WEB
n
5
4
Burning fossil fuels
3
Increase of greenhouse gases
2
Climate change (El nino patterns)
This is an envirogram (Andrewartha and Birch 1984) for the
Yosemite toad (Bufo canorus). It depicts documented and
suspected ecological relationships between the species and
biotic and abiotic aspects of its environment. These
relationships are represented as being direct (in the
centrum) or indirect in the outer webs.
CENTRUM
1
Rain: summer (survival, overwintering)
Resources
Snowpack: winter (survival)
Water: depth 2-4 cm (16)
Acid precipitation (1A)
Length of grazing season
pH <5 neg effect (1A)
Livestock, packstock, deer grazing
eggs
Cover: vegetation & silty substrate (12)
Food: detritus, plant material, lodgepole pine
pollen, other tadpoles, diving beetle larvae
and dead mammals
larvae
Water: warm & shallow (day), deep (night)
40-50 days permanence (4)
Length of fishing season
Angling
Length of winter
Winter kill
Snowpack
Food: beetles, ants, centipedes, spiders, dragonfly
larvae, mosquitos, moth and butterfly larvae, flies,
bees, wasps, millipedes, spider mites, crane flies,
springtails, owl flies, and damsel flies (5, 9A,16, 17)
sub-adults
Rodent control
Mammalian predators
Cattle trampling of burrows
This is considered a draft document and should be cited as
such:
Lind, A..J. and R. L. Grasso. 2005 (draft). Envirogram for
the Yosemite toad (Bufo canorus). USDA Forest Service,
Sierra Nevada Research Center, Davis, CA.
Cover: emergent vegetation
Nonnative trout
West Nile virus
Avian predators
We have linked documented relationships to appropriate
literature as identified by the number in the parentheses
[e.g. (9)] and on the reference list below.
Voles, Belding ground squirrels,
Yellow-Bellied marmots (9)
Cover: rodent burrows (overwintering) (8)
Precipitation (snow & rain)
Water: moist upland habitat for foraging (9, 16)
temporary refuge (logs & rocks) (12)
adults
breeding (wet meadows & slowflowing streams (8)
Hikers
Automobiles
Off-hwy vehicles
snowmobiles
Human disturbance (12)
Temperature
Avian predators
Mates
Cessation
predation traveling to breeding site (9A)
Above avg. snowpack effect on adult survivorship
Mortality from crossing snow/ice
Mammalian predators
Snow thaw (9A)
Attraction: male calling females
Shortage: reduced number of mates
Fecundity: frequency of female mating
Females hiatus (9A)
Distance to breeding site
Bufo canorus
adults
Breeding: factors for successful mating
Predators
Emergence timing (9A)
Maturity (3-5 yr) (9A)
?
eggs
Invertebrate: Predaceous diving beetle (larvae & adult)
drgagonfly larvae (8, 9A, R. Grasso, pers. obs.)
Vertebrate: adult mountain yellow-legged frogs*, larval
long-toed salamanders, American robins^, garter snakes,
cannibalism (17*; 8; 16; 12; 10^)
“The hardihood of the [Yosemite toad] is indicated by the way in
which the adults jubilate in the melting snow water during the spring
and early summer months.”
Grinnell and Storer (1924)
Vertebrate: Garter snakes (9A, 16) Brewer’s
blackbirds (M. Cane, pers. comm.); nonnative trout?
Vertebrate Predators: Clark’s nutcrackers,
Black-billed magpies, common ravens,
California gull, racoons, striped skunks (10)
larvae
sub-adults
adults
Malentities
Fungal infection (9)
Freezing (9A)
eggs
Dessication (9A)
Predation
Competition
larvae
Dessication (9A)
sub-adults
Inability to feed (9)
Premature emergence (9)
Weather exposure (9)
Garter snakes (9)
Nonnative trout (9)
Multiple amplexus
Asphyxiation (9)
Mountain yellow-legged frog
Food competitors (Growth)
Nonnative trout (9)
adults
Exposure to freezing crossing
snow or ice (9A)
Exposure to predators while crossing
snow or ice (9A)
Grazing (4)
Roads & Timber Harvest (4)
Fire suppression (4)
Vegetation control (4)
Recreation (4)
Dams & water diversion (4)
Chytridiomycosis
Red-leg disease
Saprolengia
Overutilization (scientific research)
Disease (4)
Habitat loss (4)
Acid Precipitation (3)
Chemical pollution (3)
Drought (3)
Immunosuppression (10)
Climate change
Envirogram for the Yosemite toad (Bufo canorus)
Synergism (3)
Draft 5/4/05 – A.J. Lind & R. L. Grasso
References in the Envirogram
(1A) Bradford, D.F., C. Swanson, and M.S. Gordon. 1992. Effects of low pH and aluminum on two declining species of
amphibians in the Sierra Nevada, California. Journal of Herpetology 26:369-377.
(3) Drost, C.A. and G.M. Fellers. 1996. Collapse of a regional frog fauna in the Yosemite Area of the California Sierra Nevada,
USA. Conservation Biology 10:414-425.
(4) Federal Register. 2002. 12-month finding for a petition to list the Yosemite toad. Vol 67, No 237:75834-75843.
(5) Grinnell, J. and T.I. Storer. 1924. Animal life in Yosemite. University of California Press, Berkeley, California.
(8) Jennings, M. R. and M. P. Hayes. 1994. Amphibian and Reptile Species of Special Concern in California. A Report to the
California Department of Fish and Game, Rancho Cordova, California. 255 pp.
(9) Kagarise Sherman, C. 1980. A comparison of the natural history and mating system of two anurans: Yosemite Toads (Bufo
canorus) and Black Toads (Bufo exsul). PhD Thesis, University of Michigan No. 8106225:i-394. University Microfilms
International.
(9A) Kagarise Sherman, C. and M. L. Morton. 1984. The toad that stays on its toes. Natural History 93(3):72-78.
(10) Kagarise Sherman, C. and M. L. Morton. 1993. Population declines of Yosemite Toads in the Eastern Sierra Nevada of
California. J. Herpetol. 27(2):186-198.
(12) Karlstrom, E.L. 1962. The toad genus Bufo in the Sierra Nevada of California. University of California Publications in
Zoology 62: 1-104.
(16) Martin, D. L. , In Prep and Personal Communication. Bufo canorus, the Yosemite toad. PhD. Dissertation. University of
California, Santa Barbara.
Other References for the Yosemite Toad
Andrewartha, H.G. and L.C. Birch. 1984. The ecological web: more on the distribution and abundance of animals. University of
Chicago Press.
Bradford, D.F., M.S. Gordon, D.F. Johnson, R.D. Andrews, and W.B. Jennings. 1994. Acidic deposition as an unlikely causefor
amphibian population declines in the Sierra Nevada, California. Biological Conservation 69:155-161.
Davidson, C. and G.M. Fellers. In Press. Species account: Bufo canorus. Pp. xx-xx in: M.J. Lannoo, ed. Status and
Conservation of United States Amphibians. Smithsonian Institution Press, Washington, D.C.
Hayes, T.B. 1997. Steriod-mimicking environmental contaminants: their potential role in amphibian declines. Herpetologica
Bonnensis 1997:145-149.
Jennings, M.R. 1996. Status of amphibians. Pp. 921-944 in: Sierra Nevada Ecosystem Project: Final Report to Congress, vol.
II, Assessments and scientific basis for management options. Davis: University of California, Centers for Water and Wildland
Resources.
Karlstrom, E.L. and R.L. Livezy. 1955. The eggs and larvae of the Yosemite toad Bufo canorus Camp. Herpetologica 11:221227.
Karlstrom, E.L. 1973. Bufo canorus Camp, Yosemite Toad. Catalogue of American Amphibians and Reptiles.
Knapp, R.A. 2003. Habitat associations of two declining amphibian species in Yosemite National Park. Final report to U.S.
Forest Service (#43-9AD6-1-3077).
Livezey, R.L. 1955. A northern range extension for Bufo canorus. Herpetologica 11: 212.
Mullally, D. P. 1953. Observations on the ecology of the toad Bufo canorus. Copeia 3: 182-183.
Muths, E. 2003.Home range movements of boreal toads in undisturbed habitat. Copeia, 2003:160-165.
Shaffer, H.B., G.M. Fellers, A. Magee, and S.R. Voss. 2000. The genetics of amphibian declines: population substructure and
molecular differentiation in the Yosemite toad, Bufo canorus, (Anura, Bufonidae) based on single-strand conformation
polymorphism analysis (SSCP) and mitochondrial DNA sequence data. Molecular Ecology 9:245-257.
Zeiner, D.C., W.F. Laudenslayer, Jr., and K.E. Mayer. 1988. California’s Wildlife. Volume I – Amphibians and Reptiles.
California Department of Fish and Game, Sacramento, California. 272 pp.