Status of the Six-lined Racerunner (Aspidoscelis sexlineata) in

Status of the Six-lined Racerunner
(Aspidoscelis sexlineata) in Michigan
Teresa A. Yoder, Ghada Sharif, Ann Sturtevant
& Ernest Szuch
University of Michigan-Flint
Throughout its range, Aspidoscelis
sexlineata:
Distribution of subspecies from
Conant & Collins (1998)
Throughout its range, Aspidoscelis
sexlineata:
Photo taken by Dick Bartlett
A. sexlineata viridis
A. sexlineata sexlineata
“Prairie Racerunner”
“Six-lined Racerunner”
Published accounts of A. sexlineata in
Michigan:
• 1989 – “There’s a New Kid on Skinks’
Block” Detroit Free Press (Hacker)
• 1990 – Turtles and Lizards of Michigan
(Harding & Holman)
• 1997 – Amphibians and Reptiles of the
Great Lakes Region (Harding)
Published accounts of A. sexlineata in
Michigan:
• 1999 - A Phylogeographic Study of
Cnemidophorus sexlineatus using
Mitochondrial DNA Sequence Analysis
(Razzano)
• 2001 – Species of Special Concern
(MDNR & MNFI)
Why? What was known?
• Very little
• One of 2 lizards in Michigan
Five-lined Skink
(Plestiodon fasciatus)
• 1856 - documented in
MI (Ruthven 1911)
• Widely distributed in
LP
• Scales shiny
• Moist, wooded or
partially wooded
areas
• Feeds mostly on
invertebrates
Why? What was known?
•
•
•
•
Very little
One of 2 lizards in Michigan
Only one population
Occurs at Murphy Lake State Game Area
(MLSGA),Tuscola County
Murphy Lake State Game Area
Current vegetation
map of MI. Map
created by Kristin
Hawley.
Presettlement vegetation
map (circa 1800) of MI.
Map from Barnes and
Wagner, Jr. (2004).
GOAL: To demonstrate that the only known population
of Aspidoscelis sexlineata in Michigan may be
endemic and is deserving of threatened/endangered
species status
Materials & Methods
Materials & Methods
• Non-MI blood/tissue samples obtained from
Researchers and Institutions
– Non-MI samples: AR, FL, IN, NE, TX
• DNA sequencing of ND2 mitochondrial gene
(2007 – 2008)
• Samples sent to DNA Sequencing Core, UM
Ann Arbor
• Phylogenetic trees constructed using
PAUP*(4.0)
Hatchlings
Juveniles
Adults
6 light
stripes
1
7 light
stripes
15
13
21
8 light stripes/divided
vertebral
27
1
Number of A. sexlineata hatchlings, juveniles and adults with 6
light stripes, 7 light stripes or 8 light stripes/divided vertebral
stripe at MLSGA. All individuals had a green background color.
50 % Majority-rule Consensus Tree
Bootstrap Consensus Tree
Hatchlings
(N = 44)
Snout-Vent Length (mm)
Min Max
Mean
28.9 37.9
33.70 +
0.32
Tail Length (mm)
Min
Max
Mean
45.6
65.4
55.09 +
0.75
Min
0.6
Mass (g)
Max
Mean
1.5
1.03 +
0.04
Juveniles
(N = 13)
36.2
48.3
41.10 +
0.83
59.9
83.3
69.91 +
2.14
1.5
2.5
1.94 +
0.08
Adults
(N = 23; For
TL, N = 21)
47.1
67.7
55.49 +
0.96
85.5
127.5
106.08 +
2.32
3.1
10.0
5.33 +
0.33
Table 1.
Minimum, maximum
and mean
snout-vent
tail length and
mass for
hatchling,
Minimum,
maximum
and
meanlength,
snout-vent
length,
tail
length
mass sexlineata
for hatchling,
and Area,
adultTuscola County,
juvenile
and adultand
Aspidoscelis
in Murphyjuvenile
Lake State Game
Aspidoscelis sexlineata in Murphy Lake State Game Area,
Michigan.
Tuscola County, Michigan.
Hatchlings
Juveniles
Adults
VES
2005
98
32
55
VES
2006
120
60
53
Mark/
Recapture
91
20
51
Population size estimates of A. sexlineata based
on visual encounter surveys (2005, 2006) and
mark/recapture studies (2006, 2007).
Number of Individuals
Adults
Juveniles
Hatchlings
90
80
70
60
50
40
30
20
10
0
June 16
June 29
July 12
Aug 1
Aug 16
Sept 1
Sept 15
Date
Number of A. sexlineata found during visual encounter
surveys at MLSGA from June to September 2005.
Sept 28
Photo taken by James Dake
2005
2006
2007
2008
Date 1st
Observed
9 Aug
7 Aug
N/A
31 Aug
Max Number Date Max
Observed
Observed
98
8 Sept
120
7 Sept
N/A
N/A
42
1 Sept
Overwinter
Survivorship
N/A
61.2 %
26.7 %
TBA
Data for hatchling A. sexlineata at MLSGA in
2005 – 2008.
B
A
C
D
Vegetative cover types occurring within A. sexlineata habitat at MLSGA and
percentage of total habitat each vegetative cover type represents
A: Tree/Forest = 32.4 %; B: Bare/Sparse = 40.3 %; C: Other (typically beneath
cover objects, natural or artificial) = 0.6 %; D: Thick = 26.7 %.
Number of A. sexlineata found in each vegetative cover
type during visual encounter surveys at MLSGA in 2005.
Bare/Sparse and Thick were preferred vegetative cover
types (c2 = 15.85; df = 3; p < 0.05).
What have we learned?
• Subspecies status:
Aspidoscelis sexlineata
viridis
• Population appears to be
of Midwestern origin
• Hatchling over-winter
survivorship has extreme
variation from year to
year
• Low recruitment observed
from juvenile to adult age
classes
What have we learned?
• Short activity season with
hatchlings active 1 month
longer than adults
• Late date of hatching and
low numbers of
hatchlings in 2008
followed by cool fall
temperatures may lower
reproductive success
extremely in 2009
What have we learned?
• Preferred cover types
(PCT) include
bare/sparse and thick
vegetation
– PCT make up 67 % of
habitat occupied by
lizard population and
are vulnerable to
natural succession
and/or normal
roadside maintenance
What is the status of Six-lined
Racerunners in Michigan?
• Endemic
• Only one known viable population
– Carrying capacity
• Occupy small patch of Upland Shrub/Low
Density Trees
– MLSGA is surrounded by mostly agricultural
land
• Threatened Species (MDNR 2008)
What’s in the foreseeable future…
• Continue population monitoring
– VES
• Further investigate habitat preference &
use
– Radio Transmitters and Powder Tracking
• Look for other isolated populations within
the state of MI
– GIS
Acknowledgements
Funding
Biology Department (Murchie Memorial Research Fund), College of Arts &
Sciences, Office of Research (Nick S. and Sharon G. George Research Fund)
& Office of Graduate Studies (GSRA for Teresa Yoder) of UMF
Contributions to Field and/or Lab Work
Larry Atherton (UMF); Melissa Borowiak; Fred Case (Saginaw, MI); Ashley
Cornett; The Field Museum, Chicago; Florida Fish & Wildlife Conservation
Commission; Michael Forstner (TSU); James Harding (MSUM); Nickole Hatley;
John Iverson (Earlham College); Arnold Karr (MDNR); Courtney Ostipow; Greg
Schneider (UMMZ); Annie Szuch (UMF); Stanley Trauth (ASU); Dennis Viele
(UMF); Acacia White
Literature Cited
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•
•
•
•
•
•
•
•
Barnes & Wagner, Jr. 2004. Michigan Trees: A Guide to the Trees of the Great Lakes
Region. Univ. Michigan Press, Ann Arbor, Michigan
Conant & Collins. 1998. Reptiles and Amphibians of Eastern/Central North America.
3rd ed. Houghton Mifflin, Boston, Massachusetts
Hacker. 1989. There’s a New Kid on Skinks’ Block. Detroit Free Press, Detroit,
Michigan
Harding. 1997. Amphibians and Reptiles of the Great Lakes Region. Univ. Michigan
Press, Ann Arbor, Michigan
Harding & Holman. 1990. Michigan Turtles and Lizards: A Field Guide and Pocket
Reference. Michigan St. Univ. Coop. Extension Serv. Publ. E-2234, East Lansing,
Michigan
Michigan Department of Natural Resources. 2008. Proposed List of Endangered &
Threatened Species. Updated 12 September 2008.
Michigan Natural Features Inventory. 2007. Rare Species Explorer (Web Application).
Available online at http://web4.msue.msu.edu/mnfi/explorer [Accessed Oct 7, 2007]
Razzano
Ruthven
Yoder. 2007. Unique Herpetofauna of Murphy Lake State Game Area, Tuscola
County, Michigan: Northern Dusky Salamander (Desmognathus fuscus) and Six-lined
Racerunner (Aspidoscelis sexlineata). MSc. Thesis, University of Michigan-Flint, Flint,
Michigan