Shenandoah National Park
Streamside Amphibian Monitoring Protocols and Initial Results

Below, we present details on objectives, hypotheses being tested, methods, and some initial results of the various streamside salamander studies.

Studies

Streamside Amphibians
Electroshocking
Leaf Litter Bags
Streamside 1 m² Quadrats
50 m x 1 m Streamside Transect

Environmental Variables Measured at the Stream Sites

Streamside Amphibians

In 1998, we surveyed nine streams representing a range of water quality (pH, acid-neutralizing capacity) and habitats throughout the park.  Four survey techniques were compared at the nine streams: electroshocking, leaf litter bags, 1 m² quadrats, and 50 x 1 m transects.  The figure below shows the locations of the stream survey sites (Fig. 1).

Figure 1.  Stream survey sites at Shenandoah National Park.

Objectives:

1) To compare the use of four survey methods for streamside amphibians at nine streams in Shenandoah National Park.

2) To compare species richness and abundance in relation to stream habitat and water quality variables.  Some of these streams are monitored for water quality (pH, ANC, conductivity, sulfate, nitrate, chloride, calcium, magnesium, potassium, sodium, silica, aluminum) by Rick Webb and Dr. James Galloway at the University of Virginia.

Hypotheses:

Ho:  Amphibian species richness and abundance are similar among streams differing in pH and ANC or other water quality variables.

Ho:  The four survey methods yield similar species richness and abundance data.

Electroshocking

Two 100 m transects for each of nine streams were electroshocked by the fish crews at Shenandoah National Park from June-August 1998.  Two amphibian technicians work behind the fish crews to capture and identify all amphibians encountered during the three-pass electroshocking period.  All amphibians are identified to species, measured for snout-vent length (measured to posterior end of cloaca) and total length, and weighed using a field portable OHaus scale(200 ± 0.01 g).   If individuals escape prior to measurement, record age class (larva, juvenile, adult) on the data sheet.

Leaf litter bags

We use the leaf litter bag method designed by Tom Pauley to survey streamside salamanders (Pauley 1995).  Leaf litter bags are placed at 5 m intervals along 100 m transects adjacent to yet upstream of the 100 m electroshocking transects.  At each 5 m interval along the 100 m transect, two bags are placed on the right and left sides of the stream, yielding a total of 42 bags per 100 m transect.   Leaf litter bags are placed in streams two weeks prior to the first check.   Leaf litter bags are constructed of plastic netting (Deer Block, 7' x 100' roll, 1.5 cm² mesh, $12.83/roll, available at Lowe’s), which are cut into 50 cm² squares.  In the field, approximately 0.5 pounds of small rocks, leaves, and moss are placed in the center of the netting, and the sides are gathered together and cinched together using a cable tie to make a sac.  A 12" piece of orange flagging tape is tied through the netting at the top of the leaf litter bag so that they are more visible in the stream.  The bags are placed at the edge of the stream and surrounded and topped with large rocks to keep them in place.

To check leaf litter bags, the rocks are carefully moved away from the bag (noting if any salamanders are under the rocks), and a dipnet is immediately placed underneath the leaf litter bag.  Shake the bag for 10 seconds inside the dipnet.  During the shaking, salamanders tend to fall out of the leaf litter bag.  Pick through leaf debris that falls into the dipnet to make sure you don't miss salamanders.   Salamanders in the dipnet are caught and placed into a ziploc bag.  The leaf litter bag is subsequently shaken for 10 seconds in a bucket of water.  This water is then poured through the dipnet to check for salamanders.  On the data sheet, record whether the salamander is caught from the initial shake or from the water bucket.

In 1998, leaf litter bags at each of the nine streams were checked twice, initially two weeks after placement, and again two weeks later.  On the second check, leaf litter bags were opened to make sure salamanders were not missed during the dipnet and water bucket shakes.  At two streams (North Fork Thornton and Jeremy’s Run), leaf litter bags were checked weekly until the end of October.  Over time, leaf litter often disintegrates in the bags.  Therefore, it is necessary to replace leaf litter once a month.

In 1999, we plan to continue monitoring leaf litter bags at the nine streams as well as other sites.  We will also use VIE marking to conduct capture-recapture studies of streamside salamanders at a subset of sites where leaf litter bags will be placed in clumps of three every 2 m along a 20 m transect.  We will also try a new technique of placing elongated leaf litter bags (0.25 m x 1 m) on the bank perpendicular to the stream channel.  We noted in 1998 that adult salamanders and anurans liked to hide under leaf litter bags in dry channels.  These will be checked weekly for amphibians.

Streamside 1 m² Quadrats

At five meter intervals next to the leaf litter bags, we use streamside 1 m² quadrat sampling (Mitchell 1998).  Quadrats are conducted on both sides of the stream, yielding 42 quadrats per 100 m transect.   This technique was previously used by Dr. Joe Mitchell at Shenandoah National Park at three streams (Staunton, Piney, and Paine).  In 1998, we repeated his sampling at these three streams, and initiated sampling at 6 new streams.  This sampling is destructive, as all stones within a 1 m² quadrat are overturned, and the area is raked.  Data collected within the quadrat is recorded on the Shenandoah Stream Quadrat  and the Shenandoah Stream Habitat data sheets.

50 m x 1 m Streamside Transects

A team of two people turn over rocks and other objects on the right and left sides of the stream along a 50 m x 1 m transect.  One person conducts the survey on the right side and one person works on the left side.  Time begin and time end are noted (search usually takes from 30 minutes to 1 hour), and the number of overturned objects is recorded on the data sheet.  A clicker assists the observer by counting the number of overturned objects within the 50 m transect.   When salamanders are found, the size of the cover object is recorded. Salamander species, age class, and size class are recorded.

Results

Table 1.  Amphibian species encountered in Shenandoah National Park, VA, watersheds during 1998 based on all methods used in this study.   Abbreviations:  A = abundant (> 20), C = common (5 - 19), and U = uncommon (< 5).  Dashed spaces indicate no observations.  The species codes are as follows:  Ebis = Eurycea bislineata; Dmon = Desmognathus monticola jeffersoni; Dfus = Desmognathus f. fuscus; Prub = Pseudotriton r. ruber; Gpor = Gyrinophilus p. porphyriticus; Pcyl = Plethodon cylindraceus; Pcin = Plethodon cinereus; Rcla = Rana clamitans melanota; Bwoo = Bufo woodhousei fowleri; Rsyl = Rana sylvatica; Rcat = Rana catesbeiana; Rpal = Rana palustris.

Fig. 2.  The number of amphibian species recorded using four survey methods (electroshocking, leaf litter bags, 1 m² quadrats, and 50 m transects) at nine streams in Shenandoah National Park.  In general, the 50 x 1 m transects tended to yield the greatest number of species.

Fig. 3.   The number of two-lined salamanders (Eurycea bislineata) recorded using four survey methods at nine streams in Shenandoah National Park.  All survey methods revealed the presence of this species, but none of the methods consistently yielded the highest counts.

Fig. 4.   The number of seal salamanders (Desmognathus monticola jeffersoni) recorded using four survey methods at nine streams in Shenandoah National Park.  1 m² quadrats appeared to be the best survey method for this species. 

Variation in Counts From Leaf Litter Bags
Eurycea bislineata and Desmognathus monticola

Table 2.  The mean number and coefficient of variation in counts of two-lined and seal salamanders in leaf litter bags at Jeremy's Run and North Fork Thornton visited biweekly from June-October 1998.  Note that at both streams the leaf litter bags caught more larvae than adults, and that the CV in counts was higher for adults than larvae.

Environmental Variables Measured at Stream Sites

Water Analysis Protocol

In 1998, we measured water temperature, conductivity, and pH at all sites monitored.  In 1999, we will also measure ANC (acid - neutralizing capacity).

We collect data on various habitat features at the stream sites (see below).  For the electroshocking transects, habitat data collected by the Shenandoah National Park electroshocking fish crew is provided by Jim Atkinson.

Stream width:  Measure using a meter stick.  Stream width is measured at each 10 m interval along transects.

Water depth:  Measure using a meter stick.  Water depth is measured at the leaf litter bag locations and also at each 10 m interval along transects 0.5 m from the edge of the stream and at the deepest part of the channel.

Water flow:  In 1999, we will use a flow meter.  Water flow will be measured next to each 1 m² quadrat, at each leaf litter bag, and also at each 10 m interval along transects.

Channel Type:

RU = Run (current is smooth on the surface and moves with great swiftness)
RA = Rapid (current moves with great swiftness and the surface is broken by obstructions but has no actual waterfall or cascade)
PO = Pool (a small body of standing or stagnant water, a quiet place in a stream)
CA = Cascade (a fall of water over steeply slanting rocks; a small fall or one of a series)
RI = Riffle (a patch of ripples or small waves, as caused by a light breeze on an otherwise calm or unbroken surface of water.)
DR = Dry (no visible moisture or water)

Substrate Type (% cover in 1 m² quadrats):

BA = Bank (river edge, soil, lacks rocks)
BL = Boulder (> 1.5 m in diameter)
LR = Large Rocks (0.5 - 1.5 m in diameter)
SR = Small Rocks (0.1 - 0.5 m in diameter)
RG = Rubble/Gravel (< 0.1 m in diameter)
WD = Woody Debris
HP = Herbaceous Plants
SH = Shrub
TR = Tree
LL = Leaf Litter

Bank Slope:  In 1999, the bank slope will be estimated by eye in 10° increments (e.g., 0-10°, 11-20°, 21-30°, etc.).

REFERENCES

PRIMENet Amphibian Monitoring Program Homepage

Patuxent Homepage