The Footprint of Urbanization
Changes in Land-use and Land- cover
• Global changes:17001990 (Meyer and Turner 1992)
(Lambin et al. 2001)
–
–
–
–
–
–
–
–
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
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
Cold (northern) climates favor large body,
especially in males so sexual dimorphism is
also greater, and short appendages
Longer bills may be response to heat or new
foods
Wet climates favor dark plumage
Bill Length of Male House Sparrows
(Johnston and Selander 1964)
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)
Foraging Innovations and Human Behavior
(Nihei and Higuchi 2001)
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.