Editing City (section)

==Ecology==
{{Main|Urban ecology}}
[[File:Trash in Paramaribo.JPG|thumb|An urban scene in [[Paramaribo]] featuring a few plants growing amidst [[municipal solid waste|solid waste]] and [[rubble]] behind some houses]]
[[File:Urban heat island (Celsius).png|thumb|An [[urban heat island]]]]
[[File:Dublin Stephen's Green-44 edit.jpg|thumb|[[St Stephen's Green]], an [[urban park]] in [[Dublin]], Ireland]]
Urban [[ecosystem]]s, influenced as they are by the density of human buildings and activities, differ considerably from those of their rural surroundings. Anthropogenic [[building]]s and [[waste]], as well as [[Agriculture|cultivation]] in [[garden]]s, create physical and chemical environments which have no equivalents in the [[wilderness]], in some cases enabling exceptional [[biodiversity]]. They provide homes not only for immigrant humans but also for [[introduced species|immigrant plants]], bringing about interactions between species that never previously encountered each other. They introduce frequent [[disturbance (ecology)|disturbances]] (construction, walking) to plant and animal [[habitat]]s, creating opportunities for [[Secondary succession|recolonization]] and thus favoring [[ecological succession|young ecosystems]] with [[r/K selection theory|r-selected species]] dominant. On the whole, urban ecosystems are less complex and productive than others, due to the diminished absolute amount of biological interactions.<ref>{{Cite journal |last=Rebele |first=Franz |year=1994 |title=Urban Ecology and Special Features of Urban Ecosystems |url=https://www.jstor.org/stable/2997649 |journal=Global Ecology and Biogeography Letters |volume=4 |issue=6 |pages=173–187 |doi=10.2307/2997649 |jstor=2997649 |issn=0960-7447|url-access=subscription }}</ref><ref>Herbert Sukopp, "On the Early History of Urban Ecology in Europe"; in Marzluff et al. (2008).</ref><ref name=PickettEtAl2008>S.T.A. Pickett, M.L. Cadenasso, J.M. Grove, C.H. Nilon, R.V. Pouyat, W.C. Zipperer, & R. Costanza, "Urban Ecological Systems: Linking Terrestrial Ecological, Physical, and Socioeconomic Components of Metropolitan Areas"; in Marzluff et al. (2008).</ref><ref>Ingo Kowarik, "On the Role of Alien Species in Urban Flora and Vegetation"; in Marzluff et al. (2008).</ref>

Typical urban [[fauna]] includes [[insect]]s (especially [[ant]]s), [[rodent]]s ([[mouse|mice]], [[rat]]s), and [[bird]]s, as well as [[cat]]s and [[dog]]s ([[domestication|domesticated]] and [[feral]]). Large [[predator]]s are scarce.<ref name=PickettEtAl2008 /> However, in North America, large predators such as coyotes and other large animals like white-tailed deer persist.<ref>{{Cite journal |last1=Gallo |first1=Travis |last2=Fidino |first2=Mason |last3=Lehrer |first3=Elizabeth W. |last4=Magle |first4=Seth B. |year= 2017|title=Mammal diversity and metacommunity dynamics in urban green spaces: implications for urban wildlife conservation |url=https://onlinelibrary.wiley.com/doi/10.1002/eap.1611 |journal=Ecological Applications|volume=27 |issue=8 |pages=2330–2341 |doi=10.1002/eap.1611|pmid=28833978 |bibcode=2017EcoAp..27.2330G |url-access=subscription }}</ref>

Cities generate considerable [[ecological footprint]]s, locally and at longer distances, due to concentrated populations and technological activities. From one perspective, cities are not ecologically [[sustainable]] due to their resource needs. From another, proper management may be able to ameliorate a city's ill effects.<ref>Roberto Camagni, Roberta Capello, & Peter Nijkamp, "Managing Sustainable Urban Environments"; in Paddison (2001).</ref><ref>{{cite web |url=http://www.michellenijhuis.com/ |title=National Geographic Magazine; Special report 2008: Changing Climate: Village Green |publisher=Michelle Nijhuis |date=26 August 2008 |access-date=7 February 2009 |archive-date=15 May 2008 |archive-url=https://web.archive.org/web/20080515234352/http://www.michellenijhuis.com/ |url-status=live }}</ref> [[Air pollution]] arises from various forms of combustion,<ref>{{cite web |url=http://www.aklung.org/air-quality/indoor-air-quality/ |title=Indoor Air Quality&nbsp;– American Lung Association of Alaska |publisher=Aklung.org |access-date=7 February 2009 |archive-url=https://web.archive.org/web/20090211234047/http://www.aklung.org/air-quality/indoor-air-quality/ |archive-date=11 February 2009 |url-status=dead }}</ref> including fireplaces, wood or coal-burning stoves, other heating systems,<ref>{{cite web |url=http://newsminer.com/news/2008/aug/20/epa-put-fairbanks-air-pollution-problem-list/ |title=Newsminer.com; EPA to put Fairbanks on air pollution problem list |publisher=Newsminer.com |date=20 August 2008 |access-date=7 February 2009 }}{{dead link|date=December 2017 |bot=InternetArchiveBot |fix-attempted=yes }}</ref> and [[internal combustion engine]]s. Industrialized cities, and today third-world megacities, are notorious for veils of [[smog]] (industrial [[haze]]) that envelop them, posing a chronic threat to the health of their millions of inhabitants.<ref name=Adey2013>Peter Adey, "Coming up for Air: Comfort, Conflict and the Air of the Megacity"; in Brighenti (2013), p. 103.</ref> Urban soil contains higher concentrations of [[heavy metals]] (especially [[lead]], [[copper]], and [[nickel]]) and has lower [[pH]] than soil in the comparable wilderness.<ref name=PickettEtAl2008 />

Modern cities are known for creating their own [[microclimate]]s, due to [[concrete]], [[Asphalt concrete|asphalt]], and other artificial surfaces, which heat up in [[sunlight]] and channel [[rain]]water into [[Storm drain|underground ducts]]. The [[Geography of New York City#Climate|temperature in New York City]] exceeds [[Climate of New York (state)|nearby rural temperatures]] by an average of 2–3&nbsp;°C and at times 5–10&nbsp;°C differences have been recorded. This effect varies nonlinearly with population changes (independently of the city's physical size).<ref name=PickettEtAl2008 /><ref>{{Cite journal |last1=Brazel |first1=Anthony |last2=Selover |first2=Nancy |last3=Vose |first3=Russel |last4=Heisler |first4=Gordon |year=2000 |title=The tale of two climates-Baltimore and Phoenix urban LTER sites |url=https://www.int-res.com/articles/cr/15/c015p123.pdf |url-status=live |journal=Climate Research|volume=15 |pages=123–135 |doi=10.3354/cr015123 |bibcode=2000ClRes..15..123B |issn=0936-577X |archive-url=https://web.archive.org/web/20201022003654/http://www.int-res.com/articles/cr/15/c015p123.pdf |archive-date=2020-10-22}}</ref> Aerial [[particulates]] increase rainfall by 5–10%. Thus, urban areas experience unique climates, with earlier flowering and later leaf dropping than in nearby countries.<ref name=PickettEtAl2008 />

Poor and working-class people face disproportionate exposure to environmental risks (known as [[environmental racism]] when intersecting also with racial segregation). For example, within the urban microclimate, less-vegetated poor neighborhoods bear more of the heat (but have fewer means of coping with it).<ref>Sharon L. Harlan, Anthony J. Brazel, G. Darrel Jenerette, Nancy S. Jones, Larissa Larsen, Lela Prashad, & William L. Stefanov, "In the Shade of Affluence: The Inequitable Distribution of the Urban Heat Island"; in Robert C. Wilkinson & William R. Freudenburg, eds., ''Equity and the Environment'' (Research in Social Problems and Public Policy, Volume 15); Oxford: JAI Press (Elsevier); {{ISBN|978-0-7623-1417-1}}.</ref>

One of the main methods of improving the [[urban ecology]] is including in the cities more [[urban green space]]s: parks, gardens, lawns, and trees.<ref>{{cite journal |last1=Zhao |first1=Jiacheng |last2=Zhao |first2=Xiang |last3=Wu |first3=Donghai |last4=Meili |first4=Naika |last5=Fatichi |first5=Simone |title=Satellite-based evidence highlights a considerable increase of urban tree cooling benefits from 2000 to 2015 |journal=[[Global Change Biology]] |year=2023 |volume=29 |issue=11 |pages=3085–3097 |doi=10.1111/gcb.16667|pmid=36876991 |bibcode=2023GCBio..29.3085Z |s2cid=257363670 }}</ref><ref>{{cite journal |last1=Simpkins |first1=Graham |title=City cooling from trees |journal=[[Nature Reviews Earth & Environment]] |year=2023 |volume=4 |issue=8 |pages=516 |doi=10.1038/s43017-023-00474-1|bibcode=2023NRvEE...4..516S |s2cid=260403104 }}</ref> These areas improve the health and well-being of the human, animal, and plant populations of the cities.<ref name="fuller">{{cite journal |last1=Fuller|first1=R.A.|last2=Irvine|first2=K.N.|last3=Devine-Wright|first3=P.|last4=Warren|first4=P.H.|last5=Gaston|first5=K.J. |year=2007 |title=Psychological benefits of green-space increase with biodiversity|journal=Biology Letters|volume=3|issue=4|pages=390–394|doi=10.1098/rsbl.2007.0149 |pmc=2390667|pmid=17504734}}</ref> Well-maintained urban trees can provide many social, ecological, and physical benefits to the residents of the city.<ref>{{Cite journal |last1=Turner-Skoff|first1=J. |last2=Cavender|first2=N. |title=The Benefits of Trees for Livable and Sustainable Communities |journal=Plants, People, Planet |volume=1 |issue=4 |pages=323–335 |year=2019 |doi=10.1002/ppp3.39|doi-access=free |bibcode=2019PlPPl...1..323T }}</ref>

A study published in ''[[Scientific Reports]]'' in 2019 found that people who spent at least two hours per week in nature were 23 percent more likely to be satisfied with their life and were 59 percent more likely to be in good health than those who had zero exposure. The study used data from almost 20,000 people in the UK. Benefits increased for up to 300 minutes of exposure. The benefits are applied to men and women of all ages, as well as across different ethnicities, socioeconomic statuses, and even those with long-term illnesses and disabilities. People who did not get at least two hours – even if they surpassed an hour per week – did not get the benefits. The study is the latest addition to a compelling body of evidence for the health benefits of nature. Many doctors already give nature prescriptions to their patients. The study did not count time spent in a person's own yard or garden as time in nature, but the majority of nature visits in the study took place within two miles of home. "Even visiting local urban green spaces seems to be a good thing," Dr. White said in a press release. "Two hours a week is hopefully a realistic target for many people, especially given that it can be spread over an entire week to get the benefit."<ref>{{cite news |last1=Sam Nickerson |first1=Sam |title=Two Hours a Week in Nature Can Boost Your Health and Well-Being, Research Finds |url=https://www.ecowatch.com/nature-time-health-wellness-2638941663.html |access-date=23 June 2019 |agency=Ecowatch |date=21 June 2019 |archive-date=10 December 2021 |archive-url=https://web.archive.org/web/20211210070030/https://www.ecowatch.com/nature-time-health-wellness-2638941663.html |url-status=live }}</ref><ref>{{cite journal|last1=White|first1=Mathew P.|last2=Alcock|first2=Ian|last3=Grellier|first3=James|last4=Wheeler|first4=Benedict W.|last5=Hartig|first5=Terry|last6=Warber|first6=Sara L.|last7=Bone|first7=Angie|last8=Depledge|first8=Michael H.|last9=Fleming|first9=Lora E.|year=2019|title=Spending at least 120 minutes a week in nature is associated with good health and wellbeing|journal=[[Scientific Reports]]|volume=9|issue=1|pages=7730|bibcode=2019NatSR...9.7730W|doi=10.1038/s41598-019-44097-3|pmc=6565732|pmid=31197192}}</ref>