of life on our planet.
It is natural to ask ourselves how we contribute to these problems and what we can do to help to ameliorate the effects of our way of life. This article will explore a few of the ways in which residential real estate development, especially of single-family residences, contributes to habitat loss and endangerment of species populations. The good news, however, is that restoration of native habitat (typically vegetation) will restore native animals as well. How do we get from here to there? This article will suggest different legal tools to effect habitat restoration, offer some strategies to combat the harm that development causes, and suggest additional sources to consult.
Why Connect to Nature?
Numerous studies have shown that connection to nature has a very positive effect on human health and happiness. Out of numerous examples, one recent study conducted over an eight-year period showed that higher levels of green vegetation in residential areas are associated with decreased mortality, supporting the conclusion that policies to increase vegetation may not only mitigate effects of climate change but also improve health of residents. Peter James et al., Exposure to Greenness and Mortality in a Nationwide Prospective Cohort Study of Women, National Institute of Environmental Health Sciences, Environmental Health Perspectives (Apr. 14, 2016), [document location no longer available].
Such benefits are not restricted to those living in more high-priced areas. A Canadian study of Toronto concluded that having ten more trees in a city block improved health perception in ways comparable to a significant increase in personal income and residence in a higher-median-income neighborhood, or a health perception equivalent to being years younger. Omid Kardan et al., Neighborhood Greenspace and Health in a Large Urban Center, Scientific Reports 5, Article number 11610 (July 9, 2015), https://www.nature.com/articles/srep11610. A British study found that people who engaged with nature every day for a month experienced increased happiness and health, a greater connection to nature, and engaged in more activities supporting nature. Miles Richardson et al., 30 Days Wild: Development and Evaluation of a Large-Scale Nature Engagement Campaign to Improve Well-Being, PLoS ONE 11(2) (Feb. 18, 2016), http://journals.plos.org/plosone/article/file?id=10.1371/journal.pone.0149777&type=printable.
Exposure to nature has a beneficial effect on the development of children as well. See generally Richard Louv, Last Child in the Woods: Saving Our Children from Nature-Deficit Disorder (Algonquin Books rev. ed. 2008), for well-researched arguments as to why connecting children to nature is so important. “Nature-deficit disorder,” first coined by this book, has become a popular term and can be suffered by adults as well as children.
Real estate development affects the environment adversely in many ways. It can diminish natural habitat or completely eliminate it. It can contribute to climate change by the removal of trees and by energy use that increases greenhouse gases. It can contribute to environmental degradation by nonsustainable use of materials and energy and increased surface runoff due to buildings and pavement.
Housing types having the most effect on natural habitat are the newest and, according to the US Forest Service, fastest growing type of exurban community, located in the “Wildland Urban Interface,” the zone between developed and undeveloped land. A recent study concluded that this “rural sprawl” will constitute a significant threat to the conservation value of protected areas such as wilderness areas and national forests and will interfere with their ability to function as “Noah’s Arks.” Volker C. Radeloff et al., Housing Growth in and near United States Protected Areas Limits Their Conservation Value, PNAS (Jan. 12, 2010), http://www.pnas.org/content/107/2/940.full. Not only does housing located in urban and suburban areas wipe out animal species in proportion to the amount of native habitat destroyed, but exurban housing has the ability to seriously threaten biodiversity in its last strongholds. The following subsections will discuss some specific ways in which various aspects of residential development cause habitat loss.
Life cannot exist without taking in energy, either in the form of food or more basic elements. Plants form the first “trophic” level, or level of the food chain. Plants pull nutrients from the soil and manufacture their own food by means of photosynthesis. They also produce oxygen, serve as “carbon sinks” by capturing carbon, improve air quality, filter water, and in turn serve as food for herbivores and habitat for numerous species. An oak tree can support over 500 species of butterflies and moths, not to mention the many birds and mammals that nest in the tree or eat its leaves and acorns. Douglas W. Tallamy, Bringing Nature Home: How Native Plants Sustain Wildlife in Our Gardens 147 (Timber Press ed. 2009). Contrast this with the gingko, which in many parts of the US supports only five species of caterpillars.
Clear-cutting of trees and shrubs removes those animals that eat plants and that constitute the second trophic level. Of these, insects are the animals that pass on most of the energy held within plants. Herbivorous insects are essential to the health of ecosystems and essential for the existence of animals of higher trophic levels, such as purple martins and foxes (which eat herbivores) and eagles (which eat carnivores). Thus, removal of vegetation removes a host of insects and amphibians, reptiles, birds, and mammals from the landscape, and not only members of animal populations, but sometimes entire species.
Can’t cleared-out oaks be replaced with other tree species, like Bradford pears and Russian olives? Although for decades the suburban planting of non-native trees and shrubs was carried out for reasons including status and easy maintenance, replacing an oak with a Bradford pear (a non-native cultivar) will kill the insects that depended on the oak tree for subsistence. Replace enough oak trees with Bradford pears, and other animals up the food chain will disappear, too. In recent decades, scientists have learned that 90 percent of insect herbivores are quite limited in what they can eat, unlike humans. One study has shown that native plants in the eastern United States (black oak, black cherry, black walnut, and fox grape) produced over four times more herbivore biomass and supported over three times as many herbivorous species than did the most common alien plants (autumn olive, mile-a-minute weed, oriental bittersweet, multiflora rose, and Japanese honeysuckle). Tallamy, Bringing Nature Home at 59-61. There is a growing awareness that non-native plants should only be used in landscaping with extreme care; the preference should always be for native plants. However, non-native species are sometimes deliberately introduced during the landscaping phase of real estate development, when developers and contractors will plant non-natives perceived to be more desirable than native species.
Invasive species are those that are introduced into an area by intention or accident and reduce or eliminate the population of native species. Some examples of invasive species introduced into residential environments include Chinese privet, Japanese honeysuckle, English sparrows, and starlings. Invasive species are responsible for the decline of 42 percent of United States threatened and endangered species and affect an area roughly the size of California. The Nature Conservancy, Impacts of Invasive Species: Invading Our Lands and Waters, https://www.nature.org/ourinitiatives/urgentissues/land-conservation/forests/invasives-101.xml (last visited Apr. 9, 2018). Invasive plant species typically have short generation times, a high rate of reproduction, and few natural enemies.
Lawns deserve a special mention because they may have played the largest part in habitat destruction in urban and suburban neighborhoods. A 2005 study estimated that lawns cover 2 percent of the surface of the continental United States, making them the largest irrigated crop in the United States. Cristina Milesi et al., Mapping and Modeling the Biogeochemical Cycling of Turf Grasses in the United States, 36 Envtl. Mgmt. 426 (2005), https://link.springer.com/article/10.1007/s00267-004-0316-2. The ubiquitous “industrial lawn,” until recently found even in desert areas of the United States, typically comprises only certain species of grass, is free of weeds and as green as possible, and is regularly mowed. F. Herbert Bormann et al., Redesigning the American Lawn: A Search for Environmental Harmony 48-49 (Yale University Press 2d ed. 2001). Whereas native habitat exists without the assistance of anything except water and pollinators, the industrial lawn is the object of a multi-billion-dollar-a-year industry that encompasses lawn care services, equipment, and supplies and assiduously markets these products to homeowners. Consider the many environmental costs associated with the industrial lawn: use of herbicides and pesticides, which affect other plant and animal species, including us; use of fertilizers, most of which are produced using fossil fuels and which contaminate runoff; motorized maintenance, which in most cases consumes fossil fuels; and use of vast quantities of water. The EPA estimates that residential outdoor water use accounts for nearly 9 billion gallons of water use per day, mainly for landscape irrigation. EPA WaterSense, Outdoors, https://www.epa.gov/watersense/outdoors (last visited Apr. 9, 2018). Lawn clippings represent as much as 20 to 35 percent of solid waste in landfills, making them the second largest component, in those states that have not banned their disposal. Environmental Protection Agency, Environmental Fact Sheet: Recycling Grass Clippings, EPA/530-F-92-012 (July 1992). An industrial lawn is essentially “dead space” to wildlife. It is better than pavement—a lawn provides space for play, sequesters carbon, and reduces the heat island effect caused by pavement—but overall is one of the main drivers of habitat loss.
Pavement, Streets, and Stormwater
The United States has more than two million miles of paved roads, not including parking lots, driveways, or sidewalks. Paved surfaces are of course concentrated in urban areas; a 2001 study found that Baltimore and its bordering counties were covered with between 20 and 40 percent impervious surface area. National Aeronautics & Space Administration, New Satellite Maps Provide Planners Improved Urban Sprawl Insight, Science Daily (June 8, 2001), https://www.sciencedaily.com/releases/2001/06/010605072451.htm. Pavement seals the earth’s surface and is one of the most absolute losses of habitat possible. Pavement in cities contributes significantly to the heat-island effect. As noted above, pavement also more than doubles runoff, and runoff is a contributing factor to the “dead zones” now present in the Gulf of Mexico and the Atlantic. The larger the paved space, the higher velocity of the runoff, which can also disturb habitat and adversely affect the hydrological cycle. Finally, asphalt is a fossil fuel product.
Fences and Fragmentation
Fences can cause habitat fragmentation. Most obviously, they restrict movement of animals in the wild. They can cause animals to lose access to food, water, and mates. They can prevent animals from escaping in the case of fire, and fences themselves can injure and kill animals. Scientists estimate that the movement of mammals in areas with a comparatively high human footprint are as much as half of the extent of their movements in areas with a low human footprint. Marlee Tucker et al., Moving in the Anthropocene: Global Reductions in Terrestrial Mammalian Movements, Sci. Mag. (Jan. 26, 2018), http://science.sciencemag.org/content/359/6374/466.full. To name one example, in the spring, Eastern box turtles (considered threatened by many conservationists) can travel up to half a mile to their nesting sites. They may not reproduce at all if their habitat becomes highly fragmented; fencing constitutes one barrier to their migration. Steven D. Wilson, Thesis, Movement and Ecology of the Eastern Box Turtle in a Heterogeneous Landscape (May 2012) (thesis, Bowling Green State University), https://etd.ohiolink.edu/rws_etd/document/get/bgsu1334252208/inline.
Bright light during the night can lead to habitat loss and species decline in several ways. First, light may attract animals, subjecting them to the increased threat of predation or interfering with their normal activities. Second, light may repel some species, excluding them from their habitat. Third, light interferes with sleep, reproduction, and migration of some species. In areas where night lighting is prevalent, the night ecosystem is effectively turned into day.
The following types of legal tools can be used to counteract environmental problems caused by residential real estate development. There are others, of course. Statutes in some states expressly protect wildlife habitat. See, e.g., Alaska Stat. Ann. § 41.17.910 (authorizing the Department of Fish and Game to purchase fees simple or conservation easements or to transfer land to protect wildlife habitats); Cal. Fish & Game Code § 1930 (protecting wildlife habitats and corridors); Conn. Gen. Stat. Ann. 26-107f (authorizing a conservation program for nonharvested wildlife and its habitat). Many of these statutes are of limited scope, protecting wildlife only in certain areas of the state, or certain types of wildlife. Statutes are outside the scope of this article but may be available in a particular state to authorize actions to protect habitat.
Local governments can enact or amend zoning ordinances that regulate all the factors discussed above. A government can conduct a wildlife inventory, after which habitat preservation can be addressed in the comprehensive plan and zoning code. Density bonuses (allowing landowners to build excess units in return for a set-aside of open space by the developer); transfer of development rights (allowing development rights to be transferred to an already-developed area, thus leaving more sensitive areas undeveloped); use tax assessment (taxing land on the basis of current use rather than the highest and best use); special wildlife habitat zones and overlay zones; and adjusting zoning standards to require clustering (arranging homes on multiple lots to optimize environmental benefit of the open land), setbacks, and buffers. Zoning ordinances have the advantage of being able to affect a broader subset of property than do restrictive covenants, since the latter typically apply only to a common interest community (CIC). There is significant overlap in what types of land use they cover, so zoning ordinances can serve as a drafting guide for restrictive covenants.
A helpful source for those interested in pursuing change through zoning is Karen Strong, Conserving Natural Areas and Wildlife in Your Community: Smart Growth Strategies for Protecting the Biological Diversity of New York’s Hudson River Valley, New York State Department of Environmental Conservation (2008), https://www.dec.ny.gov/docs/remediation_hudson_pdf/hrebch.pdf.
Some states allow the creation of special districts, quasi-governmental entities in which residents of designated geographical areas are subject to special assessments. The revenues from these assessments are used to pay off bonds issued by the local government to fund various objectives. Environmental objectives for which special districts might be created include creation of wildlife habitat, wildlife corridors, rain gardens (to lessen water use and surface runoff), and green roofs, to name a few. The drawback to special districts may be, depending on state law, lack of built-in oversight and consequent danger of corruption. However, careful structuring can mitigate this problem. See Ark. Code Ann. §§ 14-93-101 through 133 for an example of a property owners’ improvement district statute.
Developers can create environmentally friendly restrictive covenants at the outset of a common interest community’s creation. “Conservation subdivisions” develop land while reducing the environmental impact. See generally Randall Arendt, Rural by Design: Planning for Town and Country (American Planning Association 2015). Property owners not fortunate enough to live in such a subdivision can amend covenants according to the procedure for amendment set out in the master declaration. Regulation of fencing, lighting, and landscaping is often found in guidelines issued by a committee most commonly known as the architectural review committee. Often these guidelines are easier to change than the restrictive covenants. Summaries of habitat-friendly covenants and guidelines are found below.
During the process of development itself, developers can always choose to impose a higher standard on themselves than required by environmental laws. We recommend an Irish publication, Notice Nature, Wildlife, Habitats & Development: Guidelines for the Protection of Biodiversity in Construction Projects, http://www.noticenature.ie/files/Construction_v12.pdf (last visited Apr. 9, 2018), which contains a table matching the types of construction activity (such as establishment of temporary roads) with the effects on wildlife (habitat fragmentation, road kills, dust contamination of habitat, noise and light pollution, soil pH change due to leaching), and recommends specific actions to take to mitigate effects on wildlife during each phase of a construction project.
Some common interest communities have drafted ecosystem policies. One example is that of Prairie Crossing, Illinois, a community located in a prairie that replaced chemically dependent farmland. Part of a larger document titled The Land Management Plan Summary 2016, the short-term Ecosystem Goal is as follows:
Establish and maintain healthy prairies and wetlands that are stable, functional native ecosystems with broad plant diversity and minimal weed pressure. Healthy prairies and wetlands have minimal woody shrubs and trees, and are not compromised by Eurasian weeds. While fully mature native prairies and wetlands need minimal management with occasional prescribed burns, the planted prairies are still in the establishment phase and still require more active management for the control of weed species.
Joe Marencik, Jim O’Connor, Bill Pogson, and Michael Sands, Prairie Crossing Homeowner Association Common Areas (Nov. 5, 2015), https://www.pchoa.com/picture/3982016_land_management_summary_-_final.pdf.
These easements are increasingly used to attempt to bind uses of land in perpetuity. The conservation easement for environmental purposes typically will be held by a nonprofit committed to biodiversity, like the Nature Conservancy. Although they are powerful tools for habitat preservation, conservation easements are seldom found in connection with residential housing and thus are outside the scope of this article.
The U.S. Green Building Council administers the Leadership in Energy and Environmental Design program, better known as LEED, the “platinum standard” for sustainable building construction. LEED has advanced from certifying buildings to neighborhoods. Its Citizen’s Guide provides early-stage information developers to determine where and what to build, and how to incorporate and manage environmental concerns. It is also intended for planners, officials, and citizens. This manual would be helpful to CIC residents interested in greater sustainability and habitat preservation. U.S. Green Building Council et al., A Citizen’s Guide to LEED for Neighborhood Development: How to Tell If Development Is Smart and Green, https://www.nrdc.org/sites/default/files/citizens_guide_LEED-ND.pdf (last visited Apr. 7, 2018).
Ideally, restrictive covenants should require native trees on every lot. Native shrubs are desirable, too. The National Audubon Society maintains a database of native trees and shrubs searchable by zip code, at www.audubon.org/native-plants. Lawn area should be limited to a percent of the lot. In areas where turf lawns cannot be grown without being watered, restrictive covenants should require xeriscaping (landscaping minimizing water use). Numerous Western governments and POAs are now limiting turf grass—in fact, Colorado has voided restrictive covenants that required turf grass. Colo. Rev. Stat. § 37-60-126. Various cities and water providers in California and Nevada have paid homeowners to replace their turf lawns with xeriscaping.
The Estates of North Park, in Covington, Louisiana, allows the planting of native Louisiana trees only and requires one tree for every 2000 square feet of lot area. Estates of North Park, Homeowners Association Design Guidelines (Aug. 2002), http://estatesofnorthpark.com/wp-content/uploads/2009/07/northpark-design-guidelines.pdf. Cedar Creek Community in Olathe, Kansas, requires street and yard trees on each lot, and any lots with “areas of existing heavy native vegetation” must be left “undisturbed and in the natural state.” Cedar Creek Realty, LLC, Cedar Creek Architectural Guidelines (Nov. 2017), http://cedarcreek-kc.com/wp-content/uploads/2017/04/12__1435601505.pdf.
For examples of xeriscaping guidelines, see those of the Canyon Creek CIC, located in Austin, Texas. Canyon Creek HOA, Canyon Creek Xeriscaping Guidelines (Sept. 20, 2017), http://www.canyoncreek.net/new-blog/2017/9/20/canyon-creek-xeriscaping-guidelines.
Restrictive covenants forbidding or greatly limiting the use of herbicides and pesticides are not easily found. Only seven states allow local governments to restrict the use of pesticides. Around 30 have statutes that completely preempt local governments from adopting legislation stricter than that of the state. Matthew Porter, State Preemption Law, at https://www.beyondpesticides.org/assets/media/documents/lawn/activist/documents/StatePreemption.pdf. South Portland, Maine, appears to be one of the very few local governments that has banned pesticides for residential turf and outdoor pest management. South Portland City Council, Position Paper of the Interim City Manager (Sept. 7, 2016), http://www.maine.gov/dacf/php/pesticides/documents2/municipal%20ordinances/South_Portland_Ordinance_2016.pdf. However, preemption should not be a bar to restrictive covenants prohibiting use. Ideally, herbicides and pesticides should be allowed only to control invasive species, when no other means are available, but the CIC’s architectural review committee should be able to grant waivers.
Invasive plant species should not be planted by the developer or allowed by landscaping guidelines. If in doubt, one can check with state agencies or extension services, which publish lists of local invasive species. See, e.g., the Florida list published by the Florida Fish and Wildlife Conservation Commission. Invasive Species (2018), http://myfwc.com/wildlifehabitats/invasive-plants/.
Developers can use permeable pavement for streets, parking lots, driveways, and sidewalks. For a manual on “green street” design, see Robb Lukes and Christopher Kloss, Managing Weather with Green Infrastructure: Green Streets, Environmental Protection Agency (2008), at https://www.epa.gov/sites/production/files/2015-10/documents/gi_munichandbook_green_streets.pdf.
Covenants can prohibit boundary fencing. They can allow fences of limited areas and for specific purposes. For example, the Tree Farm in Bend, Oregon, allows boundary fencing only if the property borders open space or common areas and then the fence must be split rail, at least 15 inches above the ground and no taller than 48 inches high. Welded wire fencing up to eight feet high is allowed for gardens, in specified locations. Privacy fencing up to five feet high can enclose no more than 5,000 square feet. The Tree Farm Architectural Design Guidelines (August 2017) at treefarmbend.com/ResourceCenter/Download/43828~2229832.
For a helpful guide to designing wildlife-friendly fences, see Sonoma County Agricultural Preservation and Open Space District, Fencing Guidelines and Specifications for Conservation Easements (2003), https://knowledge.sonomacreek.net/files/FencingGuidelines.pdf.
Outdoor lighting should be kept as minimal as possible, with amber or red wavelengths, and low to the ground and shielded. The Prairie Crossing community in Grayslake, Illinois, prohibits stand-alone light poles. Walkway lighting is not preferred, and if used must be lower than 18 inches high. No exterior lighting can exceed 60 watts, but 20 to 40 watts are preferred. For their Association Guidelines, see Prairie Crossing Homeowners Ass’n, Association Guidelines (July 1, 2009), http://www.prairiecrossinghomes.com/pdfs/Prairie%20Crossing%20-%20Guidelines%20%28Homeowners%20Association%29.pdf.
For more information on issues with night lighting, including the text of a model ordinance, see the International Dark-Sky Association’s web site at www.darksky.org.
Wildlife habitat in the United States is continuing to disappear. Residential development causes a significant amount of habitat loss. It is imperative for us to reverse this trend, not only for the biosystems of the earth, but also because connection with nature is beneficial to human beings’ health and happiness. One could argue it is a necessary corollary to the human condition. Numerous legal tools can help to save and restore natural habitat. Common interest communities are becoming more aware of their natural environment. The restrictive covenants of some reflect the desire to keep natural habitat, but many more should begin to grapple with this issue.
Imagine common interest communities that all attempt to eliminate invasive species and encourage native species to flourish. The desert common interest communities practice xeriscaping, and prairie and wooded common interest communities conduct periodic controlled burns. As we look out our window at home, coffee in hand, we will see coneflower, milkweed, purple mulberry, and possumhaw outside near the oak and pine trees. Hummingbirds feed on flowers, while a wood thrush sings in the undergrowth. Red-cockaded woodpeckers hunt for insects in the pine tree. These examples may not be from your habitat, but no matter where we live, as real estate professionals we can all work toward restoring the balance in our backyards, so that more birds can sing.