Urban Biodiversity: Patterns, Processes and Implications for Conservation


As the world becomes increasingly urbanised, more and more species either reside in cities, suburbs and exurbs or are influenced by their growth. On the bases of our literature survey, species richness and diversity of animals, especially vertebrate animals, and plants usually declines in cities. However, contrary to the prevailing notion that bird abundances usually increase in cities, studies reporting increases or decreases of bird abundances are about equal. The mechanisms underlying patterns of urban biodiversity are complex and not well‐understood. Explanations for the observed changes in species diversity and composition in cities focus on local processes involving species responses to local abiotic environmental factors and interactions with other species and regional processes, such as dispersal. Recently, metacommunity theory has been applied to urban habitats to explore the relative importance of local and regional processes. This theory also provides insights into how biodiversity can be maintained and promoted in urban areas.

Key Concepts:

  • Urbanisation creates highly fragmented, heterogeneous and altered environments that act as selective filters for urban organisms and species.

  • Urbanisation is often associated with declines in animal and plant richness, abundance and diversity.

  • Studies showing increases or decreases in urban bird abundances are about equal, contrary to conventional wisdom of increased bird abundances in cities.

  • Various ecological concepts have been applied to explain urban biodiversity, including disturbance and productivity gradient hypotheses and island biogeography theory.

  • Metacommunity theory has been used recently to ascertain relative contributions of local and regional processes to urban biodiversity.

  • Understanding local and regional processes leads to better insights in conserving and promoting urban biodiversity.

  • Conservation efforts depend on connections to nature; therefore, it is important to engage city‐dwellers with their urban biotas.

Keywords: biodiversity; cities; conservation; metacommunity theory; socioecology; species richness; urbanisation

Figure 1.

The effects of urbanisation on (a) diversity (as measured by a diversity index such as the Shannon–Weiner index), (b) abundance (number of individuals), (c) species richness of organisms separated by taxa. Number of studies is in parentheses.



Bang C and Faeth SH (2011) Variation in diversity, trophic structure and abundance in response to urbanization: seven years of arthropod monitoring in a desert city. Landscape and Urban Planning 103: 383–399. doi:10.1016/j.landurbplan.2011.08.013.

Bang C, Faeth SH and Sabo JL (2012) Control of arthropod abundance, richness and composition in a heterogeneous desert city. Ecological Monographs 82(1): 85–100.

Bang C, Sabo JL and Faeth SH (2010) Reduced wind speed improves plant growth in a desert city. PLoS ONE 5(6): e11061.

Buczkowski G (2011) Suburban sprawl: environmental features affect colony social and spatial structure in the black carpenter ant, Camponotus pennsylvanicus. Ecological Entomology 36(1): 62–71. doi:10.1111/j.1365‐2311.2010.01245.x.

Connell JH (1978) Diversity in tropical rain forests and coral reefs. Science 199: 1302–1310.

Crooks KR and Soulé ME (1999) Mesopredator release and avifaunal extinctions in a fragmented system. Nature 400(6744): 563–566.

Davis A and Glick T (1978) Urban ecosystems and island biogeography. Environmental Conservation 5(4): 299–304.

Dearborn DC and Kark S (2010) Motivations for conserving urban biodiversity. Conservation Biology 24(2): 432–440. doi:10.1111/j.1523‐1739.2009.01328.x.

Donnelly R and Marzluff JM (2004) Importance of reserve size and landscape context to urban bird conservation. Conservation Biology 18(3): 733–745.

Donnelly R and Marzluff JM (2006) Relative importance of habitat quantity, structure, and spatial pattern to birds in urbanizing environments. Urban Ecosystems 9: 99–117.

Douglas I and Ravetz J (2011) Urban ecology – the bigger picture. In: Niemelä J (ed.) Urban Ecology: Patterns, Processes, and Applications, pp. 246–262. New York: Oxford University Press.

Dunn RR, Gavin MC, Sanchez MC and Solomon JN (2006) The pigeon paradox: dependence of global conservation on urban nature. Conservation Biology 20(6): 1814–1816. doi:10.1111/j.1523‐1739.2006.00533.x.

Faeth SH, Bang C and Saari S (2011) Urban biodiversity: patterns and mechanisms. Annals of the New York Academy of Sciences 1223: 69–81. doi:10.1111/j.1749‐6632.2010.05925.x.

Faeth SH and Kane TC (1978) Urban biogeography – city parks as islands for Diptera and Coleoptera. Oecologia 32(1): 127–133.

Faeth SH, Warren PS, Shochat E and Marussich W (2005) Trophic dynamics in urban communities. BioScience 55(5): 399–407.

Ficetola GF and De Bernardi F (2004) Amphibians in a human‐dominated landscape: the community structure is related to habitat features and isolation. Biological Conservation 119(2): 219–230. doi:10.1016/j.biocon.2003.11.004.

Fokidis HB, Orinichik M and Deviche P (2011) Context‐specific territorial behavior in urban birds: no evidence for involvement of testosterone or corticosterone. Hormones and Behavior 211(1): 133–143.

Gade KJ (2010) Plant Migration along Freeways in and around an Arid Urban Area: Phoenix, Arizona. PhD dissertation. Tempe: Arizona State University.

Gaston KJ, Warren PH, Thompson K and Smith RM (2005) Urban domestic gardens (IV): the extent of the resource and its associated features. Biodiversity and Conservation 14(14): 3327–3349. doi:10.1007/s10531‐004‐9513‐9.

Goddard MA, Dougill AJ and Benton TG (2010) Scaling up from gardens: biodiversity conservation in urban environments. Trends in Ecology & Evolution 25(2): 90–98. doi:10.1016/j.tree.2009.07.016.

Gordon A, Simondson D, White M, Moilanen A and Bekessy SA (2009) Integrating conservation planning and landuse planning in urban landscapes. Landscape and Urban Planning 91(4): 183–194. doi:10.1016/j.landurbplan.2008.12.011.

Grimm NB, Faeth SH, Redman CL et al. (2008) Global change and the ecology of cities. Science 319: 756–760.

Hall SJ, Sponseller RA, Grimm NB et al. (2011) Ecosystem response to nutrient enrichment across an urban airshed in the Sonoran Desert. Ecological Applications 21(3): 640–660.

Hess G (1996) Disease in metapopulation models: implications for conservation. Ecology 77(5): 1617–1632.

Hope D, Gries C, Zhu W et al. (2003) Socioeconomics drive urban plant diversity. Proceedings of the National Academy of Sciences of the USA 100(15): 8788–8792.

Horváth G, Kriska G, Malik P and Robertson B (2009) Polarized light pollution: a new kind of ecological photopollution. Frontiers in Ecology and the Environment 7(6): 317–325. doi:10.1890/080129.

Imhoff ML, Bounoua L, DeFries R et al. (2004) The consequences of urban land transformation on net primary productivity in the United States. Remote Sensing of Environment 89(4): 434–443. doi:10.1016/j.rse.2003.10.015.

Knapp S, Kühn I, Schweiger O and Klotz S (2008) Challenging urban species diversity: contrasting phylogenetic patterns across plant functional groups in Germany. Ecology Letters 11(10): 1054–1064.

Kühn I, Brandl R and Klotz S (2004) The flora of German cities is naturally species rich. Evolutionary Ecology Research 6: 749–764.

Kuo FE and Sullivan WC (2001) Aggression and violence in the inner city – effects of environment via mental fatigue. Environment and Behavior 33(4): 543–571.

Kuttler W (2008) The urban climate – basic and applied aspects. In: Marzluff JM, Schulenberger E, Endlicher W et al. (eds) Urban Ecology – An International Perspective on the Interaction between Humans and Nature, pp. 233–248. New York: Springer.

Larson KL, Casagrande D, Harlan SL and Yabiku S (2009) Residents’ yard choices and rationales in a desert city: social priorities, ecological impacts, and decision tradeoffs. Environmental Management 44(5): 921–937. doi:10.1007/s00267‐009‐9353‐1.

Leibold MA, Holyoak M, Mouquet N et al. (2004) The metacommunity concept: a framework for multi‐scale community ecology. Ecology Letters 7(7): 601–613. doi:10.1111/j.1461‐0248.2004.00608.x.

MacArthur RH and Wilson EO (1967) The Theory of Island Biogeography. Princeton, NJ: Princeton University Press.

Marzluff JM (2005) Island biogeography for an urbanizing world: how extinction and colonization may determine biological diversity in human‐dominated landscapes. Urban Ecosystems 8(2): 157–177. doi:10.1007/s11252‐005‐4378‐6.

McDonald R and Marcotullio (2011) Global effects of urbanization on ecosystem services. In: Niemelä J (ed.) Urban Ecology: Patterns, Processes, and Applications, pp. 193–205. New York: Oxford University Press.

McDonnell MJ and Pickett STA (1990) Ecosystem structure and function along urban‐rural gradients: an unexploited opportunity for ecology. Ecology 71(4): 1232–1237.

McGranahan G, Marcotullio P, Bai X et al. (2005) Urban systems. In: Hassan R, Scholes S and Ash N (eds) Millennium Ecosystem Assessment, Current State and Trends: Findings of the Condition and Trends Working Group Ecosystems and Human Well‐Being, Vol. 1, pp. 795–825. Washington DC: Island Press.

McIntyre N and Hostetler ME (2001) Effects of urban land use on pollinator (Hymenoptera: Apodidea) communities in a desert metropolis. Journal of Applied and Theoretical Biology 2: 209–218.

McKinney ML (2002) Urbanization, biodiversity and conservation. BioScience 52(10): 883–890.

McKinney ML (2008) Effects of urbanization on species richness: a review of plants and animals. Urban Ecosystems 11(2): 161–176.

Menge BA and Sutherland JP (1987) Community regulation – variation in disturbance, competition, and predation in relation to environmental‐stress and recruitment. American Naturalist 130(5): 730–757.

Miller JR and Hobbs RJ (2002) Conservation where people live and work. Conservation Biology 16(2): 330–337.

Mittelbach GG, Steiner CF, Scheiner SM et al. (2001) What is the observed relationship between species richness and productivity? Ecology 82: 2381–2396.

Parris KM (2006) Urban amphibian assemblages as metacommunities. Journal of Animal Ecology 75(3): 757–764. doi:10.1111/j.1365‐2656.2006.01096.x.

Paul MJ and Meyer JL (2001) Streams in the urban landscape. Annual Review of Ecology and Systematics 32: 333–365.

Pautasso M (2007) Scale dependence of the correlation between human population presence and vertebrate and plant species richness. Ecology Letters 10: 16–24.

Quigley MF (2011) Potemkin gardens: biodiversity in small designed landscapes. In: Niemelä J (ed.) Urban Ecology: Patterns, Processes, and Applications, pp. 85–92. New York: Oxford University Press.

Raupp MJ, Shrewsbury PM and Herms DA (2010) Ecology of herbivorous arthropods in urban landscapes. Annual Review of Entomology 55: 19–38.

Richardson PJ, Lundholm JT and Larson DW (2010) Natural analogues of degraded ecosystems enhance conservation and reconstruction in extreme environments. Ecological Applications 20(3): 728–740.

Sadler J, Bates A, Donovan R and Bodnar S (2011) Building for biodiversity: accomodating people and wildlife in cities. In: Niemelä J (ed.) Urban Ecology: Patterns, Processes, and Applications, pp. 286–297. New York: Oxford University Press.

Sattler T, Duelli P, Obrist MK, Arlettaz R and Moretti M (2010) Response of arthropod species richness and functional groups to urban habitat structure and management. Landscape Ecology 25(6): 941–954. doi:10.1007/s10980‐010‐9473‐2.

Sattler T, Obrist MK, Duelli P and Moretti M (2011) Urban arthropod communities: added value or just a blend of surrounding biodiversity? Landscape and Urban Planning 103: 347–361.

Sauerwein M (2011) Urban soils – characterization, pollution, and relevance in urban ecosystems. In: Niemelä J (ed.) Urban Ecology: Patterns, Processes, and Applications, pp. 45–58. New York: Oxford University Press.

Shochat E, Lerman SB, Anderies JM et al. (2010) Invasion, competition, and biodiversity loss in urban ecosystems. BioScience 60(3): 199–208. doi:10.1525/bio.2010.60.3.6.

Smith RM, Warren PH, Thompson K et al. (2006) Urban domestic gardens (VI): environmental correlates of invertebrate species richness. Biodiversity and Conservation 15(8): 2415–2438.

Soulé ME (1985) What is conservation biology? BioScience 35(11): 727–734.

Sperling CD and Lortie CJ (2010) The importance of urban backgardens on plant and invertebrate recruitment: a field microcosm experiment. Urban Ecosystems 13(2): 223–235.

Steinberg DA, Pouyat RV, Parmelee RW and Groffman PM (1997) Earthworm abundance and nitrogen mineralization rates along an urban‐rural land use gradient. Soil Biology and Biochemistry 29(3–4): 427–430.

Swan CM, Pickett STA, Szlavecz K, Warren P and Willey KT (2011) Biodiversity and community composition in urban ecosystems: coupled human, spatial, and metacommunity processes. In: Niemelä J (ed.) Urban Ecology: Patterns, Processes, and Applications, pp. 179–186. New York: Oxford University Press.

Tallamy DW (2010) Bringing Nature Home, 4th printing edn. Portland, OR: Timber Press.

Tszoulas K and Greening K (2011) Urban ecology and human health. In: Niemelä J (ed.) Urban Ecology: Patterns, Processes, and Applications, pp. 263–271. New York: Oxford University Press.

Walker JS, Grimm NB, Briggs JM, Gries C and Dugan L (2009) Effects of urbanization on plant species diversity in central Arizona. Frontiers in Ecology and the Environment 7(9): 465–470. doi:10.1890/080084.

Warren PS, Katti M, Ermann M and Brazel A (2006) Urban bioacoustics: it's just not noise. Animal Behaviour 71: 491–502.

Further Reading

Blair RB (1996) Land use and avian species diversity along an urban gradient. Ecological Applications 6(2): 506–519.

Illgen M (2011) Hydrology of urban environments. In: Niemelä J (ed.) Urban Ecology: Patterns, Processes, and Applications, pp. 59–70. New York: Oxford University Press.

McKinney ML (2006) Urbanization as a major cause of biotic homogenization. Biological Conservation 127(3): 247–260.

Niemelä J (1999) Is there a need for a theory of urban ecology? Urban Ecosystems 3: 57–65.

Oberndorfer E, Lundholm J, Bass B et al. (2007) Green roofs as urban ecosystems: ecological structures, functions, and services. BioScience 57(10): 823–833. doi:10.1641/b571005.

Rosenzweig ML (2003) Win‐Win Ecology: How the Earth's Species can Survive in the Midst of Human Enterprise. New York: Oxford University Press.

Shochat E, Warren PS, Faeth SH, McIntyre N and Hope D (2006) From patterns to emerging processes in mechanistic urban ecology. Trends in Ecology & Evolution 21(4): 186–191.

Contact Editor close
Submit a note to the editor about this article by filling in the form below.

* Required Field

How to Cite close
Faeth, Stanley H, Saari, Susanna, and Bang, Christofer(Jul 2012) Urban Biodiversity: Patterns, Processes and Implications for Conservation. In: eLS. John Wiley & Sons Ltd, Chichester. http://www.els.net [doi: 10.1002/9780470015902.a0023572]