Transcript Seminar divesrity recent

Conservation Biology (Ecology)
Lecture 5
November 2009
Salit Kark
The Biodiversity Research Group
Department of Evolution, Systematics and Ecology
The Silberman Institute of Life Sciences
The Hebrew University of Jerusalem
Dr. Salit Kark. The Hebrew University of Jerusalem
Conservation of peripheral populations:
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
Dr. Salit Kark. The Hebrew University of Jerusalem
Peripheral populations - spatial scale:
A
Periphery?
B
Periphery?
C
Periphery?
Dr. Salit Kark. The Hebrew University of Jerusalem
Conservation of peripheral populations:
Predictions (truisms?):
Small
Fragmented
Isolated
Higher disturbance
More variable
Higher stress
Dr. Salitand
Kark. The
Hebrew
Genetic diversity
demography
patterns
University of Jerusalem
Trends from periphery to core across a species range
Decrease
Genetic diversity
Genetic diversity
Increase
Distance from range periphery
Distance from range periphery
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
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)
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 Kark
Dr. 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
Percentage of plant species belonging to major chorotypes
across chukar sampling sites in Israel from south to north*
*Data from A. Danin
South
North
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
Range contraction
From: Rob Channell web page
(http://www.fhsu.edu/biology/rchannell/)
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
area
Equal
distance
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
BioScience 2004 54:123-137
 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
Dr. Salit Kark. The Hebrew University of Jerusalem
Dr. Salit Kark. The Hebrew University of Jerusalem
Dr. Salit Kark. The Hebrew University of Jerusalem