Influence of Little Ice Age on New England Vegetation

Data

• hf078-01: diatoms

Overview

• Lead: David Foster, Donna Francis, Janice Fuller
• Investigators: Sylvia Barry, Dorte Koster, Reinhard Pienitz
• Contact: David Foster
• Start date: 2000 BP
• End date: present
• Location: Connecticut, Massachusetts, New Hampshire and Vermont
• Latitude: 41.7 to 44.5
• Longitude: -73.3 to -71.3
• Elevation:
• Taxa: Betula (birch), Castanea (chestnut), Fagus (beech), Picea (spruce), Pinus (pine), Quercus (oak), Tsuga (hemlock)
• Research topic: historical, community, regional
• Study type: paleological
• LTER core area: disturbance
• Keywords: climate change, forest dynamics, lake sediments, Little Ice Age, paleoenvironmental records, pollen
• Release date: 2006
• EML version: knb-lter-hfr.78.8
• Revisions:
• Related links:
• Abstract:

  This multi-proxy study uses paleoecological, paleolimnological, and historical approaches to reconstruct climate, vegetation, and cultural dynamics over the past 1500 years at sites arrayed across the climatic and forest gradients of New England and to place these results in a regional framework through analysis of pollen records from the North American Pollen Database. High resolution records were obtained using pollen to interpret vegetation history; chironomids, stable isotopes, geochemistry, and diatoms, supplemented by historical reconstructions, to interpret climate history; charcoal and land-use data to document the human impacts; and Pb-210 and C-14 for chronological control. Results will provide: (1) an objective characterization of the Little Ice Age and climate history in New England, (2) comparison of pre- and post-European forest dynamics in relationship to independent environmental and land-use histories, (3) a reexamination of historical vegetation dynamics in light of prior climate an vegetation change, and (4) widespread availability of data and results through publications, symposium presentation, and the Harvard Forest Archives and web pages.

• Methods:

  Sediment cores were obtained from ponds around New England with a 7-cm diameter surface core and 5-cm diameter modified Livingstone corer. The cores were sampled at 1-cm intervals, and selected samples were analyzed for pollen assemblage, % organic carbon, and microscopic carbon. The cores were dated using 210Pb, AMS 14C dating on organic sediment, and pollen stratigraphic markers (rise in Ambrosia).

• Use:

  This dataset is released to the public and may be freely downloaded. 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. For more information on LTER Network data access and use policies, please see: http://www.lternet.edu/data/netpolicy.html.

• Citation:

  Foster D, Francis D, Fuller J. 2006. Influence of Little Ice Age on New England Vegetation. Harvard Forest Data Archive: HF078.

Detailed Metadata

hf078-01: diatoms

1. Site: site name
   • BP: Bates Pond
   • LP: Levi Pond
   • NP: Northround Pond
   • WP: Walden Pond
2. Depth: depth of sample in centimeters in the sediment column (centimeter )
3. total.diatoms: total number of counted valves (number )
4. TP.GLR: inferred total phosphorus concentration. Values of limnological variables in summer surface lake water reconstructed by the use of diatom models based on a 82-lake calibration set from New England (U.S.) and using the methods of Gaussian Logit regression (GLR) for total phosphorus (TP). (microgramsPerLiter )
5. TP.er.li: lower error value for inferred total phosphorus concentration (microgramsPerLiter )
6. TP.er.re: higher error value for inferred total phosphorus concentration. These values are different when models are based on log-transformed environmental data. Reconstructed values are back-transformed using an exponential transformation. Therefore, back-transformed values at the lower end are smaller than back-transformed values at the higher end. (microgramsPerLiter )
7. ER.LI.1: lower error value for inferred dissolved organic carbon concentration (milligramsPerLiter )
8. ER.RE: higher error value inferred dissolved organic carbon concentration. These values are different when models are based on log-transformed environmental data. Reconstructed values are back-transformed using an exponential transformation. Therefore, back-transformed values at the lower end are smaller than back-transformed values at the higher end. (milligramsPerLiter )
9. DOC.WAPLS.2: inferred dissolved organic carbon concentration. Values of limnological variables in summer surface lake water reconstructed by the use of of a diatom model based on a 59-lake calibration set from Quebec (Canada) using weighted averaging partial least squares (WA-PLS) for reconstructing dissolved organic carbon (DOC) (milligramsPerLiter )
10. pH.WA.inv: pH vulues using weighted averaging with inverse deshrinking (WAinv) (number )
11. pH.error: pH error (number )
12. Taxa: taxa name
    • "Genus" GB: number of valves in girdle band view identified to the Genus level only
    • GB: number of unidentified valves in girdle band view
    • Unidentified: number of unidentified diatom valves
    • Chrysophceae cysts: number of chrysophyte cysts in the same fields of view on the same slide used for diatom analysis
    • Chrysophyceae scales: number of chrysophyte scales in the same fields of view on the same slide used for diatom analysis
13. Count: numbers of individual valves identified for each taxon in diatom assemblage (one complete frustule counting 2 valves) (number )