An ecology for the Anthropocene
Urban ecology has expanded in the last couple decades as a major, global, interdisciplinary field that advances biodiversity, sustainability, and fundamental ecological research in the context of cities and urbanization. With all this accumulated learning, has urban ecology made its mark in the field of ecology more generally?
In some of the most important peer-reviewed ecology journals, and on social media, it seems even the most basic of urban ecology concepts have yet to be appreciated or incorporated in the broader ecology discipline. For example, it’s been 25 years since Humans as Components of Ecosystems was published, and yet many ecologists still don’t see humans as part of how we define and study nature—despite the fact that every ecosystem on earth is affected by, and has effects on, people.
In November 2017, Nature Ecology and Evolution published a major review of the field of ecology, titled “100 articles every ecologist should read” (behind a paywall, unfortunately). It must be noted that the list was a product of a extensive survey of ecologists. Nevertheless, many ecologists around the world took exception to the lack of gender and racial diversity, and its general lack of inclusivity (see here, here, and here). Notably lacking from these academic discussions has been a recognition of core contributions from urban ecology to how we understand, manage, and plan ecosystems on our urban planet.
It begs the question: what would a reading list be for the discipline of ecology in the Anthropecene? But we are getting ahead of ourselves.
No one disputes that the 100 papers listed by Nature Ecology and Evolution are important in the history of ecology. Indeed, everyone should read these papers. But is this the right list of 100 papers to understand ecology today? There are other papers that should make a reading list for a complete understanding of modern ecology. An alternative version of a “key reading” prompt could be this: what are the 100 papers that every ecologist must read to understand ecology today, in the Anthropocene? Social ecology, biophilia, justice, poverty, gender, values, the Global South, design, climate change, policy; these are just some of the topics that are core material for understanding the broad science of ecology today, These topics are largely missing from the 100 papers list.
And also missing, of course, is urban ecology.
As it happens, urban ecology routinely includes the aforementioned list of additional topics: social ecology, biophilia, justice, policy, and so on. How does urban ecology advance the state of the art in ecology more generally? It advances our understanding of how our current world works, how it might work better, and it lays foundations to turn that learning towards pressing Anthropocene challenges, both urban and non-urban.
We asked a diverse group to help our non-urban ecological colleagues understand some of the most important contributions from urban ecology for advancing the field of ecology. We asked them this question: What is one thing every ecologist should know about urban ecology? (We asked them to suggest a reading also—a start on a reading list.)
Along the way, let’s expand the idea of “ecology”.
Ecology in cities is always different to its rural counterpart, and as a result often requires a more creative approach to understanding. I think as long as ecologists try to do pure ecological research in cities, overlooking the presence, and role of, the large human populations that define these areas, will always render their findings problematic. There is that great article by Emma Marris, Ragamuffin Earth, where she presents an analysis of peer-reviewed journal articles and ‘outs’ ecologists who in fact work in, or in close proximity to, cities but fail to engage with the significant drivers pertinent to cities (https://www.nature.com/news/2009/090722/full/460450a.html). To think that one can turn a blind eye to the role of the different soil chemistry, atmospheric conditions of, or significant social presence in cities in exploring ecology in these spaces is naive.
Traditionally trained ecologists, and by that I mean those schooled in pure ecological theory and methods who have been ‘raised’ in pristine environments, are often challenged by the urban context. Here challenges abound. Reference sites are often lacking, sample size and replication constrained by the urban form, access and sampling hampered by safety or issues of social distrust. Field work entails navigating dogs, walls and fences, and budgeting for the fact that at least some field equipment will likely go missing or be vandalized. Ecological study in cities requires something of a maverick attitude. This is by no means to say one can abandon the underpinning requisites of good science, but a creative and adaptive approach needs to be drawn on. In addition to this, an ecologist working in a city must be willing to engage with people. Access at the least, and social insights and perceptions, as well as engaging with land managers are all parts of the study of urban ecology. In addition to these more formal engagements, any greenspace in a city is likely to produce curious citizens, homeless people, and wily children.
These are all elements which must be engaged with or at the very least anticipated, and if encountered, navigated. In my view these are the bits and pieces that make urban ecology fun, and keep us in a learning space; resisting dogged views and mantras. It is possible of course that there may be bits and pieces of remnant land in cities where the system is ticking along as it was before the settlement of the city and in which case that would be a fantastic find. But I would still argue that even if you carried out ecological research in a city and demonstrated that a system was entirely pristine or original in nature your research would still need to first ask “is this urban remnant patch akin to its rural counterpart?” The research would need to include all the relevant urban dimensions to be able to really confidently state this system is unaffected by the myriad of urban drivers. At that point a further interesting question would be “why?” and at that point you are back to doing urban ecology research again!
Marris, E. 2009. Ecology: Ragamuffin Earth. Nature 460: Pages 450-453. https://www.nature.com/news/2009/090722/full/460450a.html
The one thing? For the sake of diversity I will choose one of the many things I believe that someone with an interest in ecology and its place in our cities would benefit from being familiar with. I have always had a liking for landscape approaches, especially when applied to cultural landscapes (and yes, cities are very definitely cultural landscapes)—they often combine solid ecological theory with an application where people and their activities are embedded parts. Understanding both the processes driving change and the implications of emergent patterns is essential—and this ideally at a scale where we can try to influence things (always attractive for the more action oriented among us).
To this point, I would suggest two publications: R.T.T. Forman’s Land mosaics from 1995. It offers a solid background to drivers of change and the patterns they create, and the latter key principles for assessing the ecological outcomes. Ecology is framed by social dynamics, and anyone interested in more than ecological outcomes need to take the humans-in-nature approach to understanding ecological dynamics. Understanding this cumulative effect of multiple, sometimes complex, factors is essential if we are to make sense of our cities. And perhaps make them better places.
Forman, R. T. T. (1995) Land mosaics. Cambridge, UK.: Cambridge University press.
Despite warnings about the state of the planet’s health, ecology lacks recognition and is hardly known as a discipline in its own right. Furthermore, among the ecologist community, urban ecology struggles to find a place. Yet I consider it to be one of the most promising disciplines in our century, when nearly 50% of the population lives in cities and urbanization greatly affects biodiversity.
The one thing that every ecologist should know about urban ecology is that it gives ecology—often perceived negatively—a concrete project and useful applications for the people. Urban ecology has the potential to reconcile cities and their inhabitants with biodiversity. Urban ecology provides our society with solutions, all for better health and a better living environment. I like urban ecology because it is experimental, because it requires interdisciplinary knowledge, because it is uncertain and at the same time, it is a “no-regrets” ecology: increasing biodiversity and reclaiming ecosystems it cannot be worse than not doing it! Urban ecology takes its inspiration in nature: we say “nature-based solutions” for preserving, reclaiming and managing functional ecosystem in order to mitigate climate change and adapt to its effects (storms, floods, dryness, heat waves).
Urban ecology has a wide scope of applications from the building scale to the whole city. Urban ecologist can work together with city gardeners to create ecologically-designed and managed green spaces (zero pesticide, no-mowing policy, etc.). Urban ecologist are also working with city planners and urbanists to find space for ecological corridors in planning documents. At the district level, many solutions are being created by land developers and urban ecologist to create “sponge cities”, using soils as natural filters, and bioswales, rain gardens or phyto-purification basins. Under our feet, the challenge of urban soil rehabilitation is so important. Many research projects try to understand the role of urban soils and encourage “depaving” policies or phyto-remediation for polluted soils. Urban agriculture within community gardens is also an opportunity to enhance nature spaces, even cultivated, in urban areas. At the building level, a wide range of solution has emerged over the last few years to promote green architecture: green roofs and green living walls are becoming smart solutions to increase biodiversity while reducing urban heat effect and storing more rainwater. Some researchers try to understand how these new ecosystems can contribute to restoring ecological connectivity within cities as well as being new habitats for wildlife.
One of the challenges of smart green cities is to switch from grey to green infrastructure. So far, cities have always used civil engineering techniques largely based on “gray” systems that consume a lot of non-renewable resources and emit pollutants (CO2, NOx) involved in climate change. Green infrastructure based on urban ecology knowledge has reduced the urban environmental footprint and is cost efficient.
Urban ecology is an opportunity to reconnect people with nature. In the next years, citizen science programs or participatory events should play a major role in cities for the success of urban ecology.
Dusza, Y., S. Barot, Y. Kraepiel, J-C. Lata, L. Abbadie, and X. Raynaud. 2017. Multifunctionality is affected by interactions between green roof plant species, substrate depth, and substrate type. Ecol Evol. 7:2357–2369. https://doi.org/10.1002/ece3.2691
Since Rio in 1992, urban ecology has developed in three stages: a first step was built around the ideas of transversality of public action, and research grappling with issues of complexity and systemic thinking. The public policies and the urban ones were then sectorized, to the point of developing specialized and non-transversal actions. Research focused on environmental problems in terms of solutions. Today, we see a third phase of public action in environmental matters with a re-territorisalisation of issues and modes of governance around the management of territories. This, above all, represents the exploitation of urban nature considered, in most cases, primarily in productive terms. Nature is put to work, whether it is sewage treatment, agricultural yield, or green roofing, to name just a few examples. Nature is thus called upon to render services. This vision forgets the ecosociosystemic complexity of the human and non-human living.
In truth, we can speak of “locking” when it comes to urban ecology: a set of articulated operating regimes lock a trajectory, condemn to insignificance any possibility of creating other relationships (Stengers, 2014). Thus if it seems that lifestyles are taken into account though works of prospective, they are often not in sync with the current preference for techno-centered solutions in urban planning, and only at the margins address the broader questions of society beyond individuals and consumers needs. How do we strengthen the dynamic for moving toward of adapting populations, collectives and individuals? How to take into account the infinitesimal choices that weave ordinary lives, in the sense of creating an ecological transformation? Finally, how can one account for the dynamics tending to distribute “agencies”, that is, the power to act, to the elements of nature-culture, be they plants, animals, or elements of the substratum? Our reading of urban ecology is based on the way in which the actors view their environment, according to political, scientific, and more largely cultural injunctions.
Suggested reading, in French and English:
Isabelle Stengers, Une autre science est possible ! Manifeste pour un ralentissement des sciences, Paris, Les empêcheurs de penser en rond – La Découverte, 2013.
Braidotti, R. 2013. The Posthuman. Cambridge : Polity Press.
There are so many things that ecologists don’t yet know about urban ecology, none the least of which is the very real likelihood that there is no longer a distinction between what is urban and what is not! The urban landscape is itself an ecosystem, within which there are diverse habitats not too dissimilar in form and function to their wilder, distant counterparts. Can we distinguish between the urban and the urbanising? But that debate is for another day!
Personally, I love urban habitats and urbanised / urbanising species. They are truly resilient; having rapidly and efficiently adapted to the relentless, unsettling pace of human progress. We hear of novel, mongrel, hybrid, chance, unplanned, brownfield habitats. We hear of chance discoveries of rarely seen species and plagues of all-too-often seen species. We marvel to see certain iconic species in cities that we don’t get to see in the wild, we revile at many others. Urban ecology is vexing because it is fraught with emotion, opinion, value and fear. Urban ecology is a topsy-turvy world of contrasts. While scientists will often agree that it is difficult to do urban research (in any field, not just ecology), it can also be very revealing and sometimes wonderful to explore.
For me, what every ecologist needs to know about urban ecology is that urbanised, novel ecosystems, replete with a plethora of urban-adapted species, escaped garden plants, remnants of the past, and unusual species associations, tell us quite a lot about ecological processes in general. However, perhaps they go further and tell us so much more about ourselves, our society, our crazy values, our attitudes and emotions, and what we think of as progress. Urban ecology is the study of the palimpsest. It provides us with glimpses of the past, snapshots of the distant, and potential directions for the future.
There are Brains in the Urban Ecosystem
It is difficult to hazard any sense of optimism about our cities when times are such that “To be aware of the wonders of the living planet is to take on an unbearable burden of grief.” The urban world is more commonly regarded as a blight on the planet than a wonder and offers countless examples of burdensome human behaviour but if we can’t unearth beauty and purpose in its Frankenstein ecology then how can we hope to place our cities “in balance with nature”? Humans are now collectively one of the largest forces in the biosphere and nowhere is our perverse exercise of that power more evident than in the morphology and metabolism of our urban systems.
Barry Commoner’s first law of ecology is that “everything is connected to everything else” and it’s one of those statements of the obvious that wasn’t obvious to a lot of people until he said it. Another obvious fact that doesn’t have anything like the same degree of familiarity is the connected (of course) idea that the built environment is an extension of human physiology in the same way that termite mounds are extensions of termite physiology. Where does an organism stop and its environment begin? In The Extended Organism, J. Scott Turner describes how structures made by animals are “the agents whereby organisms adaptively modify flows of matter and energy through the environment.” And how structures like termite mounds, which transform wind energy to serve their termite colonies, are examples of organisms co-opting the environment “into a physiology that extends well beyond their conventionally defined boundaries”. Which is what humans do. It’s what our cities do. Humans modify their environment to make it more suitable for humans. The ability to make shelter is a fundamental requirement for human survival. It is much easier for social creatures like humans to build shelter together, rather than as individuals. Even if an individual was able to make useful shelter through their own efforts, they would still be relying on collectively generated knowledge and most likely collectively developed and manufactured tools. The most simple human settlement is a result of complex interactions between multiple individuals and the end result of their efforts is a means of co-opting and modifying their environment to improve their chances for survival.
In considering the ecology of urban systems it should perhaps be considered that all human settlement is fundamentally about extending the capacity and resilience of human physiology through environmental means and our present-day urban ecologies are extraordinary but flawed attempts at maintaining homeostasis to sustain life.
In The Tinkerer’s Accomplice, Turner continues his exploratory thinking to show “How design emerges from life itself.” After a while you begin to see how the human impulse to design may be an evolutionary result of a basic need to modify our environment in order to survive. I can’t identify just one paper in particular that explores the idea, but I would argue that the one thing that every ecologist should know is that the urban ecosystem is a designed system and an example of extended physiology at a very large scale. Now that this human device is affecting the entire planet it is clear that because consciousness and the propensity of humans to design and manipulate the environment for their own benefit is integral to the function of urban ecosystems, they should be abiding concerns for any ecologist.
Turner, J. Scott. 2010. The Tinkerer’s Accomplice: How Design Emerges from Life Itself. Harvard University Press. 304 pages. http://www.hup.harvard.edu/catalog.php?isbn=9780674057531
When an area is urbanized, important transformations take place in soils, climate, water bodies and native biota. So far, nothing new for an ecologist that understands that any biotic or abiotic disturbance can trigger changes in the geochemical cycles and in the assemblages of species.
The consequences of city sprawl on the urban ecosystem`s resilience are long-lasting and in most cases irreversible, just as it happens in Nature: think of the destroying effects that a hurricane or a devastating fire may have on a coastal ecosystem or on a forest.
Most theoretical concepts of classic ecology that deal with populations, communities, ecosystems and landscapes are applicable to cities; from viability, niche theory, density dependence, succession, interspecific relationships, gain and loss of species, intermediate disturbance, to island theory, edge effects, corridors, significance of habitat heterogeneity, and even the tragedy of the commons.
But the urban ecosystem is a very special one. It is comprised of physical, ecological and social spheres. In the city, humans are the dominant species. Their decisions in city planning and management may make it intricate for the different components to reach a new ecological balance. Cities differ in traditions, history, economic and political power. Because of these socio-cultural characteristics it is more difficult to develop a consistent general theoretical framework.
To get into the subject, and develop an understanding of the cross-disciplinary nature of urban ecology, every ecologist should first read Pickett and Cadenasso (2017) How many principles of urban ecology are there?.
One of the most applied theories in urban ecological studies is the gradient theory of Mc Donnell and Pickett (1990), recognizing general ecological patterns from the city center to the peripheries. Nevertheless, the theory does not always work in cities where growth is poorly planned such as in Latin America, suggesting the need for more local studies.
What every ecologist should know about urban ecology is that it is mainly an applied discipline where human needs and impacts on the ecosystem are integral parts to solving problems. It principal aim is to make cities more livable and environmentally resilient but this is not an easy task as the social sphere is always decisive.
Most of these problems are wicked ones: difficult to solve because of incomplete, contradictory and changing requirements. Because they are interdependent, socially complex, and involve behavioral changes, an interdisciplinary approach that goes beyond ecology is the only way out.
Mc Donnell, M. J. and Pickett, S. T. A. (1990) The study of ecosystem structure and function along urban-rural gradients: an unexploited opportunity for ecology. Ecology 71,1231–1237.
Ecologists have to acknowledge and to know that society is shaping patterns and flows in urban ecosystems, and that green, blue, and grey are complementary to providing for human well-being. Co-evolution and co-development is thoroughly existing and evident in cities, thus if urban ecologists would know one thing about urban ecosystems, this is it: Humans and nature share the same habitat and they share it together—the more readily ecologists accept humans and society being part of urban ecosystems and the more actively they accept the complementarity of the social, ecological, and infrastructure-technical systems, the more sustainable and resilient our co-evolution will be.
Alberti, M. 2015. Eco-evolutionary dynamics in an urbanizing planet. In Trends in Ecology & Evolution. 30:2, pages 114-126. http://www.cell.com/trends/ecology-evolution/fulltext/S0169-5347(14)00249-3
Every ecologist should know that urban ecosystems evolve and relate to the community/society that lives, being maintained and relates to them. Urban social-ecological systems are coupled, meaning that are interrelated and erosion of social conditions and the institutions therein manifest in unprotected, and unrestored urban ecosystems as. And in turn, deteriorating or unhealthy urban ecosystems do not allow for human to nature relations and fail to support human wellbeing, resulting in depriving urban environments for humans.
For this interrelationship to be balanced and ensure mutual benefits, adaptive institutions that guide open, innovative governance for healthy resilient urban socio-ecological systems are very important. Dividing (1) understanding in how urban ecosystems function and benefit humans from (2) understanding how institutions and governance processes that ensure a human-nature relation creates chasms in knowledge and misfit knowledge for urban planning and policy. What therefore every ecologist should know about urban ecology is that he/she needs to be open to interdisciplinary collaborations with social and political scientists for making knowledge of urban ecology relevant and actionable for better institutions and good governance to be realized in cities. He/She needs to recognize not the limits to his/her knowledge but the opportunities to research, learn and apply knowledge in collaborative and co-creative ways (involving also citizens and urban communities) for progressing urban science on socio-ecological systems. It is about the way knowledge is acquired that is changing and how it becomes socially and policy relevant and actionable that changes the role and the skills required for ecologists to “know about urban ecology”.
Three elements are fundamentals in the mindset of ecologists of the future: first, openness in asking different questions and asking questions differently to allow for interdisciplinary inquiry to be relevant; second, curiosity in engaging in multi-disciplinary research processes and learn from them; and third, the courage and passion to translate knowledge on urban socio-ecological systems for policy and society to act upon restoring and protecting urban ecosystems. The ecologists of future cities work in teams, learn from and with other scientists and communities, recognize the value of the discovery of knowledge and of making knowledge actionable for policy and community to pursue livable, just, resilient and sustainable cities.
Frantzeskaki, N., and Kabisch, N., (2016), Designing a knowledge co-production operating space for urban environmental governance – Lessons from Rotterdam, the Netherlands and Berlin, Germany, Environmental Science and Policy, 62, 90-98.
Ecological services are well understood to advance human health and happiness. I am sure that is true whether one is in New York’s Times Square or Yosemite Valley in California. But, if one integrates the value of some trees to clean the air with the density of people around those trees, the value of that planting enhancement is magnified by the number of people nearby who will experience less respiratory distress. A line of trees improves the microhabitat for thousands of people on this city street, but only the occasional hiker in that pristine mountain valley. Think of a shade structure, such as tree canopy, in a quiet rural hot spot. The occasional person who passes by gets relief from the brutal sun. Whoopee-do. But, if we put that shade structure near a constant line of commuters or laborers, the value of the local shade is multiplied by the density of people that experience it. It is urban centers where ecological structure has most value to the human population. We must talk about this constantly with decision-makers in our cities.
Planning to enhance ecological features in cities often gets push back from people who define nature as a rural feature and thus inappropriate in a commercial zone. It is certainly true that a hectare of landscape pays less property tax than a strip mall or high-rise; its values don’t usually appear on a municipal balance sheet. But people who are oblivious to the concept of ecological services can be educated, understanding can be enhanced, and urban ecology can eventually be celebrated. Attitudes change. Thousands of people who once considered aluminum cans and bottles as garbage now define them as recyclable resources. People who today see a patch of woodlands as “empty space” can learn the new taxonomy of valuable ecological structure.
Many urban designers and planners today are learning how to include ecological structures and function into their work. Through new curricular offerings and the action of many public groups and media outreach, such as TNOC, new design renderings and criteria are more frequently including ecological features. There is a slow moving increase in the expression of urban ecology in designs, which I believe will become the new normal.
Many public and private land managers/clients have become aware of and are requesting ecological zones in cities. We must continue to stress the real value of these ecological parcels in the mosaic of city plans. The ecological spaces have value beyond the aesthetic aspects of nature that most city slickers see and will someday insist upon. I hope every ecologist will someday know that the structure and function of nature downtown are as interesting and valuable as that memory of nature at their childhood summer camp.
Elmqvist, T., Setälä, H., Handel, S.N., van der Ploeg, S., Aronson, J., Blignaut, J.N.,
Gómez-Baggethun, E., Nowak, D.J., Kronenberg, J., and de Groot, R. 2015. Benefits
of restoring ecosystem services in urban areas. Current Opinion in Environmental
In a tele-connected world, ecosystems are increasingly interacting with social systems—most obviously in urban areas. In the Anthropocene, cities are the primary human habitat and in the demand to deal with social-ecological transformations. Given the current global changes of climate change and urbanisation, and their associated effects on natural systems, social systems and their interactions worldwide, cities are the foreground for experimenting with new approaches towards livability, sustainability and resilience; all of which are important parts of urban ecology.
With increasing densification, loss of open spaces, the environmental burdens of air pollution, noise and heat, developing and maintaining the ecosystems are increasingly important in urban areas. To increase knowledge about the quantity and quality of benefits that urban residents may gain from ecosystems is to increase their quality of life, health and well-being. All known as ecosystem services, understanding their function necessitates interdisciplinary research in urban ecology which bridges knowledge from natural and social science. Even more, the recent scientific advances to include transdisciplinary approaches to interdisciplinary projects opens the field of urban ecology for assessing the implementation of socio-ecological, governance and technical innovations in terms of planning approaches, governance modes and policy experiences across disciplines, policy domains and governmental departments.
I believe that taking an inter-and transdisciplinary social-ecological systems approach to cities, and assessing how urban ecosystem services are provided to city residents in quantity and quality, are important parts of urban ecology to understand social-ecological transformations under global challenges of climate change and urbanisation. This goes hand in hand with potential new avenues for governing and managing urban systems in a knowledge co-production operating space in which scientists, urban planners, policy officers or practitioners can learn from each other and establish relationships and trust in mutual dialogues to find solutions to environmental problems for increasing resilience and sustainability in urban areas (Frantzeskaki et al., 2016).
Frantzeskaki, N., Kabisch, N., McPhearson, T. (2016) Advancing urban environmental governance: Understanding theories, practices and processes shaping urban sustainability and resilience. Environmental Science and Policy, 62, Special Issue, Pages 1-144.
It has been 25 years since Humans as Components of Ecosystems (McDonnell and Pickett 1993) was published, so it is a bit shocking to think that decades of research linking social and ecological systems is not part of the main stream of what every ecologist should know. Of course, urban ecology goes back much further to Herbert Sukopp’s work in Berlin post-World War II (Sukopp 2008) and to early Chinese scholars even earlier working on integrating ecosystems into urban life (Wu 2014).
McDonnell and Pickett’s book was seminal to launching urban ecology in the US. Urban ecology is fundamental social-ecological systems research intended to open the eyes of all ecologists to the fact that every ecosystem on earth has human drivers, influence, and impacts on both structure and function of the system. Ecologists of every stripe must fundamentally understand that humans are not somehow outside the domain of ecology. In Europe, China and elsewhere, there is a wide embrace of ecosystems as being fundamentally social-ecological systems (Niemela et al. 2011). Translation: humans are part of ecosystems, and humans and other biophysical components of ecosystems are deeply intertwined, with reciprocal influence. There is not an ecosystem on earth that does not have human influence. It feels like going back to basics to argue this point, and yet if there is one thing all ecologists must realize, it is that to study ecology in the Anthropocene, on this urban planet, we must consider ecosystems now as not simply biophysical systems somehow operating in a closed box without human interaction. That box must be opened to link exogenous drivers like climate change but also direct endogenous human actions.
It is an unnecessary, biased, and even counterproductive approach to define what is important in ecology as somehow distinct from the human dominated natural world. Ecosystems do not exist in a biophysical vacuum. Ecosystems exist in the Anthropocene like the rest of us and humans are part of these systems exerting influence on them and affecting fundamental ecological processes. The broader ecology field must recognize that social-ecological system research is an area of study that has made significant advances in how we think about, study, and manage ecosystems in urbanizing and human-dominated socio-ecological contexts all over the world (Vitousek et al. 1997; Grimm et al. 2008). Ecology cannot afford to completely miss the Anthropocene context that all ecosystems exist in, nor the enormous potential that lies in reflexive and respectful human-nature interaction (Alberti et al. 2003).
Urban ecology is a field that is expanding rapidly (McPhearson et al. 2016). The next generation of ecologists should be encouraged, not discouraged, from taking a more inclusive definition of ecology where ecosystems are social-ecological systems which can help us improve management in all ecosystems, not only in urban areas. This is a fundamental step to advancing ecology as a source of knowledge that can help shift the needle on some of the most important challenges we face, from climate change, to environmental injustice and pollution, to social inequality in access to health and well-being benefits ecosystems in and outside of cities provide.
McDonnell, M., and S.T.A Pickett. 1993. Humans as Components of Ecosystems: The Ecology of Subtle Human Effects and Populated Areas. Springer-Verlag New York, Inc.
Over the 25 or so years that I have worked in the area of ecology, I have been privileged to witness an overall transformation of the discipline, from one that was overwhelmingly interested in “pure” evolutionary and ecological processes in “pristine” areas (i.e. areas where there was no obvious human footprint), to a field that now recognises the ubiquity of human-nature interaction—embracing social-ecological approaches to frame, investigate, interpret and intervene in issues of ecology and conservation. Thus, for instance, while many ecologists once believed that protected areas should be kept isolated from people, we now overwhelmingly recognise the role that so many indigenous communities have played in creating specific ecologies unique to many protected landscapes across the world.
Yet cities remain a particular blind spot for many ecologists—though the field of urban ecology has grown almost exponentially in recent years. Urban systems are arguably one of the most human-dominated of all ecosystems, and it is practically impossible to conduct studies on “pure” ecological or evolutionary processes in a city without acknowledging the role of people. Social-ecological framing lies at the heart of urban ecological research, and this is something that most traditional schools of ecology, across the world, continue to be uncomfortable with.
What should every ecologist know about urban ecology? They need to know that the urban now affects every part of the world—however distant, or seemingly pristine. It is futile, indeed impossible to study ecology in isolation from the human thought processes, industrial systems, cultures of consumption, and teletransfers of money and data that imply the urban. But this does not mean that ecology and conservation are doomed—quite the contrary, ecology has entered a most exciting period of knowledge discovery. The interconnectedness of cities, culture and nature requires collaborations between ecologists, economists, social scientists and scholars of the humanities to advance the frontiers of knowledge. And, given the speed at which things are changing, we cannot be content only to study and to observe—we must simultaneously engage and act, which demands further collaborations between scientists, practitioners, city government, activists, and regular citizens—all too often, one of us carries these various categories within ourselves as well, wearing multiple hats!
Thus, at times, I am an urban ecologist, at others I am a mother of a child who loves her local park and lake, the daughter of another mother who is a fierce proponent of urban nature, as well as an educator, an activist, and a neighbour with different—but equally compelling responsibilities to society, community, nature and city. All of us carry these multiple identities within us. Within or outside, we need multiple perspectives for urban ecology to flourish—the knowledge of a street vendor who spends decades selling flowers under a Ficus tree canopy is of as much value as that of a rag picker who keeps the city clean by recycling its trash, and the insights of a cattle grazer who has seen a healthy lake transform into a polluted mess are as important as that of an urban ecologist studying surface water hydrology.
In short, urban ecology can bring much to an ecologist in terms of insights into the interconnectedness of everything—nature, culture, and concrete. For me, at least, this is what it has brought over time—and the complexity is at once humbling and deeply fascinating and educative.
Elmqvist, T., M. Fragkias, J. Goodness, B. Guneralp, P.J. Marcotullio, R. I. McDonald, S. Parnell, M. Schewenius, M. Sendstad, K.C. Seto, C. Wilkinson, Eds. 2013. Urbanization, Biodiversity and Ecosystem Services: Challenges and Opportunities: A Global Assessment. Springer Netherlands. 755 pages. https://link.springer.com/book/10.1007%2F978-94-007-7088-1
One Thing That All Ecologists Should Know about Urban Ecology
Urbanization is like succession: It doesn’t have a single pathway; it doesn’t have a single end point; it influences all ecological systems; and it results from a continuous interaction of migrations, extinctions, interactions, and accidents.
Succession is one of ecology’s oldest ideas. But in its contemporary form, it is poorly appreciated. Too often, it is summarized as the old textbook generalization, involving facilitative species replacement, a regular sequence of dominants, and ending with a stable community. This textbook rendition has fortunately been replaced over the one hundred-year history of the discipline. (Frederic Clements’ magisterial but flawed book that first codified succession theory was 100 years old in 2016.) So succession, or if you prefer, community dynamics or community assembly, now is the epitome of a contingent, dynamic process conditioned by fluxes of organisms, resources, disturbance, and stressors across complex landscapes.
Urbanization can be considered similarly to the evolution of successional thinking. It used to be that urbanization was defined simply as conversion of rural, pastoral, forest, or wild lands to urban cover. That is, urbanization produces cities and towns. The subsequent trajectory following conversion was modeled on North temperate cities that “developed” through the industrial revolution, often changing from focus on natural resource commodification, to industrial production, to sanitary engineering, and finally to post-industrial service. This is urbanization like Clementsian succession. It is directional, step-wise, and terminates in some sort of “advanced” stage. It is also implicitly universal, with all cities following the same logic. Urbanists will immediately see the flaws in this analogy with classical succession. But the similarities with contemporary thinking about succession or community assembly may actually be useful in urban ecology itself, as well as helpful in linking urban ecology with the ecology in general.
If we hypothesize that urbanization and succession are conceptually analogous, the following principles can help guide research and comparison:
- Urbanization doesn’t have a single pathway. This is especially clear in countries or regions that are only recently industrialized. Even more pointedly some regions have become “cities of consumption” without passing through an industrial or a sanitary state. China, India, and countries in Africa, for example exhibit distinctive trajectories of urban change.
- Urbanization isn’t only unidirectional. Within urban regions, there are places that grow, and places that thin out. Change in cities, towns, and their connected regions is patchy, just as heterogeneous ecological mosaics of any type can be. Treating urban change as a “red blob” that continuously spreads across a region is one model of urbanization, but it is one that ignores important internal dynamics.
- Urbanization, like succession, is everywhere. Urbanization isn’t just the production of cities. Urban conditions influence both nearby and distant ecosystems. They do so by distal changes in livelihoods, lifestyles and consumption choices, investment shifts influencing both hinterlands, wild places, and central cities, and infrastructural diffusion across broad regions. The percentage of land covered by cities and towns is a poor index of urban influence in regions and the world.
- Urbanization, like biotic community assembly, reflects a multitude of interacting processes, influences, and “actors” (that is, species, social groups, institutions, environmental changes, etc.). The complexity of ecologically familiar processes such as feedbacks, priority effects, spatial legacies, indirect effects, natural disturbances, and social perturbations, combine to make urbanization a contingent process. Some drivers will be intentional, and some with be accidental.
The single thing that ecologists in general should think of when they hear the term “urbanization” is that urban change is very much like the contemporary, dynamic view of community assembly they already know.
McHale, M. R., S. T. A. Pickett, O. Barbosa, D. N. Bunn, M. L. Cadenasso, D. L. Childers, M. Gartin, G. R. Hess, D. M. Iwaniec, T. McPhearson, M. N. Peterson, A. K. Poole, L. Rivers, S. T. Shutters, and W. Zhou. 2015. The new global urban realm: complex, connected, diffuse, and diverse social-ecological systems. Sustainability 7:5211–5240.
Every ecologist should know that urban ecosystems are, in large part, shaped, structured, and governed by human activity. That much seems obvious—but still worth unpacking for a moment before getting to the one thing I believe every ecologist should know about urban ecology. Some cities are home to patches of landscape that seem untouched by urban development. The municipal park system here in New York City, for example, boasts more than 10,000 acres of grasslands, forests, and wetlands designated as “natural areas”—little bits of Eden that offer an escape from the bright lights of the big city. Yet these natural areas are often manipulated and managed with the same purposeful intensity as any of New York’s hundreds of community gardens, tens of thousands of acres of landscaped parks, and hundreds of thousands of street trees. It takes real human effort to manage even the most “natural” of natural areas, not to mention all the other manicured greenery on offer in a place like New York City. And it takes a working knowledge of urban ecosystems and their many components to guide those efforts. Human knowledge, then, is itself an element of urban ecosystems, and it follows that the social process of creating, codifying, contesting, sharing, and applying that knowledge can be an object of urban ecological research.
So, here’s my main point: every ecologist should know that urban ecology is very closely related to “sociology of scientific knowledge” when it starts asking questions about the production of knowledge used to manage urban ecosystems. Where does the knowledge to manage urban ecosystems come from? A good deal of it likely results from “pure” or “basic” scientific research. Ecologists publish peer reviewed journal articles and well-informed managers read, interpret, and apply that knowledge in practice. Yet urban ecology is a young field of inquiry. Sometimes the knowledge needed for day-to-day management is missing from the scholarly literature. In these cases, professional managers and volunteer stewards construct knowledge outside the bounds of formal science. They may create useful and reliable knowledge through iterative cycles of adaptive management, making incremental changes in practice and collecting data on the outcomes to inform gradual changes in their work over and over again. Or, just as likely, they may create knowledge-in-practice without any use of formal data collection or monitoring, building up storehouses of knowledge about effective practice through daily observations of trial and error. The methods of surfacing and studying these knowledge-making practices—through formal science, through adaptive management, or through communities of practice—should be part of the urban ecology research toolkit, and every urban ecologist should have at least a passing familiarity with the concepts behind those methods.
Suggested reading: Pickering, Andrew. “Chapter One: The Mangle of Practice.” In The Mangle of Practice: Time, Agency, and Science, 1–34. Chicago: University of Chicago Press, 2014.
The one thing that every ecologist should know about urban ecology is that it can provide us with the tools we need to inspire mankind the consumer to save global biodiversity. It can provide the wisdom to help us fulfil a pressing duty as human beings and stewards of the natural world.
By understanding the intense interactions between human and non-human possible in the urban realm and the particular impacts that these can have to those in ‘nature deficit’ we have an opportunity to reinvigorate, rekindle and super-develop the oft -diminished sense of excitement and amazement that we can feel when we experience other species with which we share this fragile planet—species which we are wantonly, systematically and oh-so rapidly wiping out. In the urban realm we have a ‘captive’ audience—and a very large one—one in regular attendance. One that passes habitats, features and installations sometimes several times a day and draws meaning and wisdom from them directly and indirectly. We can welcome nature actively in new (re)combinations and often strengthen its populations to sally forth into the surrounding denuded and sprayed-out countryside. We can supersize it, display it, give it precedence, celebrate it, place it under the lens at the doorstep of every citizen regardless of income and advantage. We can graphically, artistically and eye-catchingly illustrate its wider global destruction and deterioration, explaining the rates of change in myriad ways, artistic and technological for mass public view. We can illustrate how our consumerism is driving these losses.
All the things that nature does for us in urban and rural areas are vitally important and can nurture respect and interest. But without deep love and wonder at the bizarre, extraneous, not-us, other, startling, gorgeous, frightening, instructive, aesthetically stunning nature of non-human life—the endeavour to widen the constituency for nature will fail. It will fail in the face of the lobby of destruction and ignorance that is currently taking the ascendance amongst certain administrations around the world assisted by progressive technological denaturalisation of our world and lifestyles.
Urban ecology is a framework for exploration and expression of the multiple strategies and mechanisms for positive, creative and supportive interactions between human beings and the natural world that, appropriately applied and expressed, may just redirect mankind away from its current role as they key agent of a new mass species extinction.
We have not much time.
McKinney, M.L. 2002. Urbanization, Biodiversity, and Conservation: The impacts of urbanization on native species are poorly studied, but educating a highly urbanized human population about these impacts can greatly improve species conservation in all ecosystems. BioScience, 52:10, Pages 883–890. https://doi.org/10.1641/0006-3568(2002)052[0883:UBAC]2.0.CO;2
The one thing that every ecologist should know about urban ecology is that urban areas are hybrid social and ecological systems, and understanding such systems requires ecologists working collaboratively with scholars from all the sciences—natural, social, and engineering, as well as practitioners and decision-makers. For ecological research to be of greatest use, urban ecological studies must extend well beyond scholarly and research disciplines.
The social and biophysical nature of complexity and hybridity of urban ecosystems require urban ecology to take a strong interdisciplinary lens that brings together scholars from disparate fields. This is because discrete research disciplines are inadequate to fully address the complex multi-dimensional nature of urban ecosystems. In fact, urban ecology has been increasingly growing as a field that integrates social, biophysical and engineering sciences, and links directly into practices such as urban planning and urban design. Such need, however, still remains as a grand challenge even after a few decades of development in urban ecology.
Additionally, urban ecology acts as the frontier where ecologists can effectively promote the science-policy interface for local, regional, and global sustainability. Cities play an increasingly important role in each of the three main pillars of sustainability—social, economic, and environmental, and their impacts reach far beyond the boundaries. In fact, cities are essential to a sustainable future. Ecological knowledge about urban ecosystems has become central in understanding the present and future of cities, and therefore, the living conditions of the majority of humans. As cities are where the practitioners and decision-makers live, work, and play, they provide ideal places for ecologists to work together with them to solve real-world urban problems. Consequently, urban ecology provides a platform for ecologists to interact and collaborate with practitioners and decision-makers, and therefore, accelerating uptake of ecological knowledge by practitioners and decision-makers. Consequently, urban ecology can set a model on how ecological research can be adequately directed to real-world problem applications, and thus can be of greater use in solving real-world problems.
Pickett S.T.A, M.L. Cadenasso, D.L. Childers, M.J. McDonnell, and W. Zhou. 2016. Evolution and future of urban ecological science: ecology in, of, and for the city. Ecosystem Health and Sustainability 2 (7).