Adam Galambos 1 14 · Adam Galambos October 26, 2017 Page 4 of 14 coverboard array is comprised of 42 boards along 3 transects located 50 meters apart. Along each transect, alternating

Adam Galambos October 26, 2017

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Red-Backed Salamander Abundance Relative to Plant Community Composition of a

Transitional Northern Hardwood Forest

Abstract

A 28-hectare transitional northern hardwood forest was surveyed for Plethodon

cinereus density in addition to conducting adjacent vegetation surveys using plotless and

quadrat techniques. Due to higher shading from a dense canopy cover, substantial ground litter

layer and a high soil pH, it is hypothesized that P. cinereus density is higher in areas where

higher basal areas of deciduous trees exist versus coniferous trees. The data show higher

capture numbers in areas of high dominance of coniferous trees such as white pine. The data

did not support this hypothesis and as such, failed to reject the null hypothesis. Small sample

size and lack of group identification skills were likely sources of error in this study.

Introduction

Understanding the relationship responses between eastern red-back salamander

populations and forest management techniques can provide a framework for future

management and restoration efforts to preserve or enhance biodiversity within a forest.

Plethodontid salamander populations are highly indicative of rates and efficiency in several

ecological processes, such as nutrient and energy cycling through forest floor biota (Welsh &

Droege, 2001). Plant community composition within forests can influence Plethodon cinereus

abundance in terms of soil pH, canopy cover, groundcover composition, and species

composition and changes in presence or abundance of bioindicators such as P. cinereus are


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quick to reflect the status of an ecosystem. Artificial herpetofauna coverboard arrays are often

studied due to their ability to replicate natural habitat and low cost of deployment and

maintenance. In 2013, an artificial herpetofauna coverboard array was installed at the

Massachusetts College of Liberal Arts 28-hectare forest to study trends in P. cinereus

populations. Forest management practices and use patterns can directly manipulate

microhabitat characteristics important to terrestrial plethodontid salamanders (McKenny,

Keeton, & Donovan, 2006). To further the understanding these impacts have, we surveyed P.

cinereus populations along each of the three transects in the coverboard array and compared

results to previous years to establish P. cinereus density trends relative to historic air and soil

temperature and days since last rainfall.

In addition, plotless and quadrat vegetation surveys were conducted at each of the

three transects along the coverboard array to identify if relationships exist in P. cinereus density

and vegetation composition. This is an important metric to further the understanding of how

the vegetation has responded to management practices and provides quantitative data about

structure and species composition of a plant community. Due to higher shading from denser

canopy cover, a more substantial ground litter layer and a high soil pH, it is hypothesized that P.

cinereus density is higher in areas where higher basal areas of deciduous trees exist versus

coniferous trees.

Methods

The study area is an approximate 28-hectare transitional northern hardwood forest

owned and managed by Massachusetts College of Liberal Arts in the city of North Adams,


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Massachusetts (42.686215, -73.085775) (Figure 1). This forest is abutted by parcels with varying

land uses and occupancy. Residential parcels are abutting the forest to the North and

Northwest, there is a road to the Northeast, an athletic complex to the East, a small-scale cattle

and horse farm to the South, and a small freshwater pond to the West. Additionally, there is an

approximate 5-meter maintained dirt road bisecting the forest.

Figure 1 Study area showing three transected located 50 meters apart. Coverboards are placed along each transect, 50 meters apart to create a grid.

On October 4th, 2017, we surveyed an artificial herpetofauna coverboard array for P.

cinereus. The air temperature was approximately 10.5°C to 12.2°C, 94% relative humidity, and

winds were calm. The last rainfall event in the study area was on September 30, 2017. The


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coverboard array is comprised of 42 boards along 3 transects located 50 meters apart. Along

each transect, alternating large (1.44 m2) and small (0.36 m2) coverboards are located every 50

meters. The coverboard array, installed and maintained by the Environmental Studies

department at MCLA, was first installed in 2013 and has been surveyed annually since install.

Data was tabulated and analyzed using Microsoft Excel. P. cinereus density/m2 was calculated

using the formula . Historic survey data was also obtained for

2016-2013.

On October 11, 2017 vegetation monitoring was conducted on plant community

composition along each of the coverboard array transects within the forest. The R.F.

Duabenmire quadrat vegetation survey method was used in addition to a plotless “prism”

survey using a Cruz-All prism set a BAF 10. We began the vegetation survey using the R.F.

Duabenmire modified forest sampling technique. At each of the three coverboard array

transects a 15 meter x 25 meter quadrat was established randomly by throwing a DBH tape

over our shoulder. Each quadrat was divided into three 5 meter x 25 meter sections. In total,

1,125 m2 were surveyed for trees greater than 2 meters tall, shrubs and sapling trees between

0.5 – 2 meters tall, the percent coverage of all vegetation less than 0.5 meters in height, and

the percent cover of the available ground substrate including forest litter, bare ground, rock,

water, moss, and coarse woody debris greater than 15 cm. Tree data consisted of DBH and

species. Shrubs and saplings were counted with respect to species within the quadrat. In

quadrats where shrubs and saplings were evenly distributed, only those in the central 5 meter x

25 meter section was counted and the result was multiplied by three. Percent coverage for all


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vegetation less than 0.5 meters in height was estimated and the percent cover of the available

ground substrate was established using a 25cm x 25cm plastic frame placed at every 5 meters

along the middle 25 meter transect line at each of the three transects. Each time the frame was

placed on a 5-meter mark, the percentage of the frame’s area covered by each plant species,

litter, bare ground, rock, or CWD was recorded using the coverage class table (Table 1).

Table 1: Coverage Class Table - Conversions Coverage Class Percent Coverage Mean Coverage

1 <1 t 2 1-5 3 3 5-25 15 4 25-50 37.5 5 50-75 62.5 6 75-95 85 7 95-99 97 8 100 100

We also elected to use a “plotless” prism sampling technique to survey and compare

results. A Cruz-All prism was used to measure the basal area using the center of the established

quadrat at each of the three coverboard array transects. Once the center point of the quadrat

was determined, the area was surveyed using the device calibrated to the 10 BAF slot.

Results

The highest P. cinereus density occurs along transect B at 3.25/m2 with the highest BA/A

of coniferous trees at 36.84 m2/Ha versus 23 m2/Ha of deciduous trees (Figure 2). Transect A

has the lowest P. cinereus density at 2.54/m2 and the highest BA/A of deciduous trees at 64.4

m2/Ha.


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Figure 2 Basal area per area (m2/Ha) of deciduous trees (dark bars) and coniferous trees (light bars) along all three transects of an artificial coverboard array consisting of 42 coverboards equally distributed. P. cinereus density (#/m2) is shown as dark line. Highest P. cinereus density occurs along transect B. Surveyed 9/2017, MCLA Forest in North Adams, MA.

Higher densities of P. cinereus are found under small coverboards in all three transects.

The highest density of P. cinereus occurs under small coverboards along transect C at 7.937/m2

and the lowest also occurs along transect C under large coverboards at 1.786/m2. Collectively,

P. cinereus density under small coverboards is 6.08/m2 and 2.08/m2 under large coverboards

(Figure 3). Historic data show that small coverboards have consistently higher densities as

compared with large coverboards (Figure 3).


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Figure 3 P. cinereus density along all three transects comparing large coverboards (light bars) vs small coverboards (dark bars). Large boards cover 1.44m2 and small boards cover 0.36m2.

Figure 4 Average density of P. cinereus survey results at MCLA forest artificial coverboard array 2013 – 2017. All three transects of the coverboard array were surveyed once per year. These results were added and averaged.

Mean soil temperature and air temperature relative to number of P. cinereus captures

show a record high of 111 captures occurring with record low soil and air temperatures (Figure


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4). In addition, mean soil and air temperatures are the closest together since 2013, correlating

with record high captures.

Figure 5 Mean soil temperature (light bars) and air temperature (dark bars) at MCLA forest artificial coverboard array versus total P. cinereus found (light line) during annual surveys between 2013 – 2017. Soil temperature in year 2013 was unavailable for inclusion.

Plotless tree layer vegetation survey data at transect B show sugar maple (Acer

saccharum) and white pine (Pinus strobus) equal in BA/A at 16.1 m2/ha with a frequency of

36.8% each. Total BA/A of the tree layer using the plotless “prism” method is 43.7 m2/ha (Table

2). Quadrat vegetation sampling data at transect B show is close to the plotless method at

38.28 m2/ha with beech (Fagus grandifolia) occurring in the highest frequency and white pine

(Pinus strobus) having the highest BA/A at 13.98 m2/ha (Table 3). Herb layer at transect B


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contained 93.7% leaf litter, 10% course woody debris (CWD), and 3.75% hay-scented fern

(Table 5)

Table 2. Summarized data plotless (variable) Tree Layer – Transect B

Species BA/A (m2/ha) Frequency %

Pinus strobus 16.1 36.8

unknown standing dead 4.6 10.5

Acer saccharum 16.1 36.8

Prunus serotina 4.6 10.5

Acer rubrum 2.3 5.3

Table 3. Summarized data from tree layer (fixed plot) – Transect B

Species Relative Dominance Frequency (%) Basal Area (m2/ha)

Fagus grandifolia 0.06 39.5 2.15

Betula lenta 0.02 20.9 0.83

Betula papyrifera 0.00 4.7 0.16

Prunus serotina 0.09 2.3 3.61

Acer rubrum 0.15 4.7 5.63

Acer pensylvanicum 0.01 4.7 0.24

Acer saccharum 0.12 4.7 4.75 unknown standing

dead 0.18 9.3 6.93

Pinus strobus 0.37 9.3 13.98

Total: 1.00 100 38.28

Table 4: Summarized data from shrub layer – Transect B

Species Density (stems/ha) Fagus grandifolia 240

Betula lenta 80 Viburnum lantanoides 80

Berberis thunbergii 80 Total: 480


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Table 5: Summarized herb layer – Transect B

Species/Type Mean Cover (%) Frequency (%)

CWD 10 10

Leaf litter 93.75 100

Hay-scented fern 3.75 10

Total: 107.5 120

Figure 5 Days since last rain between 2013 and 2017 versus total captures of P. cinereus. R^2= 0.03


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Discussion

In this study, it was expected that prime P. cinereus habitat would be located in areas

where there is a higher basal area of deciduous trees due to their ability to provide more

shading, create more leaf litter to trap moisture along with having a less acidic soil profile as

compared with coniferous trees. It was hypothesized that P. cinereus density is higher in areas

where higher basal areas of deciduous trees exist versus coniferous trees. The data show that

the highest P. cinereus density occurs along transect B which has higher coniferous trees than

deciduous trees, failing to reject the null hypothesis.

McKenny et. al 2006 states that forests exhibiting closed canopies that maintain cool,

moist, interior forest microclimates are prime habitat for P. cinereus. They particularly inhabit

areas with un-compacted soils combined with a large percent of course woody debris and an

undisturbed leaf litter layer. Our data show that this transitional northern hardwood forest,

albeit lacking some of the more northern species in the classification, does have variability

within the parcel (Swain et al 2000). There is clear evidence of past anthropogenic disturbances,

likely logging and land clearing, as evidenced by white pine being the most dominant species

within the parcel.

There were also significantly higher salamander densities under small coverboards as

compared to large coverboards. This observation is also applicable to available historic data

back to 2013. The increase was nearly 2-fold and it is unclear what attributes to that trend,

however, it is an excellent indicator of forest health.


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Time since last rainfall is an important metric to consider as it allows an understanding

of water/moisture retention within the soil as well as drought indices. Historic data (2017-2013)

show a decrease in P. cinereus captures as days since last rain increases (R=0.031) (Figure 5). In

addition to precipitation, mean air and soil temperature greatly influence P. cinereus behaviors

such as depth of burrow, mating, and foraging (Pough, Smith, Rhodes, & Collazo, 1986). Mean

soil and air temperatures were the lowest they have been since 2013 which, as mentioned,

correlates with record high captures.

Vegetation survey methods were likely the largest source of errors. Specifically, the

groups’ lack of a standard level of botanical knowledge and undeveloped identification skills has

been identified as a source of error. The accepted vegetation survey sample size in any given

plot is approximately 5% and this study was only about 0.4% of the entire 28-hectare forest.

Although both quadrat and plotless sampling techniques were used, they were relatively similar

for some plots while others were significantly varying. It cannot be inferred that the forest

composition is skewed towards high dominance of white pine although aerial photography

shows high percentage of needle-canopy cover (evergreen) during a late fall/early spring view.

The lack of a sufficient sample size is coupled with a skewed sample area. The sample area was

weighted towards the southern end of the forest when it should have been randomly selected

to provide and increase confidence factor about the data.

Conclusion

Due to higher shading from denser canopy cover, a more substantial ground litter layer

and a high soil pH, it is hypothesized that P. cinereus density is higher in areas where higher


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basal areas of deciduous trees exist versus coniferous trees. The data show higher capture

numbers in areas of high dominance of coniferous trees such as white pine. The data did not

support this hypothesis and as such, failed to reject the null hypothesis. Small sample size and

lack of group identification skills were likely sources of error in this study.

Bibliography

McKenny, H. C., Keeton, W. S., & Donovan, T. M. (2006). Effects of structural complexity enhancement on eastern red-backed salamander (Plethodon cinereus) populations in Northern Hardwood Forests. Forest Ecology and Management, 186-196. Retrieved from https://www.uvm.edu/rsenr/vtcfwru/spreadsheets/occupancy/Occupancy%20Exercises/Exercise8/McKenney%20et%20al.%20Published.pdf

Pough, H. F., Smith, E. M., Rhodes, D. H., & Collazo, A. (1986). The abundance of salamanders in forest stands with different histories of disturbance. Forest Ecology and Management, 1-9. Retrieved from https://www.srs.fs.usda.gov/pubs/ja/ja_pough001.pdf

Semlitsch, R. D. (2002). Critical elements for biologically based recovery plans of aquatic-breeding amphibians. Conservation Biology, 619-629.

Swain, P. C., & Kearsley, J. B. (2000). Classification of the Natural Communities of Massachusetts. Natural Heritage and Endangered Species Program, Mass DFW, T-80.

Welsh, H. H., & Droege, S. (2001). A case for using plethodontid salamanders for monitoring biodiversity and ecosystem integrity of North American forests. Conservation Biology, 558-569.


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Adam Galambos 1 14 · Adam Galambos October 26, 2017 Page 4 of 14 coverboard array is comprised of 42 boards along 3 transects located 50 meters apart. Along each transect, alternating