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Harvard Forest Data Archive

HF203

Ungulate-Disturbance Interactions in Hemlock Ecosystems at Harvard Forest since 2012

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Data

Overview

  • Lead: Edward Faison, Stephen DeStefano, Aaron Ellison
  • Investigators: Audrey Barker Plotkin
  • Contact: Edward Faison
  • Start date: 2012
  • End date: 2013
  • Status: ongoing
  • Location: Simes Tract (Harvard Forest)
  • Latitude: +42.47 to +42.48
  • Longitude: -72.22 to -72.21
  • Elevation: 200 to 240 meter
  • Taxa: Alces alces (moose), Betula lenta (black birch), Erethizon dorsatum (porcupine), Odocoileus virginianus (white-tailed deer), Tsuga canadensis (eastern hemlock)
  • Release date: 2013
  • Revisions:
  • EML file: knb-lter-hfr.203.7
  • DOI: digital object identifier
  • Related links:
  • Study type: long-term measurement
  • Research topic: biodiversity studies; conservation and management; invasive plants, pests and pathogens; large experiments and permanent plot studies; physiological ecology, population dynamics and species interactions
  • LTER core area: populations, disturbance
  • Keywords: browsing, deer, disturbance, hemlock, hemlock woolly adelgid, moose, regeneration
  • Abstract:

    Densities of ungulates are often associated with recent forest disturbances such as fire, logging and insect outbreaks, as increased resources stimulate tree regeneration, leading to abundant available browse. Despite the often significant role that ungulates play in disturbed forests, surprisingly little is known about ungulate-disturbance interactions, and ungulate herbivory is often excluded from examinations of forest response to disturbance. In the Northeastern United States, a large-scale insect outbreak, the hemlock wooly adelgid (HWA), has begun to have important effects on hemlock forests both directly and indirectly (i.e., by preemptive salvage logging). No studies have examined the interactions of both moose and deer activity with these associated canopy disturbances. Our objectives are twofold: to determine (1) the response of ungulates to varying disturbance types and intensities and (2) the influence of ungulate interactions with canopy disturbance on vegetation, other biota, and ecosystem processes. We will examine the relative abundance of moose and deer in four treatments (2 replicates) at the Hemlock Removal Experiment using three indices of ungulate activity: pellet group density, evidence of past browsing on seedlings and saplings, and the occurrence of animals using game cameras. We will also monitor the response of vegetation to ungulate browsing by sampling woody and herbaceous vegetation in fenced exclosures and paired controls in disturbed and undisturbed plots.

  • Methods:

    Exclosures

    A single 15x30m exclosure was erected in the center of each of the eight, 90m x 90m treatment plots at the Hemlock Removal Experiment at Simes in the Fall of 2011. Paired 450 m2control plots were established adjacent to the exclosures. Pre-exclosure data on tree regeneration and browsing were gathered in 2008 using an 8 x 3 grid of 4m2 circular subplots (96m2 total) in both the control and exclosure plots.

    Woody Regeneration

    In each of the 24 subplots in the fenced and unfenced plots, tree and upright shrub seedlings at least 30 cm and less than 2.5 cm DBH are recorded, identified, and measured for height. Regeneration for at least 2.5 cm DBH is measured for DBH.

    Low Shrubs and Herbaceous Vegetation

    In each of the 24 subplots in the fenced and unfenced plots, the percent cover of graminoids, Rubus, Fern, Forb, and Ericaceous shrubs are estimated using the following cover classes: 0 = absent, 1 = 1-24%, 2= 25-49%, 3 = 50-74%, 4 = 75-100%.

    Browsing

    Each woody stem at least 30 cm and no more than 3m is assessed for past browsing by estimating the percentage of twigs branching off the main stem that are browsed. Stems are assigned to one of the following browsing classes: (0 = none, 1=1-33% twigs browsed, 2 = 34-66% twigs browsed, 3 = 67-100% twigs browsed). Browsers are identified as either U for ungulate (torn, ragged, squared off bite), P for porcupine (45 degree angle clean cut), or UP if both browsers have foraged on the stem. For stems above maximum browse height (3m), legacies of past browsing are assessed by recording the number and heights of crooks (resulting from a single lateral bud replacing damaged terminal shoot) and forks (two lateral buds that have replaced damaged terminal twig) on the stem.

    Pellet Groups

    Pellet Groups are sampled in each of the 15 x 30 m control plots using five 3x30 m belt transects. Two observers walk the transects in tandem and record pellet groups. A group is defined as having at least 15 pellets. Pellet groups are sampled once a year (or once every other year) without removal so as not to disturb other measurements such as soil characteristics and vegetation growth that may be influenced by ungulate pellet deposition.

    Game Cameras

    Game Cameras are installed on the post of each exclosure (approximately in the center of the plot at 1.5 m high) facing into the control plot. Cameras are checked bi-weekly for pictures and average visitation time to plots (per week), total time recorded in plots, and average duration of single visits will be determined for moose, deer, and other wildlife.

  • 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:

    Faison E, DeStefano S, Ellison A. 2013. Ungulate-Disturbance Interactions in Hemlock Ecosystems at Harvard Forest since 2012. Harvard Forest Data Archive: HF203.

Detailed Metadata

hf203-01: woody regeneration and browsing

  1. canopy.treat: canopy treatment
    • Girdled: girdled
    • Hardwood: hardwood
    • Hemlock: Hemlock
    • Logged: logged
  2. block: block
    • Ridge: ridge
    • Valley: vally
  3. browsing.treat: browsing treatment
    • Control: unfenced
    • Exclosure: fenced
  4. subplot: twenty-four 4 m² sampling areas per plot (numbered 1-24)
  5. species: tree or tall shrub species or genus name; “none” means no stems between 30cm and 2.4 cm DBH were present in subplot
  6. height: height of stems at least 30 cm in height and less than 2.5 cm DBH (unit: meter / missing value: NA)
  7. dbh: diameter at breast height of stems ≥2.5 cm DBH (unit: centimeter / missing value: NA)
  8. browsing.intensity: categorical assessment of browsing pressure on individual stems within reach of moose (≤3m in height)
    • 0: 0 twigs browsed
    • 1: 1-33% of twigs browsed
    • 2: 34-66% of twigs browsed
    • 3: 67-100% of twigs browsed
    • NA: not assesed
  9. herbivore: herbivore
    • U: ungulate, moose or deer
    • P: porcupine
    • UP: ungulate and porcupine
  10. broken.browse: stem pulled down and snapped by browsing moose
    • 0: no
    • 1: yes
  11. crooks: assessed on stems over 3m; The number of leading shoots damaged with single lateral bud becoming new dominant shoot (0,1,2,...) (unit: number / missing value: NA)
  12. crook.height1: height of crook on the stem (unit: meter / missing value: NA)
  13. crook.height2: height of crook on the stem (unit: meter / missing value: NA)
  14. crook.height3: height of crook on the stem (unit: meter / missing value: NA)
  15. crook.height4: height of crook on the stem (unit: meter / missing value: NA)
  16. forks: assessed on stems over 3m; The number of leading shoots damaged resulting in forked growth from two lateral buds on stem (0,1,2,…) (unit: number / missing value: NA)
  17. fork.height1: height of fork on the stem (unit: meter / missing value: NA)
  18. fork.height2: height of fork on the stem (unit: meter / missing value: NA)
  19. fork.height3: height of fork on the stem (unit: meter / missing value: NA)
  20. fork.height4: height of fork on the stem (unit: meter / missing value: NA)
  21. fork.height5: height of fork on the stem (unit: meter / missing value: NA)
  22. fork.height6: height of fork on the stem (unit: meter / missing value: NA)
  23. fork.height7: height of fork on the stem (unit: meter / missing value: NA)
  24. fork.height8: height of fork on the stem (unit: meter / missing value: NA)
  25. fork.height9: height of fork on the stem (unit: meter / missing value: NA)

hf203-02: pellet groups

  1. canopy.treat: canopy treatment
    • Girdled: girdled
    • Hardwood: hardwood
    • Hemlock: Hemlock
    • Logged: logged
  2. block: block
    • Valley: valley
    • Ridge: ridge
  3. browsing.treat: browsing treatment
    • Control: unfenced
  4. species: large herbivore species
    • moose: Alces alces
    • deer: Odocoileus virginianus
  5. pellet.groups: number of pellet groups (defined as at least 15 individual pellets) per 450m² plot (unit: number / missing value: NA)

hf203-03: low shrubs and herbs

  1. canopy.treat: canopy treatment
    • Girdled: girdled
    • Hardwood: hardwood
    • Hemlock: Hemlock
    • Logged: logged
  2. block: block
    • Valley: valley
    • Ridge: ridge
  3. browsing.treat: browsing treatment
    • Control: unfenced
    • Exclosure: fenced
  4. subplot: twenty-four 4 m² sampling areas per plot (numbered 1-24)
  5. graminoids: percent cover estimate of combined grasses and sedges in each 4m² circular subplot
    • 0: absent
    • 1: 1-24%
    • 2: 25-49%
    • 3: 50-74%
    • 4: 75-100%
  6. rubus: percent cover estimate of all Rubus spp. in each 4m² circular
    • 0: absent
    • 1: 1-24%
    • 2: 25-49%
    • 3: 50-74%
    • 4: 75-100%
  7. ferns: percent cover estimate of combined ferns in each 4m² circular subplot
    • 0: absent
    • 1: 1-24%
    • 2: 25-49%
    • 3: 50-74%
    • 4: 75-100%
  8. forbs: percent cover estimate of all forbs in each 4m² circular
    • 0: absent
    • 1: 1-24%
    • 2: 25-49%
    • 3: 50-74%
    • 4: 75-100%
  9. ericads: percent cover estimate of all low ericaceous shrubs in each 4m² circular subplot
    • 0: absent
    • 1: 1-24%
    • 2: 25-49%
    • 3: 50-74%
    • 4: 75-100%