Urban Ecology

The male showed up with breakfast.

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As we get started with our series on the urban Anthropocene, I’d like to approach the topic as a biologist, and think of cities as places filled with various kinds of life.

Of course cities are built by humans for humans. Everywhere humans settle, like other organisms we act as ecosystem engineers. Nowhere is this more dramatic than in cities; we create our own environment–and benefit immensely.

La Ligue des RatsBut urban environments are also habitat for countless species of microbes, plants, and animals, all of which have to adjust to the conditions we have created. Some are under our direct care and control, like the pets we live with or the mowed lawns we maintain. Others follow us around; rats, for instance, have lived with humans for a very long time, benefiting from the environment we provide. Many more creatures, I assume, have been unable to adjust to human presence and were forced out of the way. I speculate that the number of species extinctions due to urbanization must be high.

Something that fascinates me in particular is the way that modern cities especially create unique and relatively new habitats that lead to novel ecological interactions. This type of interaction is criticized by some as a massive departure from the natural state. But for others they make for an interesting topic of study. For example, as discussed in a previous post, Emma Marris has argued that a “rambunctious garden” also has value as an ecosystem, even if it is made up of components that without human intervention would not have ended up in the same space.

High Line extension, New York City. Photo by Zev Trachtenberg.

In one way, perhaps. A novel ecosystem can certainly provide people with aesthetic pleasure and other important values. This, we might be tempted to think that a green area is a green area. But to an ecologist or conservationist, however, I think the picture looks different.

Mainly, the crucial difference is that not all species are equally well embedded into an existing ecosystem. This is particularly relevant to the issue of invasive species. These often thrive in the highly disturbed habitats humans create, and are not true parts of that ecosystem: very few other species can interact with them. In fact, the absence of natural competitors, predators, or parasites is often part of the success story of invasive species (Sakai et al. 2001).

Sometimes, however, charismatic animals do very well in urban environments. One example is the Peregrine falcon (Falco peregrinus), pictured at the top of this post. It is a raptor that is often found breeding on cliffs or other high vertical structures. They hunt birds in flight and, probably starting with the first high buildings–churches in Europe–humans have provided them with a home away from their natural breeding sites. By keeping pigeons in abundance in cities (both by creating suitable habitat for them nad by breeding them), humans also provide falcons a food source. What is good for Peregrine falcons, however, is bad for one of the small species in the same family, the Eurasian kestrel (Falco tinnunculus): they are specialized on feeding on small mammals, which in cities are less abundant and more difficult to find, as compared to more open landscapes (Kettel et al. 2017).

Falco tinnunculus -El Rubicon, Lanzarote, Canary Islands, Spain-8

Eurasian kestrel (Falco tinnunculus)

Urbanization is studied by biologists of all specializations, though a distinct field of Urban Ecology is now emerging. (Lepczyk et al. 2017). Let me mention some of its findings. In a previous post I already mentioned the mosquito species that evolved in the London Underground (Byrne & Nichols 1999). Animal behaviorists study how bird species respond to urban noise and how they change the frequencies of their songs so that they can communicate despite the noise that surrounds them (LaZerte et al. 2016). These are cases where apparently selection induced by humans is changing animals, not because they are domesticated in the strict sense, but simply because they are associated with human habitation.

The association we observe in urban settings among animals and humans may not only have bad outcomes for the former, but can also lead to negative consequences for the latter. One of the central effects of living in high density is that information and goods can be moved around quickly – but the same is true for parasites and diseases. Arguably, the high density in medieval and modern cities helped the spread and the speed of spread of the bubonic plague. This deadly disease is caused by a bacterium (Yersinia pestis); it is transmitted by fleas living primarily on rats, which due to the close cohabitation with humans can jump onto them. Urban centers were not alone in being devastated by the Black Plague, but some of the most dramatic accounts come from cities (Curtis 2016).
As more and more humans move into urban areas, more and better knowledge of the effects of this global transition is needed. Urban Ecology makes a germane contribution to our understanding of the Anthropocene.

K. Byrne & R.A. Nichols (1999) ‘Culex pipiens in London Underground
tunnels: differentiation between surface and subterranean populations,’ Heredity 82:1, 7-15. DOI: 10.1046/j.1365-2540.1999.00412.x.
D.R. Curtis (2016) ‘Was plague an exclusively urban phenomenon? Plague mortality in the seventeenth-century low countries,’ Journal of Interdisciplinary History 47:2, 139-170. doi: 10.1162/JINH_a_00975.
E.F. Kettel et al. (2017) ‘The breeding performance of raptors in urban landscapes: a review and meta-analysis,’ Journal of Ornithology. https://doi.org/10.1007/s10336-017-1497-9.
S.E. LaZerte et al. (2016) ‘Learning to cope: vocal adjustment to urban noise is correlated with prior experience in black-capped chickadees,’ Proceedings of the Royal Society B 283: 20161058. http://dx.doi.org/10.1098/rspb.2016.1058.
C.A. Lepczyk et al. (2017) ‘Biodiversity in the city: fundamental questions for understanding the ecology of urban green spaces for biodiversity conservation,’ BioScience, 67:9, 799–807. https://doi.org/10.1093/biosci/bix079.
A.K. Sakai et al. (2001) ‘The population biology of invasive species,’ Annual Review of Ecology and Systematics 32:1, 305-332. https://doi.org/10.1146/annurev.ecolsys.32.081501.114037.

Et in Arcadia ars: Thoughts on Volcanism and Urbanism in Southern Italy, Part Two

[This is the continuation of the post from last week.]

The Plain of Catania, atop which the city of Catania sits, is land reclaimed from the Ionian Sea by Etna’s lava and other subterranean volcanic uplift. Johann Wolfgang Goethe, who traveled across it while writing the letters and notes that became his Italian Journey, refers quite accurately on May 1, 1787 to Continue reading

Prospection and the Anthropocene

I’d like to share two recent items from the news that make a sobering pairing.

The first is an opinion piece in the New York Times by psychologist Martin Seligman and Times science writer John Tierny summarizing a new theory about human beings that emphasizes our orientation toward the future. Continue reading

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We welcome Ellie Irons, an artist and educator based in Brooklyn, NY, as a guest on the blog . . . click for her own website, or see her bio under the “Who we are” tab.

resistance (Biology): Ability (of an organism, tissue, or cell) to withstand a destructive agent or condition such as a chemical compound, a disease agent, or an environmental stressor. (American Heritage® Medical Dictionary) Continue reading

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Stratigraphy is the science of rock strata; in geological terms, this translates to the science of time. But what IS time? Difficult to define, for certain, but most of us can agree that it marks the passage of events. We experience the passage of Continue reading

Loving the Anthr*pocene

My previous post was a provocation on refusal.  How, I asked, might the Anthr*pocene concept naturalize and even magnify the violent, dispossessionary forces it purports to describe?  And how might refusing this concept relate to Continue reading

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Ivo Bazzechi Cimabue FloodOn November 4, 1966, the Arno overflowed its banks into the streets of Florence. A number of prominent foreign art historians, including Frederick Hartt and John Shearman, arrived soon thereafter to assist their Italian colleagues, working generally under the oversight of the Uffizi’s conservation director Umberto Baldini, in developing a response to a cultural emergency: the Italian Renaissance was underwater. Their collective expertise facilitated the arduous work of restoring what could be salvaged from the flood, which had Continue reading

The Roles for Indigenous Peoples in Anthropocene Dialogues: Some Critical Notes and a Question

We welcome Kyle Powys Whyte, of Michigan State University, as a guest on the blog . . . click for his bio, or go to the “Who we are” tab.

I bet there have probably been more than a hundred events organized for the purpose of fostering dialogue of all kinds on what meanings and futures are presupposed by the “anthropocene.” I have been to some of them. I even just Continue reading

New Year’s Greetings for 2017




In this season of the solstice, the natural world reminds us that at the darkest moment light can return. But our own nature is such that brighter days in the human sense are not inevitable–they must be strived for and accomplished.  Here’s to the joy of imagining, and working toward, a truly habitable future.

CRISPR as Niche Construction: an Aristotelian View

CRISPR (pronounced “crisper”) is part of a system, noticed in certain bacteria, by which a cell can make changes in strands of DNA. This mechanism appears to be a proto-immune system: it enables a bacterium to recognize Continue reading

Cities as Human Niches: Against the ‘Natural City’

We welcome to the blog Nir Barak, of the Hebrew University of Jerusalem, for the next in our series on Environmental Political Theory.

The city is in some sense our niche; we belong there, and no one can achieve full humanity without it. (Holmes Rolston III[1])

In this post, I want to turn our gaze to cities as the paradigmatic embodiment of niche construction in the Anthropocene. I wish to outline Continue reading

Stewarding the planet? The Anthropocene and nondualist ontologies

We welcome to the blog Luigi Pellizzoni, of the University of Trieste, for the next in our series on Environmental Political Theory.

The ontological claims embroiled in the notion of the Anthropocene have so far attracted less attention than other issues. However, as I will try to show, it is important to engage in a thorough reflection on them—which I hope to kick start with the following contribution. Continue reading

Interdisciplinarity as conversation

This blog is premised on the need for an interdisciplinary approach to the Anthropocene—indeed, to the general question of human beings’ relationship with their environment. And it aspires to embody a certain conception of interdisciplinarity—one which uses conversation as a model for the interaction among people from diverse intellectual backgrounds. Continue reading