Geoscience Reference
In-Depth Information
aspects.of.climate.vulnerability.that.were.not.addressed,.including.susceptibility.
to.changes.in.phenology,.disease.dynamics,.upland.habitat,.invasive.species,.and.
more.detailed.changes.in.hydrology.
p
henology
One. direct. approach. for. assessing. whether. amphibians. have. been. affected. by. cli-
mate.change.comes.from.studies.of.amphibian.breeding.phenology.(Table 2.1)..Some.
examples.are.provided.in.the.following.
Beebee.(1995),.plotting.the.start.of.breeding.activities.for.six.amphibian.species.
in.southern.England.over.16.years,.suggested.that.amphibians.in.temperate.countries.
may.be.responding.to.climate.change.by.breeding.earlier..Furthermore,.he.found.that.
the.breeding.dates.of.two.species.of.April-June.breeding.anurans.were.negatively.
correlated.with.average.minimum.temperatures.in.March.and.April.and.maximum.
temperatures. in. March.. The. spawning. date. of. one. early-breeding. anuran. species.
whose. breeding. date. did. not. change. from. 1978. to. 1994. was. negatively. correlated.
with. overall. winter. maximum. temperatures. since. 1978.. An. analysis. of. the. most.
abundant.newt.species.showed.a.strong.negative.correlation.of.when.they.arrive.at.
the.pond.and.average.maximum.temperature.in.the.month.before.arrival.
Scott.et.al..(2008).observed.the.common.frog.(
Rana temporaria
).at.various.sites.
in.the.United.Kingdom.for.5-11.years.since.1999..They.found.that.common.frogs.
were.congregating.earlier.and.spawning.earlier.but.hatching.was.not.occurring.ear-
lier..The.observed.changes.were.strongly.correlated.with.temperature.
Chadwick. et. al.. (2006).examined. the. breeding. phenology. of. two. newt. species,.
Triturus helveticus
and.
Triturus vulgaris
,
in.Wales.from.1981.to.1987.and.from.1997.
to.2005..Spring.temperatures.over.this.period.explained.up.to.74%.of.among-year.
variability.in.median.arrival.date,.with.a.signiicant.advance.of.2-5.days.with.every.
degree. centigrade. increase.. Males. of. both. species. displayed. greater. changes. than.
females..Moreover,.changes.were.greater.for.
T. helveticus
.compared.with.
T. vulgaris
within. the. sexes.. Thus,. climate. change. may. have. differential. effects. on. sexes. and.
between.species.
Not. all. amphibians. in. Europe. appear. to. be. responding. to. climate. change. in.
the. same. fashion. as. those. described. above. (Table 2.1).. Reading's. (1998). study. of.
the.common.toad.(
Bufo bufo
).in.England.from.1980.to.1998.showed.that.the.main.
arrival. to. breeding. sites. was. highly. correlated. with. the. mean. daily. temperatures.
over. the. 40. days. immediately. preceding. the. main. arrival.. However,. a. signiicant.
trend. toward. earlier. breeding. in. recent. years. compared. with. previous. years. was.
not.found.
Gibbs.and.Breisch.(2001).showed.that.over.the.last.century,.daily.temperatures.
increased.near.Ithaca,.New.York,.and.several.species.of.anurans.have.shifted.their.
breeding. patterns. accordingly. (Table 2.1).. Consequently,. four. species. of. anurans.
irst(?).vocalized.10-13.days.earlier,.two.were.unchanged,.and.none.called.later.dur-
ing.1990-1999.compared.with.calling.dates.between.1900.and.1912.
In. Oregon,. at. one. site. there. was. a. nonsigniicant. trend. for. western. toads. (
Bufo
[=
Anaxyrus
]
boreas
).to.breed.earlier,.and.this.was.associated.with.increasing.mean.
maximum. daily. temperature. (Blaustein. et. al.. 2001b).. However,. at. four. other. sites.
