Download Species, lineages, functions: Why are they most diverse in the tropics?

JH Brown 10-8-13
Species, lineages, functions:
Why are they most diverse in the
tropics?
James H. Brown
Department of Biology
University of New Mexico
Modified from Wallace Award Lecture
International Biogeography Society
6th Annual Meeting, Miami, Florida, 2013
JH Brown 10-8-13
THE PATTERNS ARE CLEAR
• Species richness increases from poles to
equator
• Very general pattern
all major taxa: animals, plants, microbes
all major habitats: terrestrial, marine,
freshwater
• Also applies to:
clades
human languages and cultures
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SPECIES: VASCULAR PLANTS
Diversity Zones:
Species Numbers of
Vascular Plants
per 10,000 km2
< 20
1
20-200
2
200-500
3
500-1000
4
1000-1500
5
1500-2000
6
7
2000-3000
3000-4000
8
9
4000-5000
> 5000
10
Barthlott, Kier, Kreft, Küper, Rafiqpoor &
Mutke 2005
Nees Institute for Biodiversity of Plants
University of Bonn, Germany
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SPECIES: TERRESTRIAL MAMMALS
Hawkins et al. (2011)
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FAMILIES: TERRESTRIAL MAMMALS
Hawkins et al. (2011)
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SPECIES: FRESHWATER FISH
http://www.sciencedirect.com/science/article/pii/S1546509805210014
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SPECIES: CORAL REEF ANIMALS
fish
corals
snails
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SPECIES: SEA GRASSES
Short et al. (2007)
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SPECIES: MARINE PHYTOPLANKTON
The Darwin Project - http://darwinproject.mit.edu/?page_id=14
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THREE MAIN MECHANISMS FOR LDG ARE
STILL UNRESOLVED AND CONTROVERSIAL
• Geography of diversification and dispersal
“Out of the tropics with conservative niches”
indirect effects of kinetics?
• Resources / productivity
“A larger pie can be divided into more pieces”
indirect effects of kinetics?
• Ecological and evolutionary rates
“The Red Queen runs faster when she is hot”
direct effects of kinetics
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RESOURCES / PRODUCTIVITY
Key elements:
• Net primary productivity (NPP) of terrestrial
ecosystems is correlated with latitude
(highest in tropical rain forests)
• Higher productivity allows coexistence of
more individual organisms
• More resources and individuals can be
divided among more species, with each
share enough to resist stochastic
extinction
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Net primary productivity
JH Brown 10-8-13
SPECIES: VASCULAR PLANTS
Diversity Zones:
Species Numbers of
Vascular Plants
per 10,000 km2
< 20
1
20-200
2
200-500
3
500-1000
4
1000-1500
5
1500-2000
6
7
2000-3000
3000-4000
8
9
4000-5000
> 5000
10
Barthlott, Kier, Kreft, Küper, Rafiqpoor &
Mutke 2005
Nees Institute for Biodiversity of Plants
University of Bonn, Germany
JH Brown 10-8-13
Net primary productivity
Primary
production
(gC m-2yr -1)
1000
500
0
Jennings et al. (2012) from Mélin and Forster
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SPECIES: CORAL REEF ANIMALS
fish
corals
snails
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Hubbell (1997)
ECOLOGICAL AND EVOLUTIONARY
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RATES / KINETICS
Key elements:
• Environmental temperature is correlated
with latitude
high in tropical rain forests and oceans
• Rates of biological processes increase
near-exponentially with temperature
• High rates of evolution and ecological
interactions generate and maintain high
diversity in the tropics
especially rates of speciation/extinction,
Red Queen coevolution, and ecological
predation/parasitism/disease interactions
JH Brown 10-8-13
TEMPERATURE
Global Warming Art
http://montessorimuddle.org/2011/09/01/global-warming-art/
KINETICS OF METABOLISM AND ECOLOGY
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FROM METABOLIC THEORY
Pseudomonas flourescens
Knies and Kingsolver (2010)
Temperature and species diversity: China
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Slope = -0.87
Wang et al. (2009)
SPECIES RICHNESS INCREASES MORE RAPIDLY WITH NPP
AND LATITUDE THAN NUMBER OF INDIVIDUALS JH Brown 10-8-13
Currie et al. (2004)
Our data:
NSF Macrosystems
grant for
kinetics of
biodiversity
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Our data:
NSF Macrosystems
grant for
kinetics of
biodiversity
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Temperature: higher turnover in warmer
environments: trees
Slope of species-area relationship (z)
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Wang et al. 2009
China
North America
20oC
|
0 oC
|
1/kT
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Hubbell (1997)
Our data: NSF Macrosystems grant for
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kinetics of biodiversity
Arctic-alpine conifer forest: Niwot
2031 individuals, 6 species
Temperate deciduous forest: Coweeta
1730 individuals, 52 species
Tropical rain forest: Barro Colorado
Island
4971 Individuals, 263 species
A
B
D
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Niwot
Harvard
Barro Colorado Island
Log number of species
Productivity via species-area relation:
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small effect
S = S0 AZ
Log area
If Z = 0.25,
S increases
only 10-fold
with
10,000-fold
increase in area
Productivity via species-abundance
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distribution: small effect
ln (Abundance)
productive
unproductive
Rank
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WHERE DO WE GO FROM HERE?
• Three classes of mechanisms, which are
not mutually exclusive:
1) Earth and phylogenetic history
includes “niche conservatism”
2) Productivity
includes abundance and biomass
3) Kinetics
includes ecology and evolution
“the Red Queen runs faster when she is hot”
• Elements of all of them will be required,
but the synthesis cannot be too complex,
because the phenomena are so general
RATES OF ECOLOGICAL INTERACTIONS INJH Brown 10-8-13
EXPERIMENTS ARE TEMPERATURE DEPENDENT
Burnside, Hammond and Brown (submitted)
RATES OF ECOLOGICAL INTERACTIONS INJH Brown 10-8-13
EXPERIMENTS ARE TEMPERATURE DEPENDENT
Burnside, Hammond and Brown (submitted)
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INTERACTION RATES IN ECOLOGICAL
EXPERIMENTS ARE TEMPERATURE DEPENDENT
Burnside, Hammond and Brown (submitted)
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INTERACTION RATES IN ECOLOGICAL
EXPERIMENTS ARE TEMPERATURE DEPENDENT
Burnside, Hammond and Brown (submitted)
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Red Queen or Janzen-Connell effect of
enemies via species-abundance distribution
ln (Abundance)
Find and suppress dominants
COLD
HOT
Increase, colonize,
and speciate when rare
Rank
SPECIATION RATES OF FOSSIL FORAMINIFERA
ARE TEMPERATURE DEPENDENT
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Allen et al. (2006)
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HUMAN LANGUAGES
Data and analysis by Marcus Hamilton
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MAMMAL SPECIES
Data and analysis by Marcus Hamilton
Linguistic diversity and mammal
species diversity:
variation with latitude
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JH Brown 10-8-13
Linguistic
diversity and
mammal species
diversity:
variation with
latitude and
temperature
Data and analysis by
Marcus Hamilton