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Harvard Forest Data Archive

HF186

Lake Sediment Pollen from Little Pond in Royalston MA from 15000 BP to Present

Related Publications

Data

Overview

  • Lead: Wyatt Oswald, David Foster
  • Investigators: Elaine Doughty, Edward Faison, Barbara Hansen
  • Contact: Wyatt Oswald
  • Start date: -13000
  • End date: 2010
  • Status: completed
  • Location: Little Pond (Royalston MA)
  • Latitude: +42.675
  • Longitude: -72.19167
  • Elevation: 302 meter
  • Taxa: Betula spp. (birch), Fagus spp. (beech), Picea spp. (spruce), Pinus spp. (pine), Quercus spp. (oak), Tsuga spp. (hemlock)
  • Release date: 2011
  • Revisions:
  • EML file: knb-lter-hfr.186.6
  • DOI: digital object identifier
  • Related links:
  • Study type: paleological
  • Research topic: historical and retrospective studies
  • LTER core area: disturbance, populations
  • Keywords: lakes, paleoecology, pollen, region, sediments, vegetation dynamics
  • Abstract:

    Aim

    We analysed lake-sediment pollen records from eight sites in southern New England to address: (1) regional variation in ecological responses to post-glacial climatic changes, (2) landscape-scale vegetational heterogeneity at different times in the past, and (3) environmental and ecological controls on spatial patterns of vegetation.

    Location

    The eight study sites are located in southern New England in the states of Massachusetts and Connecticut. The sites span a climatic and vegetational gradient from the lowland areas of eastern Massachusetts and Connecticut to the uplands of north-central and western Massachusetts. Tsuga canadensis and Fagus grandifolia are abundant in the upland area, while Quercus, Carya and Pinus species have higher abundances in the lowlands.

    Results

    Our analyses revealed a sequence of vegetational responses to climate changes occurring across southern New England during the past 14,000 calibrated radiocarbon years before present (cal yr BP). Pollen assemblages at all sites were dominated by Picea and Pinus banksiana between 14,000 and 11,500 cal yr BP; by Pinus strobus from 11,500 to 10,500 cal yr BP; and by P. strobus and Tsuga between 10,500 and 9500 cal yr BP. At 9500-8000 cal yr BP, however, vegetation composition began to differentiate between lowland and upland sites. Lowland sites had higher percentages of Quercus pollen, whereas Tsuga abundance was higher at the upland sites. This spatial heterogeneity strengthened between 8000 and 5500 cal yr BP, when Fagus became abundant in the uplands and Quercus pollen percentages increased further in the lowland records. The differentiation of upland and lowland vegetation zones remained strong during the mid-Holocene Tsuga decline (5500-3500 cal yr BP), but the pattern weakened during the late-Holocene (3500-300 cal yr BP) and European-settlement intervals. Within-group similarity declined in response to the uneven late-Holocene expansion of Castanea, while between-group similarity increased due to homogenization of the regional vegetation by forest clearance and ongoing disturbances.

    Main conclusions

    The regional gradient of vegetation composition across southern New England was first established between 9500 and 8000 cal yr BP. The spatial heterogeneity of the vegetation may have arisen at that time in response to the development or strengthening of the regional climatic gradient. Alternatively, the differentiation of upland and lowland vegetation types may have occurred as the climate ameliorated and an increasing number of species arrived in the region, arranging themselves in progressively more complex vegetation patterns across relatively stationary environmental gradients. The emergence of a regional vegetational gradient in southern New England may be a manifestation of the increasing number of species and more finely divided resource gradient.

  • Methods:

    We collected sediment cores from three lakes in eastern and north-central Massachusetts (Berry East, Blood and Little Royalston Ponds). Pollen records from those sites were compared with previously published pollen data from five other sites. Multivariate data analysis (non-metric multi-dimensional scaling) was used to compare the pollen spectra of these sites through time.

  • 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:

    Oswald W, Foster D. 2011. Lake Sediment Pollen from Little Pond in Royalston MA from 15000 BP to Present. Harvard Forest Data Archive: HF186.

Detailed Metadata

hf186-01: pollen

  1. cal.age.bp: calibrated age before present (years; present=1950 AD) (unit: number / missing value: NA)
  2. depth: depth in sediment column (unit: centimeter / missing value: NA)
  3. taxa: name of taxa
  4. count: number of pollen grains or spores of individual taxa (unit: number / missing value: NA)

hf186-02: age

  1. depth: depth in sediment column (unit: centimeter / missing value: NA)
  2. cal.age.bp: calibrated age before present (years; present=1950 AD) (unit: number / missing value: NA)
  3. notes: notes and methods of age determination; 210Pb=lead-210 dating; 14C=radiocarbon dating; Euro settlement=determined by rise in abundance of weedy and agricultural taxa
  4. c14: un-calibrated radiocarbon years (unit: number / missing value: NA)
  5. error: analytical error for 14C dates in years (unit: number / missing value: NA)

hf186-03: microchar

  1. depth: depth in sediment column (unit: centimeter / missing value: NA)
  2. char.area: area of charcoal pieces greater than 10 and less than 180 microns in length (unit: squareMillimeters / missing value: NA)
  3. exotic.char: number of exotic marker grains encountered during charcoal analysis (unit: number / missing value: NA)
  4. pollen.sum: number of pollen grains and spores of upland taxa encountered during pollen analysis (unit: number / missing value: NA)
  5. exotic.pollen: number of exotic maker grains encountered during pollen analysis (unit: number / missing value: NA)
  6. exotic.added: total number of exotic marker grains added to sample (unit: numberPerCentimeterCubed / missing value: NA)
  7. sed.vol: volume of the sediment samples (unit: centimeterCubed / missing value: NA)