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Harvard Forest Symposium Abstract 2007

• Title: The Vascular Flora of Harvard Forest
• Primary Author: Glenn Motzkin (University of Massachusetts - Amherst )
• Additional Authors: Jerry Jenkins (Wildlife Conservation Society)
• Abstract:

  For nearly a century, Harvard Forest has been the focus of a wide range of ecological investigations, with a strong emphasis on studies of vegetation, disturbance history, and stand dynamics. However, there have been few attempts to document the flora of Harvard Forest at specific time periods, and no previous attempt to evaluate changes in the flora over time. Little is known of the local flora prior to the establishment of Harvard Forest in 1907. Soon after, a small herbarium was established and John G. Jack (Jack 1911) published a list of the woody flora of Harvard Forest. Hugh Raup developed the first checklist of vascular plants of Petersham, MA, based on his collections in the early 1930s (Raup 1938). Subsequently, C. Earle Smith Jr. (Smith 1948, 1949) summarized what was known of the vascular flora of Petersham, based on the collections of several botanists working with Dr. I. M. Johnson in 1947, as well as a review of specimens in the Harvard Forest and New England Botanical Club herbaria. Smith (1948, 1949) also noted species recorded by Raup (1938) for which no herbarium specimens were located. However, after rather intensive botanical investigations in the 1930s and 1940s, there was little attempt to document the flora of Harvard Forest or Petersham, MA in more recent decades. As a result, of ~2,000-2,500 specimens of vascular plants found in the Harvard Forest Herbarium at the beginning of this study, ~80% were collected in the 1930s and 1940s, with very few more recent specimens.
  
  
  
  In 2004-2006, we conducted field inventories across Harvard Forest properties, recording species lists and noting abundances in broad categories within each compartment in order to map species distributions and general abundances. Comparison of our field records with herbarium records, databases, and relevant literature has enabled us to determine which species have previously been found at Harvard Forest and where they were found. Specimen collections or photographic documentation have been made of nearly all species that we observed that have not previously been documented from Harvard Forest, are uncommon, or are of interest for other reasons.
  
  
  
  Based on analyses to date, we have current records for > 700 species at Harvard Forest, including numerous species that were not previously reported from Harvard Forest. An additional ~ 80-100 species were documented in the past that we have not been able to re-locate. Despite dramatic changes in the landscape over the past century, our analyses suggest that the overall flora has been relatively stable. Although some species characteristic of agricultural or disturbed habitats have been lost since earlier surveys, numerous such species persist on roadsides, in the few open fields at Harvard Forest, and in other disturbed habitats. Interestingly, despite an increase in the extent and age of woodlands over the past century, there is little evidence of a dramatic increase in the number of woodland species; most woodland species for which we have current records were also documented in the early 20th century. Several invasive plant species that occur at Harvard Forest were not documented in previous inventories (e.g., Japanese barberry, glossy buckthorn, etc.) suggesting that they may have arrived (or increased in abundance) over the past 60 years.
  
  

• Research Category: Biodiversity Studies
  Historical and Retrospective Studies
  Invasive Plants, Pests & Pathogens