SPECIES FACT SHEET
Common Name:
Western Pond Turtle
Photo by Chris Brown
Scientific Name: Actinemys marmorata marmorata
Phylum:
Class:
Order:
Family:
(Baird and Girard, 1852)
Craniata
Chelonia
Cryptodeira
Emydidae
The taxonomic status of the western pond turtle is in a state of fluctuation. First
classified as Emys marmorata by Baird and Girard when, in 1841, they collected the first
specimen in the vicinity of Puget Sound (Baird and Girard 1852). Strauch (1862)
changed the genus to Clemmys based on examination of 158 specimens. In 1945, the
two subspecies; northwestern pond turtle (Clemmys marmorata marmorata) and
southwestern pond turtle (Clemmys marmorata pallida) were formally recognized (Seeliger
1945). In 2001, a new arrangement for the genus Clemmys was published by Holman
and Fritz (2001), placing it into the monotypic genus Actinemys. But in 2002, Feldman
and Parham (2002) placed it back to its earliest genus Emys because they did not
recognize Actinemys as a monotypic genus. In 2003, the Society for the Study of
Amphibians and Reptiles used Actinemys and Pacific pond turtle (Crother et al. 2008).
Recent genetic studies indicate the presence of four groups or clades within the species
(Bury and Germano 2008).
OR/WA BLM and FS Region 6 Units where Documented:
Both the Forest Service and BLM have listed the pond turtle as a Sensitive Species in
Oregon and Washington.
This species has been documented occurring on six National Forests/Scenic Areas (CRG,
FWI, RRS, SIU, UMP, WIL) and six BLM districts in Oregon (CB, EU, KF, LV, MD, RO).
Natural Heritage Program Rank and Status:
 Oregon State Rank: S2; imperiled in Oregon.
 Washington State Rank: S1; critically imperiled.
 National Rank: N3;
 Global Rank: G3G4T3Q.
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State Status:
 Oregon State Status: SC; sensitive critical.
 Washington State Status: E; endangered. In danger of becoming extinct or
extirpated from Washington.
Federal Status1:
 SOC2; species of concern; appears to be in jeopardy, but insufficient information to
support listing.
Figure 1. NatureServe (2007) map of the conservation status of the western pond turtle in the United States and Canada.
A species is not shown in a jurisdiction if it is not known to breed in the jurisdiction or if it occurs only accidentally or
casually in the jurisdiction. Thus, the species may occur in a jurisdiction as a seasonal non-breeding resident or as a
migratory transient but this will not be indicated on this map.
Technical Description:
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It was petitioned in 1992 for federal listing, but in 1993 USFWS found that listing was not warranted.
Species of Concern: Taxa whose conservation status is of concern to the U.S. Fish and Wildlife Service (many previously known
as Category 2 candidates), but for which further information is still needed. Such species receive no legal protection and use of the
term does not necessarily imply that a species will eventually be proposed for listing.
(http://www.fws.gov/oregonfwo/Species/Lists/default.asp)
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Although described as an aquatic turtle found in streams, ponds, lakes, and ephemeral
wetlands, the pond turtle spends a large amount of time away from water. Even though
pond turtles spend much of their lives in water they require terrestrial habitats for
nesting. They also often overwinter on land, disperse via overland routes, and may
spend part of the warmest months in aestivation on land (Hays et al 1999). Individuals
in one study spent seven months of the year at overwintering sites in Northern California
(Reese and Welsh 1997).
The western pond turtle is a moderate-sized turtle with a relatively low carapace (Lovich).
It reaches a maximum length of 18-24 centimeters and its weight may exceed 1200
grams (Holland 1994, NatureServe 2007; Lubcke and Wilson 2007). Turtles become
sexually mature at a carapace length (CL) of about 120 mm (Nussbaum et al. 1983).
Maximum size varies geographically, with the largest animals (210 mm) occurring in the
northern part of the range (Hays et al. 1999). Their color and markings vary
geographically and sexually (Holland 1994). They are usually dark brown to olive
dorsally, or blackish with darker reticulations. There is usually a pattern of dark
radiating spots or lines on each scute. The plastron is yellowish, often with dark
blotching in the center of the plasteral shields (Storm et al. 1995). The top of the head
has black spots or lines (NatureServe 2007).
The western pond turtle displays sexual dimorphism at maturity. Holland (1994) found
over 10 significantly different sexually dimorphic characteristics that allow the gender of
adults to be distinguished. The degree of dimorphism is variable for each character and
each individual. No single characteristic is 100% reliable, so it is best to look at several
characters per individual for gender determination.
Adult






males tend to have:
flatter carapace
concave plastron posteriorly
thicker tail base
the cloacal opening at or beyond the margin of the carapace
larger head with a longer nose and pointier snout
larger neck with yellow or whitish chin and throat
Adult






females tend to have:
higher, domed carapace
flatter plastron
thinner tail base with the cloacal opening at or within the margin of the carapace
blunt snout
mustache-like markings on the upper jaw
dark markings on the chin and throat
Juveniles
 Juveniles (< 120 m CL) of both sexes tend to resemble females.
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Hatchlings
 measure 25 - 31 mm CL
 weigh 3 - 7 grams at the time of emergence from the nest
 tend to be a lighter brown, darkening with age
 shell is soft and pliable
 tail is relatively long
In general, the female has a smaller head, less heavily angled snout, relatively higher and
rounder carapace, and a thinner tail. Males have a slightly concave plastron.
Life History:
The western pond turtle is one of only two native west coast aquatic turtles (the other
being the western painted turtle (Chrysemys picta belli) and is one of only a few North
American aquatic turtle species that has populations that routinely overwinter on land
(Ultsch 2006). They live at least four decades and are most active when water
temperatures are above 15ºC (Bury and Germano 2008).
Females may reproduce at about 4-6 years of age in the southern and 7-10 years in the
northern portions of their range (Bury 1979, Holland 1993). The time required for males
to achieve sexual maturity is not known, but is thought to be at least 10-12 years in
Washington (Hays et al. 1999). Mating takes place underwater and may occur in early
spring (Reese 1996) or April-May in central coastal California (Rathbun et al. 1992). In
general, courtship and mating behavior have been observed from February to November
(Holland 1988). Possible courtship behavior reported by Holland (1988) describes an
interaction between a male and a female turtle in late August that involved scratching of
the anterior edge the female’s carapace by the male’s fore limbs, followed by the female
raising her posterior end up off the substrate. Copulation has been observed in the field
in mid-June in Southern California and in captive specimens in late August and early
September (Holland 1998). Adult females of several turtle species can store sperm for
months or years (Galbraith 1993, Gist and Jones 1989).
Most mature females oviposit every year, and some may “double-clutch” (Holland 1994,
Goodman 1997, Reese 1996). Clutch sizes range from 3-13, with most clutches
containing 4-7 eggs (Holland 1994). Eggs are deposited from April to August, depending
on the location, and probably peaks in June-July throughout most of the range
(NatureServe 2007).
Oviposition occurs on land, usually above the flood plain, from 1-50 meters from water’s
edge (Holland 1994) although some females have moved as far as 402 meters from water
and up to 90 meters in elevation above it (Storer 1930; Rathbun et al. 1992). For
nesting, gravid (with eggs) females tend to seek out open areas with sparse, low
vegetation (annual grasses and herbs), low slope angle, and dry hard soil. After voiding
her bladder to soften the soil, the female excavates a pear-shaped nest chamber (scrape)
with her hind feet. Females may have many “false scrapes.” Eggs are deposited and the
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nest chamber is plugged by kneading wet soil and vegetative fragments into the throat of
the nest chamber (Holland 1994, Reese 1996). Nest site philopatry (the tendency of an
animal to return to a specific location in order to breed) has been observed in several
species of turtles and there is some evidence to suggest nest site philopatry is exhibited
by this species (Holland 1994).
Eggs are hard shelled and oval in shape, measuring 31-38 mm long by 20-24 mm wide
and weighing 8-10 g (Holland 1994). Incubation takes about three months and hatching
rates are about 70% (Holland 1994). Upon hatching, hatchlings have an umbilical yolk
sac, which provides nourishment in the early stages of growth (Holland 1991, Voight
1963). Hatchlings either emerge in the fall or overwinter in the nest chamber and emerge
in the spring (Holland 1994, Reese 1996). Hatchlings over-wintering in the nest chamber
receive nourishment from their umbilical yolk sack (Holland 1994, Voight 1963).
Variable growth rates are seen in this species. Growth rates are highest in hatchlings,
which can almost double in size by the end of the first growing season (Holland 1991).
Growth rates may be regulated by environmental factors, such as water temperature and
prey base (Goodman 1997). Age structure studies often rely on counting annuli on the
plastral scutes (Zug 1991, Germano and Bury 1998). Annuli are the result of alternating
periods of maximum growth and minimum growth; counting annuli is based on the
assumption that one growth ring is added each season (Ashton et al. 1997). Numerous
studies show that growth rings on scutes match age in young turtles (Germano and Bury
1998).
Western pond turtles locate food by sight or smell. Under normal conditions feeding
behavior is solitary (Hays et al. 1997) and foraging apparently does not occur on land
(Rathbun et al. 2002). The pond turtle is considered a dietary generalist (Bury 1986).
They prefer live prey, which they capture by opportunistic foraging tactics, but will also
scavenge carrion and browse on plant material. Prey items are ingested in the water and
it appears this species is unable to swallow in air (Holland 1994). Preferred food items
include aquatic insect larvae, crustaceans, and annelids. On occasion, small vertebrates
(including Rana boylii tadpoles and egg masses) have been found in its diet (Bury 1986;
Holland 1994).
Western pond turtles spend several hours per day basking, and are more abundant in
habitats that have basking sites. Basking has been noted in all months of the year, but
generally increases in frequency through the spring to a peak in early to mid-June
(Holland 1994). Turtles use a variety of sites for basking, such as rocks, mud, downed
logs, branches of near-shore vegetation, and emergent or submerged aquatic vegetation
(Hays et al. 1999). Turtles engage in aquatic basking (Holland 1985a) by concealing
themselves in or under floating vegetation or cover in shallow water.
Overwintering is a period of reduced or no activity, which may include periods of a
hibernation-like state of reduced physiological activity, from mid-October or November to
March or April the following year (Hays et al. 1999). According to Holland (1994), there
is a tendency for turtles from ponds and lakes to hibernate underwater while turtles from
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rivers and streams overwinter on land (possibly to avoid being swept away by winter and
early spring floods). They can overwinter on land up to 500 m from the nearest
watercourse (Reese and Welsh 1997), sometimes changing sites during the season
(Holland 1994, Slavens 1992). When overwintering terrestrially, turtles will burrow in
duff or soil (Ashton et al. 1997) where the duff and leaf or needle litter is 2–20 cm thick
(Holland 1994). Radio-telemetry studies have shown individuals often return to the same
terrestrial overwintering site each fall (Reese 1996, Goodman 1996). Movement to
overwintering sites occurs from September to November, while emergence from terrestrial
overwintering sites occurs from March to June. Occasional overland movements (usually
less than 3 km) occur. Turtles can overwinter in the mud at the bottom of ponds,
sometimes communally. If there is no suitable terrestrial habitat available for
overwintering, then they will not leave the water during winter (Lovich & Meyer 2002). At
one site in Oregon, there were 43 turtles found within one square meter. There is also
some degree of winter activity in aquatic hibernacula; they have moved freely in one lake
in Oregon at temperatures down to 1°C, and basked in air temperatures as low as 6°C
(Holland, 1994).
Most western pond turtles are somewhat sedentary, although they are capable of moving
significant distances and occasionally travel several hundred meters in just a few days
(Bury 1979). Most of their movements occur along river and stream courses (Rathbun et
al. 1992). Reese (1996) found that over the summer months (May-September) juvenile
turtles have an average maximum movement of approximately 84 meters. Their mean
weekly aquatic travel is 19.9 meters. Juveniles sometimes travel back and forth between
low-flow portions of the river and adjacent ponds. Their home range is smaller than
adults and also includes terrestrial components (Reese 1996). Western pond turtles in a
stream environment in northern California had average home ranges of about 1 ha for
adult males, 0.25 ha for adult females, and 0.4 ha for juveniles (Bury 1979).
Considerable overlap in home ranges of individuals of both sexes occurred in this area.
Individuals may occasionally make sporadic long-distance aquatic movements outside
their home range (Holland 1994).
Range, Distribution, and Abundance:
The western pond turtle has an appreciable geographic range, from Washington
(historically British Columbia) to northern Baja California (NatureServe 2007). It
appears to be declining in numbers in parts of its range, particularly in Washington,
northern Oregon, southern California, and Baja. It remains fairly common in the center
of its range from southern Oregon to central California (Bury and Germano 2008).
It is now reduced from most of its range in Washington. Two populations remain in the
Columbia River Gorge. The total number of western pond turtles in Washington was
estimated at only 250-350 individuals in 1999 (Hays et al. 1999). Additional turtles were
believed to still occur in wetlands that have not been surveyed in western Washington
and the Columbia Gorge (Hays et al. 1999). Today, there are an estimated 1,250 wild
turtles in Washington, according to the Woodland Park Zoo in Seattle, Washington, as a
result of an active captive breeding and re-introduction program.
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Figure 2. Approximate historic range of the western pond turtle in Washington (circa 1850) and in North America (figure
from Hays et al. 1999).
Distribution and abundance of the pond turtle have declined as a result of past
commercial exploitation, habitat loss and degradation, introduced species, and disease.
The pond turtle is discontinuously distributed and uncommon in parts of its range.
Isolated populations occur in the Mojave River in California, the lower Columbia River
(two populations in Washington, one in Oregon), the Puget Sound Trough in northern
Washington (rarely observed), and in areas south of the Transverse Ranges in southern
California and adjacent Baja California (NatureServe 2007). An isolated population east
of the Sierra Nevada in extreme western Nevada may be an introduction (Cary 1887),
although this has never been formally examined and a better review of the literature is
needed.
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Figure 3. A compilation of northwestern pond turtle observations in OR and WA from the NRIS, GeoBob and ORHIC
databases (as of the date of this document). Additional observations outside of these databases are not represented here.
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Pond turtle densities range from a few to an estimated 3,700 turtles/ha (this from one
small pond; Holland 1991). Typically, they are found at much lower densities. In
western Oregon, Nussbaum et al. (1983) stated that one oxbow lake of 1.5-2.0 ha
contained an estimated 75 individuals. Another oxbow lake of about the same size
contained an estimated 180 individuals.
There are estimates that population declines may be occurring over 80% of its range
(Holland 1994; Hays et al 1999), but field surveys are lacking. Northern California and
southern Oregon support extensive populations (Ashton et al. 1997), representing over
half the species’ range.
Habitat Associations:
The name "pond" turtle is something of a misnomer, as ponds are relatively scarce
throughout most of the range of this species, and the turtles are more often associated
with rivers and streams (Hays et al 1999). They occur in rivers, streams, lakes, ponds,
reservoirs, stock ponds, and permanent and ephemeral wetland habitats (Bury et al
2001). They are usually rare or absent in reservoirs, impoundments, canals, or other
bodies of water heavily altered by humans (Hays et al. 1999), but there are notable
exceptions. Further research is needed on this topic. They can be found from sea level
up to 1,370m or even at higher elevations in the southern part of their range (Bury et al
2001).
Favorable pond turtle habitat is characterized by deep, slow-flowing pools with
underwater cover and emergent basking sites, warm water, or both (Reese and Welsh
1998). Habitats used by western pond turtles may have a variety of substrates including
solid rock, boulders, cobbles, gravel, sand, mud, decaying vegetation, and combinations
of these. In many areas turtles are found in rocky streams with little or no emergent
vegetation. In other areas they occur in slow-moving streams or backwaters with
abundant emergent vegetation such as cattails or bulrush (Holland 1991). Terrestrial
basking sites include mud banks, rocks, logs, and root wads on the bank and are within
or immediately adjacent to water (Ashton et al. 1997).
Pond turtles nest on sandy banks near water or in fields or sunny spots up to a few
hundred meters from water (Nussbaum et al. 1983, Storer 1930). The nest site has good
exposure to the sun and compact soil (Holland 1994, Reese 1996). Aspect is usually
south or west facing and on a slope of 25 degrees or less (Bury et al 2001). Overwintering can be aquatic or terrestrial (Holland 1994). Terrestrial overwintering site
characteristics are highly variable, but the microsite usually includes a thick duff layer
(Holland 1994).
Aquatic habitats with access to areas of deep slow water with underwater refugia and
emergent basking sites are favored by adult and juvenile turtles. Hatchlings are relatively
poor swimmers and tend to seek areas with slow, shallow, warmer water, often with
emergent vegetation (Ashton et al. 1997). Bodies of water can be classified based on the
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suitability of aquatic habitat. Those habitat quality classifications may be considered
from a range from unsuitable to favorable. Three major habitat features to consider are
(Bury et al. 2001):



Size of water - Large bodies of standing water tend to have low mean temperatures,
and thus generally provide less suitable habitat than smaller bodies of water.
Depth of water - Bodies of water where most of the system has a depth less than 2
meters provide accessible underwater refugia for turtles.
Basking structures – Basking is an important activity and lack of emergent
basking structures can indicate poorer habitat.
Threats:
The greatest single threat to the pond turtle is habitat destruction, alteration and
fragmentation (Ashton et al 1997, NatureServe 2007). Habitat impacts can be caused by
conversion of wetlands to farmland, water diversions and dams, channelization, mining,
logging, and urbanization. Associated with habitat fragmentation is the effect of genetic
isolation, although genetic inbreeding is unproven.
Basking, foraging, nesting, and other behaviors can be significantly limited by human
presence, including foot, bicycle, boat, and motor vehicle traffic (Holland 1991).
Incidental catches by fisherman may account for significant losses in some areas
(Holland 1991). Turtles that don’t die from trauma associated with ingestion of fishing
tackle probably starve to death. Encounters with automobiles may also contribute
significantly to mortality. Turtles are hit by traffic when moving to and from the
watercourse during terrestrial journeys, such as overwintering or nesting movements
(Holland 1991). Hatchlings on their way from the nest to water are also at risk from
vehicular traffic (Holland 1991).
Commercial harvest of pond turtles was extensive in California from at least the 1870’s
to ca. 1930’s. Many turtles were sold in San Francisco markets for human consumption,
probably resulting in significant declines in many populations (Holland 1991; Bettelheim
2005). Commercial harvest of pond turtles is now prohibited in all states where the
species lives. Illegal collection of pond turtles for the pet trade still occur, but at an
undetermined level. Death by gunshot wound is also a significant threat in some areas
(Holland 1991).
Chemical spills pose a threat, especially near highways, railways and industrial areas.
Holland (1994) reports there were several contaminant spills into aquatic habitats
inhabited by this species in Oregon during 1993. One was a diesel oil spill that impacted
50 to 100 turtles, resulting in the death of some animals and physiological complications
in many others. Chemical spills and pollution can kill turtles directly, or indirectly by
removing prey base, degrading habitat quality, and/or increasing the risk of disease
(Holland 1991).
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Raccoon, spotted skunks, coyote, fox, feral and domestic dogs, black bear, river otter,
mink, osprey, bald eagle, bullfrog, and largemouth bass are known to prey on pond
turtles (Holland 1994). In some areas, most of the turtle nests are lost to predation
(Holland 1994). Invasive species such as bullfrogs (Rana catesbeiana) and largemouth
bass (Micropterus salmoides) may eat hatchlings (Holland 1994). As many large
populations of turtles occur in the presence of these predators this is not a universal
threat. Other suspected predators include herons, golden eagle, beaver, and nutria
(Holland 1994). Adult turtles often show scarring on the shell and/or missing limbs,
indicating attempted predation. Holland (1994) found a six-fold greater scarring rate on
females and attributed it to greater exposure to predators during nesting movements.
Hatchlings are especially vulnerable to predators because their shell is soft and they can
be swallowed whole. In many cases only nests that are dug up are observed and so it is
difficult to determine how many nests survive.
Reports on disease epidemics are limited. In 1990, an upper respiratory disease (URD)
outbreak in Washington resulted in losses of up to 40% (Holland 1994), leaving a total
population of fewer than 100 individuals in the wild (Hays et al. 1999). In 1993, a single
pond turtle carcass was found near Eugene, Oregon, exhibiting symptoms of URD. The
method of disease introduction to these populations is unknown, but exotic turtles are
known to have been introduced into Washington and Eugene waters with native western
pond turtles and may have acted as vectors (Holland 1994).
Severe drought can have a significant negative impact on pond turtle populations. The
1987-1992 drought in California reduced southern and central state populations by up
to 85% (Holland 1994). Estivation occurs in response to drought. Pond turtles utilizing
a vernal pool in Napa County, California moved upland and burrowed into leaf litter
when the pond dried up (Reese 1996). Estivation may also occur in response to
unseasonally cold water releases from upstream dams (Goodman 1997).
Pond turtles are not especially strong swimmers and can be washed downstream in high
flows. Over-wintering on land may be an adaptation to escape winter high flows. Turtle
nests may be inundated during floods (Ashton et al 1997).
Loss of lakeside emergent wetland vegetation to grazing and trampling may have made
habitat less suitable for hatchlings and juveniles.
Fire can kill turtles over-wintering on land and hatchlings still in the nest. Fire can also
have adverse effects on the aquatic environment and macroinvertebrate prey base by
increasing siltation (Holland 1991). Successional changes through fire suppression on
native grasslands may have resulted in excessive shade on nesting grounds (Hays et al.
1999).
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Conservation Considerations:
NatureServe (2007) recommends protecting known large3 populations and also suggests
focusing on protection of natural ecosystems, rather than on captive breeding or
translocation. For adequate protection, these areas should include aquatic habitat and
adjacent upland habitat for nesting (NatureServe 2007).
The Washington Department of Fish and Wildlife is actively engaged in management and
recovery efforts for the western pond turtle. These conservation activities are being
conducted in cooperation with the Woodland Park Zoo in Seattle, Washington and the
Oregon Zoo in Portland. This program is called the “Western Pond Turtle Recovery
Project” and is focused on the Puget Sound and Columbia Gorge populations. The
objective of the program is to increase the survival chances of young turtles in the wild
by allowing hatchlings to grow to a size where they are too big to be preyed upon by
bullfrogs. This method has been demonstrated to be effective (Haskell et al. 1996).
Captive juvenile turtles attain the size of a 2-year old wild turtle in a single year. As of
1999, the Zoos had successfully reared and released 187 juvenile western pond turtles
under this head-start program (Hays et al. 1999). Currently, over 1,000 turtles have
been released back into the wild. The recovery objectives for the State of Washington are
to establish at least 5 populations of >200 pond turtles, composed of no more than 70%
adults, which occupy habitat that is secure from development or major disturbances. It
is also necessary that the populations show evidence of being sustained by natural
recruitment of juveniles. The core pond turtle sites should be wetland complexes that
may be less susceptible to catastrophes than sites of a single water body (Hays et al
1999).
The majority of the populations on National Forests or BLM Districts in Oregon and
Washington occur within “Riparian Reserves”, a land management classification under
the Northwest Forest Plan Standards and Guidelines (USDA and USDI 1994). Riparian
reserves are designed to provide protection to riparian and aquatic systems and the
species associated with those systems. Riparian reserve widths are generally determined
by whether the water body is fish-bearing or not as well as the potential for tree growth
within the area. However, Aquatic Conservation Strategy Objectives also encourage
riparian widths to be designed to “maintain and restore habitat to support welldistributed populations of native plant, invertebrate, and vertebrate riparian-dependent
species”. Where populations of pond turtles are present on FS and BLM managed lands,
consider increasing riparian reserve widths to encompass known or potential
overwintering habitat if monitoring indicates that not doing so would put these
populations at risk.
Consider protection of pond turtle nesting habitat in areas of high human use such as
recreation or fishing sites. Turtle habitat adjacent to camping or fishing areas can be
fenced and signed to reduce impacts from disturbance. Trails that impact turtle habitat
can be relocated to avoid these sensitive areas. Interpretive signing in high use areas
can also be considered.
3
Large is not defined nor are locations specified
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Protect known turtle areas from prescribed fire to reduce mortality to overwintering
adults and hatchlings still in the nest. In areas of pond turtle habitat, conduct burning
after turtles have returned to ponds or streams.
Where feasible, eradicate invasive species such as bullfrogs and bass to reduce juvenile
mortality.
Development of a “site management plan” may be considered where threats to the
site/population may be numerous or complex. The format for the Site Management Plan
can be found at:
http://www.fs.fed.us/r6/sfpnw/issssp/documents/planning-docs/cp-smp-format-200704.doc
Other pertinent information (references to Survey Protocols, etc):
See Bury et al 2001 for Survey Protocol (57 pages).
Bury, R.B., C. Barkhurst, R. Horn, L. Todd, S. Wray, R. Goggans, K. Beal, N. Sisk.
February 2001. Western Pond Turtle: Survey Protocol and Monitoring Plan. Interagency
Western Pond Turtle Working Group. Final Draft.
ATTACHMENTS:
Appendix 1. Key To Sexually Dimorphic Characters In The Western Pond Turtle
(Clemmys marmorata) (Holland 1994).
Preparer:
Theresa Stone, Umpqua National Forest, Roseburg, OR
Date Completed:
5 October 2007
Updated:
May 2009
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References:
Ashton, D.T., A.J. Lind, and K.E. Schlick. 1997. Western Pond Turtle (Clemmys
marmorata) Natural History. USDA Forest Service, Pacific Southwest Research
Station, Redwood Sciences Laboratory, Arcata CA. 22 pp.
Bettelheim, Matthew P. 2005. Marmorata: The Famed Mud Turtle of the San Francisco
Market. California History. 82(4): pp 26-42.
Bury, R. B. 1972. The effects of diesel fuel on a stream fauna. California Department of
Fish & Game Bull. 58:291-295.
Bury, R. B. 1979. Population ecology of freshwater turtles. Pages 571-602 in M. Harless
and H. Morlock, editors. Turtles: perspectives and research. John Wiley & Sons,
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Herpetology, Vol. 20, No. 4, pp.515-521.
Bury, R. B., C. Barkhurst, R. Horn, L. Todd, S. Wray, R. Goggans, K. Beal, N. Sisk.
February 2001. Western Pond Turtle: Survey Protocol and Monitoring Plan.
Interagency Western Pond Turtle Working Group. Final Draft.
Bury, R. B., and D. J. Germano. 1998. Annual deposition of scute rings in the western
pond turtle, Clemmys marmorata. Chelonian Conservation and Biology 3:108-109.
Bury, R. B. and D. J. Germano. 2008. Actinemys marmorata (Baird and Girard 1852) –
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P. van Dijk, R. A. Saumure, K. A. Buhlmann, and J. B. Iverson (eds.). Conservation
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Monographs No. 5, pp. 001.1-001.9.
Cary WM (1887) Biennial report of the fish commissioner of the State of Nevada.
Appendix to the journals of Senate Assembly 14th session, 1889, GPD 24-A5, 4:
889.
Crother, B.I., et al. (Committee on Standard English and Scientific Names). 2008.
Scientific and standard English names of amphibians and reptiles of North
America north of Mexico. Society for the Study of Amphibians and Reptiles,
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Appendix 1. Key To Sexually Dimorphic Characters In The Western Pond Turtle (Clemmys Marmorata)
(Holland 1994).
CHARACTER
a. neck
FEMALE
lateral and dorsal surfaces of
head and neck usually mottled
or ocellate
MALE
lateral and dorsal surfaces of
head and neck often uniformly
colored, especially in older
animals
b. nose
nose relatively short
nose relatively long
c. maxilla
maxilla often with fine dark
vertical lines or “mustache”
maxilla lightly marked or
unmarked, especially in older
animals
d. snout
angle of nose vertical or
nearly vertical
angle of nose usually
10-15 from vertical
e. throat
often flecked with numerous
small dark flecks
usually lightly marked or
unmarked
f. vent
usually at or slightly posterior
to posterior edge of carapace
usually well posterior to
posterior edge of carapace
g. tail
usually relatively long and
thin
usually relatively short and
thick
h. plastron
area of femoral/anal seam
junction usually flat
area of femoral/anal seam
junction usually slightly
concave
i. shell
shell relatively high/deep in
relation to length of carapace
shell relatively low/shallow in
relation to length of carapace
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