California Tiger Salamander Workshop 4/23/2015 Presentation Workshop Topics California Tiger Salamander 1) Tiger salamander evolution – how is CTS unique Biology and Conservation 2) Range and habitat basics 3) Causes of decline; future threats 4) CTS life cycle and identification of different stages 5) Life history, demography, and population dynamics 6) Predators and prey 7) Habitats and ecology 8) Movements, populations, metapopulations, and landscapes 9) Strategies for avoidance, minimization, conservation and Pete Trenham & Chris Searcy recovery [email protected] & 10) Survey methods, requirements, and strategies [email protected] Key Facts for Understanding CTS What is a CTS • Amphibian • Breed in ponds – develop as aquatic larvae – aquatic eggs, thin scale- – ponds must hold water until at least May less skin • Larger ponds are better (but not permanent ponds) • Salamander • The CTS is primarily a terrestrial beast – four legs and a tail – lives mainly in small mammal burrows • Mole salamander – observed to move >1.5 km overland – Family Ambystomatidae • Large areas of contiguous or interconnected habitat • Tiger salamander is what’s needed for its conservation – large terrestrial salamanders and the only – CTS coexist with certain human land uses group to occupy grasslands – Habitat loss (and hybridization) are main threats • Ambystoma californiense Pattern and Head Shape Differ CTS larvae are smaller and are not From Ambystoma tigrinum known to become sexually mature CTS larvae (paedomorphs) A. mavortium A. tigrinum Shaffer and McKnight 1996 CTS Pete Trenham and Chris Searcy, presenters Elkhorn Slough Coastal Training, sponsor 1 California Tiger Salamander Workshop 4/23/2015 Presentation CTS is Genetically Different CTS Distribution (est. 3-5 million years independent evolution) • extremely broad range – to 3900 ft in Coast Range – to 1200 ft in Sierra foothills • habitat/climate differs 9 to 38 in rainfall • often generalizing based on studies Shaffer and McKnight 1996 from a few sites Focal populations Climatic factors significantly correlated with recruitment 2 Jepson Prairie Bioclim variable Sign R Preserve: Annual precipitation + 0.53 9 years of data (2005-2013) Precipitation wettest quarter + 0.33 Minimum temperature of coldest + 0.28 month Hastings Natural History Reservation: Mean diurnal range - 0.28 6 years of data (1992-1997) Precipitation wettest month + 0.27 Precipitation coldest quarter + 0.22 Searcy, C. A. & H. B. Shaffer. In revision. The American Naturalist. Concordance with factors Concordance with factors governing spatial distribution governing spatial distribution 2 2 R = 0.72 R = 0.72 Annual precipitation P < 0.001 P < 0.001 Precipitation of wettest quarter Mean diurnal range Minimum temperature of coldest month Pete Trenham and Chris Searcy, presenters Elkhorn Slough Coastal Training, sponsor 2 California Tiger Salamander Workshop 4/23/2015 Presentation CTS Genetics Habitat Basics • Aquatic Habitat • Upland Habitat Six Genetic Groups – Ponds* – Grassland* – Vernal Pools* – Oak savanna* Sonoma – Ditches – Oak woodlands Central Valley – Sometimes chaparral and Bay Area shrublands Southern San Joaquin Central Coast Range Santa Barbara Basic Life Cycle and Morphology CTS Life Cycle Rainy Adult Embryos season Pond Pond fills dries Metamorphs Eggs Larvae emerge from pond Young-of-year Travelling Juveniles between burrows If pond dries before Immigrating In Emigrating metamorphosis to pond pond from pond occurs, all Females larvae from that year die Immigrating In Emigrating to pond pond from pond Males Jun. Jul. Oct. Nov. Jan. Feb. Mar. Apr. May Aug. Sep. Dec. Juvenile/Metamorph Larva F-Endangered S-Threatened Causes of Decline F-Threatened • #1 – Habitat Conversion S-Threatened • CTS Occur On Few – of wetlands and uplands Currently Protected – to agriculture, residential and Lands urban uses • #2 – Introduced Species *From: CDFG F-Endangered *From: CDFG 2009 Status S-Threatened 2009 Status Evaluation Evaluation Pete Trenham and Chris Searcy, presenters Elkhorn Slough Coastal Training, sponsor 3 California Tiger Salamander Workshop 4/23/2015 Presentation Cause of Decline Introductory Main Points *#2 - Hybrids* • initial introduction • CTS habitat and range – South of Salinas – Breed in ponds – 1940’s – Upland habitat with grasslands Salinas • discovered late – From Sonoma Co. to Santa Barbara Co., in areas with appropriate climate 1990’s • Annual cycle driven by rainfall and pond • situation evolving drying • Key threats/reasons for listing – Habitat loss – Hybridization Embryo Identification/Morphology • 2-3mm diameter • whitish to grey to yellow • w/jelly 4.5-10mm A B • attached to vegetation Joseph DiDonato or other materials • singly or small clusters • grape-like (each in its C own separate membrane) • Detectable mainly E Dec-Feb Shirley Tudor D Larvae - Identification/Morphology A • Fish-like • Feathery external gills B • Four legs • 30 to 150 mm D – 1 to 6 inches • Color variable C • No stripes or real pattern E • Potentially detectable year-round (mainly March-June) F Pete Trenham and Chris Searcy, presenters Elkhorn Slough Coastal Training, sponsor 4 California Tiger Salamander Workshop 4/23/2015 Presentation Adult Identification/Morphology Sexing Adults • 6-10 inches long • NO nasolabial • Males have groove longer tail and a swollen vent • black to light brown backgound • Females appear • white to light yellow fat when they are rounded spots gravid with eggs – size/amount of spots • Both sexes have varies a laterally • toes pointed compressed tail – NOT squared Immature Age Classes • Metamorphs – At metamorphosis B – Muddy color A patterns – Remnant gill stubs – 100-150 mm long • 4 – 6 inches C – Fat D • Juveniles (after 1st summer) E – Resemble adults, but smaller F Hybrids Identification – Main Points • Genetic test needed for conclusive ID • Embryos are distinctive and detectable – Adults with barring are suspicious – Single embryos alone or in clumps – Giant larvae are suspect also (CTS larvae • Larvae are easily differentiated from newt usually <6” total length) larvae by larger size and no eye stripe • Metamorphs have muddy/blotchy color – Often with remnants of gills/fins • Juveniles and adults – Black/brown ground with cream/yellow spots – Lack nasolabial groove, pointed toe tips • Hybrid/Natives? – Genetic test required for conclusive ID – Large size and odd color patterns suggest hybrid Pete Trenham and Chris Searcy, presenters Elkhorn Slough Coastal Training, sponsor 5 California Tiger Salamander Workshop 4/23/2015 Presentation Timing of Captures: Adults At Ponds Group Exercise 1 - Identification • In a group of 3-4 discuss the different at pond at pond stages of A. californiense and how you would identify them. • What other amphibians might you encounter and how are they different from Trenham et al. 2000 (Monterey Co.) A. californiense? Cook et al. 2006 (Sonoma Co.) Activity differs by region! Largely driven by rainfall. Adult/juvenile movement period Adult/juvenile movement period Year Start End Year Start End 05-06 29-Nov 27-Feb 05-06 29-Nov 27-Feb 06-07 14-Nov 22-Feb 06-07 14-Nov 22-Feb Positively Positively 07-08 11-Nov 20-Feb 07-08 11-Nov 20-Feb correlated with correlated with 08-09 2-Nov 2-Mar 08-09 2-Nov 2-Mar Nov. rainfall, date at which negatively annual 09-10 14-Oct 24-Feb 09-10 14-Oct 24-Feb correlated with precipitation Feb. rainfall reaches 0.56 in. 10-11 24-Oct 2-Mar 10-11 24-Oct 2-Mar (Jepson Data) (Jepson Data) 11-12 11-Oct 15-Mar 11-12 11-Oct 15-Mar 12-13 17-Nov 20-Mar 12-13 17-Nov 20-Mar Overall 30-Oct 28-Feb Overall 30-Oct 28-Feb Timing Adult Immigration Timing Adult Immigration 0.04 0.03 P = 0.03 /day) 2 ft 0.02 R = 0.73 0.01 0 10-Jun 18-Sep 27-Dec 6-Apr 15-Jul 23-Oct -0.01 Average change in depth in depth ( change Average -0.02 -0.03 Immigration Period Pete Trenham and Chris Searcy, presenters Elkhorn Slough Coastal Training, sponsor 6 California Tiger Salamander Workshop 4/23/2015 Presentation Weather Patterns Adult/Juvenile Activity Movement 1) Even during seasonal activity periods, Year Days CTS are active in the terrestrial 05-06 21 environment on a small fraction of the 06-07 16 days. Out of a ~140 day activity season, 07-08 18 only 15 days (11% 08-09 6 of days) have 2) Daily activity is driven by weather 95% of the 09-10 11 movement patterns. 10-11 23 11-12 14 12-13 13 Average 15.25 Correlations Metamorph emergence period • Movement days are correlated with: Year Start End – Precipitation 04-05 19-May 20-Jun – High minimum temperature 05-06 30-May 10-Jul – Wind speed 07-08 14-May 20-May Positively 08-09 23-May 10-Jun – Humidity correlated with Mar. rainfall 09-10 21-May 26-Jun (Jepson Data) • However, amongst nights when rain is 10-11 2-Jun 30-Jun predicted (~32 per year), there is no clear 11-12 1-Jun 19-Jun rule for when CTS will be active 12-13 7-May 18-May Overall 17-May 3-Jul Metamorph emergence period Dates of Metamorph Capture Monterey Co. (1992-1997) Contra Costa Co. (1992-1993) Year Start End 04-05 19-May 20-Jun 05-06 30-May 10-Jul 07-08 14-May 20-May Positively 08-09 23-May 10-Jun correlated with drying date of 09-10 21-May 26-Jun breeding pond (Jepson Data) 10-11 2-Jun 30-Jun 11-12 1-Jun 19-Jun 12-13 7-May 18-May Overall 17-May 3-Jul Trenham et al. 2000 Loredo and Van Vuren 1996 Pete Trenham and Chris Searcy, presenters Elkhorn Slough Coastal Training, sponsor 7 California Tiger Salamander Workshop 4/23/2015 Presentation Conclusions – To Avoid Migrating Salamanders Avoid activities that will impede salamander movement in the terrestrial environment: - after the first ~0.5 inches of rain in the fall until mid-March - from mid-May until the breeding ponds are dry Breeding pond occupancy-larvae Breeding pond occupancy - larvae Year Start End Year Start End 05-06 2-Dec 5-Jul 05-06 2-Dec 5-Jul 06-07 14-Nov 25-Feb 06-07 14-Nov 25-Feb 07-08 11-Nov 17-May 07-08 11-Nov 17-May Positively Positively correlated with first 08-09 2-Nov 9-Jun 08-09 2-Nov 9-Jun correlated with 0.82 in.