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Ecology
• Global climate and productivity
• Species diversity
• Island biogeography
• Niche partitioning
Discussion readings• Stevens RD, Cox SB, Strauss RE, Willig MR 2003 Patterns of
functional diversity across an extensive environmental gradient: vertebrate consumers, hidden treatments and latitudinal trends. ECOLOGY LETTERS 6: 1099-1108
• Aguirre LF, Herrel A, van Damme R, et al. 2002 Ecomorphological analysis of trophic niche partitioning in a tropical savannah bat community. P ROY SOC LOND B BIO 269: 1271-1278.
• Giannini NP, Kalko EKV 2004 Trophic structure in a large assemblage of phyllostomid bats in Panama. OIKOS 105: 209-220.
• Bernard E, Fenton MB 2002 Species diversity of bats (Mammalia : Chiroptera) in forest fragments, primary forests, and savannas in central Amazonia, Brazil. CANADIAN JOURNAL OF ZOOLOGY 80: 1124-1140.
• Freeman PW 2000 Macroevolution in Microchiroptera: Recoupling morphology and ecology with phylogeny. EVOLUTIONARY ECOLOGY RESEARCH 2: 317-335.
Source of the seasons
Earth’s axis tilts 23.5o
Orbital cycles influence temperature
100,000 y period
41,000 y period
22,000 y period
Ice ages can be predicted from orbital cycles
Ice sheets influence species ranges
Greenhouse emissions may lead to accelerated warming
Global atmospheric patterns
Ocean currents
Surface ocean temperaturesPacific coast Atlantic coast
Rain shadows
Temperature and precipation create biomes
Biome distribution
Global primary productivity
Annual productivity increases with mean temperature and rainfall
Energy flow
• Only 1% of energy from sun is trapped by plants during photosynthesis
• Approximately 10% of energy is passed to next trophic level
Food chain length depends on primary productivity and ecological efficiency of each trophic level
Energy pyramid
Bat species diversity
Bat species diversity by
latitude
Reasons for tropical diversity
• Energy stability: more solar energy allows for more diversity
• Greater specialization: individual abundance decreases as diversity increases
• Habitat diversity is greater so there are more niches to fill
Species range patterns
• Tropical species have smaller ranges than expected
• Temperate species have larger ranges than expected
Restricted vs widespread species
Gleaners haverestricted ranges
Body size and species abundance
• Bergman’s rule: species become larger away from the equator - bats do not show this
• Body mass does not correlate with abundance in bats. Other mammals show negative correlation between body mass and abundance.
Per
cent
spe
cies
Log body mass
Island biogeography
How many species do we expect on the island?
Island biogeography
• S = equilibrium number of species
• I = immigration rate
• E = extinction rate
Island biogeography predictionsArea effect
Island biogeography predictionsDistance effect
Species-area relationships
Bat species-area patterns
Tropical forests
Habitats
Larger areas sustain more species
Area and distance effect for Polynesian
megachiroptera
Bat wing shape has been used to define feeding guilds
• Wing loading = mass/wing area
• Aspect ratio = wingspan2/wing area– Low AR =
short, broad wings– High AR =
long, narrow wings
Niche partitioning
Niche space
expansion
Temperate
Tropical