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Axolotls and Other Amphibians Bryce A. Maxell Senior Zoologist Montana Natural Heritage Program (406) 444-3655

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Presentation on theme: "Axolotls and Other Amphibians Bryce A. Maxell Senior Zoologist Montana Natural Heritage Program (406) 444-3655"— Presentation transcript:

1 Axolotls and Other Amphibians Bryce A. Maxell Senior Zoologist Montana Natural Heritage Program (406) 444-3655 bmaxell@mt.gov http://mtnhp.org

2 Who Are They and How Many? Amphibians ~ 6,500 species (15) - Caudata (Salamanders) ~ 556 (4) - Gymnophiona (Caecilians) ~ 171 (0) - Anura (Frogs and Toads) ~ 5,773 (10) Reptiles ~ 8,240 species (18) - Rhyncocephalia (Tuatara) 2 (0) - Crocodylia (Crocodiles) 23 (0) - Testudines (Turtles) ~ 307 (3) - Sauria (Lizards) ~ 4,765 (5) - Serpentes (Snakes) ~ 2,978 (10) - Amphisbaenia (Worm Lizards) ~ 165 (0)

3 Decade Number of New Amphibian Species Described per Decade Köhler (2005) BioScience 55:693-696 6,483 Species Currently Described

4 Global Amphibian Species Diversity IUCN, Conservation International, and NatureServe (2004) Global Amphibian Assessment

5 Complex Life Histories Breeding ForagingWintering Complex Habitat Use Need to Consider Full Triangle of Habitats Required and Migration Corridors

6 Ectothermy and Importance to Food Web

7 Painted Turtle Montana Turtles Snapping Turtle Spiny Softshell

8 Montana Lizards Greater Short-horned LizardCommon Sagebrush Lizard Western SkinkNorthern Alligator Lizard

9 Montana Snakes Gophersnake Rubber BoaEastern Racer Western Rattlesnake Smooth GreensnakeMilksnake Western Hog-nosed Snake Common Gartersnake Plains Gartersnake Terrestrial Gartersnake

10 Snake Bite What to do: -Stay calm and keep heart rate low -Seek medical attention ASAP What not to do: -Use a tourniquet -Pack with ice -Make an incision and suck out poison -Try to denature proteins with electricity

11 Montana Toads Western Toad Woodhouse’s ToadGreat Plains Toad Plains Spadefoot

12 Montana Frogs American Bullfrog Boreal Chorus FrogPacific Treefrog Rocky Mountain Tailed Frog Columbia Spotted Frog Northern Leopard Frog Exotic!

13 Montana Salamanders Long-toed Salamander Barred Tiger Salamander Coeur d’Alene Salamander Idaho Giant Salamander

14 Barred Tiger Salamander (Ambystoma mavortium) Identification Eggs: -Ovum diameter ~ 2-3mm -Total diameter ~ 7-9mm -Ovum surrounded by 3 jelly layers -Singly or in linear clusters Larvae: -Olive green dorsally -Silvery white ventrally -3 pairs of feather gills on sides of head (15-25 gill rakers) -SVL up to 98mm Adults: -Mottled dorsally with green, yellow, or tan on a brown or black background -Ventrally gray or same as dorsal pattern Vocalization: None. From Stebbins (2003) Field Guide to Western Amphibians and Reptiles From Maxell (2009)

15 Some of Montana’s Barred Tiger Salamander Populations Exhibit Breeding ForagingWintering Paedomorphosis = becoming sexually mature in the larval form Neotony = retention of juvenile features in sexually mature adults

16 Only True Axolotl is the Mexican Salamander (Ambystoma mexicanum)

17 Barred Tiger Salamander (Ambystoma mavortium) Issues of Concern -Fish stocking -Tilled agriculture -Use as bait -Pathogens Habitat Use Breeding: -Temporary or permanent standing waters with or without emergent vegetation Foraging: -Terrestrial habitats with soil cover -Often in areas with mammal burrows Overwintering: -Terrestrial habitats with soil cover -Often in areas with mammal burrows Migration: -Individuals are known to migrate several hundred meters between terrestrial burrows and breeding sites Elevation: -Up to and slightly above treeline Elevation Distribution From Maxell (2009)

18 Barred Tiger Salamander (Ambystoma mavortium) Occupancy Rates Strata Total Number Watersheds / Sites Percent Watershed Occupancy (95% CI a ) Percent Site Occupancy (95% CI b ) 12 / 170 ( - ) 614 / 22250 (13–24)20 (14–25) 727 / 74930 (14–45)3 (2–4) 1037 / 92273 (60–86)11 (9–13) 1126 / 13977 (62–92)40 (31–48) 1234 / 48779 (67–91)28 (24–32) Overall140 / 253664 (56–71)14 (13–15)

19 Barred Tiger Salamander (Ambystoma mavortium) From Maxell (2009) CART Model

20 Global Amphibian Declines Stuart et al. (2004) Science 306:1783-1786 43% of species have declined 33% are globally threatened with extinction 427 (7%) Critically Endangered 23% are too poorly known to assess 40% of Montana Amphibians are Species of Concern

21 Montana Declines - Northern Leopard Frog (Lithobates pipiens) From Stebbins (2003) - Field Guide to Western Amphibians and Reptiles Pre and Post-1990 Distributions

22 Loss and Deterioration of Habitat Breeding Foraging Wintering Habitat Direct Loss *Filling in of wetlands *Destruction of Hibernacula *Flooding habitats Functional Loss *Introduced predators *Hydroperiod alteration *Impassible roads/traffic *Altered vegetation *Loss of prey

23 Introduction of Exotic Species Sport Fish Mosquito Fish Cane Toads Bullfrogs Crayfish Native Mesopredators (e.g., racoons, crows)

24 Concerns Related to Proliferation of Fish Ponds Pond Created Specifically for Fish Pond Created Specifically for Amphibians, Insects, and other Natives native overwintering native breeding/foraging

25 Response Summary SpeciesFishEvegHydroperiod Long-toed Salamander-+*+*Perm/Ephem Barred Tiger Salamander-+*+*Perm/Ephem Plains Spadefoot●●Ephemeral Western Toad●+Perm/Ephem Great Plains Toad-+Ephemeral Woodhouse’s Toad-+Perm/Ephem Boreal Chorus Frog-+Perm/Ephem Pacific Treefrog-+Perm/Ephem Northern Leopard Frog++Permanent Columbia Spotted Frog●+Permanent Painted Turtle●+Permanent Terrestrial Gartersnake++Perm/Ephem Plains Gartersnake++Permanent Common Gartersnake-+Perm/Ephem + = Positive Response - = Negative Response ● = No clear response

26 Diseases / Pathogens 1.Saprolegnia ferax - a water mold 2.Ranavirus – introduced with fish and results in necrosis and hemorrhagic disease 3. Batrachochytrium dendrobatidis – a chytrid fungus

27 Life History From Berger et al. (1998) PNAS 95:9031-9036 Free-swimming flagellated zoospores penetrate host cells Chytrid thallus digests keratin in epidermal skin cells Sporangia release clonal zoospores via discharge tubes Field Identification Lethargy & skin sloughing in adults Keratinized mouthparts reduced or absent in tadpoles From Vredenburg (2001) Herp Review 32(3):151-152 Normal Infected Batrachochytrium dendrobatidis

28 Distribution of Chytrid Fungus = Historic samples all negative = Recent negative = Recent Positive

29 Lab Study of Xenopus laevis Hayes et al. (2002) - PNAS 99:5476-5480 Demasculinization and the Herbicide Atrazine Field Study of Rana pipiens Hayes et al. (2003) – Nature 419:895-896 Arrows indicate oocytes within testes White = 0 or no data Gray = <0.4 Kg/Km 2

30 Deformities Pest/Herbicides or Parasites? Missing Limbs Multiple Limbs

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34 Beaver, Willow, and Cattle Grazing in the Big Hole Valley 19422005

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