Ecology of the California Tiger May 2016 Salamander Workshop Workshop Topics California Tiger Salamander 1) How is the CTS different from other tiger salamanders? Biology and Conservation 2) Where does it occur and what limits its distribution? 3) Why has it declined and what are the greatest threats? 4) How to identify the different stages in the CTS life cycle. 5) Life history, demography, and population dynamics. 6) Ecology: habitat attributes, prey, and predators. 7) Movements, metapopulations, and landscapes. 8) Strategies for avoidance, minimization, conservation and recovery Presentation Authors: Pete Trenham & Chris Searcy 9) Survey methods, requirements, and strategies ptrenham@gmail.com Getting your own permit Key Facts for Understanding CTS • Start early! It will likely take a year (or more) • Breed in ponds – develop as aquatic larvae – talk to agency representatives throughout process – ponds must hold water until at least May • Larger ponds are better (but not permanent ponds) • FWS requirements • The CTS is primarily a terrestrial beast – B.S. in biology (or equivalent experience) – live in small mammal burrows – Course work in herpetology (or eq. exp.) – observed to move >1.5 km overland – Study/survey design experience (5surveys/40hrs) • Large areas of contiguous or interconnected habitat – Handling experience (>25, including >5 larve) is what’s needed for its conservation – Familiarity with habitats – CTS coexist with certain human land uses – Familiarity with co-occurring amphibians – Habitat loss (and hybridization) are the main threats – Ability to identify vegetative components of habitat Pattern and Head Shape Differ What is a CTS From Ambystoma tigrinum • Amphibian – aquatic eggs, thin scale- CTS less skin • Salamander – four legs and a tail • Mole salamander – Family Ambystomatidae • Tiger salamander A. tigrinum – large terrestrial salamanders and the only group to occupy grasslands • Ambystoma californiense Shaffer and McKnight 1996 Pete Trenham, presenter 1
Ecology of the California Tiger May 2016 Salamander Workshop CTS is Genetically Different CTS larvae are smaller and are not (est. 3-5 million years independent evolution) known to become sexually mature larvae (paedomorphs) A. mavortium Shaffer and McKnight 1996 CTS Focal populations CTS Distribution • extremely broad Jepson Prairie range Preserve: – to 3900 ft in 9 years of data Coast Range (2005-2013) – to 1200 ft in Sierra foothills Hastings • habitat/climate Natural History differs Reservation: 9 to 38 in rainfall 10 years of data • often generalizing (1992-2001) based on studies from a few sites Climatic factors significantly correlated CTS Genetics with recruitment R 2 Bioclim variable Sign Six Genetic Groups Annual precipitation + 0.53 Sonoma Precipitation wettest quarter + 0.33 Central Valley Minimum temperature of coldest + 0.28 Bay Area month Southern San Joaquin Mean diurnal range - 0.28 Central Coast Range Precipitation wettest month + 0.27 Precipitation coldest quarter + 0.22 Santa Barbara Searcy, C. A. & H. B. Shaffer 2016. The American Naturalist . Pete Trenham, presenter 2
Ecology of the California Tiger May 2016 Salamander Workshop Habitat Basics Agreement between factors associated • Aquatic Habitat • Upland Habitat with recruitment and spatial distribution – Vernal Pools* – Grassland* – Ponds* – Oak savanna* R 2 = 0.72 Annual precipitation – Ditches – Oak woodlands P < 0.001 – Sometimes chaparral and Precipitation of wettest quarter shrublands Mean diurnal range Minimum temperature of coldest month Basic Life Cycle and Morphology CTS Life Cycle Rainy season Adult Embryos Pond fills Pond dries Juveniles Travelling between burrows Young-of-year Immigrating In Emigrating to pond pond from pond Breeding If pond dries Males before metamorphosis Immigrating In Emigrating occurs, larvae Breeding to pond pond from pond from that year Females die Metamorphs Eggs Larvae emerge from pond Nov. Oct. Feb. Mar. Jun. Aug. Sep. Dec. Jan. Apr. May Jul. Larva Juvenile/Metamorph F-Endangered S-Threatened Causes of Decline F-Threatened • #1 – Habitat Conversion • CTS Occur On Few S-Threatened – of wetlands and uplands Currently Protected – to cropland, residential and Lands urban uses • #2 – Introduced Species • #3 – Climate Change? *From: CDFG *From: CDFG F-Endangered 2009 Status 2009 Status S-Threatened Evaluation Evaluation Pete Trenham, presenter 3
Ecology of the California Tiger May 2016 Salamander Workshop Cause of Decline Introductory Main Points *#2 - Hybrids* • CTS habitat and range • initial introduction – Breed in ponds – South of Salinas – Upland habitat with grasslands – 1940’s Salinas – From Sonoma Co. to Santa Barbara Co., in • discovered late areas with appropriate climate 1990’s • Annual cycle driven by rainfall and pond • situation evolving drying • Key threats/reasons for listing – Habitat loss – Hybridization B Embryo Identification/Morphology A • 2-3mm diameter • whitish to grey to yellow • w/jelly 4.5-10mm C • attached to vegetation Joseph DiDonato or other materials • singly or small clusters • grape-like (each in its own separate membrane) D • Detectable mainly F E Dec-Feb Shirley Tudor A Larvae - Identification/Morphology • Fish-like B • Feathery external gills • Four legs D • 30 to 150 mm – 1 to 6 inches C • Color variable • No stripes or real pattern E • Potentially detectable year-round (mainly F March-June) Pete Trenham, presenter 4
Ecology of the California Tiger May 2016 Salamander Workshop Adult Identification/Morphology Sexing Adults • 6-10 inches long • Males have • NO nasolabial longer tail and a groove swollen vent • black to light brown • Females appear backgound fat when they are • white to light yellow gravid with eggs rounded spots – size/amount of spots • Both sexes have varies a laterally compressed tail • toes pointed – NOT squared Immature Age Classes • Metamorphs B – At metamorphosis A – Muddy color patterns – Remnant gill stubs – 100-150 mm long C • 4 – 6 inches D – Fat • Juveniles (after 1 st summer) – Resemble adults, but smaller E F Hybrids Identification – Main Points • Embryos are distinctive and detectable • Genetic test needed for conclusive ID – Single embryos alone or in clumps – Adults with barring are suspicious – 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, presenter 5
Ecology of the California Tiger May 2016 Salamander Workshop 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 in the same ponds? – What species could cause problems? Trenham et al. 2000 (Monterey Co.) Cook et al. 2006 (Sonoma Co.) – In what regions do these species occur? 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 Positively 05-06 29-Nov 27-Feb correlated with 06-07 14-Nov 22-Feb 06-07 14-Nov 22-Feb Positively Nov. rainfall, 07-08 11-Nov 20-Feb 07-08 11-Nov 20-Feb correlated with negatively 08-09 2-Nov 2-Mar 08-09 2-Nov 2-Mar date at which correlated with annual 09-10 14-Oct 24-Feb 09-10 14-Oct 24-Feb Feb. rainfall precipitation 10-11 24-Oct 2-Mar 10-11 24-Oct 2-Mar (Jepson Data) reaches 0.56 in. 11-12 11-Oct 15-Mar 11-12 11-Oct 15-Mar (Jepson Data) 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 Average change in depth (ft/day) 0.03 P = 0.03 R 2 = 0.73 0.02 0.01 0 10-Jun 18-Sep 27-Dec 6-Apr 15-Jul 23-Oct -0.01 -0.02 -0.03 Immigration Period Pete Trenham, presenter 6
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