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Harvard Forest Data Archive

HF131

Eastern Redback Salamander Abundance in North Central Massachusetts 2005

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Data

Overview

  • Lead: Brooks Mathewson, Elizabeth Colburn
  • Investigators: David Foster, Paul Sievert
  • Contact: Elizabeth Colburn
  • Start date: 2005
  • End date: 2005
  • Status: completed
  • Location: North Central Massachusetts
  • Latitude: +42.45 to +42.68
  • Longitude: -72.39 to -71.89
  • Elevation: 212 to 560 meter
  • Taxa: Adelges tsugae (hemlock woolly adelgid), Plethodon cinereus (eastern redback salamander), Tsuga canadensis (eastern hemlock)
  • Release date: 2009
  • Revisions:
  • EML file: knb-lter-hfr.131.12
  • DOI: digital object identifier
  • Related links:
  • Study type: short-term measurement
  • Research topic: physiological ecology, population dynamics and species interactions; regional studies
  • LTER core area: populations, disturbance
  • Keywords: abundance, hemlock, hemlock woolly adelgid, salamanders
  • Abstract:

    Throughout the twentieth century several dominant tree species suffered severe decline in the eastern United States due to exotic pests and pathogens, yet little is known of the effects these losses have on ecosystem processes or associated wildlife populations (Orwig 2002). Eastern hemlock (Tsuga canadensis), an important late-successional tree species, is currently threatened throughout its range by the hemlock woolly adelgid (Adelges tsugae; HWA), an invasive insect pest native to Japan (Orwig and Foster 1998). The unique structure and microenvironment of hemlock-dominated forests create critical landscape level heterogeneity, providing habitat for numerous bird and mammal species several of which are strongly associated with hemlock stands in the Northeast (Yamasaki et al. 2000). The effects of hemlock loss on associated wildlife is largely unknown, but is of particular concern for terrestrial salamanders as they are sensitive to microclimatic conditions that are likely to change as hemlocks decline. In this study, populations of eastern red-backed salamanders (Plethodon cinereus), significant contributors to the overall vertebrate biomass in northeastern forests (Burton and Likens 1975a), are compared in hemlock-dominated and mixed deciduous forest.

    The objectives of this study was to 1) to determine whether the relative abundance, body condition, and size class structure of P. cinereus populations differ in hemlock-dominated forests versus mixed deciduous forests in north-central Massachusetts. A difference in age-class structure in the two forest types may suggest a difference in survivorship, while differences in body condition are driven by differences in the energy expenditure required to obtain food resources and can lead to differences in reproductive success 2) to evaluate how structure and microenvironment differ and determine which variables best predict the variation in relative abundance and body condition of P. cinereus in the two forest types. Results from earlier work as well as evidence that cooler, moister habitat and higher abundance of prey is found in hemlock-dominated forest led me to hypothesize that P. cinereus relative abundance and body condition would be higher in plots in this forest type.

  • Methods:

    Fifteen paired, circular, 0.33 ha plots were distributed throughout north central Massachusetts (Figure 1) on land owned by the state of Massachusetts or Harvard University. I used maps developed from aerial photography (Orwig et al. unpubl) to identify potential paired sites, less than 750 m apart, in which the basal area (m2 ha-1) of hemlock was greater than 50% in one and less than 25% in another. If field surveys confirmed that sites were likely to meet these criteria, a random center point, farther than 57.5 m from the edge of the stand, and compass heading were selected and perpendicular 50 m transects intersecting at the center point were established. ACO stations were then set up at the ends of each transect and at their intersection. At each ACO station a pair of green, rough-cut, untreated, 2-cm thick, 1 m x 0.25 m, eastern hemlock boards were installed 3m apart parallel to one another and the transect between May 11, 2005 and June 13, 2005. Each ACO was monitored every two to three weeks between June 13th, 2005 and November 4th, 2005 (n = 2380 ACO observations). Paired hemlock-dominated and adjacent mixed deciduous plots at each site were always sampled on the same day. All amphibian and reptile species observed under ACOs were recorded. Snout-vent length (SVL) (+/- 1mm) was recorded for all amphibians, and weight (+/- 0.01g), total length (TL) (+/- 1mm), and sex were also measured for all P. cinereus.

  • Use:

    This dataset is released to the public under Creative Commons license CC BY (Attribution). Please keep the designated contact person informed of any plans to use the dataset. Consultation or collaboration with the original investigators is strongly encouraged. Publications and data products that make use of the dataset must include proper acknowledgement.

  • Citation:

    Mathewson B, Colburn E. 2009. Eastern Redback Salamander Abundance in North Central Massachusetts 2005. Harvard Forest Data Archive: HF131.

Detailed Metadata

hf131-01: plot

  1. plot: plot code
  2. site: site code
  3. ft: forest type
    • TS: eastern hemlock dominated (greater than 50% basal area eastern hemlock)
    • MD: mixed deciduous (less than 25% basal area eastern hemlock)
  4. asn: artificial cover object (ACO) station number
  5. lat: latitude of center point of ASN (hddd°mm.mmm')
  6. long: longitude of center point of ASN (hddd°mm.mmm')
  7. datum: datum for latitude and longitude coordinates
  8. ba: average basal area as measured in a 7.5m radius subplot surrounding the ACO station (unit: meterSquaredPerHectare / missing value: NA)
  9. st.ha: average number of stems (DBH > 5cm) per hectare as measured in a 7.5m radius subplot surrounding the ACO station (stems / hectare) (unit: numberPerHectare / missing value: NA)
  10. ts: the percentage of overall basal area accounted for by eastern hemlock in a 7.5 m radius sub-plot surrounding the ACO station (unit: dimensionless / missing value: NA)
  11. bearing: compass heading
    • numeric value: compass heading (degree)
    • FLAT: no compass heading
    • NA: missing value
  12. aspect: aspect
  13. slope: slope as measured by clinometers (percentage)
    • numeric value: slope as measured by clinometers (percentage)
    • FLAT: no slope
    • NA: missing value
  14. canopy.cover: percentage canopy cover above center point of ASN as measured by densitometer (unit: dimensionless / missing value: NA)
  15. cwd.no: number of pieces of coarse woody debris (diameter greater than 2.5 cm) encountered along three 7.5m transects originating from center point of ACO station at 30°, 150°, and 270° (unit: number / missing value: NA)
  16. cwd.con: number of pieces of coarse woody debris (diameter greater than 2.5 cm) in contact with the soil encountered along three 7.5m transects originating from center point of ACO station at 30°, 150°, and 270°. (unit: number / missing value: NA)
  17. vcwd: all pieces of coarse woody debris (diameter greater than 2.5 cm) encountered along three 7.5m transects originating from center point of ACO station at 30°, 150°, and 270° were measured and the volume of coarse woody debris was then calculated using the formula V= 9.869* (d /8L), where L is squared (Harmon & Sexton 1996) (unit: meterCubedPerHectare / missing value: NA)
  18. vcwd.con: all pieces of coarse woody debris (diameter greater than 2.5 cm) in contact with the soil encountered along three 7.5m transects originating from the center point of each ACO station at 30°, 150°, and 270° were measured and the volume of coarse woody debris was then calculated using the formula V= 9.869* (d /8L), where L is transect length and d is diameter of CWD squared (Harmon & Sexton 1996) (unit: meterCubedPerHectare / missing value: NA)
  19. avg.dc: average decay class of coarse woody debris. Scale of 1 to 5: 1 being the least decayed.
    • 1: solid wood, recently fallen, bark and twigs present
    • 2: solid wood, significantly weathered, branches present
    • 3: wood not solid, bark may be sloughing but nail still must be pounded into the wood
    • 4: wood sloughing and/or friable, nail may be forcibly pushed into wood
    • 5: wood friable, barely holding shape, nail may be easily pushed into wood
  20. tot.snags: total number of snags within 7.5 m sub-plot around center point of ASN (unit: number / missing value: NA)
  21. avg.snag.ht: average height of snags in 7.5 m sub-plot surrounding ACO station (unit: meter / missing value: NA)
  22. avg.snag.dbh: average diameter at breast height of snags in 7.5 m sub-plot surrounding ACO station (unit: centimeter / missing value: NA)
  23. soil.ph: soil pH measured from soil sample of organic layer taken at one randomly selected point in each sub-plot (-log[H+]) (unit: dimensionless / missing value: NA)

hf131-02: trees

  1. stem.master: number of stem overall
  2. plot: plot code
  3. asn: artificial cover object (ACO) station number
  4. stem.asn: stem number within ASN
  5. species: tree species. Standard four letter tree codes (first two letters of genus and species
  6. dbh: diameter at breast height (all specimens with DBH greater than 5 cm were recorded (unit: centimeter / missing value: NA)
  7. alive: whether tree was alive or dead
    • Y: yes
    • N: no
  8. sh: height of snag (only applicable with dead specimens) (unit: meter / missing value: NA)

hf131-03: coarse woody debris

  1. cwd.no: number of coarse woody debris (diameter greater than 2.5 cm)
  2. site: site code
  3. ft: forest type
    • TS: eastern hemlock dominated (greater than 50% basal area eastern hemlock)
    • MD: mixed deciduous (less than 25% basal area eastern hemlock)
  4. plot: plot code
  5. asn: artificial cover object (ACO) station number
  6. tr: degree heading of 7.5m transect (30°, 150°, or 270°) (unit: degree / missing value: NA)
  7. species: species of coarse woody debris observed. Standard tree species codes (1st two letters of genus and 1st two letters of species)
  8. diam: diameter of coarse woody debris (unit: centimeter / missing value: NA)
  9. dc: decay class. Scale of 1 to 5: 1 being the least decayed.
    • 1: solid wood, recently fallen, bark and twigs present
    • 2: solid wood, significantly weathered, branches present
    • 3: wood not solid, bark may be sloughing but nail still must be pounded into the wood
    • 4: wood sloughing and/or friable, nail may be forcibly pushed into wood
    • 5: wood friable, barely holding shape, nail may be easily pushed into wood
  10. c: whether the CWD is in contact with the soil
    • Y: yes
    • N: no

hf131-04: aco observations

  1. datetime: date and time
  2. date: date
  3. aco: artificial cover object (ACO) number
  4. plot: plot code
  5. asn: artificial cover object (ACO) station number
  6. airt: air temperature at the surface of the soil measured at one ACO per plot per monitoring session (unit: celsius / missing value: NA)
  7. rh: relative humidity (percentage) (unit: dimensionless / missing value: NA)
  8. soilt: soil temperature at 5cm measured at one ACO per plot per monitoring session (unit: celsius / missing value: NA)
  9. time: time of ACO monitoring and climatic measurements
  10. pca: number of Plethodon cinereus observed under ACO (unit: number / missing value: NA)
  11. pcn: Plethodon cinereus specimen number
  12. em.aco: ACO at which soil temperature, air temperature, and relative humidity were measured for sampled plot
  13. osn: specimen number of other species of herpetofauna observed
  14. other.sp: species of other species of herpetofauna observed
    • NOVI: Notophthalmus viridescens viridescens
    • THIS: Thamnophis sirtalis
    • AMMA: Ambystoma maculatum
    • RASY: Rana sylvatica
    • STOC: Storeriea o. occipitomaculata
    • EUBI: Eurycea bislineata

hf131-05: pc abundance

  1. pc.no: number of Plethodon cinereus observed
  2. date: date
  3. plot: plot in which species was observed
  4. aco: artificial cover object (ACO) number
  5. p: phase
    • R: redback phase
    • L: leadback phase
  6. svl: snout-vent length in millimeters as measured from tip of snout to behind back leg (+/- 1mm) (unit: millimeter / missing value: NA)
  7. tl: total length in millimeters as measured from tip of snout to end of tail (+/- 1mm) (unit: millimeter / missing value: NA)
  8. wt: weight in centigrams (+/- 0.01 g) (unit: centigram / missing value: NA)
  9. sex: sex of adults (SVL greater than 35 mm) determined by snout shape - males square snout females - rounded snout
    • M: male
    • F: female

hf131-06: other herps

  1. osn: number of observation
  2. date: date
  3. plot: plot in which species was observed
  4. aco: artificial cover object number
  5. species: species of amphibians or reptile observed
    • NOVI: Notophthalmus viridescens viridescens
    • THIS: Thamnophis sirtalis
    • AMMA: Ambystoma maculatum
    • RASY: Rana sylvatica
    • STOC: Storeriea o. occipitomaculata
    • EUBI: Eurycea bislineata
  6. svl: snout-vent length in millimeters as measured from tip of snout to behind back leg (+/- 1mm) (unit: millimeter / missing value: NA)
  7. tl: total length in millimeters as measured from tip of snout to end of tail (+/- 1mm) (unit: millimeter / missing value: NA)
  8. weight: weight in centigrams (+/- 0.01 g) (unit: centigram / missing value: NA)