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Salit Kark
The Biodiversity Research Group
Department of Evolution, Systematics and Ecology
The Silberman Institute of Life Sciences
The Hebrew University of Jerusalem
Conservation Biology (Ecology)
Lecture 5
November 2009
Dr. Salit Kark. The Hebrew University of Jerusalem
Species ranges - concepts:
periphery vs. core - geographical
margin vs. center - ecological
edge vs. interior - geographical
sink vs. source - metapopulation dynamics
outland vs. homeland - metapopulation dynamics
island vs. mainland - geographical or ecological
Conservation of peripheral populations:
Dr. Salit Kark. The Hebrew University of Jerusalem
A
B
C
Periphery?
Periphery?
Periphery?
Peripheral populations - spatial scale:
Dr. Salit Kark. The Hebrew University of Jerusalem
Conservation of peripheral populations:
Predictions (truisms?):Predictions (truisms?):
Small
Fragmented
Isolated
Higher disturbance
More variable
Higher stress
Genetic diversity and demography patternsDr. Salit Kark. The Hebrew University of Jerusalem
Carson hypothesis - core populations maintain higher genetic diversity, undergoing balancing selection, while peripheral populations - small, fragmented and isolated have low diversity. Marginal conditions permit survival of a limited number of genotypes only (Carson ‘59, Lewontin ‘74)
Distance from range periphery
Gen
etic
div
ersi
ty
Distance from range periphery
Fisher hypothesis - peripheral populations sustain higher levels of genetic diversity, undergoing fluctuating selection in spatially heterogeneous and unpredictable environments while core populations experience stabilizing selection (Fisher ’30)
DecreaseDecrease
Gen
etic
div
ersi
ty
Distance from range periphery
IncreaseIncrease
Trends from periphery to core across a species range
Mayr hypothesis Dr. Salit Kark. The Hebrew University of Jerusalem
Diversity in chukar partridges across the distribution gradient in Israel
Photo: Mosaic from Madaba Jordan, 6th century (Byzantine period)
Salit KarkDr. Salit Kark. The Hebrew University of Jerusalem
Mean annual rainfall in study region
Ecotone
Dr. Salit Kark. The Hebrew University of Jerusalem
Genetic diversity in chukar partridges across the range
Dr. Salit Kark. The Hebrew University of Jerusalem
South North
Percentage of plant species belonging to major chorotypes across chukar sampling sites in Israel from south to north*
*Data from A. Danin
Dr. Salit Kark. The Hebrew University of Jerusalem
Natural vs. agri
Dr. Salit Kark. The Hebrew University of Jerusalem
Dr. Salit Kark. The Hebrew University of Jerusalem
From: Rob Channell web page (http://www.fhsu.edu/biology/rchannell/)
Range contraction
Dr. Salit Kark. The Hebrew University of Jerusalem
Range contraction
Channell and Lomolino 2000
Mapped 245 species from various groups
Divided range to two parts: core and periphery
Dr. Salit Kark. The Hebrew University of Jerusalem
Locating the historical range core using GIS
core
Dr. Salit Kark. The Hebrew University of Jerusalem
A dichotomous approach:
Equal area
Dr. Salit Kark. The Hebrew University of Jerusalem
A dichotomous approach:
Equal distance
Equal area
Dr. Salit Kark. The Hebrew University of Jerusalem
Giant Panda historical and current range
(from web page of AMNH, map by Joyce Penola)Dr. Salit Kark. The Hebrew University of Jerusalem
From: IRF web page Dr. Salit Kark. The Hebrew University of Jerusalem
Fisher historical and current range
Dr. Salit Kark. The Hebrew University of Jerusalem
Range contraction
Channell and Lomolino 2000
Found that 98% maintained populations in part of the periphery
68% maintained higher than expected in periphery
91 species occurred only in periphery (5 only in core)
Relate their findings to human activity
Different patterns in Africa
Dr. Salit Kark. The Hebrew University of Jerusalem
Adding an intermediate area
Equal area
Equal distance
Dr. Salit Kark. The Hebrew University of Jerusalem
From a dichotomous to a more continuous approach (equal area)
2 belts
3 belts
10 belts
Dr. Salit Kark. The Hebrew University of Jerusalem
Studied 43 North American carnivores and ungulates
17 contracted over 20% of original range
Related to human influence and history, as predicted
Differs among regions
Rapid change in distributions over a century
BioScience 2004 54:123-137
Dr. Salit Kark. The Hebrew University of Jerusalem
Dr. Salit Kark. The Hebrew University of Jerusalem
Dr. Salit Kark. The Hebrew University of Jerusalem
