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Harvard Forest Data Archive

HF075

Salamander Abundance at Harvard Forest 2003-2004

Related Publications

Data

Overview

  • Lead: Brooks Mathewson, Elizabeth Colburn
  • Investigators: David Foster
  • Contact: Elizabeth Colburn
  • Start date: 2003
  • End date: 2004
  • Status: completed
  • Location: Harvard Forest
  • Latitude: +42.45 to +42.54
  • Longitude: -72.22 to -72.17
  • Elevation: 230 to 340 meter
  • Taxa: Adelges tsugae (hemlock woolly adelgid), Ambystoma maculatum (spotted salamander), Notophthalmus viridescens (eastern red-spotted newt), Plethodon cinereus (eastern redback salamander), Tsuga canadensis (eastern hemlock)
  • Release date: 2006
  • Revisions:
  • EML file: knb-lter-hfr.75.16
  • DOI: digital object identifier
  • Related links:
  • Study type: short-term measurement
  • Research topic: physiological ecology, population dynamics and species interactions
  • LTER core area: populations
  • Keywords: abundance, hemlock, hemlock woolly adelgid, salamanders
  • Abstract:

    1. Eastern redback salamander relative abundance

    Eastern hemlock (Tsuga canadensis), an important late successional tree species, is currently threatened in this region by the hemlock woolly adelgid (Adelges tsugae), a small aphid-like invasive insect from Japan. While many species of birds and mammals have found to be associated with eastern hemlock dominated stands, there have been very few studies examining amphibian relative abundance in this forest type. Eastern redback salamanders (Plethodon cinereus) are important components of the forest ecosystem as they are extremely abundant with a biomass found to be twice that of breeding birds and equal to small mammals in the Hubbard Brook Experimental Forest. In addition, redbacks are positioned in the middle of the food web where they are important predators of soil invertebrates, potentially impacting soil respiration rates, and prey for larger vertebrates such as birds, reptiles, and small mammals. Redbacks have been cited as excellent indicators of forest health due to these characteristics as well as their low annual variation in abundance compared to other forest fauna. The objectives of this study was to 1) establish baseline data on eastern redback salamander relative abundance in eastern hemlock dominated stands and mixed deciduous stands in the Harvard Forest in Petersham, MA using artificial cover objects (ACOs) 2) test for differences in redback relative abundance based on forest type, 3) test for correlations between redback relative abundance and soil pH and forest floor temperature.

    2. Juvenile eastern red-spotted newt minimum density

    This study provides baseline estimates of juvenile eastern red-spotted newt (Notophthalmus viridescens viridescens) or "red eft" minimum density through visual surveys of transects in ten forest stands, five eastern hemlock (Tsuga canadensis) dominated and five mixed deciduous, located in the Prospect Hill, Slab City, Simes, and Tom Swamp tracts of Harvard Forest. The objectives of this study were to 1) acquire baseline minimum red eft density data at Harvard Forest, 2) test for potential differences in minimum density based on forest type, 3) test for correlations between minimum density and soil pH and forest floor temperature, 4) test for seasonal differences in minimum density estimates.

    3. Time-constrained intensive searches

    Intensive two minute searches of 1-m2 were conducted to measure eastern redback salamander (Plethodon cinereus) abundance and juvenile eastern red-spotted newt (Notophthalmus viridescens viridescens) or "red eft" abundance at ten stands, five eastern hemlock (Tsuga canadensis) dominated and five mixed deciduous stands, in the Prospect Hill, Slab City, Simes, and Tom Swamp tracts of Harvard Forest in fall 2003 and spring 2004. The objective of this study was to supplement other studies using artificial cover objects (ACOs) to measure eastern redback salamander relative abundance and transect walks to measure minimum density of red efts at Harvard Forest.

    4. Artificial cover objects

    Plethodontid salamanders are increasingly being cited as important indicators of forest health as they are major contributors to the overall faunal biomass in a forest. In addition, they are positioned in the middle of the food web where they are important predators of soil invertebrates, potentially impacting soil respiration rates, as well as prey for higher vertebrates such as birds, small mammals, and reptiles. Plethodon species also have lower annual coefficients of variation than other animals due to their small home ranges and terrestrial breeding habits. A relatively new technique used in assessing plethodontid abundance is the installation and monitoring of artificial cover objects (ACOs). Wood ACOs of different sizes have been effectively used as terrestrial salamander monitoring tools. However, there is a concern that the quality of habitat under wooden cover objects may change over time as they weather thus altering their ability to track real changes in salamander abundance. More rot-resistant materials such as asphalt shingles may provide more consistent habitat over time. This study compared the observation rates of the most common plethodontid species in this region, the eastern redback salamander (Plethodon cinereus) under artificial cover objects (ACOs) of the same surface area - 1m x 0.25m - but different materials - 2cm thick rough-cut eastern hemlock boards and asphalt shingles.

  • Methods:

    1. Eastern redback salamander relative abundance

    ACO stations were set up at 50m intervals along transects in the Prospect Hill, Slab City, Simes, and Tom Swamp tracts of Harvard Forest. Each ACO station consisted of one 2cm thick rough-cut eastern hemlock board (1m x 0.25m) and one asphalt shingle (1m x 0.25m) located 3m apart and parallel to the transect. Each of the ten stands in this study contained between four and twelve ACO stations. ACOs were monitored between one and six times per season. Temperature measurements were obtained through the installation of one remote temperature sensor (iButton) placed in the center of each transect and set to record temperature every half hour in spring 2004 (4/22/04 - 6/7/04) and every hour in fall 2004 (9/22/04 - 11/12/04). In early winter 2003 five soil samples were taken from random points just below the leaf litter in each transect and left to dry for two weeks and then soil pH was measured in the lab.

    2. Juvenile eastern red-spotted newt minimum density

    Minimum red eft density estimates were obtained by counting the number of red efts encountered within 0.5m of both sides of a transect. Between two and six transects were established in each stand. Transect lengths were between 73m and 107m, with the majority (20 of 31 transects) 90m long. Only red efts entirely within the surveyed area were counted. All searches were conducted by the same observer. The number of surveys per season in each stand varied from one to eight. The highest density value obtained for a stand in a season was used as the minimum density of red efts in that stand. This value was used as opposed to the average, because it is assumed that values lower than the maximum were a result of conditions that were not optimal for red efts to be on the surface of the forest floor. Both seasonal averages and maximums are reported in the data set. Temperature measurements were obtained through the installation of one remote temperature sensor (iButton) placed in the center of each transect and set to record temperature every half hour in spring 2004 (4/22/04 - 6/7/04) and every hour in fall 2004 (9/22/04 - 11/12/04). In early winter 2003 five soil samples were taken from random points just below the leaf litter in each transect and left to dry for two weeks and then soil pH was measured in the lab.

    3. Time-constrained intensive searches

    Twenty 1-m2 quadrats were searched in each of the ten stands both fall 2003 and spring 2004. Quadrats were selected randomly along transects established in each stand for a companion study examining red eft density using transect walks. Searches were conducted in the last week of September 2003 and the first week of October 2003. In the spring, intensive searches were conducted on eight separate dates between mid-April 2004 and mid-June 2004. On all sampling days an equal number of quadrats were searched in eastern hemlock and mixed deciduous stands, except at one site in the fall in which different forest types were searched on successive days. I searched for redbacks and red efts on the surface of the forest floor, within the leaf litter, and under natural cover objects such as stones and decaying logs. After each search cover objects were restored to as close to their original position as possible.

    4. Artificial cover objects

    ACO stations were set up at 50m intervals along transects established for a separate study of red eft minimum density in the Prospect Hill, Slab City, Simes, and Tom Swamp tracts of Harvard Forest. Each ACO station consisted of one 2cm thick rough-cut eastern hemlock board (1m x 0.25m) and one asphalt shingle (1m x 0.25m) located 3m apart and parallel to the transect. Each of the ten stands in this study contained between four and twelve ACO stations. ACOs were monitored between one and six times per season. Temperature measurements were obtained through the installation of one remote temperature sensor (iButton) placed in the center of each transect and set to record temperature every half hour in spring 2004 (4/22/04 - 6/7/04) and every hour in fall 2004 (9/22/04 - 11/12/04). In early winter 2003 five soil samples were taken from random points just below the leaf litter in each transect and left to dry for two week and then soil pH was measured in the lab.

  • 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. 2006. Salamander Abundance at Harvard Forest 2003-2004. Harvard Forest Data Archive: HF075.

Detailed Metadata

hf075-01: eastern redback salamander

  1. aco: artificial cover object number
  2. asn: ACO station number
  3. aco.name: original name given to ACO. First two letters are for Simes. Second two letters indicate forest type (TS = hemlock, HW = hardwood or mixed deciduous). First number indicates replicate number of forest type. Following letter indicates which transect ACO is perpendicular to (S = South, N = North, E = East, W = West). Next letter indicates whether ACO is board (B) or shingle (S). Next number indicates position along transect (2 = 20 meters from origin, 7 = 70 meters from origin).
  4. tract: Harvard Forest tract in which ACO is located
  5. forest.type: forest type
  6. aco.type: ACO type
  7. lat: latitude of ACO
  8. long: longitude of ACO
  9. datum: datum for latitude and longitude coordinates
  10. fa03.n: number of times ACO was monitored in fall 2003 (unit: number / missing value: NA)
  11. fa03.avg: average number of redbacks found during ACO searches in fall 2003 (unit: number / missing value: NA)
  12. sp04.n: number of times ACO was monitored in spring 2004 (unit: number / missing value: NA)
  13. sp04.avg: average number of redbacks found during ACO searches in spring 2004 (unit: number / missing value: NA)
  14. su04.n: number of times ACO was monitored in summer 2004 (unit: number / missing value: NA)
  15. su04.avg: average number of redbacks found during ACO searches in summer 2004 (unit: number / missing value: NA)
  16. fa04.n: number of times ACO was monitored in fall 2004 (unit: number / missing value: NA)
  17. fa04.avg: average number of redbacks found during ACO searches in fall 2004 (unit: number / missing value: NA)

hf075-02: eastern red-spotted newt

  1. id: identification number
  2. replicate: replicate number
  3. subsample: subsample number
  4. transect: transect name
  5. forest.type: forest type
    • MD: mixed deciduous
    • TS: eastern hemlock dominated
  6. tract: Harvard Forest tract. Simes 1 = plots 1-3 and plot 8 in HWA study at Simes Tract. Simes 2 = plots 4-6 and plot 7 in HWA study at Simes Tract.
  7. lat: latitude of origin of transect
  8. long: longitude of origin of transect
  9. datum: datum for latitude and longitude coordinates
  10. orientation: orientation of transect (degrees) (unit: number / missing value: NA)
  11. length: length of transect (unit: meter / missing value: NA)
  12. su03.n: number of times transects were walked in summer 2003 (unit: number / missing value: NA)
  13. su03.max.density: maximum red eft density found summer 2003 transect walks (individuals/m2) (unit: number / missing value: NA)
  14. su03.avg.density: average red eft density found during summer 2003 transect walks (individuals/m2) (unit: number / missing value: NA)
  15. fa03.n: number of times transects were walked in fall 2003 (unit: number / missing value: NA)
  16. fa03.max.density: maximum red eft density found fall 2003 transect walks (individuals/m2) (unit: number / missing value: NA)
  17. fa03.avg.density: average red eft density found during fall 2003 transect walks (individuals/m2) (unit: number / missing value: NA)
  18. sp04.n: number of times transects were walked in spring 2004 (unit: number / missing value: NA)
  19. sp04.max.density: maximum red eft density found spring 2004 transect walks (individuals/m2) (unit: number / missing value: NA)
  20. sp04.avg.density: average red eft density found during spring 2004 transect walks (individuals/m2) (unit: number / missing value: NA)
  21. su04.n: number of times transects were walked in summer 2004 (unit: number / missing value: NA)
  22. su04.max.density: maximum red eft density found summer 2004 transect walks (individuals/m2) (unit: number / missing value: NA)
  23. su04.avg.density: average red eft density found during summer 2004 transect walks (individuals/m2) (unit: number / missing value: NA)
  24. fa04.n: number of times transects were walked in fall 2004 (unit: number / missing value: NA)
  25. fa04.max.density: maximum red eft density found fall 2004 transect walks (individuals/m2) (unit: number / missing value: NA)
  26. fa04.avg.density: average red eft density found during fall 2004 transect walks (individuals/m2) (unit: number / missing value: NA)
  27. ph: measurement of pH directly below leaf litter taken from five samples along each transect (unit: number / missing value: NA)
  28. ibutton.lat: latitude of location of iButton (remote temperature sensor)
  29. ibutton.long: longitude of location of iButton (remote temperature sensor)
  30. ibutton.datum: datum for iButton latitude and longitude coordinates
  31. avg.temp.spring: average daily temperature (4/22/04 - 6/03/04) measured by one iButton located in the middle of the transect on the surface of the forest floor (unit: celsius / missing value: NA)
  32. avg.temp.sd.spring: standard deviation of daily temperatures (4/22/04 - 6/03/04) measured by one iButton located in the middle of the transect on the surface of the forest floor (unit: celsius / missing value: NA)
  33. avg.daily.max.spring: average daily maximum temperature (4/22/04 - 6/03/04) measured by one iButton located in the middle of the transect on the surface of the forest floor (unit: celsius / missing value: NA)
  34. avg.daily.min.spring: average daily minimum temperature (4/22/04 - 6/03/04) measured by one iButton located in the middle of the transect on the surface of the forest floor (unit: celsius / missing value: NA)
  35. avg.temp.fall: average daily temperature (9/22/04 - 11/13/04) measured by one iButton located in the middle of the transect on the surface of the forest floor (unit: celsius / missing value: NA)
  36. avg.temp.sd.fall: standard deviation of daily temperatures (9/22/04 - 11/13/04) measured by one iButton located in the middle of the transect on the surface of the forest floor (unit: celsius / missing value: NA)
  37. avg.daily.max.fall: average daily maximum temperature (9/22/04 - 11/13/04) measured by one iButton located in the middle of the transect on the surface of the forest floor (unit: celsius / missing value: NA)
  38. avg.daily.min.fall: average daily minimum temperature (9/22/04 – 11/13/04) measured by one iButton located in the middle of the transect on the surface of the forest floor (unit: celsius / missing value: NA)

hf075-03: time-constrained searches

  1. transect: name of transect along which quadrat was positioned
  2. tract: Harvard Forest tract in which quadrat was located
    • PH: Prospect Hill
    • TS: Tom Swamp
    • SC: Slab City
    • SI1: Simes tract (plots 1-3 and plot 8 in HWA experiment)
    • SI2: Simes tract (plots 4-6 and plot 7 in HWA experiment)
  3. forest.type: forest type of stand in which quadrat was located
    • MD: mixed deciduous
    • TS: eastern hemlock dominated
  4. lat: latitude of the origin of transect in which quadrat was located
  5. long: longitude of the origin of transect in which quadrat is located
  6. datum: datum for latitude and longitude coordinates
  7. orientation: orientation of transect along which quadrat was located
  8. fa03.date: date on which quadrats along transect were sampled
  9. sp04.date: date on which quadrats along transect were sampled
  10. fa03.pc.ab: redback abundance in fall 2003 (individuals/m2) (unit: number / missing value: NA)
  11. fa03.nv.ab: red eft abundance in fall 2003 (individuals/m2) (unit: number / missing value: NA)
  12. sp04.pc.ab: redback abundance in spring 2004 (individuals/m2) (unit: number / missing value: NA)
  13. fa04.nv.ab: red eft abundance in spring 2004 (individuals/m2) (unit: number / missing value: NA)