NEBC Meeting News

Abstract

New England Botanical Club President Jesse Bellemare welcomed participants to the 1151st meeting on Saturday, April 3, 2021. He introduced the 2021 NEBC Distinguished Speaker, Dr. Robert I. Bertin, Professor of Biology, Emeritus, College of the Holy Cross, Worcester, Massachusetts. Dr. Bertin is currently studying the effects of recent climate change on flowering phenology and changes in the floristic composition of New England over time. He coauthored the Flora of Worcester County and more recently, the Flora of Franklin County, and has made major contributions to the understanding of floristic change in our region. Dr. Bertin’s presentation was titled “Regional Floras and the Assessment of Regional Change.” Published floras and herbarium collections are vital sources of historic data on plant distributions. Most herbarium specimens held at New England institutions can be viewed in digital form on the Consortium of Northeastern Herbaria website. The NEBC Herbarium has the most extensive collection of New England specimens, going back 200 years. MassWildlife’s Natural Heritage and Endangered Species Program (NHESP) is another valuable source, providing town occurrences of rare (state-listed) species. Dr. Bertin worked on the Franklin County Flora Project with Dr. Karen Searcy, Matt Hickler, Glenn Motzkin, and Pete Grima, with contributions from other botanists. They logged 46,000 field records, collected 4300 specimens, and examined 16,000 herbarium specimens and thousands of literature records. The resulting Flora of Franklin County includes 1205 native species and 635 nonnative species, with 67 historic species not found and 50 species documented that had not been reported historically. The highest diversity was found in the towns of the Connecticut River Valley. Dr. Bertin briefly described three collaborative floristic projects in which he is currently involved: 1) analysis of changes in the flora of Franklin County, 2) analysis of changes in rare species in Massachusetts that have northern affinities, and 3) changes in abundance of orchids. Dr. Bertin and collaborators examined changes in Franklin County species using an index based on the number of towns in which a species was recorded recently (since 2010) and historically (pre-2010). The median change index was modestly positive (0.18) for native species, presumably reflecting the greater intensity of recent than historical sampling, but much higher (0.52) for nonnative species, reflecting their increasing frequency. This increase in nonnative taxa could cause problems for insect herbivores— such as moths and butterflies—since other studies have shown lower diversity and abundance of these insects on nonnative plants. Dr. Bertin and collaborators looked at changes in native species in different habitat types. A large apparent increase in species of aquatic habitats was probably an artifact of the more thorough sampling of these