The Footprint of Urbanization

Changes in Land-use and Land- cover

• Global changes:1700-1990 (Meyer and Turner 1992)– Cropland +392 - 466%– Irrigated Cropland +2400%– Closed Forest -15.1%– Forest and woodland -14.9%– Grassland/pasture -1%– Lands drained 1.6 x 106 km2

– Urban settlement 2.5 x 106 km2

– Rural settlement 2.1 x 106 km2

(Lambin et al. 2001)

Settlement Affects Native Habitat

• Habitat Loss• Reduced connection

among remaining patches

• Perforation of large patches

• Introduction of exotics• Degradation of

remaining habitat

Settlement Benefits Some Wildlife

• Reduced predation• Reduced climatic extremes• Available water• Supplemental food• New nest sites• Increased edge and vegetative diversity

Change is Rapid and Dramatic

Population Size is a Critical Determinant of Whether Species Adapt or go Extinct in Urban Environments

Industrial Melanism

• Pigeons as well as peppered moths

Differential Survival and Mortality Can Lead to Evolution

Bill Length of Male House Sparrows(Johnston and Selander 1964)

Cold (northern) climates favor large body, especially in males so sexual dimorphism is also greater, and short appendagesLonger bills may be response to heat or new foodsWet climates favor dark plumage

Seen in House Sparrows and Mynas

Evolution in Dark-eyed Juncos

http://kaweahoaks.com/html/de_junco.html

(Yeh 2004)

Junco Details

• Phenotypic plasticity – Rare traits were favored in urban area, including

low stress response and early/late breeding which would not be favored in ancestral mountain populations

– Males that invested in early broods would garner faithful females which enabled several broods to be reared per year, a distinct benefit

• Heritability

People Respond(Marzluff and Angell 2005)

Cultural Coevolution

• Cultural coevolution: coupled changes in two or more species’ cultures that evolve in response to interactions between the species

(Knight 1984, Knight et al. 1987)

(Nihei and Higuchi 2001)

Foraging Innovations and Human Behavior

Adjusting Learned Song to Urban Noise

• Singing Earlier– Spotted starlings and house sparrows in Spain; robins in US

• Singing Louder– Noisy miners on busy versus calm Australian streets– Nightingales on weekdays versus weekends

• Singing Higher– Great tits in Leiden, Netherlands– Song sparrows in Portland– White-crowned sparrows in San Francisco

• Singing Faster– Great tits in Europe

• Costs?– High frequency sounds less imposing

Italian Sparrows• Evolution by hybridization

– Humans crossed Alps from northern Europe about 1600 BC

• House sparrows had been commensals for 5500 years, joined them

– When rare, house sparrows interbred with native Spanish sparrows

– Created a distinct, viable hybrid– As numbers of house sparrows rose in north,

they kept to themselves– Cold winter 350-450 years ago closed passes and

slowed advance of house sparrows enabling hybrids to breed mostly with other hybrids

– Now similar mates are selected, likely from imprinting on parents

– Italian sparrow is distinct and occupies most of Italy

Blackcap Migration and Morphology

• Typically migrate from Germany to southern Spain, Portugal, and North Africa

• Some variation, some going to Britian– Shorter, access to food in London and elsewhere– Daylength changes more quickly in autumn and

spring, so response to migrate happens sooner– Return to Germany earlier, and select mates from

others there at that time• Allows for sympatric speciation• Reinforced by heritability of migratory direction and

distance– Shorter migratory route favors shorter, rounder

wings– Bird Food selects for slender bills

• Walk out of your door and find some evolution (S.R. Palumbi 2001)

For Details

• Marzluff JM 2012 Urban Evolutionary Ecology. Studies in Avian Biology 45:287-308.

• Marzluff JM and T Angell 2005 In the Company of Crows and Ravens. Yale University Press.

• Marzluff JM 2014 Subirdia. Yale University Press.