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 Prairie Racerunner A. sexlineata sexlineata 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)
6 light stripes 7 light stripes 8 light stripes/divided vertebral Hatchlings - 15 27 Juveniles - 13 - Adults 1 21 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) Tail Length (mm) Mass (g) Min Max Mean Min Max Mean Min Max Mean 28.9 37.9 33.70 + 45.6 65.4 55.09 + 0.6 1.5 1.03 + 0.32 0.75 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 length, tail length and mass for hatchling, juvenile and adult Aspidoscelis sexlineata in Murphy Lake State Game Area, Tuscola County, Michigan. Minimum, maximum and mean snout-vent length, tail length and mass for hatchling, juvenile and adult Aspidoscelis sexlineata in Murphy Lake State Game Area, Tuscola County, Michigan.
VES 2005 VES 2006 Mark/ Recapture Hatchlings 98 120 91 Juveniles 32 60 20 Adults 55 53 51 Population size estimates of A. sexlineata based on visual encounter surveys (2005, 2006) and mark/recapture studies (2006, 2007).
Number of Individuals 90 80 70 60 50 40 30 20 10 0 Adults Juveniles Hatchlings June 16 June 29 July 12 Aug 1 Aug 16 Sept 1 Sept 15 Sept 28 Date Number of A. sexlineata found during visual encounter surveys at MLSGA from June to September 2005.
Photo taken by James Dake Date 1 st Observed Max Number Observed Date Max Observed Overwinter Survivorship 2005 9 Aug 98 8 Sept N/A 2006 7 Aug 120 7 Sept 61.2 % 2007 N/A N/A N/A 26.7 % 2008 31 Aug 42 1 Sept TBA Data for hatchling A. sexlineata at MLSGA in 2005 2008.
A B 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 (c 2 = 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 Endemic Racerunners in Michigan? 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 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