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D. Survey Protocol for Larch Mountain Salamander (Plethodon larselli)
Charles M. Crisafulli, Gifford Pinchot National Forest, Mount St. Helens National Volcanic Monument, 42218 NE Yale Bridge Road, Amboy, WA 98601
Introduction
The following survey protocol was developed for determining the presence and absence of Larch Mountain salamanders (Plethodon larselli, PLLA) on federally-owned and managed lands. It provides the conceptual framework and steps involved to conduct surveys in areas where ground disturbing projects have been proposed.
Larch Mountain salamanders tend to be very patchily distributed, but locally abundant across the majority of their range (Crisafulli unpubl). This type of distribution pattern coupled with fact that PLLA occupy a variety of habitat types requires that a broad brush survey methodology be adopted in order to cover extensive areas that may support isolated (non-continuous or disjunct) populations of salamanders.
For this species, an area-constrained survey method is described, utilizing belt-transects arrayed in parallel across a forest slope. There are defined seasons and environmental conditions for sampling. To designate absence, an animal of this species should not be found during 3 site-visits, which are to be separated by an interval of at least 4 days.
The Van Dyke's Salamander, Plethodon vandykei (PLVA), is another Survey and Manage species that occurs in roughly the same range in Washington. Although PLVA can occur in stream/riparian areas, the two are known to occur together at some sites (Aubry et al. 1987, C. Crisafulli, pers. comm.), so both species should be looked for during surveys.
Read the entire document before initiating any survey.
1. Prerequisites for Performing Surveys.
Prior to conducting surveys for the Larch Mountain salamander, field personnel should become acquainted with the species' general biology and ecology, habitat associations (relationships), geographic distribution, seasonal activity patterns and description, including the specific anatomical and morphological features that will lead to an unequivocal identification once a salamander is encountered. This and other information about the Larch Mountain salamander can be found in the management recommendations for Survey and Manage salamanders in Pacific Northwest forests (Olson et al. 1996, in prep.). Additional references include Leonard et al. (1993) and Blaustein et al. (1995).
Personnel that will be conducting surveys should attend training sessions on amphibian species identification and survey protocol implementation prior to initiating survey work. You can obtain information about training, including a schedule of course dates by contacting the Forest Wildlife Biologist in the Gifford Pinchot or Mt. Hood National Forest Headquarters (Supervisor's Office).
2. State Regulations.
PLLA:
In Oregon, this is a State Sensitive species, listed in the Vulnerable category, and considered Protected wildlife (OAR 635-44-130). A permit from the Oregon Department of Fisheries and Wildlife is required to capture or take this species.
In Washington, a Scientific Collection Permit is required to collect wildlife for research or public display. Activities that involve killing, capturing, controlling or attempting to control wildlife requires this permit. The Larch Mountain salamander is a State Sensitive species. Requests to collect specimens are scrutinized.
Survey Procedures
1. Spatial and Temporal Aspects.
a. Site location.
Surveys should be conducted for Larch Mountain salamanders at sites containing suitable habitat (see below; also Olson et al. 1996, in prep.) that are found between the extreme limits of the species' known range, and in areas where it may occur but remains unrecorded, including south of the Columbia River Gorge and in the Cascade Range of Oregon . Along a north-south axis, the area is defined by Mt. Hood to the south and Mount Rainier to the north and from east to west, from the foothills of the west slope of the Cascades to the crest. Additional areas include the Columbia River Gorge from Bingen (Washington) and Hood River (Oregon) to the east to where the Columbia River bisects the foothills of the western slope of the Cascade Range (see Olson et al. 1996, in prep., for a listing of counties, or "spot" maps of known PLLA locations).
Generally, suitable habitat in the Columbia River Gorge is found in forested and non-forested talus areas. Such habitat can be on or near steep (>40%) slopes, and sites with sparse understories, high litter content, and little mineral soil. In the Washington Cascade Range, these animals inhabit forested talus or boulder fields, cave entrances (basalt tubes), and mature and old-growth forest. They may be found under exfoliated bark of large Douglas-fir snags and on steep slopes (>40%). While it is typically thought of as an upland species the PLLA can also be found in close proximity (e.g., <10m) to streams, but where the vegetation is clearly an upland association.
If suitable habitat occurs within a proposed project area or an area within a 180 m perimeter of a project area (Fig. 1), then the protocol is triggered.
b. Survey timing.
Seasons
Columbia River Gorge (OR & WA from 10-500 m elevation).
There are two general periods of time when the appropriate environmental conditions are present for conducting surveys in this portion of the species' range: 1) late winter/spring (mid-February through late-May) and 2) autumn/winter (late September through late-November). Specific times within these two general periods when sampling is most appropriate will vary, to some extent among sites, due to differences in exposure, plant community structure, orographic features, and also between and within years due to vagaries in temperature and moisture conditions.
Cascade Range of Southern and Central Washington and Northern Oregon.
There are two general windows of time when environmental conditions are typically appropriate to conduct surveys in the Cascade Range: 1) spring/early summer (April through mid-June) and 2) autumn (late September through late November). Strong environmental gradients exist in this portion of the Larch Mountain salamander's range which can profoundly affect animal activity patterns. This is largely due to the general relationship between increased precipitation and decreased temperature with increasing elevation. As a result, lower elevation sites typically provide suitable environmental conditions earlier in the spring and later in the autumn. High elevation sites are usually available later in the spring and into early summer, but may be limited by cold weather and snow in the fall.
Number of Site-Visits - The objective of the survey is to determine whether Larch Mountain salamanders are either present or absent in a given project planning area. In order to make this assessment, surveys will be conducted a maximum of three times at any given site. If an animal is not observed during the first survey than subsequent visits should not occur until at least 4 days have elapsed (i.e., a sampling frequency interval of 4 or more days). Each site-visit is to be conducted in the required time period and under the necessary microclimate conditions, described below (see Environmental Conditions).
2. Environmental Conditions.
The activity patterns of PLLA are tightly coupled to prevailing microclimatic conditions, particularly soil/substrate moisture and temperature. Past monitoring activities conducted for this species have revealed that both moisture and temperature should be within certain ranges or the likelihood of finding animals diminishes greatly (C. Crisafulli, unpubl.).
Soil/substrate moisture - These animals are typically active on or near the surface (under cover objects) only when soil and substrate moisture levels are moist or wet. Currently, there are no inexpensive, portable instruments available on the market that yield accurate and precise soil moisture data. Consequently, two options are left, the first is to collect a known volume of soil from the field and bring it back to the lab where it is oven dried to a constant weight and the gravimetric water content is calculated. The second and more pragmatic approach is a very qualitative method that calls for a simple appraisal of moisture status by sight (color) and touch (feel). In the later case, the soil/substrate and underside of cover objects (e.g., woody debris, rock) should feel at least moist, and preferably wet to the touch. If this is not the case, then surveys should not be conducted.
Soil/substrate temperature - PLLA appear to be very sensitive to temperature and are found consistently in the upper soil strata and beneath cover objects only when temperatures in the top 10cm of soil and underneath cover objects are between 4 and 14oC (C. Crisafulli, unpubl.). If the temperature values are either above or below this range then surveys should not be conducted.
Particular air temperatures are not specified at this time. Attention should be paid to limiting soil/substrate conditions, above, because these pertain to the microhabitats occupied by these animals.
3. Reference Sites.
Care should be taken to not overly disturb known sites because of their extreme rarity. Routine use of Reference Sites prior to surveys of new areas is not recommended at this time.
4. Detection.
Presence is determined by the observation of a single individual PLLA during any of the three surveys. Once an animal is found, no subsequent surveys are required unless a finer-scale delineation of known sites is needed.
Absence is determined only after three surveys have been conducted, all resulting in no PLLA being observed.
5. Voucher Specimens.
Preserved voucher specimens are not required for this species, due to its status as State Sensitive in both Oregon and Washington. Photographic vouchers are suggested. This animal is not easily mis-identified, once its key characters have been assessed. If there is doubt as to the identification of a captured salamander, local species-experts can be sought to verify the identity of the animal.
Survey Method
A modified Area-Constrained search method is described for Larch Mountain salamanders. This method utilizes belt transects that traverse a site at set intervals along slope contours (Figure 2). It represents a "plotless" subsampling scheme rather than a census of the entire area or a quadrat design. This method effectively maximizes the area covered by a survey, and is "broad brush" to cover extensive areas that may support isolated (non-continuous or disjunct) populations of salamanders.
An analysis of surveys conducted in 57 forested stands in the Washington Cascade Range yielded a mean acres per person-hour (acres/ph) value of 3.2 (range 0.8-7.2; C. Crisafulli unpubl.). These stands varied tremendously with respect to habitat complexity (i.e., type and amount of woody debris and rock substrates), forest structure, and age (90 to > 500 years) and, thus cover the range of conditions anyone is likely to encounter while surveying for this species. Hence, the 3.2 acres/ph value, on average, should indicate the time required to implement surveys.
1. Prior to Sampling:
Review Survey Area
A contour map covering the specific proposed project area (e.g., forest management activity, recreational development) is needed when conducting a survey. Features such as pockets of late seral forest, cliffs, talus and areas of steep terrain (>40%) should be delineated within the project area boundary, as these areas are the most likely to support PLLA populations.
Prior to initiating a survey soil/substrate moisture and temperature need to be measured (temperature) or assessed (moisture). If either environmental factor is outside the range described under the "environmental condition" section then the survey should be halted for the day.
Data form
Record entries 1-8 on data form (Appendix 2).
2. Belt-transects.
The procedure for implementing a survey is as follows (see Figure 2). First, the surveyor(s) locates one of the lower corners of the survey area (project area plus 180 m perimeter extension) and walks 25m upslope (from the corner) and attaches flagging that has the observer's initials, date and line # (lines will be numbered one through X, where X = the last 25m interval possible, before going beyond the upslope boundary of the survey area). This indicates the beginning point for a given transect survey line. If there is more than one surveyor, then each crew member will position themselves at 25 m intervals upslope from one another and indicate their beginning point with flagging (as described above). The crew member(s) will travel along the contour of the slope, following a zig zag path, searching under all available cover objects [woody debris (bark, branches, logs) and rocks] within a 10m wide swath (5m on each side of the transect line). In talus habitats, where cover objects are usually too abundant to completely search, the width of the swath is reduced to 4m (i.e., 2m on each side of the line). Additional flagging is labeled and hung on vegetation at about 50m intervals along each transect route. Once a surveyor has traveled across the site (along a transect line) reaching the distal side, they position themselves upslope at the next 25m location and survey back across the slope as described above. This is continued until the entire area has been surveyed at the 25m resolution. All cover objects searched should be carefully returned to their original position.
Soil temperature is measured at four positions spaced at 25 m intervals along the transect line. At distances of 25, 50, 75, and 100m from the beginning (0m) of each transect, slip a thermometer under the nearest cover object (e.g., wood, rock) to the line.
Moisture condition is evaluated at these four positions and at two additional locations. At distances of 25, 50, 75, 100, 125 and 150m from the beginning (0m) of the transect, determine the closest cover object (e.g., wood, rock) to the line, turn the object and determine moisture condition. At the first four positions, measure temperature first.
In most cases a survey could be performed by a single surveyor, but if the area is >10 acres, a 2-4 member crew is strongly recommended. This would ensure that sites in the 20-40 acre range would be finished in a single day, thus reducing the likelihood that changes in salamander detectability would occur due to variations in prevailing weather conditions.
If animals are captured, record the following information:
a. Species - four letter code (see code sheet, Appendix 2) determined by identification keys provided during field training. Record all amphibian species captured.
b. Stage - juvenile/subadult or adult (see entry 12, Appendix 2)
c. Capture location - When a PLLA is captured, the location is marked on a map, the site is flagged and labeled.
To forward our ecological knowledge of this species, additional information may be gathered at capture locations (numbered 9-31, Appendix 2). These data include collection of several site characteristics and microhabitat features. The animal is released at the point of capture.
Delineation of Occupied Sites.
Once the Larch Mountain salamander is found at a site, conservative site-delineation is recommended for this rare species. Until surveys are conducted throughout a site, all suitable habitat that is contiguous with an occupied site will be considered occupied, and should be delineated. If suitable habitat is separated by no more than 75 meters, then it also may be considered occupied. If there is doubt as to the occupancy status of suitable habitat near a known site, survey the site using this same survey protocol. This may include contiguous or adjacent habitat areas.
A finer-scale known site delineation of apparently disjunct populations may be accomplished by additional, more intensive surveys conducted at flagged locations of individual captures. Such surveys can be conducted along multiple transects outward from known site locations, or in a circular path spiraling-out from the flagged site. This more intensive survey effort should include obvious patches of suitable microhabitats. The method used, area searched (transect or path width and length, total area covered), and time spent searching (excluding time spent handling animals and recording data) during these additional surveys should be recorded.
The potential ecological value of contiguous but apparently unoccupied habitat should be considered, especially in regard to desired future conditions, population dynamics, and connectivity issues. Conservative measures are recommended when dealing with this type of rare endemic vertebrate species.
