Prepared in cooperation with the Interagency Special Status / Sensitive Species Program 

(ISSSSP). The ISSSSP is a cooperative program of the Pacific Northwest Regional Office of the 

U.S. Forest Service and Oregon/Washington State Office of the Bureau of Land Management

Short-Term Occupancy and Abundance Dynamics of the 

Oregon Spotted Frog (Rana pretiosa) Across Its Core Range

U.S. Department of the Interior

U.S. Geological Survey

Open-File Report 2014–1230
Cover: Oregon Spotted Frog, Rana pretiosa. Photograph by Brome McCreary, U.S. Geological Survey.
Short-Term Occupancy and Abundance Dynamics 

of the Oregon Spotted Frog (Rana pretiosa) Across 

Its Core Range

By Michael J. Adams, Christopher A. Pearl, Brome McCreary, and Stephanie K. Galvan

Prepared in cooperation with the Interagency Special Status / Sensitive Species Program (ISSSSP). The ISSSSP is 

a cooperative program of the Pacific Northwest Regional Office of the U.S. Forest Service and Oregon/Washington 

State Office of the Bureau of Land Management 

Open-File Report 2014–1230

U.S. Department of the Interior

U.S. Geological Survey
U.S. Department of the Interior

SALLY JEWELL, Secretary

U.S. Geological Survey

Suzette M. Kimball, Acting Director

U.S. Geological Survey, Reston, Virginia: 2014 

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Suggested citation:

Adams, M.J., Pearl, C.A., McCreary, B., and Galvan, S.K., 2014, Short-term occupancy and abundance dynamics

of the Oregon spotted frog (Rana pretiosa) across its core range: U.S. Geological Survey Open-File Report 2014-

1230, 10 p., http://dx.doi.org/10.3133/ofr20141230. 

ISSN 2331-1258 (online)
iii

Contents

Abstract ......................................................................................................................................................................... 1

Introduction.................................................................................................................................................................... 1

Methods......................................................................................................................................................................... 2

Sampling Design........................................................................................................................................................ 2

Field Surveys ............................................................................................................................................................. 2

Analysis ......................................................................................................................................................................... 4

Probability of Occupancy, Colonization, and Local Extinction.................................................................................... 4

Abundance................................................................................................................................................................. 5

Results........................................................................................................................................................................... 5

Discussion ..................................................................................................................................................................... 6

Summary ....................................................................................................................................................................... 7

Acknowledgments ......................................................................................................................................................... 7

References Cited........................................................................................................................................................... 8

Appendix A. Site Names, Cluster Names, Frame Assignments, and Coordinates of Survey Sites ............................... 9

Figure

Figure 1. Map showing locations surveyed for Oregon spotted frogs (Rana pretiosa) in the Deschutes 

and Klamath Basins, Oregon, 2010–13......................................................................................................................... 3

Table

Table 1. Multi-season occupancy models describing the probability that a site was occupied by breeding stages of 

Oregon spotted frog (Rana pretiosa), Deschutes and Klamath Basins, Oregon, 2010–13............................................ 6
iv

Conversion Factors and Datum

Conversion Factors

SI to Inch/Pound

Multiply By To obtain

Length

meter (m) 3.281 foot (ft) 

kilometer (km) 0.6214 mile (mi)

meter (m) 1.094 yard (yd) 

Datum

Horizontal coordinate information is referenced to the North American Datum of 1983 (NAD 83).
1

Short-Term Occupancy and Abundance Dynamics 

of the Oregon Spotted Frog (Rana pretiosa) Across 

Its Core Range

By Michael J. Adams, Christopher A. Pearl, Brome McCreary, and Stephanie K. Galvan

Abstract

The Oregon spotted frog (Rana pretiosa) occupies only a fraction of its original range and is

listed as Threatened under the Endangered Species Act. We surveyed 93 sites in a rotating frame design

(2010–13) in the Klamath and Deschutes Basins, Oregon, which encompass most of the species’ core 

extant range. Oregon spotted frogs are declining in abundance and probability of site occupancy. We did 

not find an association between the probability that Oregon spotted frogs disappear from a site (local 

extinction) and any of the variables hypothesized to affect Oregon spotted frog occupancy. This 4-year 

study provides baseline data, but the 4-year period was too short to draw firm conclusions. Further study 

is essential to understand how habitat changes and management practices relate to the status and trends 

of this species.

Introduction The Oregon spotted frog (Rana pretiosa) is listed as Threatened under the Endangered Species 

Act (U.S. Fish and Wildlife Service, 2014) and Vulnerable on the Red List of Threatened Species 

(International Union for Conservation of Nature, 2013). Our understanding that this species has declined 

is based on its absence from portions of its range (Pearl and Hayes, 2005), but there is a lack of reliable 

information on trends in abundance or on the probability of site occupancy. For example, there is 

currently no information to suggest whether Oregon spotted frogs are still disappearing from occupied 

sites, if they are colonizing new sites, or if their abundance on average is increasing or decreasing. This 

information is essential to a basic understanding of the status and trends of this species. 

The current core extant range of the Oregon spotted frog is from southern British Columbia to 

southern Oregon. Distribution is disjunct in the northern part of the range and the species is thought to 

be absent from the Willamette Valley (Jones and others, 2005). The core extant range is mostly in the 

Deschutes and Klamath Basins of Oregon, with a few additional sites occupied near the headwaters of 

the Willamette and McKenzie Rivers just west of the divide from the Deschutes Basin drainage (Pearl 

and others, 2009) and in the northern Oregon Cascades. Hypothesized threats to Oregon spotted frog 

persistence are invasive species, disease, habitat changes, population isolation, and climate change. 

Habitat changes may result from changes in beaver (Castor canadensis) activity, management practices 

that enable encroachment of woody vegetation on historically open wetlands, fire and fuels 

management, or hydrological manipulations (Pearl and Hayes, 2005). We emphasize that there is little 

empirical support for any of these hypotheses and, although the species is clearly absent from portions 

of its historical range, there is little information on current trends.
2

We are addressing three objectives for the core extant range of the Oregon spotted frog: (1) to 

estimate site-level probability of occupancy, colonization, and extinction rates; (2) to estimate the 

overall trend in abundance; and (3) to determine the correlation of site characteristics related to habitat 

succession and disturbance with the probability of local extinction. These objectives are fundamental to 

understanding the status and trends of Oregon spotted frogs, but will take many years of data to 

convincingly assess. Here, we report an analysis of the first 4 years of data from this effort.

Methods

Sampling Design

We used a 4-year rotating frame design to sample lentic habitats in the core range of the Oregon 

spotted frog (fig. 1). Lentic habitats, hereafter “sites,” were ponds, lakes, wetlands, oxbows, and 

sloughs. The core range was defined as all known occupied sites in Oregon at the initiation of this study 

plus most known historical sites plus lentic habitats in close proximity to current and historical sites 

(appendix 1). Exceptions were (1) the Willamette Valley where Oregon spotted frogs have not been 

seen in decades, (2) nine sites where intensive population monitoring was already occurring, and (3) 

three sites that were too large to survey. Our rotating frame design consisted of one fixed frame sampled 

each year and four rotating frames sampled once each during the 4-year study (appendix 1; fig. 1). This 

definition of the sampling frame resulted in 93 sites. All 93 sites were grouped into spatial clusters for 

ease of sampling. Clusters were all randomly assigned to frames. Each site was surveyed for the 

presence of Oregon spotted frog one to three times in any year that it was part of the sample (appendix 

1). Survey frequency was randomly assigned to sites. Our aim was to survey 50 percent of sites two 

times and 25 percent of sites three times. When possible, additional surveys were completed in a 

random order. 

Field Surveys

A survey consisted of two technicians searching all portions of a site with water less than 1 m 

deep for Oregon spotted frogs. Crews recorded air temperature at start, midway, and conclusion of 

surveys. Technicians searched by slowly walking the perimeter of the site, visually searching for 

amphibians of any stage, and completing a minimum of five dip-net sweeps at least 10 m apart in 

microhabitats that could conceal amphibians. Surveys were conducted between 08:00 and 20:00 hours 

from early June to mid-August from 2010 through 2013. 

Habitat variables were recorded during each survey. Between 5 and 15 plots were spread evenly 

around the perimeter of each site and were used to assess shading and vegetation. “Shade” was the 

average height (in degrees) of vegetation or the horizon affecting the plot. It was measured using a 

clinometer aimed at the compass bearings of 170, 180, and 190 degrees. “Veg” was the average 

percentage of a transect that had visible emergent, submergent, or floating vegetation. Transects ran 

perpendicular to shore from each plot to the other side of the site. 

“Beaver” was coded as “1” if a site was influenced by beaver activities and was otherwise coded 

“0.” We considered a site beaver-influenced if any beaver sign was recorded, including old and inactive 

dams. We used “deep” = 1 if the maximum depth of a site appeared greater than 2 m; otherwise “deep” 

= 0. We obtained elevation (“elev”) from a Digital Elevation Model. We classified “basin” for each site 

based on whether it was located in the Deschutes or Klamath hydrographic basins. We combined the 

three Willamette Basin sites with the Deschutes Basin sites because they were few and were near the 

divide between basins. 
3

Figure 1. Map showing locations surveyed for Oregon spotted frogs (Rana pretiosa) in the Deschutes and 

Klamath Basins, Oregon, 2010–13.
4

Analysis

Probability of Occupancy, Colonization, and Local Extinction

For this analysis, occupied sites were those that had eggs, larvae, or metamorphic stages of 

Oregon spotted frogs. We used the function “colext” from the package “unmarked” (v. 0.10-2) in R (v. 

3.0.2) to estimate site-level probabilities for initial occupancy, colonization, and local extinction while 

accounting for the fact that surveys will sometimes fail to detect Oregon spotted frogs when they are 

present and that the probability of detecting frogs that are present (p) is likely to vary (Fiske and 

Chandler, 2011; R Core Team, 2013). The function “colext” fits the multi-season occupancy model of 

MacKenzie and others (2003). We used this model to investigate how the probability of local extinction 

(ε) related to site characteristics and to derive estimates of ψ, the probability that a site is occupied. 

Because we only had 4 years of data and because those data included rotating frames, we expected that 

it would be difficult to estimate the transition probabilities. We therefore used a simplifying assumption 

that colonization (γ) was constant across years and sites. 

We used the global model: 

ψ(veg), ε(veg,shade,beaver,basin,elev,deep), γ(.), p(day,Atemp,year,veg,beaver,basin,elev,shade,deep) 

We included ordinal date of surveys (day) because changes in behavior and abundance over the 

season might affect p. “Atemp” was the average of the air temperatures measured at the beginning and 

end of a survey. It was included because it is known to affect frog activity so might affect p. The 

covariate “year” was included because we were interested in the trend in occupancy over years and p 

might vary over years with changes in crew or habitat changes. All others were included so that 

variation in p would not bias estimates of their effects on ε. We investigated quadratic effects on p for 

“day” and “Atemp,” but neither convincingly improved the model (ΔAIC less than 2; AIC=Akaike’s 

Information Criteria). We removed p (year) for subsequent analysis because doing so decreased AIC by 

4.8. We retained all other covariates of p because removing them individually did not convincingly 

improve the model. 

We included “veg” as a covariate of ψ because emergent vegetation has often been associated 

with Oregon spotted frogs and other anuran occurrence and abundance (Pearl and others, 2005; Adams 

and others, 2011). 

To estimate initial occupancy (ψ1), γ, and ε, we fit a colext model with the following covariates 

of each parameter:

ψ1(veg), ε(),γ(), p(day, Atemp, veg, beaver, basin, elev, shade, deep) 

To compare the effects of site characteristics on ε, we fit the following variations on the ε 

portion of the model leaving the ψ, γ, and p portions as shown above:

ε(veg), ε(beaver), ε(basin), ε(elev), ε(shade), ε(deep), ε(.)

We ran the occupancy analysis with data from all frames and repeated the analysis with data 

from the fixed frame only to determine if the lack of multiple years of data for the rotating frames could 

be biasing results. Because the fixed frame only includes 17 sites, we used a model for p that did not 

include basin, elev, shade, and deep. These variables had little effect on AIC when all data were 

included and we needed to simplify the fixed-frame model to accommodate the small number of sites.
5

Abundance

We used the function “pcountOpen” from the package “unmarked” in R to estimate trends in 

abundance of post-metamorphic stages of Oregon spotted frogs (that is, juveniles, subadults, and 

adults). This function fits an N-mixture model that accounts for the fact that the number of animals 

counted during a field survey is less than the number of animals present and that the difference is both 

variable and unobserved (Royle, 2004; Dail and Madsen, 2011). We used the negative binomial error 

structure because it fit better than the Poisson or zero-inflated Poisson structures based on AIC. We used 

the “trend” parameterization of the model, which estimated the trend in abundance instead of survival 

and compared the best model with the “no-trend” parameterization to assess evidence for a trend. In the 

trend model, the parameter γ is used as the finite rate of increase, which is often referred to as λ in the 

ecological literature and that is how we refer to it in the Results section below. We used K=675 as an 

estimate of maximum population size, which was enough to stabilize parameter estimates. This model 

evaluates every population size up to K at every site so becomes very slow with higher values of K. For 

this reason, we removed one site that had an abnormally high count during one visit. Attempts to 

analyze the full dataset including that site were unsuccessful.

The abundance models took days of computer time to run, so we sought the simplest reasonable 

parameterization. To estimate the trend in abundance we fit:

N(veg), λ(), p(day, day2

, Atemp, Atemp2, veg, year) 

Results

The probability of detecting Oregon spotted frogs at a site when the species was present varied 

among years with mean of the annual estimates ranging from 0.38 (SE=0.078) to 0.72 (SE=0.087). This 

variation was best explained by the timing of surveys and air temperature. A model with p(day+temp) 

was supported over p(year), and adding year to p(day+temp) did not improve the model based on AICc

(Akaike’s Information Criteria for small sample size). 

There was little differentiation in the support for various models of extinction probability with 

only the null model, the global model, and a model with separate estimates of extinction probability for 

each year being clearly dismissed (table 1). The constant model ε(.) was marginally best and was used 

for parameter estimation.

The overall estimate of ψ decreased from 0.69 (SE=0.085) to 0.53 (SE=0.093) in 4 years. The 

probability that a site unoccupied 1 year was colonized the next year was 0.238 (SE=0.11; CI=0.09–

0.50). The probability that a site occupied 1 year became unoccupied (locally extinct) the next year was 

0.225 (SE=0.080; CI=0.11–0.42). The naïve occupancy each year sequentially was 0.31, 0.39, 0.43, 

0.35. 

When only the data from the fixed frame were used, the estimate of ψ decreased from 0.66 

(SE=0.156) in the first year to 0.37 (SE=0.130) in the fourth year. The naïve occupancy for the fixed 

frame each year sequentially was 0.41, 0.47, 0.52, 0.29. 

Mean weighted counts of adults at the fixed frame sites were 14.4, 5.3, 4.9, and 6.4 annually 

from 2010 to 2013. Using data from all frames, the open abundance model compensated for variation in 

capture probability among years and visits and suggests a decrease in the number of adult and juvenile 

Oregon spotted frogs with an instantaneous growth rate of λ=0.80 (SE=0.051; CI=0.70–0.90). The trend 

model was strongly favored over the no trend model (ΔAICc=124). 
6

Table 1. Multi-season occupancy models describing the probability that a site was occupied by breeding stages of 

Oregon spotted frog (Rana pretiosa), Deschutes and Klamath Basins, Oregon, 2010–13. 

[K, number of parameters; AICc, Akaike Information Criterion for small sample size; ΔAICc, 

difference with top ranked model; ModelLik, model likelihood; AICcWt, model weight; LL, log 

likelihood; CumWt, cumulative weight of models] 

Models K AICc ΔAICc ModelLik AICcWt LL CumWt

constant 13 289.95 0.00 1.00 0.27 -129.67 0.27

depth 14 290.97 1.02 0.60 0.16 -128.79 0.44

beaver 14 291.10 1.15 0.56 0.15 -128.86 0.59

shade 14 291.69 1.74 0.42 0.11 -129.15 0.70

basin 14 291.75 1.80 0.41 0.11 -129.18 0.81

vegetation 14 291.79 1.84 0.40 0.11 -129.20 0.92

elevation 14 292.58 2.63 0.27 0.07 -129.60 1.00

year 17 298.64 8.69 0.01 0.00 -128.24 1.00

global 19 302.48 12.53 0.00 0.00 -127.04 1.00

null 4 313.38 23.43 0.00 0.00 -152.46 1.00

Discussion

We found declines in abundance and probability of site occupancy for Oregon spotted frogs over 

a 4-year period. These results suggest that declines are ongoing, but 4 years is a short period to establish 

trends, and we suggest that these parameter estimates are best viewed as a baseline for future 

comparison. 

Both the colonization and local extinction probabilities were high (0.238 and 0.225, 

respectively), suggesting more annual occupancy dynamics than we expected. As a comparison, one 

study found that wood frog local extinction probability ranged from 0.09 to 0.24, with the higher rates 

associated with ponds considered to be sinks (Peterman and others, 2013). Based on the detection 

histories, the occupancy dynamics in our study appear to mostly involve marginal sites with very small 

populations. Our sites do not equate with populations and the occupancy dynamics may have more to do 

with year-to-year changes in use of marginal sites by populations occupying multiple sites than with 

actual changes in the number of populations. Populations can be difficult to define, but we did not see 

anything we might consider to be a population disappear or become established in the course of this 

study. The trend towards fewer occupied sites and lower abundance overall remains a concern but does 

not necessarily equate with a loss of populations. The probability of local extinction was not strongly 

related to any of the explanatory factors we hypothesized but the time series is not yet long enough for a 

convincing analysis. 

We estimated the overall trend in abundance using an N-mixture model (Royle, 2004). This 

model allowed us to account for variation in detection probability among sites and over time, but it does 

not accommodate variation in individual detection probabilities. Such variation likely occurs when 

differences in microhabitats around a site affect our ability to detect frogs that are present. Violation of 

this assumption adds unknown bias to the trend estimates but we still consider it an improvement over 

inferring trends from counts. 
7

The use of a rotating frame is problematic in a monitoring study (MacKenzie and others, 2006). 

We used this design rather than monitoring a fixed random subset of sites because the funding agencies 

requested that all sites within the range of inference be visited. A rotating frame design adds year-toyear variation associated with the different frames surveyed in a given year. Although most of the 

information for estimating transition probabilities comes from the fixed frame, these estimates must be 

reconciled in the likelihood with the variation in ψ indicated by both the fixed frame and the rotating 

frames. This requires an assumption that the transition probabilities are the same for each frame. This 

assumption is theoretically plausible in our study because we randomly assigned clusters of sites to 

frames. The magnitude of decline was greater for the fixed frame than for the full data, which adds 

credibility to the conclusion that Oregon spotted frogs continue to decline in our study area. 

Our detection probabilities were somewhat low, with an average of 0.62 (SE=0.056). This leads 

to a loss of precision and potentially biases parameter estimates (McKann and others, 2013). Future 

work might improve p with more repeat surveys or constraints on when sampling occurs. For example, 

a minimum air temperature for field surveys could limit observations under marginal conditions for 

detecting species that are present.

Although there is much information suggesting unprecedented declines in amphibians as a 

group, there remains little quantitative data on individual species trends (Adams and others, 2013). The 

U.S. Fish and Wildlife Service is required to evaluate the status of candidate, threatened, and 

endangered species. Obtaining reliable information on status and trends requires studies that: (1) have 

broad statistical inference to an area of interest either by probabilistic or, as in our study, by complete 

sampling; and (2) are designed to accommodate imperfect detection. Our study provides quantitative 

information that Oregon spotted frogs may be continuing to decline in Oregon. The 4-year period of this 

study is too short to draw firm conclusions about current trends but lays a foundation for a more 

rigorous future assessment of trends and options to manage habitats to the benefit of the species. 

Summary 

The Oregon spotted frog (Rana pretiosa) is considered Threatened under the Endangered 

Species Act. Over the past 4 years, we used a rotating frame design to monitor Oregon spotted frogs in 

their core extant range located in the Klamath and Deschutes Basins, Oregon. We assessed occupancy, 

colonization, and extinction rates, overall trends in abundance, and determined the correlation between 

habitat succession and disturbance variables with the probability of local extinction. Although our 

analysis indicates that the Oregon spotted frog is experiencing declines in abundance and probability of 

site occupancy, we acknowledge that 4 years is brief time over which to establish convincing trends. 

Acknowledgments

This study was made possible in part by funding from the Interagency Special Status / Sensitive 

Species Program (ISSSSP). The ISSSSP is a cooperative program of the Pacific Northwest Regional 

Office of the U.S. Forest Service and Oregon/Washington State offices of the Bureau of Land 

Management. Additional funding was provided by the U.S. Geological Survey’s Amphibian Research 

and Monitoring Initiative (ARMI). We thank Kelli Van Norman (Bureau of Land Management) for 

continued support of our work. We also thank our public and private cooperators, among them Klamath 

Marsh National Wildlife Refuge, the Deschutes, Willamette, and Fremont-Winema National Forests, the 

Prineville Resource Area (BLM), and Sunriver Nature Center. This is product 489 of the Amphibian 

Research and Monitoring Initiative.
8

References Cited

Adams, M.J., Miller, D.A.W., Muths, E., Corn, P.S., Grant, E.H.C., Bailey, L.L., Fellers, G.M., Fisher, 

R.N., Sadinski, W.J., Waddle, H., and Walls, S.C., 2013, Trends in amphibian occupancy in the 

United States: PLoS One, v. 8, e64347. 

Adams, M.J., Pearl, C.A., Galvan, S., and McCreary, B., 2011, Non-native species impacts on pond 

occupancy by an anuran: Journal of Wildlife Management, v. 75, p. 30–35. 

Dail, D., and Madsen, L., 2011, Models for estimating abundance from repeated counts of an open 

metapopulation: Biometrics, v. 67, p. 577–587. 

Fiske, I., and Chandler, R.B., 2011, Unmarked—An R package for fitting hierarchical models of 

wildlife occurrence and abundance: Journal of Statistical Software, v. 43, p. 1–23. 

International Union for Conservation of Nature, 2013, The IUCN Red List of Threatened Species: 

International Union for Conservation of Nature, v. 2014.2, accessed August 6, 2014, at

http://www.iucnredlist.org.

Jones, L.L.C., Leonard, W.P., and Olson, D., 2005, Amphibians of the Pacific Northwest: Seattle, 

Washington, Seattle Audubon Society, 227 p. 

MacKenzie, D.I., Nichols, J.D., Hines, J.E., Knutson, M.G., and Franklin, A.B., 2003, Estimating site 

occupancy, colonization, and local extinction when a species is detected imperfectly: Ecology, v. 84, 

p. 2,200–2,207. 

MacKenzie, D.I., Nichols, J.D., Royle, J.A., Pollock, K.H., Bailey, L.L., and Hines, J.E., 2006, 

Occupancy estimation and modeling: Boston, Massachusets, Academic Press, 344 p. 

McKann, P.C., Gray, B.R., and Thogmartin, W.E., 2013, Small sample bias in dynamic occupancy 

models: The Journal of Wildlife Management, v. 77, p. 172–180. 

Pearl, C.A., Adams, M.J., and Leuthold, N., 2009, Breeding habitat and local population size of the 

Oregon spotted frog (Rana pretiosa) in Oregon, USA: Northwestern Naturalist, v. 90, p. 136–147. 

Pearl, C.A., Bowerman, J., and Knight, D., 2005, Feeding behavior and aquatic habitat use by Oregon 

spotted frogs (Rana pretiosa) in central Oregon: Northwestern Naturalist, v. 86, p. 36–38. 

Pearl, C.A., and Hayes, M.P., 2005, Rana pretiosa, Oregon spotted frog, in Lannoo, M.J., ed., 

Amphibian declines—The conservation status of United States species: Oakland, University of 

California Press, p. 577–580. 

Peterman, W.E., Rittenhouse, T.A.G., Earl, J.E., and Semlitsch, R.D., 2013, Demographic network and 

multi-season occupancy modeling on Rana sylvatica reveal spatial and temporal patterns of 

population connectivity and persistence: Landscape Ecology, v. 28, p. 1,601–1,613. 

R Core Team, 2013, R—A language and environment for statistical computing: Vienna, Austria, R 

Foundation for Statistical Computing, accessed August 6, 2014, at http://www.R-project.org/. 

Royle, J.A., 2004, N-mixture models for estimating population size from spatially replicated counts: 

Biometrics, v. 60, p. 108–115. 

U.S. Fish and Wildlife Service, 2014, 50 CFR Part 17—Endangered and threatened wildife and plants: 

U.S. Fish and Wildlife Service, p. 51,657–51,710, accessed August 29, 2014, at

http://www.gpo.gov/fdsys/pkg/FR-2014-08-29/pdf/2014-20059.pdf. 
9

Appendix A. Site Names, Cluster Names, Frame Assignments, and Coordinates 

of Survey Sites

[Cluster: Cluster assignment for each survey site. Frame: Frame assignment for each survey site; see 

figure 1 for rotating and fixed frames.] 

Site name Cluster Frame

100 Rd, Mill Pond, Little Deschutes River 100 Rd, Little Deschutes River B

100 Rd, Oxbow East, Little Deschutes River 100 Rd, Little Deschutes River B

100 Rd, Oxbow West, Little Deschutes River 100 Rd, Little Deschutes River B

9th Tee Pond Sunriver South E

Big Finger Lake Winopee B

Big Lake NW Bay Big Lake B

Buck Lake, NW Pasture Buck Lake A

Buck Lake, West Impoundment Buck Lake A

Camas Prairie Camas Prairie A

Casey 189-106 Casey Tract North E

Casey 868-418 Casey Tract North E

Casey 975-803 Casey Tract North E

Corral Swamp SE Corral Swamp D

Corral Swamp West Corral Swamp D

Cow Camp Excavation Crane Prairie A

Cow Camp Oxbow Crane Prairie A

Crescent Creek, Hwy 58 Crescent Creek, Hwy 58 E

Crosswater 190-157 Crosswater A

Crosswater Bullfrog Pond Crosswater A

Culvert-Weir Sunriver South E

Driving Range Oxbow Crosswater A

Duck Pond and Marsh Sunriver North B

East Borrow Pit Pond BLM Borrow Pit Ponds D

East Oxbow LaPine HS and BLM C

Fourmile, Cherry Creek Beaver Pond Fourmile C

Gold Lake Gold Lake C

Gold Lake Bog Pond Gold Lake C

Gravel Pit Pond Gravel Pit @ 97 and Paulina Hwy D

Hosmer Canoe Channel Hosmer B

Hosmer Lake North Hosmer B

Hosmer Lake South Hosmer B

Hosmer SW Channel at Boat Ramp Hosmer B

Jack Creek, USFS Reach Jack Creek C

Klamath Marsh NWR, Office Ditch KMNWR East B

Klamath Marsh NWR, Office Pool East KMNWR East B

Klamath Marsh NWR, Office Pool West KMNWR East B

Lake Aspen Sunriver North B

Lava Lake Main Lava Lake D

Lava Lake Pond 1 Lava Lake D

Lava Lake Pond 2 Lava Lake D

Lava Lake Pond 3 Lava Lake D

LDR 62RD Gravel Pit Little Deschutes 62 Rd C

LDR 62RD Oxbow Little Deschutes 62 Rd C

Little Cultus Lake/Marsh Little Cultus Lake E

Little Cultus Pond Little Cultus Lake E
10

Site name Cluster Frame

Little Lava Lake Little Lava Lake D

Little Lava NW Little Lava Lake D

Little Lava SE Little Lava Lake D

Long Prairie Long Prairie B

Long Prairie Marsh LaPine HS and BLM C

Loosely Spring Pond KMNWR D

Lower Blue Pool, Main Lower Blue Pool D

Lower Blue Pool, North Shelf Pond Lower Blue Pool D

Lower Blue Pool, South Shelf Pond Lower Blue Pool D

Mowich Log Pond Mowich on Little Deschutes River E

Muskrat Lake Muskrat Lake A

Nature Center Pond Sunriver North B

North Driving Range Pond Crosswater A

Odell Creek NE fen Odell Creek E

Odell Creek SW fen Odell Creek E

Parsnip Lakes, Lower Parsnip Lakes C

Parsnip Lakes, Main Beaver Pond Parsnip Lakes C

Parsnip Mid Parsnip Lakes C

Parsnip Temp pond above Main Beaver Pond Parsnip Lakes C

Pit East of Rt 46 Crane Prairie A

Pit West of Rt 46 Crane Prairie A

Pond SE of Crane Prairie Reservoir Crane Prairie A

Ranger Creek Davis Lake C

Rear Driving Range Pond Crosswater A

Sevenmile Creek, Lower Beaver Pond Sevenmile Creek E

Sevenmile Creek, Middle Beaver Pond Sevenmile Creek E

Sevenmile Creek, Upper Beaver Pond Sevenmile Creek E

Snowshoe Lake Winopee B

Thousand 016-554 Thousand Trails D

Thousand 617-004 Thousand Trails D

Thousand 657-347 Thousand Trails D

Thousand 725-178 Thousand Trails D

Thousand 770-245 Thousand Trails D

Thousand 794-542 Thousand Trails D

Thousand 927-566 Thousand Trails D

Tunnell Creek, 2nd Beaver Pond Buck Lake A

Tunnell Creek, Upper Beaver Pond Buck Lake A

Twin Rivers Pond Crosswater A

Upper Blue Pool Upper Blue Pool E

Upper Oxbow on Little Deschutes River Mowich on Little Deschutes River E

Upper Williamson River USFS Upper Williamson B

Vista-Lodge Sunriver South E

West Borrow Pit Pond BLM Borrow Pit Ponds D

Wickiup Pit Wickiup C

Winopee 366-425 Winopee B

Winopee 858-175 Winopee B

Winopee 947-462 Winopee B

Winopee Lake Winopee B
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For more information concerning the research in this report, contact the

 Director, Forest and Rangeland Ecosystem Science Center

U.S. Geological Survey

777 NW 9th St., Suite 400

Corvallis, Oregon 97330

http://fresc.usgs.gov/
Adams and others—Short-Term Occupancy and Abundance Dynamics of the Oregon Spotted Frog (Rana pretiosa) Across Its Core Range—Open-File Report 2014–1230

ISSN 2331-1258 (online)

http://dx.doi.org/10.3133/ofr20141230