Table of Contents

Cover

Title Page

Dedication

Foreword

Preface

Acknowledgements

Chapter 1: Introduction

1.1 Setting the scene
1.2 What is urban ecology?
1.3 Why is urban ecology interesting?
1.4 The aims of this book
References

Chapter 2: Urban environments

2.1 Introduction
2.2 Primary biophysical processes associated with urbanization
2.3 Secondary biophysical processes associated with urbanization
2.4 Stochasticity in urban environments
2.5 Summary
References

Chapter 3: Population- and species-level responses to urbanization

3.1 Introduction
3.2 Responses to the secondary biophysical processes of urbanization
3.3 Biological introductions and invasions
3.4 Human disturbance
3.5 Stochastic effects on populations in urban environments
3.6 Summary
References

Chapter 4: Community-level responses to urbanization

4.1 Introduction
4.2 Selection: niche theories in urban ecology
4.3 Ecological drift: modelling stochasticity in urban communities
4.4 Dispersal: the movement of individuals through space
4.5 Diversification: the evolution of new lineages in urban environments
4.6 Summary
References

Chapter 5: Ecosystem-level responses to urbanization

5.1 Introduction
5.2 Carbon
5.3 Water
5.4 The nitrogen cycle
5.5 Summary
References

Chapter 6: The urban ecology of humans

6.1 Introduction
6.2 The urban form
6.3 Pollution and waste
6.4 Climatic changes in urban environments
6.5 Health inequities in the world's cities
6.6 Summary
References

Chapter 7: Conserving biodiversity and maintaining ecosystem services in cities

7.1 Introduction
7.2 Strategies for conserving biodiversity and maintaining ecosystem services in cities
7.3 Novel habitats, novel ecosystems
7.4 Summary
References

Chapter 8: Summary and future directions

8.1 Introduction
8.2 Do we need a new theory of urban ecology?
8.3 The definition and scope of urban ecology
8.4 Do we need a new theory of urban science?
8.5 Future directions
References

Index

End User License Agreement

List of Illustrations

Chapter 1: Introduction

Figure 1.1 (a) World population of humans in urban and rural areas and (b) the urban population of humans in less developed and more developed regions of the world, 1950–2050.
Figure 1.2 An ordered suburb in Las Vegas, Nevada, USA. Picture has been straightened, cropped and converted to black and white.
Figure 1.3 Houses in the Kibera Slum, Nairobi, Kenya. Picture has been cropped and converted to black and white. Photograph by Colin Crowley.
Figure 1.4 Ecoregions of the world with more than half their area urbanized; note the strong bias towards islands and coastal areas. Endemic species in these regions are threatened by continued urban expansion.

Chapter 2: Urban environments

Figure 2.1 Skyscrapers in Dubai, UAE.
Figure 2.2 Midtown skyline of Phoenix, Arizona. Picture has been cropped and converted to black and white.
Figure 2.3 Tree cover (%) in different urban land-use types, averaged across 12 cities built in naturally forested areas in the USA. Vacant/wild = vacant lots or wild lands, institutional = institutional areas such as hospitals and schools, other = agricultural land, orchards, roads and airports; comm/indust = commercial and industrial land. The error bars represent standard errors.
Figure 2.4 Land-cover change in Cornelius, North Carolina, USA resulting from urban expansion, 1984–2001. Impermeable-surface cover increases while the cover of trees and open space decreases.
Figure 2.5 The River Ouse in York, UK, showing the confined stream channel.
Figure 2.6 Average annual concentration of coarse particulate matter (PM₁₀) in the atmosphere (µg m^–3), recorded in 50 countries.
Figure 2.7 Municipal solid waste in the USA 1960–2012: (a) average annual generation of waste (kg/person/year); b) percentage of waste recycled.
Figure 2.8 Schematic diagram of an urban and a rural hydrograph, showing stream flow versus time since a rainfall event. The urban curve has a shorter lag time, a higher peak, a faster subsidence and a lower base flow than the rural curve, reflecting the characteristic “flashiness” of urban streams.
Figure 2.9 Ecological light pollution in Brasilia, Brazil as seen at night from space.

Chapter 3: Population- and species-level responses to urbanization

Figure 3.1 A conceptual model of the processes associated with urbanization, and the important mechanisms and pathways through which these can affect populations of non-human species. *Processes that are strongly influenced by human preferences.
Figure 3.2 A hypothetical habitat network for a butterfly comprised of seven habitat patches of varying size and proximity to each other (circles); the arrows show potential pathways for dispersal between patches. Metapopulation theory predicts that small and/or isolated patches are less likely to support a population than large and/or connected patches. In this case, patch A (small and isolated) is least likely to support a population, while patch D (large and well-connected) is most likely.
Figure 3.3 Busy highways can act as a barrier to dispersal for the coyote Canis latrans.
Figure 3.4 (a) The cover of algae and lichen on tree trunks (%) and (b) the ln(abundance) of psocids (bark lice; multiple species represented) as a function of the annual average atmospheric SO₂ concentration in Newcastle upon Tyne, UK; circles = % cover of the alga Pleurococcus naegeli, crosses = % cover of the lichen Lecanora conizaeoides.
Figure 3.5 Frequency shift in the call of the bow-winged grasshopper Chorthippus biguttulus in noisy conditions (local frequency maxima in Hz), showing results for individuals from roadside and non-roadside habitats; predicted effect ± SE for a male with overall mean body mass of 95.15 mg.
Figure 3.6 Prey items of 282 domestic cats in Great Britain: adjusted means (± S.D.) of log₁₀-transformed numbers of mammals, birds and herpetofauna brought home by (a) cats that wore bells (black columns) and those that did not (white columns); (b) cats that were allowed out at night (black columns) and those that were not (white columns).
Figure 3.7 The endangered spotted handfish Brachionichthys hirsutus is endemic to the Derwent River Estuary, Tasmania, Australia. This species is threatened by the introduced northern Pacific seastar Asterias amurensis.

Chapter 4: Community-level responses to urbanization

Figure 4.1 Schematic diagram of the ecological niche of two tree species defined by two environmental variables, annual mean air temperature and annual mean rainfall; the abundance of each species (demonstrated by a 3D dome) increases from the edges to the centre of its niche. The species on the left is adapted to cool, moist conditions and has a larger ecological niche than the species on the right, which is adapted to hotter, drier conditions.
Figure 4.2 A simplified urban food web showing (1) saprotrophs (fungi), (2) autotrophs (plants), (3) herbivores or primary consumers (ant, dove, moth), (4) primary predators (blackbird, insectivorous bat) and (5) secondary predators (cat, fox).
Figure 4.3 (a) Pretoria, South Africa, (b) the rufous-naped lark Mirafra africana, a grassland specialist lost from Pretoria following urbanization, (c) the white-bellied sunbird Cinnyris talatala, which is found in suburban and urban areas of the city. Pictures have been cropped and converted to black and white.
Figure 4.4 Schematic diagram of common patterns observed in urban bird communities; changes in population densities (solid and dotted lines) and species diversity (dashed line) along a wildland-urban gradient. 1 In wildlands, native species (solid line) out-compete invasive, synanthropic species (dotted line). 2 At intermediate levels of urbanization, both groups of species are still present. Invasive species increase in density more rapidly than native species by exploiting novel, stable, and homogenized food resources (e.g., commercial seed mixture). Native species persist through spatial partitioning, exploiting remnant patches that still contain specialized food or other resources, but may decline in the longer term. 3 At high levels of urbanization, coexistence mechanisms collapse, predation pressure relaxes, invasive species become dominant foragers and specialist native species become locally extinct.
Figure 4.5 Estimated probability of local extinction (circles) with 95% credible intervals for a plant species with traits fixed at the reference class for each categorical trait (herbaceous, annual, non-clonal, abiotic pollination, no specialised dispersal, nitrogen fixing, C3 photosynthetic pathway, no spines), and having mean height and seed mass, for each of 11 cities. The graph shows strong variation in the probability of local extinction between cities.
Figure 4.6 Relationship between the abundance of tree frog (Litoria spp.) larvae (tadpoles) and the abundance of predatory fish in urban wetlands across Melbourne, Australia, both expressed as catch per unit effort (CPUE). The solid line shows the relationship predicted by a Bayesian, zero-inflated negative binomial regression model (ZINB), and the dotted lines show the 95% credible intervals.
Figure 4.7 (a) Percentage of passes in each of 18 towns and cities in south-eastern Australia by bats belonging to five functional guilds; open-adapted (open), clutter-adapted (clutter), edge-adapted with low-frequency echolocation calls (edge-low), and edge-adapted with medium- and high-frequency calls (edge-medium and edge-high). Clutter-adapted and edge-high species have been combined in this Figure Luck et al. 2013, Figure 3. Reproduced with permission of Springer Science + Business Media. (b) A long-eared bat Nyctophilus gouldi.
Figure 4.8 Schematic diagram of the composition of local, regional and global ecological communities. Through the dispersal of species, the composition of the local community is linked to that of the regional community, and the composition of the regional community is linked to that of the global community. However, in urban environments, the local species pool is also linked to the global species pool via the introduction by humans of species that are not present in the regional community.
Figure 4.9 The southern brown tree frog Litoria ewingii persists in ponds with a vertical wall in Melbourne, Australia.

Chapter 5: Ecosystem-level responses to urbanization

Figure 5.1 (a) Global anthropogenic carbon emissions per year from the combustion of fossil fuels plus cement production (black line) and land-use change (grey line); (b) uptake of carbon emissions per year by the atmosphere (black line) and the oceans (grey line).
Figure 5.2 Annual per-capita greenhouse-gas emissions from ground transport (in Mg of equivalent CO₂) versus the human-population density of a city.
Figure 5.3 Annual frost days in Melbourne, Australia between 1850 and 2000 (circles) with the moving 10-year average of annual frost days (black line). Modified from Parris and Hazell (2005), Figure 3b. Reproduced with permission of Elsevier.
Figure 5.4 A garden allotment in York, UK, growing vegetables and berries.
Figure 5.5 Schematic diagram of the rural and urban water balance. Rates of evapotranspiration and infiltration are lower per unit area in urban than rural ecosystems, while the volume of runoff is higher. Urban ecosystems also tend to be characterized by the import of large volumes of potable water and the export of large volumes of wastewater.
Figure 5.6 The objectives of urban water management versus time.
Figure 5.7 The nitrogen mass balance of three cities, showing inputs and outputs of nitrogen: Phoenix, Arizona, USA; Gwynn's Falls Watershed, Baltimore, USA; and the Hong Kong Special Administration Area.

Chapter 6: The urban ecology of humans

Figure 6.1 Percentage of the rural and urban population living in extreme poverty, 1990–2008, in two regions of the world: (a) East Asia and the Pacific and (b) Sub-Saharan Africa. Extreme poverty is defined as living below US$1.25/day.
Figure 6.2 Contrasting urban green cover: (a) the Atlanta Botanical Gardens in Atlanta, Georgia, USA. Atlanta is known as a city of trees, supporting 48% treecover within the city limits (Giarrusso et al. 2014). (Picture has been cropped and converted to black and white.)
Figure 6.3 An eastern Rosella Platycercus eximius on a back-yard bird feeder. (Picture has been cropped and converted to black and white.)
Figure 6.4 Physical inactivity by age group and World Health Organisation region (% of population); physical inactivity varies by region and tends to increase with age.
Figure 6.5 A variant of the original map drawn by Dr John Snow, British physician and one of the founders of medical epidemiology, showing the location of deaths from cholera in Soho, London in 1854 (black circles). The source of the infection was a water pump on Broad Street.
Figure 6.6 Probability of obesity as a function of urban land-use mix, ethnicity and gender in Atlanta, Georgia, USA. The probability of obesity declines across all social groups as land-use mix increases. Obesity is defined as a body-mass index ≥30. Land-use mix is the evenness of cover by area of four types of land use (residential, commercial, office and institutional) within 1 km of each participant's household.
Figure 6.7 Scavengers at work on a garbage mountain in Brazil, collecting and sorting rubbish for recycling.

Chapter 7: Conserving biodiversity and maintaining ecosystem services in cities

Figure 7.1 A growling grass frog Litoria raniformis. This species is threatened by the continued expansion of Melbourne, Australia.
Figure 7.2 Average floor area of new, single-family houses in the USA and NZ versus year; in both countries, house sizes have increased substantially over recent decades.
Figure 7.3 The cooling effect of urban tree cover. Mean land surface temperature (LST) versus tree cover (%) across each of seven neighbourhoods in the northern Houston metropolitan area, Texas, USA. Temperature data derived from thermal remote sensing, averaged across 37 Landsat TM images taken between 2000 and 2010; tree cover data derived from the US national agricultural imagery program (NAIP) aerial photography taken on May 3, 2010.
Figure 7.4 An urban green space plan for Hanoi, Vietnam, including an ecologically effective network of parks, green wedges and linear green features along roadsides and streams.
Figure 7.5 A sign in Angelbachtal, Germany to warn motorists that frogs may be crossing the road. Picture has been straightened, cropped and converted to black and white.
Figure 7.6 Black spiny-tailed iguanas Ctenosaura similis can be found in private gardens in León, Nicaragua. Picture has been cropped and converted to black and white.

List of Tables

Chapter 2: Urban environments

Table 2.1 The primary biophysical processes of urbanization and the secondary biophysical processes that arise from these

Chapter 3: Population- and species-level responses to urbanization

Table 3.1 A summary of the main effects of habitat loss, fragmentation and isolation on populations and species in urban environments

Chapter 5: Ecosystem-level responses to urbanization

Table 5.1 The greenhouse-gas intensity of various electricity-generation technologies, in g CO₂ eq/kWh, synthesized from a review of lifecycle analyses of each technology's greenhouse-gas emissions. CCS = carbon capture and storage, PV = photovoltaic, CSP = concentrating solar power; data from Moomaw et al. (2011)

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Foreword

In the first quarter of the 21st century, we are living in a unique time in history – we are witnessing the move to the Anthropocene, a geological period in which humans have become a major driver of planetary processes. This time has also been termed the “Great Acceleration”, a period of rapid increase in a large array of human activities with correspondingly large impacts on many environmental and biological processes. One of the clearest indicators of the changes underway is the emergence of the city as the main human habitat. For most of human history, the majority of the human population lived in rural or extensive landscapes, with only a few settlements that could be called “cities”. Rapid human-population increase and industrialization from the 1800s onwards has been paralleled by a dramatic increase in the number and size of cities and an ever-increasing proportion of the human population living in urban areas. For the first time in history, humans are predominantly an urban species.

Cities are therefore extremely important environments from a human perspective: they are where most people now live. They form the centres of economic and cultural activity and are as diverse as the economies and cultures that created them. Cities come in all shapes and sizes, some developing from early hubs of trade and navigation and some springing up in entirely new locations. Early cities tended to be compact and geared for travel by foot or horse. However, cheap cars and mass transit have released cities from their earlier spatial constraints and many now sprawl extensively in all directions. Planning and management of urban form and function have become increasingly important endeavours as cities evolve, grow and require more efficient and effective private buildings, public spaces and essential services.

Cities are not only home to humans, however. Most cities are mosaics of built infrastructure and open space – parks, gardens, waterways and remnants of the nature that was present prior to the city's construction. These spaces are inhabited by a wide range of species, some of which thrive in the urban environment and some of which struggle. The mix of species present can include many species native to the region and many that have been introduced or have adapted themselves to the urban environment. Just as the city provides a focus for human creativity, it can also act as a place where new biologies play out – new combinations of species, species doing new things, and species interacting in novel ways with humans and their built environment.

Given the increasing importance of the city environment and the richness and fascination of the biological systems that develop in cities, it might seem odd that the field of urban ecology has only blossomed quite recently. Indeed, a few decades ago, it would appear that cities were not regarded as places where ecologists would want to work – seeking out instead the remote, apparently untouched areas where the ecology was “intact”. Today, cities are seen more as one end of a spectrum of humanized landscapes and are increasingly the subject of research into their ecological function. How do all the species found in cities persist and thrive? How do ecological communities develop within the altered environments found in cities? How does the urban ecosystem “work” with respect to flows of water, nutrients and energy? How do humans relate to, modify, and live in these environments? And, finally, are there better ways to plan and manage cities and their components that lead to greater liveability for humans and diverse biological communities alike?

This is the stuff of urban ecology, a growing field that seeks to understand how cities work in terms of their ecology and in relation to both their human and non-human inhabitants. This book is, a very timely contribution that provides an accessible yet fascinating synthesis of the ecology of urban environments. Within a strong framework of existing ecological theory, it explores how the construction and expansion of cities influence the characteristics of urban environments and the dynamics of populations, communities and ecosystems. It considers the ecology of human populations in cities, and presents a compelling case for conserving biodiversity and maintaining ecosystem services in urban landscapes. Overall, it seeks to help us better understand, plan and manage our primary habitat – a task that gets more pressing and important by the minute, both for ourselves and for the other species with which we share our cities.

Richard J. Hobbs
University of Western Australia

Preface

A long time ago came a man on a track

Walking thirty miles with a sack on his back

And he put down his load where he thought it was the best

Made a home in the wilderness

He built a cabin and a winter store

And he ploughed up the ground by the cold lake shore

The other travellers came walking down the track

And they never went further, no, they never went back

Then came the churches, then came the schools

Then came the lawyers, then came the rules

Then came the trains and the trucks with their loads

And the dirty old track was the Telegraph Road

Then came the mines, then came the ore

Then there was the hard times, then there was a war

Telegraph sang a song about the world outside

Telegraph Road got so deep and so wide

Like a rolling river

And my radio says tonight it's gonna freeze

People driving home from the factories

There's six lanes of traffic

Three lanes moving slow

I used to like to go to work but they shut it down

I got a right to go to work but there's no work here to be found

Yes, and they say we're gonna have to pay what's owed

We're gonna have to reap from some seed that's been sowed

And the birds up on the wires and the telegraph poles

They can always fly away from this rain and this cold

You can hear them singing out their telegraph code

All the way down the Telegraph Road

Mark Knopfler,
Telegraph Road

Acknowledgements

I have many people to thank for their encouragement, support and enthusiasm, without which this book would have remained unwritten. Alan Crowden prompted me to consider writing a text book on urban ecology; Mark Burgman convinced me that it was a good idea. Alan facilitated the book's publication with Wiley-Blackwell, and both he and Mark have been important supporters and mentors from its inception to completion.

I am grateful to many colleagues for their interest in this project and for helpful discussions about the ecology of urban environments, including Sarah Bekessy, Stefano Canessa, Jan Carey, Yung En Chee, Martin Cox, Danielle Dagenais, Jane Elith, Carolyn Enquist, Brian Enquist, Fiona Fidler, Tim Fletcher, Georgia Garrard, Leah Gerber, Gurutzeta Guillera-Arroita, Amy Hahs, Josh Hale, Andrew Hamer, Geoff Heard, Samantha Imberger, Claire Keely, Jesse Kurylo, José Lahoz-Monfort, Pia Lentini, Steve Livesley, Adrian Marshall, Mark McDonnell, Larry Meyer, Joslin Moore, Alejandra Morán-Ordóñez, Raoul Mulder, Emily Nicholson, Cathy Oke, Joanne Potts, Hugh Possingham, Dominique Potvin, Peter Rayner, Tracey Regan, John Sabo, Caragh Threlfall, Reid Tingley, Rodney van der Ree, Peter Vesk, Chris Walsh, Andrea White, Nick Williams and Brendan Wintle.

I thank all my family, friends and colleagues for their support throughout the process of writing this book. Particular thanks to Michael McCarthy, Owen Parris, Ann Parris, John Gault, Bronwyn Parris, Monica Parris, Bridget Parris, Susan McCarthy, David McCarthy, Margery Priestley, Liz McCarthy, Tom McCarthy, Kirsty McCarthy, Sarah Bekessy, Michael Bode, Gerd Bossinger, Lyndal Borrell, Janine Campbell, Jan Carey, Jane Catford, Tasneem Chopra, Glenice Cook, Martin Cox, Kylie Crabbe, Karen Day, Jane Elith, Louisa Flander, Jane Furphy, Georgia Garrard, Cindy Hauser, Colin Hunter, Helen Kronberger, Rachel Kronberger, Min Laught, Sue Lee, Prema Lucas, Pavlina McMaster, Ruth Millard, John Moorey, Anne Macdonald, Meg Moorhouse, Sarah Niblock, Lisa Palmer, James Panichi, Rebecca Paton, Joanne Potts, Tracey Regan, Di Sandars, Anna Shanahan, Peter Vesk, Graham Vincent, Terry Walsh, Andrea White, Brendan Wintle and Ian Woodrow.

The Australian Research Council, the Faculty of Science at The University of Melbourne, the Australian Research Centre for Urban Ecology, and the NESP Clean Air and Urban Landscapes Hub have provided valuable support for my research on urban ecology. I thank my intrepid and enthusiastic Research Assistant, Larry Meyer, who has helped me with many aspects of this project. I am very grateful to Mark Burgman, Michael McCarthy, Caragh Threlfall, Chris Walsh and the 2014 Graduate Seminar: Environmental Science class at The University of Melbourne for reading and providing insightful comments on the draft manuscript. Lastly, I thank Ward Cooper, Delia Sandford, Kelvin Matthews, Emma Strickland and David McDade at Wiley-Blackwell and Kiruthika Balasubramanian at SPi Global for their assistance and patience as this book became a reality.

Telegraph Road

Words and Music by Mark Knopfler

Copyright (c) 1982 Chariscourt Ltd.

International Copyright Secured All Rights Reserved

Reprinted by Permission of Hal Leonard Corporation