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Harvard Forest Data Archive

HF292

Red-backed Salamanders as Indicators of Hemlock Forest Health at Harvard Forest 2014

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Data

Overview

  • Lead: Aaron Ellison, Ahmed Siddig, Alison Ochs
  • Investigators:
  • Contact: Aaron Ellison
  • Start date: 2014
  • End date: 2014
  • Status: completed
  • Location: Simes Tract (Harvard Forest)
  • Latitude: +42.4658 to +42.4793
  • Longitude: -72.2182 to -72.2114
  • Elevation: 200 to 240 meter
  • Taxa: Plethodon cinereus (red-backed salamander), Tsuga canadensis (eastern hemlock)
  • Release date: 2017
  • Revisions:
  • EML file: knb-lter-hfr.292.2
  • DOI: digital object identifier
  • Related links:
  • Study type: short-term measurement
  • Research topic: large experiments and permanent plot studies; physiological ecology, population dynamics and species interactions; soil carbon and nitrogen dynamics
  • LTER core area: populations, disturbance
  • Keywords: carbon, leaf litter, nitrogen, salamanders, soil chemistry, soil moisture, soil temperature
  • Abstract:

    Species that react quickly to ecological changes are useful indicators for assessing forest health. Red-backed salamanders (Plethodontid cinereus) may be used as an indicator species in declining hemlock forests, allowing for assessment of soil quality and forest health. We hypothesized that decline of hemlock stands due to the effect of hemlock woolly adelgid would negatively impact the abundance of red-backed salamanders by altering soil quality. In the Hemlock Removal Experiment at Harvard Forest, eight-0.8ha plots were treated either with girdling to simulate adelgid invasion, logging to simulate preemptive logging strategies, no treatment in hemlock areas, or no treatment in hardwood areas. Within these treatments in June and July of 2014, P. cinereus relative abundance was determined from coverboard surveys. Soil quality was determined from core samples. Bulk density, pH, carbon-nitrogen ratio, moisture, soil temperature, and litter depth were measured, and ordination was used to create an index of soil quality from these. There was a significant correlation between plot treatment and soil quality (p less than 0.05). Temperature, CN ratio, and pH influenced a strong significant negative correlation between soil quality and salamander abundance (pless than 0.05). Soil quality affected by hemlock decline influenced salamander abundance. These data suggest that we could gain an understanding of forest health and soil quality by examining salamander abundance. Assessing adelgid invasion can be difficult and objective, whereas salamander abundances are easily measured; therefore, we suggest that salamander abundances could be useful in assessing the health of hemlock forest ecosystems.

  • Methods:

    Soil Collection

    Soil cores of consistent diameter were taken from 3 randomly chosen sites at each plot. The depth of leaf litter and the length of the soil core was measured in centimeters. By multiplying the diameter of the core by pi and the length of the core we determined the sample volume. We examined the soil to qualitatively determine its texture, and obtained the temperature from a thermometer inserted into the soil near the core. Samples were placed in plastic bags in a cooler and transported to the lab.

    Soil Analysis

    Soil samples were weighed and placed in brown paper bags. We dried the samples at 100*C for 48 hours, then weighed the dried samples. By subtracting the dry weight from the wet weight and dividing the difference by the wet weight, we obtained the soil percent moisture. We divided the dry weight, adjusted to account for the moisture of the bag, by the sample volume to determine the bulk density. The samples were sieved with a 2mm sieve and ground. To measure pH, we mixed 5 grams of soil with 25 mL of deionized water, stirred the solution for 1 minute using a magnetic stirrer, let the solution sit for 30 minutes, repeated the stirring and sitting process, then measured the pH with a pH electrode. C:N ratios were determined from dry combustion analysis of dried, sieved and ground samples of 5 mg.

    Salamander Data

    In each of the 8 plots, coverboards of 100x25x2 centimeters were set up and checked once a week. From the three coverboards in each plot where soil samples were taken, we averaged the number of salamanders found under the board for 6 sessions.

  • 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:

    Ellison A, Siddig A, Ochs A. 2017. Red-backed Salamanders as Indicators of Hemlock Forest Health at Harvard Forest 2014. Harvard Forest Data Archive: HF292.

Detailed Metadata

hf292-01: plot and salamander abundance data

  1. plot: plot number
  2. transect: transect number in each plot
  3. coverboard: coverboard number in each transect
  4. treatment: treatment type
    • HE: hemlock control
    • G: girdled
    • L: logged
    • HW: hardwood control
  5. moisture: percent soil moisture content of sample (unit: dimensionless / missing value: NA)
  6. bd: soil bulk density of sample (unit: dimensionless / missing value: NA)
  7. ll.depth: leaf litter depth (unit: millimeter / missing value: NA)
  8. temp: temperature of sample (unit: celsius / missing value: NA)
  9. ph: soil pH (unit: dimensionless / missing value: NA)
  10. cn: average carbon-nitrogen ratio of sample (unit: dimensionless / missing value: NA)
  11. rbs: average red-backed salamander abundance under coverboard (unit: number / missing value: NA)