Continued Progress in Desert Tortoise Conservation using...
Transcript of Continued Progress in Desert Tortoise Conservation using...
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Continued Progress in Desert Tortoise Conservation using Molecular Biology
Taylor EdwardsGenomic Analysis and Technology Core
University of Arizona
The Genographic Project
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Conservation Genetics
• Conservation Biologists strive to provide principles and tools for preserving biodiversity
• Biodiversity: The structural and functional variety of life forms at genetic, population, community, and ecosystem levels. (Sandlundet al. 1992)
DNA Fingerprinting
(GAT)15+ “microsatellite”
The Desert Tortoise Genomics Project
I. Defining the Desert Tortoise
a. Gene flow – ESU’sb. Maternal genealogy
II. PaternityIII. Behavioral GeneticsIV. Hybridization ZonesV. Mexican Tortoise Project
Photo: Curtis Bjurlin
The Desert Tortoise Genomics Project
I. Defining the Desert Tortoise
a. Gene flow – ESU’sb. Maternal genealogy
II. PaternityIII. Behavioral GeneticsIV. Hybridization ZonesV. Mexican Tortoise Project
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Molecular Support for the Established Recovery Units in the
Mojave Population of Desert Tortoises (Gopherus agassizii)
Taylor Edwards, Robert Murphy, Kristin H. Berry and Ann McLuckie
Arizona
G. agassiziiHabitat
Preferences
Mojave Population
Evolutionarily Significant Units (ESUs)
Recovery units for the desert tortoise were identified based on ESUs using data on genetic variability, morphology, behavior patterns, and habitat associations.
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CA
AZ
MX
NV UT
Western Mojave
Eastern Mojave
Northeastern Mojave
Northern Colorado
Eastern Colorado
Upper Virgin River
Col
orad
o R
iver
sample groups
recovery unitboundaries (USFWS 1994)
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14
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15
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Las Vegas
St. George
Los Angeles
N 0 100 km
Locations of 15 Sampled Groups
Sampled Desert RegionsDesert Region / Recovery Unit
Sample Group
# of Samples in Group
Western Mojave 1 622 83
Central Mojave 3 194 315 47
Southern Mojave 6 267 718 749 2710 19
Northeastern Mojave 11 60Eastern Mojave 12 31Northern Colorado 13 18Eastern Colorado 14 37Upper Virgin River 15 23
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Methods628 Tortoises
• Distribution – Sampled from all DWMAs (ex. Joshua Tree)– Representing all Recovery Units– Represent over a decade of research efforts
• DNA Fingerprinting; 15 Microsatellite markers (11 variable)
• mtDNA sequencing for 131 individuals
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Microsatellite descriptive statistics
93.93% 6.07%
Within GroupsAmong Groups
Percentage of Variation
FST = 0.061 (p<0.001)
Study sites are genetically similar:Suggests that gene flow occurs/occurred
MDS Analysis of Genetic Distance (Fst) for 15 Mojave desert tortoise groups(Stress = 1.39)
I-0.80 -0.05 0.70 1.45 2.20
II
-1.10
-0.45
0.20
0.85
1.50
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MDS Analysis of Genetic Distance (Fst) for 15 Mojave desert tortoise groups(Stress = 1.39)
I-0.80 -0.05 0.70 1.45 2.20
II
-1.10
-0.45
0.20
0.85
1.50
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2 3
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E
N
Southern Mojave
Central Mojave
Western Mojave
Northern Colorado
Northeastern Mojave
Eastern Colorado
Eastern Mojave
Upper Virgin River
Comparison of genetic distance to geographic distance:
Mantel Test; r2 = .646
The correlation accounts for approximately 65% of the variation observed
Isolation by Distance
The desert tortoise is perhaps the ideal organism for the IBD model; one that is distributed across the landscape in patches and for which the difficulty of dispersal is a function of geography.
- Edwards et al. (2004)
Assignment test
95.72223Upper Virgin River89.23337Eastern Colorado72.21318Northern Colorado54.81731Eastern Mojave81.74960Northeastern Mojave59.6118198Southern Mojave68.06697Central Mojave84.8139164Western Mojave
% correctly assigned
# correctly assigned
# of SamplesSample Group
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Maternal Lineage (mtDNA) Tree
Broadly distributedMojave Haplogroup
Northeastern Mojave Haplogroup
Sonoran Haplogroup
(~5 mya divergence from Mojave)
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CA
AZ
MX
NV UT
Col
orad
o R
iver
sample groups
recovery unitboundaries (USFWS 1994)
Las Vegas
St. George
Los Angeles
N 0 100 km
MtDNA Haplotype
Distribution
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11 1
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Haplogroup A2 2
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Haplogroup B
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1
CA
AZ
MX
NV UT
Western Mojave
Eastern Mojave
Northeastern Mojave
Northern Colorado
Eastern Colorado
Upper Virgin River
Col
orad
o R
iver
sample groups
recovery unitboundaries (USFWS 1994)
1 32
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14
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Las Vegas
St. George
Los Angeles
N 0 100 km
Revised Recovery Units suggested for the Mojave Population of the Desert Tortoise
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CA
AZ
MX
NVUT
WesternMojave
Northeastern Mojave
Northern Colorado
Eastern Colorado
Upper Virgin River
Col
orad
o R
iver
sample groups
potential recovery unit boundaries 1 3
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14
10
5
15
68
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Las Vegas
St. George
Los Angeles
Central Mojave
SouthernMojave
0 100 km
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Revised Recovery Units suggested for the Mojave Population of the Desert Tortoise Eastern
Mojave
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Structure 2.1 - Bayesian clustering method used to assess support for splitting the current “Western Mojave Recovery
Unit” into 3 separate units for management
• RED = Western RU• GREEN = Central RU• BLUE = Southern RU
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St. GeorgeSt. George
Locations of captive and translocated tortoises
Colorado Desert
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Los AngelesLos Angeles
NeedlesNeedles
Las VegasLas Vegas
BarstowBarstow
NVUT
CA
AZ
MX
Mojave Desert
0 100 kmN
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1997-2004
~1940-1983
Represents >1,000 documented releases!
The genetic affects of translocatedtortoises are observed in our data
Summary
• The 1994 Recovery Plan adequately designates Recovery Units for the Mojave population of the Desert Tortoise
• Our data suggest that the current “Western Recovery Unit” can be differentiated into 3 separate units; Western, Central, and Southern
Summary
• The Eastern Mojave and Northern Colorado Recovery Units warrant greater investigation
• The Northeastern and Upper Virgin River Recovery Units show the strongest differentiation and may in fact be more genetically isolated
Summary
• The integration of translocated tortoises could potentially compromise the genetic integrity of a desert tortoise management unit
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Tracing the Movements of SonoranDesert Tortoises with Molecular Biology
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Outcome #1Populations genetically distinct,
(gene flow does NOT occur)
Management Implications:Loss of genetic diversity
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Outcome #2Populations genetically similar, (gene
flow occurs)
Management Implications:Historical gene flow is currently
hindered by human development
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Gen
etic
Dis
tanc
e (F
st)
Geographic Distance (km)(Mantel test; r = 0.554, p = 0.030)
Isolation by Distance
Absolute number of migrants exchanged per generation
between populationsMethod:• Slatkin’s M = 2.9 (minimum)• Private allele method = 5.5
Gene flow occurred historically at a rate greater than one migrant per generation
Interstate 10
Saguaro NP
Rail line
Santa Rita Mtns.
Rincon Mtns.
10 km
Tucson
Thelma's mad dashA radio-tagged desert tortoise takes off on a wild trek that leaves her trackers stunned.
Tucson Citizen, May 12, 2003Thelma didn't exactly run away from home. For one thing, she's hardly a child - one estimate puts her age at about 30. For another, her pace was far from sizzling. After all, desert tortoises aren't known for their speed. But what she lacked in tempo, she made up for in determination. Thelma - her name was inspired by the wanderings of the famous movie duo Thelma and Louise - left Saguaro National Park's east unit in the fall of 2000, not long after being outfitted with a radio transmitter to track her movements….
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Phoenix
Tucson
= Tortoise Population
I-8
I-10
I-17
I-19
I-10 Phoenix
Tucson
= Tortoise Population
= Interstate
= Tortoise Population
Phoenix
Tucson
I-17
I-10
I-8
I-10
I-19
= Road= Interstate
= Tortoise Population
Phoenix
Tucson
= Urban buffer
Discussion
• Gene flow occurs (or historically occurred) among mountain “island” populations
• Connectivity between seemingly isolated populations is likely important to long-term population viability
• Populations that are currently isolated may require management options like translocations for long-term maintenance
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Many people have contributed
• field biologists• research
scientists• multi-
disciplinary teams
Acknowledgements• K.Berry• R. Murphy• D.J. Morafka• A. McLuckie• M. Kaplan • H-W. Herrmann• A. Lathrop• A. Ngo• R. MacCulloch• A. Demmon
• K. Anderson• R.J. Turner • T. Bailey• R. Evans• R. Woodard• P. Woodman• P. Frank• B.L. Burge• B. Henen• K. Nagy
• Cristina Jones• Bruce Weise• Josh Capps• Daren Riedle• Steve Goodman• Jeff Pebworth• Teal Richards• Cecil Schwalbe• Peter Woodman
• Arizona Game and Fish Department• University of Arizona• Saguaro National Park• U.S. Geological Survey• Southwestern Parks and Monuments Assoc.• Genomic Analysis and Technology Core• SW Cooperative Ecosystem Study Unit• U.S. Fish and Wildlife Service• California Fish & Game• Bureau of Land Management• Utah Division of Wildlife Resources
Cooperating Agencies: Funding• U.S. Army NTC Ft. Irwin• U.S. Air Force – Edwards Air Force Base• USGS• Royal Ontario Museum Foundation• Arizona Game and Fish Department• NSERC• CSUDH Foundation• Marine Corps – MCAGCC• Arizona Research Laboratories
Thank you!
CONSERVATION BIOLOGY IN NAMIBIASUMMER SESSION I:
MAY 14 - JUNE 24 2007
• Open to Undergraduate, Graduate and Non-degree Students• Take on a five week expedition into Namibia’s extraordinary Namib Desert• Experience real field research in Africa• Earn direct University of Arizona credit
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CONSERVATION BIOLOGY IN VIETNAMSUMMER SESSION II:
JULY 6 - AUGUST 16, 2007
• Open to Undergraduate, Graduate and Non-Degree Students
• Take expeditions to various biodiversity hotspots in Northern and Central Vietnam
• Experience real field research and participate first hand in
conservation efforts in tropical forests
www.studyabroad.arizona.eduAPPLICATIONS AVAILABLE AT
The Office of Study Abroad & Student Exchange (520) 626-9211
FOR MORE INFORMATION, CONTACTDr. Hans-Werner Herrmann, [email protected]
or Taylor Edwards, [email protected]
Register for: RNR 495A/595A (6 units)Field Studies in Developing Countries