nature in fragments the legacy of sprawl

NATURE IN FRAGMENTS
AMERICAN MUSEUM OF NATURAL HISTORY
CENTER FOR BIODIVERSITY AND CONSERVATION
NEW DIRECTIONS IN BIODIVERSITY CONSERVATION
Center for Biodiversity and Conservation
New Directions in Biodiversity Conservation

ELEANOR J. STERLING, SERIES EDITOR
The books in this series are based on annual symposia presented by the American
Museum of Natural History’s Center for Biodiversity and Conservation and partners.
Each symposium reviews a topic critical to biodiversity and conservation, and provides
diverse perspectives by scientists, resource managers, policymakers, and others.
EDITED BY
Elizabeth A. Johnson
& Michael W. Klemens
NATURE IN
FRAGMENTS
THE LEGACY OF SPRAWL
COLUMBIA UNIVERSITY PRESS ■ NEW YORK
COLUMBIA UNIVERSITY PRESS
Publishers Since 1893
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Copyright © 2005 Columbia University Press
All rights reserved
Library of Congress Cataloging-in-Publication Data
Nature in fragments : the legacy of sprawl / edited by Elizabeth A. Johnson and Michael W.
Klemens.
p. cm. — (New directions in biodiversity conservation)
Includes bibliographical references (p. ).

ISBN 0-231-12778-2 (cloth : alk. paper)
ISBN 0-231-12779-0 (pbk. : alk. paper)
1. Cities and towns—Growth—Environmental aspects—Congresses. 2. Fragmented
landscapes—Congresses. 3. Biological diversity conservation—Congresses. I. Johnson,
Elizabeth A. (Elizabeth Ann), 1954 Aug. 29– II. Klemens, Michael W. III. Series.
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To our children Karla, Daniel, and Robert, with whom we share our joy of
nature and our hopes for a more sustainable world.

Preface ix
Acknowledgments xiii
Contributors xv
PART I BIODIVERSITY AND THE GENESIS OF SPRAWL
1. The Context and Causes of Sprawl 3
BARBARA L. LAWRENCE
2. The Impacts of Sprawl on Biodiversity 18
ELIZABETH A. JOHNSON AND MICHAEL W. KLEMENS
PART II SPRAWL, ECOSYSTEMS, AND PROCESSES
3. Freshwater Wetland Biodiversity in an Urbanizing World 57
NICHOLAS A. MILLER AND MICHAEL W. KLEMENS
4. Ecosystems, Disturbance, and the Impact of Sprawl 90
SETH R. REICE
5. Bees, Pollination, and the Challenges of Sprawl 109
JAMES H. CANE

6. Effects of Urbanization on Decomposer Communities and Soil Processes
in Forest Remnants 125
MARGARET M. CARREIRO
7. Sprawl and Disease 144
FRED W. KOONTZ AND PETER DASZAK
CONTENTS
viii ■ CONTENTS
PART III SPRAWL AND SPECIES
8. Sprawl and Species with Limited Dispersal Abilities 157
DIANE L. BYERS AND JOSEPH C. MITCHELL
9. Sprawl and Highly Mobile or Wide-Ranging Species 181
JUSTINA C. RAY
10. Species that Benefit from Sprawl 206
STEPHEN DESTEFANO AND ELIZABETH A. JOHNSON
PART IV IDENTIFYING AND MEETING THE CHALLENGES
OF SPRAWL
11. Maintaining Connectivity in Urbanizing Landscapes 239
M. A. SANJAYAN AND KEVIN R. CROOKS
12. The Economics of Biodiversity in Urbanizing Ecosystems 263
STEPHEN FARBER
13. Conserving Biodiversity Through State and Regional Planning 284
JESSICA WILKINSON, SARA VICKERMAN, AND JEFF LERNER
14. Integrating Conservation of Biodiversity into Local Planning 313
JAYNE DALY AND MICHAEL W. KLEMENS
15. Building Public Awareness About the Effects of Sprawl on
Biodiversity 335
CYNTHIA COFFIN AND JANE ELDER
16. Creating a Framework for Change 349
MICHAEL W. KLEMENS AND ELIZABETH A. JOHNSON
Index 363

PREFACE
T
his book is based in part on the symposium “Nature in Fragments: The
Legacy of Urban Sprawl,” held in April 2000 at the American Museum of
Natural History and co-sponsored by the museum’s Center for Biodiversity
and Conservation and the Wildlife Conservation Society’s Metropolitan
Conservation Alliance. The impetus behind the conference—and this book—
was to create a platform from which to integrate biodiversity issues, concerns,
and needs into the growing number of antisprawl initiatives, including the
“smart-growth” and “new urbanist” movements. Our goal is to add biodiver-
sity to the agenda of all who are creating more sustainable human environ-
ments, but who may not be fully considering ecological issues and opportuni-
ties associated with more informed development. A second, related goal is to
deepen and broaden the discussion about sprawl’s impacts on biodiversity and
to include looking at ways in which sprawl affects species and alters or modifies
natural communities, ecosystems, and processes.
There is widespread acknowledgment that biodiversity on Earth is imper-
iled and that we are in the midst of an extinction spasm of unprecedented
proportions, caused primarily by human activities (Wilcove et al. 1998).
Overpopulation and overconsumption, the roots of this crisis, are generally
discussed in terms of the following threats: habitat loss, fragmentation, and
degradation; invasive species; pollution; overexploitation of biological re-
sources; and global climate change. Sprawl creates and contributes signifi-
cantly to these threats, thus both directly and indirectly causing the decline
of bio diversity.
For the purposes of this book, we define sprawl as poorly planned, land-con-
sumptive development, regardless of where it is located. It occurs at the edges
of cities or in rural fringes within commuting distance of metropolitan centers.
But sprawl also can be found in more remote areas. Second-home development
x ■ PREFACE

and recreational sprawl can be found in backcountry areas with significant natu-
ral features and wildlife. Sprawl also includes single-family homes and tract de-
velopments, megahouses found in upscale communities throughout the United
States, as well as commercial and industrial development. The unifying features
of these developments are that they all are placed haphazardly and wastefully
on the greater landscape.
Although this book presents examples primarily from the United States, the
link between sprawl, energy and resource consumption, and increasing afflu-
ence and population growth is a worldwide phenomenon. As global citizens,
we need to act decisively to develop more sustainable ways to live within the
dwindling resources of our planet. The Western nations, especially the United
States, have the additional responsibility to lead by example because we are
exporting (intentionally or not) this sprawl-dependent lifestyle throughout the
world.
Citizens, politicians, and municipalities are increasingly interested in ad-
dressing sprawl, and myriad individuals and organizations are working to find
solutions to the social and economic challenges presented by a decentralized,
sprawl-created environment. Interest groups are trying to rechannel develop-
ment into more productive avenues, to enhance quality of life and community
cohesion, to reinvest in established urban centers, and to discourage wasteful
patterns of development and land use.
Discussions about the biological effects of sprawl have centered on its impact
on pollution, on both air quality and water quality, and on the protection of
open space. Open space is an umbrella term that typically includes undevel-
oped land we consider “valuable,” such as farmland, scenic vistas, recreational
parks and corridors, and natural areas, as well as ecologically constrained land
such as steep slopes and wetlands. Each of these open-space components has
its constituencies, most of which are focused on meeting human wants and
needs, including farmland and watershed protection, scenic vista protection,
and recreational interest. Some efforts have been focused on the protection of

threatened and endangered species, but in general there is little advocacy for
biodiversity: for the protection of ecosystem processes on the landscape and for
the protection of the community of common and uncommon plants, animals,
fungi, and microbes living among us in the landscape. Yet biodiversity—na-
ture—is vital to our survival.
This book contains four parts. Part I provides the introduction to the topic.
In chapter 1, Barbara L. Lawrence presents an overview of sprawl and how we
got where we are today. In chapter 2, the volume editors provide an introduc-
tion to biodiversity and discuss the ways in which sprawl threatens the planet’s
biological foundation.
Parts II and III of the book explore in more detail some of the impacts of
PREFACE ■ xi
sprawl on biodiversity at different organizational levels, with part II looking at
sprawl’s effects on ecosystems and ecosystem processes, and part III examin-
ing sprawl’s impacts at the species level. In chapter 3, Nicholas A. Miller and
Michael W. Klemens discuss the impacts of sprawl on wetland ecosystems.
Although focusing on wetlands, the conclusions they draw can be applied to
terrestrial systems. In chapter 4, Seth R. Reice explains sprawl’s effects on the
processes of ecosystem disturbance. In chapter 5, James H. Cane presents an
introduction to the process of pollination with an in-depth discussion of sprawl’s
effects on our most important pollinators, the bees. Chapter 6, by Margaret M.
Carreiro, illustrates the way in which sprawl alters forest decomposer communi-
ties and soil processes. In chapter 7, Fred W. Koontz and Peter Daszak broaden
the discussion of processes to emphasize sprawl’s impacts on disease and disease
transmission. Opening part III, Diane L. Byers and Joseph C. Mitchell begin
the discussion of sprawl’s impact on species by focusing in chapter 8 on plants
and animals with limited dispersal capability. Justina C. Ray follows in chap-
ter 9 with an introduction to wide-ranging and area-sensitive species. Stephen
DeStefano and Elizabeth A. Johnson remind readers in chapter 10 that some
species tolerate and even benefit from the changes that sprawling development

brings to the landscape.
Part IV presents the challenges we face in our efforts to conserve biodiversity
by addressing the causes and effects of sprawl and by offering some examples
of what is successfully being undertaken and where we can go further in our
efforts. In chapter 11, M. A. Sanjayan and Kevin R. Crooks clarify the impor-
tance of landscape connectivity. Stephen Farber discusses in chapter 12 the
role of economics in developing more effective land-use plans for biodiversity.
Jessica Wilkinson, Sara Vickerman, and Jeff Lerner look at the role of planning
and conservation at the state and national level in chapter 13, and in chapter
14 Jayne Daly and Michael W. Klemens focus on the complementary value of
local planning efforts for biodiversity conservation. Effective communication is
a key to addressing sprawl; Cynthia Coffin and Jane Elder discuss this topic in
chapter 15. Last, in chapter 16, the volume editors offer some additional recom-
mendations to incorporate biodiversity concepts more effectively into land-use
planning in the future.
In an editorial in the journal Conservation Biology, John Marzluff wrote
that we need to “develop an understanding of how settlement affects the rich-
ness and relative abundance of species, what motivates people to develop and
settle land the way we do, how land use policy is crafted, implemented, and
informed by economic and ecological reality and how planners, managers,
developers and architects respond to human desire and policy to create settle-
ments” (2002:1176). This volume should be an important step in attaining that
understanding.
xii ■ PREFACE
REFERENCES
Marzluff, J. M. 2002. Fringe conservation: A call to action. Conservation Biology
16:1175–1176.
Wilcove, D. S., D. Rothstein, J. Dubow, and E. Losos. 1998. Quantifying threats to
imperiled species in the United States. BioScience 48:607–615.
ACKNOWLEDGMENTS

W
e thank the American Museum of Natural History’s Center for
Biodiversity and Conservation (CBC) and the Wildlife Conservation
Society’s Metropolitan Conservation Alliance (MCA) for conven-
ing the symposium “Nature in Fragments: The Legacy of Urban Sprawl,” on
which this book is based. We also acknowledge the contributions of the sympo-
sium presenters, who laid the groundwork for this volume. Although not all of
them are represented in this volume, all contributed significantly to the evolu-
tion and synthesis of our position on this topic.
To our contributing authors we owe a special debt for generously sharing
their scholarly work and for their patience during the revision and editorial pro-
cess. Their contributions have added depth to the understanding of biodiversity,
the challenges of sprawl, and the ways we can make a meaningful contribution
to reversing the frightening trajectory of ecological waste that characterized the
closing decades of the twentieth century. We are indebted to all those individu-
als and organizations working toward solutions to the sprawl crisis—they have
established a solid platform on which to build a new land-use paradigm.
We also appreciate the efforts of our many chapter reviewers, who gave
their time and expertise to ensure the accuracy and clarity of each chapter
and provided thoughtful feedback. Many thanks to Dana Beach, Diane Byers,
Donald Chen, Ray Curran, Eric Davidson, Richard DeGraaf, Amanda Dey,
Joan Ehrenfeld, Paul Epstein, Peggy Fiedler, James Gibbs, Frank Golet, John
Gowdy, Jodi Hilty, Roland Kays, William Kemp, Linda Kervin, Claire Kremen,
Gretchen LeBuhn, Jay Malcolm, R. William Mannan, Carl McDaniel, Nick
Miller, Martha Monroe, Gerry Moore, Marya Morris, Reed Noss, T’ai Roulston,
Eric Sanderson, Elizabeth Schilling, Sacha Spector, Gary Tabor, Vince
Tepedino, Adrian Treves, Thomas Wright, Jianguo Wu, and Wayne Zipperer.
We value your help in creating a better book that is not only well grounded in
science, but more closely linked to the planning and public-policy processes.
Special thanks to CBC and MCA staff and volunteers who assisted us in

various ways throughout the writing and editing process. In particular, we thank
Josh Berman, Fiona Brady, Elizabeth Cornell, Melina Laverty, Marc LeCard,
Jim McDougal, Timon McPhearson, Ho-Ling Poon, Kevin Ryan, Jennifer
Schmitz, and Jennifer Stenzel. We also appreciate the in-depth contribution of
CBC director and series editor, Eleanor Sterling.
The MCA acknowledges financial support provided by the Doris Duke
Charitable Trust, the Surdna Foundation, the Westchester Community Foun-
dation, and Vivian and Strachen Donnelly. The CBC acknowledges financial
support provided by the Sarah K. de Coizart Article TENTH Perpetual Chari-
table Trust.
Thanks to all the individuals and organizations that contributed their pho-
tographic work to this volume: Diane L. Byers, Stephen DeStefano, James
Glinski, Keith Hackbarth, Fred W. Koontz, Gene Magee, Nicholas A. Miller,
Joseph C. Mitchell, Michael B. Morrissey, Michael Reuter, Biodiversity Proj-
ect and Green Team Advertising, Defenders of Wildlife, Florida Greenways
Commission, Leyland Alliance LLC, Regional Plan Association, Rhode Island
Geographical Information System and MIT, and Wildlife Conservation Soci-
ety/Metropolitan Conservation Alliance. Special thanks to James Lui for his
original cover design and to Patricia Wynne for her fine artwork.
Many thanks also to Robin Smith, Irene Pavitt, and Lisa Hamm at Columbia
University Press and to Annie Barva for patiently guiding us through the book-
writing, -editing, and -design process.
Finally, we are also indebted to our friends and families, for their patience
and understanding as we worked on this book. Elizabeth Johnson would es-
pecially like to thank her husband, Dave, for his love and support and for the
many insightful discussions they shared about conserving the natural world that
so enriches their lives.
xiv ■ ACKNOWLEDGMENTS
CONTRIBUTORS
Diane L. Byers

Associate Professor in Evolutionary Biology
Behavior, Ecology, Evolution, and Systemat-
ics Section
Department of Biological Sciences
Campus Box 4120
Illinois State University
Normal, Illinois 61790
James H. Cane
Research Entomologist
USDA-ARS Bee Biology and Systematics Lab
Utah State University
Logan, Utah 84322–5310
Margaret M. Carreiro
Associate Professor of Biology
Department of Biology
139 Life Sciences Building
University of Louisville
Louisville, Kentucky 40292
Cynthia Coffin
Partner
About Place Consulting
225 Merry Street
Madison, Wisconsin 53704
Kevin R. Crooks
Assistant Professor
Department of Fishery and Wildlife Biology
Colorado State University
115 Wagar
Fort Collins, Colorado 80523
Jayne Daly

Attorney
Jacobowitz and Gubits, LLP
158 Orange Avenue
Walden, New York 12586
Peter Daszak
Executive Director
Consortium for Conservation Medicine
460 West Thirty-fourth Street
New York, New York 10001
Stephen DeStefano
Leader, Adjunct Professor
U.S. Geological Survey
Massachusetts Cooperative Fish and Wildlife
Research Unit
Holdsworth Natural Resources Center
University of Massachusetts
Amherst, Massachusetts 01003
Jane Elder
Executive Director
Biodiversity Project
214 North Henry Street, Suite 201
Madison, Wisconsin 53703
Stephen Farber
Professor
Graduate School of Public and International
Affairs
University of Pittsburgh
Pittsburgh, Pennsylvania 15260
Elizabeth A. Johnson
Manager, Metropolitan Biodiversity Program

Center for Biodiversity and Conservation
American Museum of Natural History
Central Park West at 79th Street
New York, New York 10024
Michael W. Klemens
Senior Conservationist, Director
Wildlife Conservation Society
Metropolitan Conservation Alliance
2300 Southern Boulevard
Bronx, New York 10460
Fred W. Koontz
Executive Director
Teatown Lake Reservation
1600 Spring Valley Road
Ossining, New York 10562
Barbara L. Lawrence
Executive Director
Henry and Marilyn Taub Foundation
300 Frank W. Burr Boulevard
Teaneck, New Jersey 07666
Jeff Lerner
Director, Conservation Planning
Defenders of Wildlife
National Headquarters
1130 Seventeenth Street, NW
Washington, D.C. 20036
Nicholas A. Miller
Program Manager
Wildlife Conservation Society
Metropolitan Conservation Alliance

2300 Southern Boulevard
Bronx, New York 10460
Joseph C. Mitchell
Research Biologist
Department of Biology
University of Richmond
Richmond, Virginia 23173
Justina C. Ray
Associate Conservation Zoologist,
Director
Wildlife Conservation Society Canada
720 Spadina Avenue, Suite 600
Toronto, Ontario M5S 2T9
Canada
Seth R. Reice
Associate Professor
Department of Biology
Campus Box 3280, Coker Hall
University of North Carolina
Chapel Hill, North Carolina 27599–3280
M. A. Sanjayan
Lead Scientist
The Nature Conservancy
4245 North Fairfax Drive, Suite 100
Arlington, Virginia 22203–1606
Sara Vickerman
Director, West Coast Office
Defenders of Wildlife
1880 Willamette Falls Drive, Suite 200
West Linn, Oregon 97068

Jessica Wilkinson
Director, State Biodiversity Program
Environmental Law Institute
2000 L Street NW, Suite 620
Washington, D.C. 20036
xvi ■ CONTRIBUTORS
PART I
BIODIVERSITY AND THE GENESIS OF SPRAWL


THE CONTEXT AND CAUSES OF SPRAWL
Barbara L. Lawrence
A
mericans living in the sprawling twenty-first century face a Three Bears’
dilemma, but with fewer choices: the places where we live, work, and
play are too far apart to offer the option of walking from one activity to
another, but too close together to move about without regular traffic snarls.
Our housing is too expensive for many to own, but too poorly built to survive
the turn of the next century. Our open space is too fragmented for wildlife hab-
itat and efficient farming, but abundant enough to attract even more sprawling
development.
Viewed from the air, the curves of cul-de-sacs and intricate patterns of
the highway interchanges that open new land to development are too clear-
ly planned to have been accidental. Planners and government officials have
helped pave the way for development with deliberate decisions that have re-
sulted in the rapid, unsustainable consumption of green fields and forests and
the abandonment of older communities. This is not a natural occurrence, nor
is it inevitable, as some would argue.
Rather, sprawl is driven by a set of public policies at the national, state, and
local levels. Many growth policies, but not all, were developed on sound logic

that fit the economic needs of the previous century. Today, such policies not
only are obsolete, but have a profound and adverse affect on both the long-term
health of our environment and the daily quality of life for millions of Ameri-
cans.
These policies—which govern housing, transportation, taxation, public in-
vestment, and even neighborhood zoning—make discarding existing homes
and communities for new ones seem the natural choice. It is not. The sprawl-
ing land-use pattern we developed in the twentieth century has no single cause
and no single cure, which makes tackling the causes of sprawl complicated and
difficult, but not impossible.
4 ■ BIODIVERSITY AND THE GENESIS OF SPRAWL
SPRAWL: THE MYTHS ABOUT CAUSE
Sprawl is a dispersed pattern of single-use, low-density land uses, most evident
as developments of large-lot, single-family homes, office campuses, and strip
malls (figure 1.1). It frequently leapfrogs, jumping beyond established settle-
ments onto farm- or forestland. Roads and highways play an important role
as incubators of retail strip development, much of which is indistinguishable
from one place to another. Roads are also precursors and companions to sprawl
because sprawl favors the automobile over all other travel options. Sprawl not
only stakes its claim to open lands, but also is clearly linked to urban and sub-
urban decline, as economic investment moves from older cities and suburbs
to newer green-field development sites. These sites frequently offer lower con-
struction costs and some form of lower taxation, at least in the initial stages of
development.
This movement to new locations is unassociated with overall regional popu-
lation growth, contrary to the popular myth that sprawl is a natural result of
population growth. A look at any number of sprawling metropolitan regions
in the country shows that urban population declines frequently cancel out the
suburban increases. Overall, between 1982 and 1997, land in the United States
was developed at approximately 1.8 times the rate of population growth. How-

ever, this national figure greatly underestimates the impact of sprawl in particu-
FIGURE 1.1. Sprawling development around Miami, Florida. (Photo by Elizabeth A. Johnson)
THE CONTEXT AND CAUSES OF SPRAWL ■ 5
lar states and regions. In Wyoming between 1982 and 1997, the state lost 5.2
percent of its population but increased developed acres by 17.1 percent. In the
same time period, New York State saw 3.2 percent population growth and 0.8
percent increase in developed acres (Department of Agriculture 1992; Bureau
of the Census 2000). Nor is there truth in the myth that sprawl is solely an arti-
fact of the market or of affluence, a consequence of decisions made by millions
of Americans to maximize their well-being by choosing a place to live or work
that best suits their taste. This explanation ignores the omnipresent government
policies and regulations—at the federal, state, and local levels—that largely pre-
scribe what choices are available.
THE POLICIES THAT CAUSE SPRAWL
Sprawling, low-density expansion is a relatively new state of affairs whose pat-
tern derives from advances in transportation technology. The history of civiliza-
tion is one of compact, walkable communities surrounded by open lands. For
most of human history, travel was by foot or animal. Both required relatively
compact communities settled at relatively high densities. Animals brought the
added requirement of preserving nearby open land for the provision of fodder
and waste disposal. Even the addition of water and rail transport did not dramat-
ically alter this pattern because after passengers departed a train or boat, they
again faced foot or animal travel to reach their destinations.
Indeed, compact, walkable communities prevailed in the United States until
the early years of the twentieth century, when technological innovations and a
series of public-policy decisions created both opportunities and incentives for
development to spread out from central cities. The rise of the automobile, the
almost magical invention of a “one-seat” all-weather ride from one’s home to a
location of choice at any time of the night or day, was destined to have a major
impact on American life. However, the revolution it brought in social form was

largely unpredicted and unseen until a plethora of public policies fully em-
braced the technology. As the century progressed, planning and other policies
overwhelmingly favored an automobile-centric highway paradigm to the utter
exclusion of traditional patterns of urban development, in which walking and
transit had played the key roles.
At the same time that these new opportunities for development were being
created along highways instead of sidewalks, disincentives were put into place
that discouraged—and in some cases prohibited—more compact urban devel-
opment. Changes in the policies governing housing, infrastructure (transporta-
tion, water, and sewers), and taxation were the primary drivers. On the local
level, zoning was invented to protect private-property owners from the impact
6 ■ BIODIVERSITY AND THE GENESIS OF SPRAWL
of nearby factories and other noisy, unsafe, and noxious facilities. However,
the unintended consequences of single-use zones provided a means of closely
regulating undeveloped land, locking in a segregation of land uses and locking
out the flexibility of the marketplace.
The public-policy influences on the use of land are manifold. Each level of
government has contributed some incentives and some restrictions. In sum total,
federal, state, and local government policies for much of the twentieth century
have produced sprawl for the most part as a largely unintended consequence.
FEDERAL POLICIES
The federal government is the level of government farthest away from the deci-
sions made in town halls about the exact shape and location of the next devel-
opment. Yet federal policy decisions, many made years earlier, serve as the
catalyst for the land-use proposals facing local decision makers. A multitude of
federal programs have the potential to influence land-use patterns. Two of the
most critical are housing and transportation.
HOUSING POLICY Beginning in the early 1930s, new federal housing policies
evolved that effectively discouraged urban investment and spurred suburban
home ownership. These policies, established 70 years ago and amplified by the

GI Bill in 1944, lured middle-class families out of older urban places by mak-
ing new suburban home ownership the most inexpensive living option for this
group of Americans.
Among the first in this series of policy decisions was the creation of the
Homeowners Loan Corporation in 1933. Its laudable goal was to protect hom-
eownership by stemming the tide of foreclosures resulting from the Great De-
pression. It did so by refinancing mortgages with lower interest rates and longer
terms—the very system we use today. In addition to improving the mortgage
as an instrument for financing housing, the Homeowners Loan Corporation
created the first standardized national system for appraising real estate. Unfor-
tunately, this system was based on ideas about what constituted a “good” neigh-
borhood. The appraisals devalued much of what we know as urban life—areas
with older housing stock and mixed uses, including retail and office uses, and
areas with dense populations and nonwhite residents. These areas were consid-
ered high risk for mortgages. The maps resulting from this classification system
were used not only by the federal government, but also by private bankers,
ensuring that the potential for urban decline was fulfilled.
A year after the Homeowners Loan Corporation enabled longer mortgage
terms, the National Housing Act of 1934 was signed into law, creating the Fed-
THE CONTEXT AND CAUSES OF SPRAWL ■ 7
eral Housing Administration (FHA). The act’s immediate goal was to increase
employment in the building trades without direct government expenditures.
However, its long-lasting impacts went far beyond unemployment relief. Among
the key features of the FHA were federal insurance for homes that met certain
building and location standards, a longer payback period for mortgages, and
a substantially lower down-payment requirement. As a result of these public-
policy changes, the costs of homeownership dropped dramatically, enlarging
the number of American families seeking and able to buy a house. According
to Kenneth T. Jackson in his classic work Crabgrass Frontier, “it often became
cheaper to buy than to rent” (1985:205).

Built into this new system of insuring mortgages were blatant antiurban and
antiblack provisions that made cookie-cutter, whites-only suburban subdivisions
the norm. The FHA, in an effort to ensure that the mortgages it backed were
for a “quality” product, established minimum requirements for “lot size, setback
from the street, separation from adjacent structures, [and] even for the width of
the house itself” (Jackson 1985:208). These standards discouraged the purchase
of traditional urban homes. The FHA also established standards for the prop-
erty, the neighborhood, and the mortgage holder. The exclusion of blacks from
its insured homes was based on the notion that homes would lose value in an
integrated neighborhood.
This codification of antiurban bias pulled resources from cities, leaving be-
hind the people for whom choice was most limited, because of either race or
financial status. It made building a new house on a cornfield or in a forest easier
and more affordable than finding the funds to renovate an existing structure.
As the middle class moved itself to the suburbs because of these incentives, im-
poverished families were moved into public housing clustered in already poor
neighborhoods. Federal housing policy allowed municipalities to choose if they
wanted to build public housing. Given this choice, newer suburbs declined to
house the poor. These policies persisted into the late 1960s. By then, the desir-
ability of many cities as places to live was substantially reduced, continuing the
downward urban spiral that fueled further sprawl.
Amplifying these midcentury housing policies were two tax policies that con-
tinue to reduce the cost of home ownership: the mortgage interest deduction
and the tax treatment of capital gains from sale of a residence. Homeownership
was and is seen generally as a net benefit to society. It was thought that where
people own their homes, they will have a stronger stake in the community. Al-
though this conclusion may be debatable, home ownership has clearly been an
effective form of wealth creation—the most substantial savings that middle-class
families have after several decades of living, working, and raising a family are
often the appreciated values of their homes.