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NOCA NRPP Amphibian Inventory |
The 1997 amphibian inventory in Bridge Creek watershed was funded as the part of a four year program to inventory amphibians in Pacific Northwest National Parks. The objectives of this study were to conduct a baseline inventory, evaluate environmental factors affecting distribution of amphibians, and develop protocols for both extensive and intensive monitoring. In 1996, the first year of this program, National Park Service staff conducted an amphibian inventory of the Big Beaver watershed. This report presents methods and data collected during the 1997 field season in Bridge Creek watershed, and an update on frogs of Big Beaver valley.
Physical, chemical, and amphibian abundance and distribution data were collected at twenty eight stream reaches, seven individual seeps, and fifteen lake/ponds. The only amphibian captured in streams was the tailed frog Ascaphus truei. One amphibian, Ambystoma macrodactylum, was found at a seep location. Five species of amphibians were found in the lake/ponds surveyed. They were: Ambystoma macrodactylum, Bufo boreas, Hyla regilla, Rana cascadae, and Rana luteiventris.
Methods
Photo Documentation
Water Chemistry
Pond Amphibian Sampling
Stream Sampling
Seep Sampling
Results
Streams
Seeps
Lake/Ponds
Big Beaver Revisited
Discussion
Bridge Creek
Big Beaver
Appendix (omitted from on-line edition)
Attachments (omitted from on-line edition)
Figure 1. Location of Bridge Creek study area in the North Cascades National Park Service Complex and Washington State
Figure 2. Bridge Creek watershed with amphibian survey sites - 1997, North Cascades National Park Service Complex, Washington
Table 1. Stream Width, Depth, Velocity, and Gradient Summary
Table 2. Stream Substrate Description Average - Summary
Table 3. Stream Habitat Type, Instream and Overstory Cover Summary
Table 4. Stream Channel Stability Ratings (Pfankuch 1975)
Table 5. Riparian Vegetation - Canopy Coverage and Species
Table 6. Chemical Characteristics of Water at Stream Survey Sites
Table 7. Chemical Characteristics of Water at Seep Survey Sites
Table 8. Intermittent Pools and Seeps Characteristics
Table 9. Pond Physical Characteristics and Fish Presence
Table 10. Chemical Characteristics of Water at Lake/pond Survey Sites
Table 11. Stream Search Effort and Captures - Summary
Table 12. Seep Search Effort and Captures
Table 13. Pond Shoreline Visual Search and Amphibian Captures - All Daytime
Table 14. Pond Amphibian Trap Effort and Captures
There are several goals concerning amphibians in North Cascades National Park (NOCA) which are reflected in management plans and various research proposals and programs. These include inventory and habitat characterization, development of a long-term monitoring program, and evaluation of the effects of fish stocking on lake amphibian populations.
NOCA has been selected as one often of the NPS National Prototype Long-term Ecological Monitoring (LTEM) parks. NOCA was selected to represent the lake and stream category of the LTEM program. In the NOCA LTEM proposal, a watershed approach that addresses park and regional needs for watershed management was selected. The approach focuses on the stream riparian corridor, but also tracks processes and environmental influences occurring within the target watersheds.
Amphibians were selected as one of the biological components of the monitoring program. LTEM objectives for amphibians include the examination of spatio-temporal changes in species occurrence in representative stream and lake habitats and associated riparian zones. Sampling design considerations require that data be collected in a manner that would support spatial and temporal analysis of distributional patterns, changes in relative abundance, and factors influencing these attributes.
Amphibians are important components in many ecosystems. They can occupy key trophic positions in food webs of both aquatic and terrestrial systems. As adults they can be top carnivores, and as larvae or juveniles, they may be the major food source of many other species including birds, mammals, fish, and invertebrates. In some forest ecosystems, amphibians may comprise the major component of the vertebrate biomass (Burton and Likens 1975, Bury 1988). Moreover, under certain conditions, amphibians may be good "bioindicators" of environmental stress because of various aspects of their life histories, including their physiological and behavioral characteristics, morphogenetic patterns, and aspects of their population biology. The decline in amphibians may be an early warning signal that, ultimately, other organisms also may be in danger of decline and extinction.
The Washington Department of Fish and Wildlife (1997) has listed for protection two species of Spotted Frog, the Oregon Spotted Frog Rana pretiosa as endangered, and the Columbian Spotted Frog Rana luteiventris as a candidate. The U.S. Fish and Wildlife Service has listed the Oregon Spotted Frog, Northern Red-legged frog Rana aurora aurora, and Cascades frog Rana cascadae as a federal candidates and the Columbian Spotted Frog as a species of concern.
Northwestern salamander neotene (adult-aquatic)
(Ambystoma gracile)
The National Park Service provided support to Oregon State University through a cooperative agreement to conduct a study of the ecological effects of stocked trout in naturally fishless lakes in NOCA. This study, conducted from 1989-1993, documented three salamanders: Ambystoma macrodactylum in both east and west slope lakes, Ambystoma gracile, and Taricha granulosa only in west slope lakes. In addition, four Anuran amphibians were found: Bufo boreas in both east and west slope lakes, Hyla regilla west slope, Ascaphus truei both east and west, and Rana luteiventris in east only.
In 1991 a Stehekin Valley Vertebrate Inventory (east slope) was conducted by NOCA staff (Kuntz and Glesne 1993). Pitfall traps in this study yielded five amphibian species: Rana cascadae, Hyla regilla, Rana luteiventris, Bufo boreas, and Ambystoma macrodactylum. In 1993-1994 pitfall traps were installed and monitored by NOCA staff at Park Slough near Newhalem (west slope). The Park Slough pitfall traps produced Ensatina eschscholtzii and Rana aurora. Nearby fish traps in the Park Slough spawning channels caught Bufo boreas.
In 1995 an arthropod study using pitfall traps was initiated in lower Big Beaver Valley, a drainage to the west of Ross Lake. This trapping effort resulted in the incidental take of nine species of amphibians: Bufo boreas, Ascaphus truei, Pseudacris (Hyla) regilla, Rana cascadae, Rana pretiosa, Ambystoma macrodactylum, Ambystoma gracile, Taricha granulosa, and Ensatina eschscholtzii.
The current study began in 1996 with an amphibian inventory in Big Beaver watershed and was funded as part of a four year program to inventory amphibians in Pacific northwest National Parks, including Olympic (OLYM), Mount Rainier (MORA), and North Cascades (NOCA). The objectives of this study were to conduct a baseline inventory, evaluate environmental factors affecting distribution of amphibians, and develop protocols for both extensive and intensive monitoring.
Funding is from the Natural Resource Preservation Program (NRPP) and is administered by R. Bruce Bury of the Biological Resources Division (BRD), United States Geological Survey (USGS) at the Forest and Rangeland Ecosystem Science Center (FRESC), Oregon State University (OSU) Corvallis, Oregon.
During 1996, physical, chemical, and amphibian abundance and distribution data were collected at twenty-seven stream reaches, thirty individual seeps, and twenty-one lake/ponds in the Big Beaver Creek watershed (Holmes and Glesne 1997). The only amphibian captured in streams was the tailed frog Ascaphus truei. Two species of amphibians were found at seep locations: Rana cascadae and Ambystoma gracile. Eight species of amphibians were found in the lake/ponds surveyed. They were: Ambystoma gracile, Ambystoma macrodactylum, Bufo boreas, Pseudacris regilla, Rana aurora, Rana cascadae, Rana (pretiosa) luteiventris, and Taricha granulosa. Ensatina eschscholtzii which was collected in pitfall traps in another study, brings to ten the number of amphibians found in Big Beaver Valley to date. All 1996 identifications of Rana cascadae, Rana pretiosa, and Rana aurora in Big Beaver Valley are unconfirmed. The reason for the ambiguity in these ranid frog identifications is the intergradation of field mark characteristics between these species.
In 1997, the second year of this study a NOCA amphibian crew conducted an inventory of Bridge Creek watershed. The objectives of this report are to only present methods and data collected during the 1997 field season in Bridge Creek watershed. Relationships between species distributions and environmental attributes will be analyzed in the final report following the last field season of this four year study.
Bridge Creek watershed is a pristine natural area located in the northwestern portion of Washington State on the east slope of the North Cascade Mountain Range (Figure 1). The crest of this mountain range runs along the northern boundary of Bridge Creek watershed. A total of 28 stream reaches, 6 seep sites, and 15 lake/ponds were sampled during 1997. Specific sampling locations are shown in Figure 2, Appendix Tables Al to A3, and Appendix Figures Al to A12. The entire Bridge Creek watershed encompasses approximately 23,800 hectares. Approximately 20,000 hectares including the tributary drainages of North Fork, Grizzly, Maple, South Fork, McAlester, and East Fork Creeks are within NOCA boundaries. The headwaters of Bridge, State, and Copper Creeks (3,800 ha) between Rainy and Washington Pass lie just outside the Park boundary (Figure 2).
The elevation of the study area ranges from 475 m on the southwest where Bridge Creek flows into the Stehekin River to 2805 m at the summit of Goode Mountain on the western boundary of the watershed. The Stehekin River flows into Lake Chelan which drains into the Columbia River. Within the Bridge Creek watershed there are 288 km of streams represented on the USGS 7.5' topographical maps and 45 lake/ponds of which 34 are on the USGS maps and an additional 11 which were mapped from aerial photos and field visits. Still more areas of small seeps and wetlands were encountered in the 1997 field season. Some of these were included in our survey and subsequently included in NOCA GIS and databases. Streams range from first order headwaters to fourth order mainstem of lower Bridge Creek. Most reaches sampled were in first and second order streams with five third order reaches sampled and one fourth order reach.
The climate in Bridge Creek watershed is determined by general weather patterns in the North Cascades, which are modified by topographic features in and around the valley. Air masses originating as frontal systems over the Pacific Ocean release moisture in the form of rain or snow as they are forced to rise over the crest of the Cascade mountain range. This results in a rainshadow effect for Bridge Creek. U.S. Weather Bureau data shows a moisture gradient within the valley, with the west end receiving more moisture than the east end. Based on records from nearby weather stations rainfall is estimated to range from approximately 150 cm in the eastern end of the valley to 250 cm in the western end of the watershed.
The bedrock geology of the Bridge Creek watershed is composed primarily of late Cretaceous and early Tertiary metamorphic and granitic rocks of the Chelan Mountains terrane. Grizzly and North Fork creeks on the west end of the watershed are composed of Skagit Gneiss. In the central watershed a band of Gabriel Peak Orthogneiss runs north - south through South Fork and Maple creeks. Dominating the geology of the eastern end of the watershed in East Fork and McAlester creeks is the granodioiritic Black Peak Batholith (Misch 1966).
Several periods of glaciation during the past 1.5 million years has given the valleys typical straight, flat-bottomed. steep-walled valleys. Headwaters of the larger streams begin in cirques, some of which contain small glaciers. Smaller tributary streams to Bridge Creek begin on the steep upper slopes of the valley walls. Cirques and lower valley slopes are choked with debris produced by glacial erosion and mass-wasting processes (pers. comm. Jon Riedel 1998).
Bridge Creek watershed vegetation is primarily subalpine forests including Pacific Silver Fir (Abies amabalis), Subalpine Fir (Abies lasiocarpa), and Mountain Hemlock (Tsuga mertensiana) Zones (Franklin and Dyrness 1973). In addition to these tree species, some parts of the study area contain varying proportions of Douglas-fir (Pseudotsuga menziesii), Englemann spruce (Picea englemannii), lodgepole pine (Pinus contorta), white pine (Pinus monticola), and at higher elevations subalpine larch (Larix lyalli), and white-bark pine (Pinus albicaulis). Broad-leaved trees encountered, mostly in the riparian areas and avalanche chutes, were: Black cottonwood (Populus balsamifera), Sitka alder (Alnus sinuata), Douglas' maple (Acer glabrum var. douglasii), Sitka willow (Salix sitchensis), and a few Big-leaf maple (Acer macrophyllum).
The shrub layer in drier open areas contained Snowbrush ceanothus (Ceanothus velutinus), Western serviceberry (Amelanchier alnifolia), Oceanspray (Holodiscus discolor), Oregon boxwood (Pachistima myrsinites), and Red mountain heather (Phyllodoce empetriformis) at higher elevations. In forested areas common shrubs were: Salmonberry (Rubus spectabilus), Devil's club (Oplopanax horridum), Elderberry (Sambucus racemosa), Fool's huckleberry (Menziesia ferruginea), and several Blueberry and Huckleberry species (Vaccinium spp.)
The stream reaches surveyed ranged in elevation from 927 meters at a lower North Fork tributary to 1817 meters at headwater of Rainbow Creek (just outside Bridge Creek watershed), and 1768 meters at the inlet to McAlester Lake (Appendix Table A1). Average gradients of these reaches ranged from 1% to 28%. Average wetted width ranged from 0.8 m in first order headwaters to 14.5 m in fourth order mainstem of Bridge Creek (Table 1). The dominant substrates were quite varied from boulder to sand as were subdominants (Table 2). The general habitat types represented in these reaches were primarily riffle, cascades, and pools. Instream cover was provided primarily by undercut banks and organic debris. Densiometer canopy cover ranged from 2% at headwaters of South Fork (site # 519-2) (alpine meadow) to 96% at Bridge Creek tributary (site # 702A) through an even-aged mature forested slope (Table 3). Bank stability as measured using a method developed by Pfankuch (1974) showed most reaches (23) in the good range, four were rated fair (Table 4). Vegetation forest types at stream sites ranged from open krumholz through various stages of young (including avalanche thickets) and mature to old-growth coniferous forests (Table 5). Water temperature in streams at time of surveys ranged from 37° to 58° F. Stream pH ranged from 5.64 at a tributary of South Fork (site # 508) to 7.12 at a tributary of North Fork (site # 208A) and conductivity from 8.2 to 75.6 uS/cm (Table 6).
A total of 6 individual seeps were sampled at three different locations near Hideaway and South Fork camps and South Fork tributary (Figure 2, Table A2). These sites ranged in elevation from 969 meters at South Fork Camp (site # SOFORK) to 1109 meters at seep off South Fork trail (site # 506). Water temperature at these seeps ranged from 41° F at (site # 506) on 7/8/97 to 45° F (site # HDWY-2) on 7/2/97. The pH of seeps where water samples were collected ranged from 5.61 at South Fork camp (site # SOFORK) to 6.69 at the seep off South Fork trail (site # 506). Descriptive data for seeps are shown in Tables 7 and 8.
A total of 13 ponds and 2 lakes were surveyed for amphibians. These 15 bodies of water were sampled using the same techniques so were lumped into a single lake/pond category. The two which are referred to as lakes were so designated based on greater depth, size, and permanence of landform creating impoundment. Physical and chemical data for lake/ponds are found in Tables 9 and 10. These bodies of water ranged in size from 0.1 acre upper Woody Creek pond (MA05) to 12.5 acres McAlester Lake (MR10). The range of elevations for the lake/pond sites was from 777 m at pond near lower Bridge Creek trailhead (MM 13) to 1932 m at upper Maple Creek pond (MM04). Fish presence was noted in four of the 15 lake/ponds. The pH of all lake/ponds ranged from 4.58 at pond near lower Bridge Creek trailhead (MM13) to 7.07 at Falls Creek headwater pond (MM01). The water temperature of the lake/ponds ranged from 39° F at Twisp Pass pond (MR03) on 7/15/97 to 70° F at pond near lower Bridge Creek trailhead (MM13) on 8/14/97.
Photo Documentation
Photos were taken at each amphibian survey site. Notes recorded on a photo log form (Attachment 1) include date, roll #, picture #, site #, reach #, stream meter, and a comment field description of subject. At each stream reach photos were taken at stream meter 0, 50, and 100 one each upstream and downstream. At ponds two to four photos were taken to document littoral habitat types and surrounding vegetation. The photos were developed into color slides and photo CD format. A flat database Photo Catalog (Appendix Table A4) was developed for these photos which includes a photo CD # and image # in addition to the above data fields. The photos on CD can be opened in any photo finishing software which handles the Kodak photo CD file format (* .pcd) such as Corel Photo CD Lab, Corel Photo-Paint, Corel Draw, Adobe Photoshop, or Microsoft Image Composer. Corel Photo CD Lab can view the images on the CD then save the image in a different format (*.bmp, *.eps, *.pcx, *.tif) with several resolution, color, and rotation choices. Then the new file can be opened in a photo finishing program and manipulated by the many tools available for image enhancement (sharpen, lighten, darken etc.) The photos from our study are also referenced in an Accessory Data Tables (Appendix Tables A5, A6) listing all sites surveyed with ancillary data such as crew members and weather conditions. A series of 1:24,000 color aerial photographs in 9"x9" format were used to map the exact locations of each survey site for future reference to assist in locating these same sites again. These photos were scanned at 600 dpi, sharpened, and zoomed in to show local landmarks (boulders, logs). Then site number labels added to indicate specific survey sites (Appendix Figures Al to A12).
Water Chemistry
Water samples were collected at most amphibian survey sites, and analyzed to determine pH, conductivity. Samples were collected in sterilized nalgene bottles, capped immediately after collection, and refrigerated upon being brought in from the field. Water temperature was also taken at each sampling site. Conductivity was read using a YSITM model 35 conductance meter. The pH of water samples was determined using an AltexTM 70 pH meter standardized with 4.0 and 7.0 pH buffers. Water samples were brought to 25° C prior to pH and conductivity analysis.
Pond Amphibian Sampling
Sampling of ponds for amphibians was done using two survey methods: shoreline search (visual encounter), and funnel trapping with collapsible nylon mesh minnow traps (unbaited).
Visual
Visual searches were done during daylight only. No nighttime searches were done due to the remoteness of most sites and danger to crew members involved in off trail travel in darkness. During our shoreline visual survey, one to three persons slowly walked the complete perimeter of ponds, with dip nets in hand, focusing on an area from the 1 m depth contour in water to the shore, then 2 m landward from shoreline. The perimeter of the lake/pond was divided up between the observers with each crew member surveying a portion of the shoreline. Time spent and number of people performing visual searches was recorded. All observations and captures of amphibians during visual searches were recorded on Lake/Pond Amphibian Survey Data Form 3b-NOCA (Attachment 2).
While observers were conducting the visual search, another crew member (the recorder) drew a map of the outline of the pond on Lake/pond Amphibian Survey Data Form 3a - NOCA (Attachment 3), noting vegetation present in the vicinity of the pond and marking locations of the individual minnow traps as they were placed in position. Several additional items of data describing the pond and habitat, fish presence, and physical characteristics were entered on this form.
Trapping
Minnow traps were placed at the surface of the water with the openings of the funnels 10-20 cm below the surface and with a portion of the top of the trap 2-5 cm above the surface to allow non-gilled amphibians (adult frogs, toads) to survive several hours in the trap without drowning. Six traps were usually placed in small ponds and twelve in larger ponds allowing at least 25 square meters per trap. An effort was made in placing the traps to try and sample as much of the heterogeneity of the habitat types as possible. Traps were placed in the pond one day, left overnight, and picked up the following day. Time and dates traps were placed into and taken out of the pond were recorded. Dominant substrate was noted along with amphibians captured and their measurements. Data on trap effort and captures was recorded on Lake/pond Amphibian Survey Data Form 3d - NOCA (Attachment 4).
Stream Sampling
Over half of the streams shown on the 7.5' USGS topographical maps as crossing the trail were dry when visited during the June to September season. Off-trail cross-county hiking in this region is extremely difficult and time consuming. Streams were chosen in the Bridge Creek watershed by their accessibility from trail. All streams that crossed the one trail through the watershed were sampled for amphibians if there was water flowing in them at the time of sampling during the season from 6/26/97 to 9/10/97 and water was not considered to be too dangerous (high gradient/velocity) to be in. In total, 28 reaches were sampled for amphibians in 1997 (Figure 2).
Streams that flowed across the trail were sampled beginning approximately 10-50 m upstream of the trail to minimize impacts of trail use on the reach sampled. At the starting point one crew member stretched a measuring tape (stream rope) upstream taking care to not disturb the stream bed. Along this route stations were marked (flagging tape) at preselected random meter intervals. Ten belt transects one meter wide were sampled in each 100 m stream reach. In two of the 28 reaches 100 m of stream was not available so a shorter (50-70 m) reach was done using the 10% rule (1 m belt transect for every 10 in).
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Amphibian crew using kick-net sampling technique to find aquatic insects and tailed frogs  |
Tailed frog adult caught in kick-net 
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First a visual observation of the one meter wide belt transect was done. Then it was sampled by placing a kick net in the stream securely against the substrate while picking up and examining all moveable substrate upstream within 1 meter of the net. Large or unmoveable substrate was rubbed by hand or kicked to dislodge any amphibians present. Substrate which was moved was replaced as near to its original position as possible to minimize disruption to the habitat. The net was moved across the stream until all the wetted width had been searched. All amphibians captured were identified, measured, and recorded on data sheet Amphibian Survey: Capture Data (Bury and Major 1996) (Attachment 5).
Stream depth was measured in three places, the center of each third of the wetted width. These measurements were recorded to nearest centimeter as left, middle, and right depths (facing downstream). Flow velocity was measured in these same places at 0.6 of the total depth with a digital flowmeter to 0.01 mps. Gradient was measured with a clinometer in % taken at stream meter 000, 050, 100. The gradient was measured upstream and downstream at each of these three stations for a 25 m distance, then averaged to produce one reading at each station.
Percent of seven habitat types were recorded for each transect; obscured, cascade, riffle, pool, tailout, subsurface, and wetland. Instream cover percent was recorded for coarse woody debris, organic debris, and undercut banks. Densiometer overstory canopy cover was measured and recorded for upstream, downstream, left and right banks.
Characterization of substrate was done at each of the belt transects along the upstream edge of the transect, following amphibian sampling. Dominant and subdominant substrate type codes were recorded at intervals that vary with the bankfull width at any particular site. A sample interval of 0.2 in was used for transect sites with a wetted perimeter of less than 1 m, 0.3 m was used for transect sites with a wetted perimeter of 1-2 m, 0.5 m intervals were used for streams that were 2 to 5 m wide, and 1 m intervals were used for streams greater than 5 and less than 10 m wide, 2 m intervals for streams greater than 10 m wide. For each transect we recorded 1) stream meter for transect location; 2) bankfull width in meters at the transect; 3) bank starting location (left and right banks are always determined facing downstream); 4) distance (interval start point) from starting bank, dominant substrate type code and subdominant substrate type code for each interval across the channel. These data were recorded on Stream Amphibian Survey Data Form 1a - NOCA (Attachment 6).
At three places (000 in, 050 m, and 100 m) in each transect a riparian vegetation survey was done. The vegetation survey covered a 20 m square on left bank and right bank. Data were recorded on a Riparian Vegetation form (Attachment 7) . Percent cover of both overstory and understory species was recorded as well as total overstory and understory canopy closure. Additionally dbh size classes were recorded for overstory as a whole to give an indication of forest age structure.
On Stream Amphibian Survey Data Form 1b - NOCA (Attachment 8) blocks representing transect intervals were sketched in with major instream cover items (logs, boulders, under cut banks). Start and stop times were recorded for each transect's amphibian search. Any amphibians found were identified to species, life stage, and sex when possible. On form Amphibian Survey: Capture Data (Buy and Major 1996) we recorded additional head, body, and limb measurements for each amphibian captured (Attachment 5).
A Streambank and Bed Stability form (Pfankuch 1975) (Attachment 9) was used to record many factors influencing these stream characteristics. Landform slope, mass wasting or failure, debris jam potential, and vegetative bank protection were evaluated for the upper banks of each stream reach. Five characteristics of lower banks were evaluated and included: channel capacity, bank rock content, obstructions, cutting, and deposition. Similarly streambed bottom was rated on six factors: rock angularity, brightness, particle packing, bottom size distribution, scouring and deposition, and clinging aquatic vegetation. These data present a picture of the susceptibility of the stream channel to erosion and change.
Seep Sampling
Intermittent pools and seeps were surveyed for amphibians and data was collected about the characteristics of these sites on Stream Amphibian Survey Data Form 2 - NOCA (Attachment 10). Habitat descriptors such as depth, area, flow, In stream cover, canopy cover, and substrate were all recorded and summarized in Intermittent Pools and Seeps Characteristics Table 8. On data form 2 a box was provided to sketch in a map of the seep site. Other general site information such as weather, crew, time, date and location are all included in Appendix Table A2 and Table A6. Seeps were sampled using a timed search method with start and stop times recorded along with any captures made. Seep searches included the use of visual search, dip net, kick net, and overturning substrate.
Streams
A total of 28 stream reaches were surveyed. The only amphibian species captured in streams was the tailed frog Ascaphus truei. Life stages found included tadpole, metamorph, juvenile, and adult both male and female. Tailed frogs were found in 9 of the 28 reaches surveyed. In four of these reaches only one individual was found, in four others just two individuals, and in one reach eight were found (Table 11, and Appendix Table A8).
Seeps
Only one amphibian was found at one of the seven seep locations sampled during 1997. An Ambystoma macrodactylum larva was found in a pothole (434A) along upper Woody Creek in a subalpine willow meadow. A summary of seep effort and results are listed in Table 12.
Lake/Ponds
Columbia spotted frog (Rana luteiventris)
Amphibians were caught in 9 of the 15 lake/ponds surveyed. A total of 5 species of amphibians were found in the lake/ponds surveyed. They were Ambystoma macrodactylum, Bufo boreas, Hyla regilla, Rana cascadae, Rana luteiventris. The highest number of species found in any one pond was 3 in lower North Fork pond MM05. This same pond yielded the first capture of a reptile in our nylon mesh minnow traps. One juvenile snake most likely a Wandering Garter Snake, Thamnophsis elegans vagrans was caught and released alive. Visual searches yielded one species of amphibians at five lake/ponds (1 to 49 individuals), two species at three places (2 to 9 individuals). Traps produced one species at six sites (1 to 6 individuals), and two species at one pond (30 individuals, MM13), and three species at one pond (108 individuals, MM05) Lake/pond amphibian captures from visual searches are summarized in Table 13, and captures from trapping in Table 14.
Big Beaver Revisited
Twice during the 1997 field season the NPS-NOCA amphibian inventory crew visited Big Beaver Valley where an inventory was conducted in 1996. The first trip was in early August when two of the streams previously surveyed were resurveyed. The two streams were a second order Thirty-nine Mile Creek (146) and a small first order permanent tributary of lower Big Beaver (128). In both streams tailed frogs Ascaphus truei were found in 1996 and in 1997. On the last day of the week we were joined by herpetologist Don Major from USGS-BRD-FRESC, Corvallis, Oregon. We went to a lower Big Beaver permanent pond/wet meadow complex (PM07-1,2) with Don to determine the identity of the ranid frogs and salamanders which were observed and reported in 1996. The NOCA crew had tentatively identified the frogs as Rana cascadae and the salamanders as Ambystoma gracile. Don concurred with the A. gracile identification but was not certain about the Rana species we found. These frogs seemed to be somewhere between R. cascadae and R. luteiventris in field mark characteristics. We decided it was worth the effort to come back and collect some tissue samples for DNA analysis to determine the identity of these frogs.
Amphibian crew preparing for snorkel survey
of wetland pond in Big Beaver Valley
A second trip to Big Beaver Valley was scheduled for the last week in August. On this trip the NOCA crew was joined by herpetologist Mike Adams of USGS-BRD-FRESC, Corvallis, Oregon and the amphibian inventory crew from Olympic National Park and their leader Patrick Loafman. This combined crew went back to ponds PM07-1 and PM07-2 and caught some adult and juvenile frogs and juvenile toads. From these specimens we collected toe clipped tissue samples which Mike Adams took to send off for DNA analysis. Other survey efforts of the USGS-BRD FRESC crew included catch and release of over 200 Ascaphus truei tadpoles in Happy Creek which appear to represent three age classes, mark-recapture of R. luteiventris population at Dagger Lake suggests multiple capture intervals over short time period can provide valid population estimates (ie., model assumptions were met) (pers. comm. Mike Adams 1997).
Bridge Creek
Overall five species of amphibians were found in lake/ponds, one in seeps, and one in streams. A total of six species of amphibians have been found in Bridge Creek watershed so far. In comparison, the Big Beaver valley (1996) amphibian inventory found nine species of amphibians from pond and stream surveys, plus one from pitfall traps. The lower number of amphibian species is consistent with the higher and drier habitat found in Bridge Creek watershed. Bridge Creek watershed lacks extensive low elevation wetland habitats including beaver ponds and bogs which are common in lower Big Beaver. Some areas of the Bridge Creek watershed were not sampled due to remoteness. Unavailability of helicopter support prevented our crew from reaching some areas scheduled for the 1997 inventory. Pitfall traps have not been used in Bridge Creek watershed. This method could possibly yield additional species of amphibians, though no other species are expected to be in Bridge Creek based on present known distributions. A total of three species of reptiles were observed during the 1997 field season in Bridge Creek. The previously mentioned garter snake, 3 Rubber Boas, Charina bottae, and 2 Northern Alligator Lizards, Elgaria coerulea were seen along the Bridge Creek Trail near Hideaway camp. The mainstem of Bridge Creek, trubutaries of Maple, North Fork, and Grizzly Creeks need more extensive amphibian inventory coverage.
Big Beaver
It should be noted that after observations by many researchers, the Ranid complex in Big Beaver Valley remains somewhat of a mystery. The former Spotted Frog, Rana pretiosa, was split into two species, the Oregon Spotted Frog, Rana pretiosa, and the Columbian Spotted Frog, Rana luteiventris (Green 1996). It is generally thought that the Oregon Spotted Frog's distribution does not presently extend into the Big Beaver Valley and is limited to southwestern Washington (McAllister and Leonard 1997). Historical records show the Oregon Spotted Frog in Concrete, Skagit County in 1930. This is 50 km southwest of Big Beaver Valley and 415 m lower elevation, both sites are within the Skagit River watershed. Historical records show the Columbian Spotted Frog as close as 15 km to the southeast and similar elevation to Big Beaver Valley, within the Skagit Valley watershed. Records show the Cascade Frog occurring in all directions around Big Beaver Valley. Red-legged frogs have been found at Newhalem, which is 18 km southwest and 340 m lower than Big Beaver Valley also in the Skagit River watershed. The frogs identified as Red-legged Frogs in this report were 2 tadpoles, that were 71 mm total length which according to some guide books Rana aurora is the only species tadpole to attain that size. Later we were told that length may not be a reliable indicator. Big Beaver Valley is within the range of R. aurora, R. cascadae, R. luteiventris, so any or all could be or have been present in this valley. There is the possibility of hybridization between R. cascadae and R. pretiosa (Green 1985, Haertel and Storm 1970). Four species of Ranid frogs have been found in the Skagit River watershed within a 50 km radius of Big Beaver Valley. Three species have been found recently within 20 km. There is presently a thriving population of Ranid frogs in Big Beaver Valley. Just what their lineage is remains to be discovered. The Ranid frogs of Big Beaver Valley seem to have a mixture of cascadae, aurora, and luteiventris characteristics that have made positive identification impossible by field marks alone. Tissue samples have been collected in 1997 from frogs in Big Beaver Valley (west slope) and Bridge Creek watershed (east slope) and are in line to be processed by DNA analysis. The results of these tests will not be available for a couple years but should shed some light on this interesting group. So meanwhile, these ranid identifications listed in the NOCA NRPP Amphibian Inventory, Big Beaver Watershed, 1996 - Progress Report should be taken as unconfirmed. We are looking forward to test results with great anticipation.
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http://www.nps.gov/noca/bcamph.htm