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Harvard Forest Data Archive

HF115

Moose Foraging in Temperate Forests of Central Massachusetts 2005

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Data

Overview

  • Lead: Edward Faison, David Foster
  • Investigators: Glenn Motzkin
  • Contact: Edward Faison
  • Start date: 2005
  • End date: 2005
  • Status: completed
  • Location: Quabbin Reservoir, Ware River Watershed
  • Latitude: +42.28 to +42.42
  • Longitude: -72.35 to -72.02
  • Elevation: 116 to 382 meter
  • Taxa: Acer rubrum (red maple), Alces alces (moose), Betula spp. (birch), Pinus strobus (white pine), Quercus spp. (oak), Tsuga canadensis (hemlock)
  • Release date: 2009
  • Revisions:
  • EML file: knb-lter-hfr.115.15
  • 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: browsing, deer, moose, regeneration
  • Abstract:

    The "re-wilding" of ecosystems with extirpated large mammals has become a focus of recent scientific and conservation initiatives; however, it is unclear how proposed re-introductions will influence systems that are often vastly different from those that occurred before these animals were extirpated. Moose, the northeast’s largest Holocene browser, have recently expanded across southern New England’s temperate forest landscape after an absence of 200 years, realizing a natural re-wilding experiment. Moose have been well-studied throughout the boreal forest biome; however, because they are rare today in temperate forests, almost nothing is known of their ecology, behavior, or potential impacts to these ecosystems. This study investigated patterns of winter moose browse in order to: (1) gain insight into the likely influences of this herbivore on the vegetation patterns of the region; and (2) to identify the most important habitat features influencing moose winter foraging activity at a landscape and site scale. Two large forested watersheds in Central Massachusetts were sampled for moose browse, habitat features, and disturbances including forest harvesting and human activity. Chi-square and t-tests were used to identify browse species preferences of moose, and step-wise multiple regression was used to identify habitat variables that are strong predictors of browse intensity. Hardwoods and hemlock were favored over white pine, and browse intensity was significantly and positively related to forest harvesting, elevation, swamps, and distance to human settlement. The results from this study suggest that in the winter months, moose populations are concentrating in remote, elevated areas that are broken by swamps and have intensive forest harvests. In areas that support high moose densities, selective browsing, particularly in regenerating harvests, could promote less favored species like white pine at the expense of hardwoods and hemlock. The strong association between moose and forest harvesting indicates that recolonizing megafauna may interact with novel human conditions and disturbances to impact ecosystems differently than in the past. Nonetheless, habitat loss and climate change may ultimately preclude the long-term viability of moose and its impacts to this region.

  • Methods:

    Study Site Selection

    Plots were established following a stratified random design by (1) forest type - four upland types: hemlock, white pine, mixed oak, and sugar maple-ash; and three wetland types: red maple swamp, conifer swamp, and terrace floodplain forest and (2) recent harvesting history (harvested vs. unharvested since 1984 for upland sites only). At least 10 sites were sampled for each forest type and harvesting stratum, which were identified on state forest type GIS layers, topographical maps, and a statewide forest harvesting database. In cases where field visits indicated that the vegetation and harvesting history of a site did not agree with the GIS layers, the site was sampled and assigned to the proper stratum. To ensure independence of plots, sample locations were separated by a minimum distance of 700 meters. A total of 156 sites met these sampling criteria and were divided between the two watersheds in approximate proportion to the relative forest area of each property.

    Vegetation Surveys

    Each study site consisted of two 100 m2 circular plots for sampling moose browse and tall shrub and tree density and composition. All trees greater than 2.5 cm DBH were recorded by species and DBH, and all tall shrubs greater than 1.8 meters high were recorded by species. In a nested 10 m2 circular subplot within each 100 m2 plot, all tree stems less than 2.5 cm DBH were recorded by species to determine seedling density and composition. The center of the two 100 m2 plots were 30 m apart, and data from the two plots were pooled for each site.

    Moose Browsing Surveys

    At each site, moose browse was assessed on trees and shrubs. To distinguish moose from deer foraging, browsing was assessed only above 1.8 m, the height limit for white-tailed deer foraging. Moose forage at all heights between 0-3 m, but feeding trials in Sweden showed that on greater than 80% of deciduous tree species they consume the most browse between 1.5 and 2.5 m. We assumed that recording browse above 1.8 would exclude most deer browse but still capture the predominant foraging activity of moose.

    In each 100m2 plot, all woody stems with live twigs between 1.8 and 3 meters were recorded by species and if browsed or not. Only twigs that were unequivocally browsed (torn or ragged stem) were recorded as "yes." Bark-stripped stems greater than 1.8 m high were also recorded as "browsed." Seedlings and saplings pulled or walked down and snapped along the major stem were also noted.

  • 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, Foster D. 2009. Moose Foraging in Temperate Forests of Central Massachusetts 2005. Harvard Forest Data Archive: HF115.

Detailed Metadata

hf115-01: plot data

  1. plot: unique plot number
  2. browse.index: sum of proportion of browsed stems and total stems browsed/2 (unit: number / missing value: NA)
  3. lat: latitude (unit: meter / missing value: NA)
  4. elev: elevation in meters (unit: meter / missing value: NA)
  5. dist.h2o: distance in meters from the plot to the nearest wetland or water body (unit: meter / missing value: NA)
  6. hilltop: plot located on hilltop
  7. swamp: plot located in a swamp as defined by saturated soils and wetland plant indicators
  8. wetland.forest: plot located in a swamp or floodplain forest
  9. tall shrubs: density of shrub stems over 1.8m high/200m² (unit: number / missing value: NA)
  10. dist.conifer: distance in meters to the nearest patch of conifer forest cover (unit: meter / missing value: NA)
  11. hemlock.ba: relative % of basal area of hemlock in the plot (unit: number / missing value: NA)
  12. sugar.maple.ba: relative % of basal area of sugar maple in the plot (unit: number / missing value: NA)
  13. red.maple.ba: relative % of basal area of red maple in the plot (unit: number / missing value: NA)
  14. spruce.fir.ba: relative % of basal area of spruce and fir combined in the plot (unit: number / missing value: NA)
  15. oak.ba: relative % of basal area of all oak species in the plot (unit: number / missing value: NA)
  16. white.pine.ba: relative % of basal area of white pine in the plot (unit: number / missing value: NA)
  17. harvest.intensity: amount of basal area removed from a harvested stand in m²/ha (unit: meterSquaredPerHectare / missing value: NA)
  18. watershed: watershed forest in which the plot was located
    • 1: Ware River Forest
    • 0: Quabbin Forest
  19. deer.density: estimated number of deer/km² in the area the plot was located (unit: number / missing value: NA)
  20. harvest: harvest status of plot
    • 1: the plot was located in a harvested area
    • 0: the plot was located in an unharvested stand
  21. dist.dev: distance in meters from the plot to the nearest developed area as defined by MassGIS. Distances greater than 1000m were assigned a value of 1000. (unit: meter / missing value: NA)

hf115-02: tree data

  1. plot: unique plot number
  2. species: tree species or genus name
  3. dbh: diameter at breast height in cm of tree (seedlings under 2.5 cm DBH assigned NA) (unit: centimeter / missing value: NA)
  4. count: number of stems (unit: number / missing value: NA)
  5. browsed: browsed
    • 0: unbrowsed at a height above 1.8m, under 3m
    • 1: browsed at a height above 1.8m, under 3m
    • NA: no stems were within the available browse range (1.8-3m in height), or stem was not assessed because browsed/unbrowsed status was inconclusive
  6. stripped: stripped
    • 1: stem bark stripped above 1.8 m
    • 0: stem not bark stripped above 1.8m
  7. broken: broken
    • 1: stem broken by moose
    • 0: stem not broken by moose