Williams College
OP-11: Biodiversity

Several areas within the forest have been identified by the Commonwealth of Massachusetts as priority areas for conservation. These include several first order stream corridors and small wooded wetlands, as well as habitats for several upland plant species, including wild ginseng (Panax quinquefolius), and crooked-stem aster (Symphiotrichum prenanthoides). Most of the rare upland plant habitat occupies lower elevation sites with enrichment from the marble bedrock that underlies the Hoosic River Valley. These areas tend to lie below 1200 feet in elevation. Several small wooded ponds, (“vernal pools”) have been identified and certified with the Massachusetts Natural Heritage Program. In the case of two of the pools, we have found a state protected (“Special Concern”) vertebrate, the Jefferson’s Salamander. Another area of conservation interest is the Taconic Range, a ridge that frames the western flank of the property (in New York), and spans from 2100 to 2500 feet in elevation; this ridgetop harbors some more northerly species, that are not necessarily state listed, but are of conservation interest nonetheless. We also own an enriched thermal spring and fen at the lower, opposite end of the forest, which harbors some interesting, though not “endangered” plant species.

In the recent past we have monitored many of the rare species on the property including crooked-stem aster, wild ginseng, the Jefferson’s salamander (Ambystoma jeffersonianum) using pitfall/drift fence arrays, and wood turtle (Glyptemys insculpta), via radio tracking. In addition we have monitored and in some cases managed several apparently healthy examples of American chestnut, (Castanea dentata). Two species that we had previously studied or monitored, the Appalachian brook crayfish (Cambarus bartonii) and the Northern spring salamander (Gyrinophilus porphyriticus), recently have been de-listed as rare species by the Commonwealth. More recently we have been tracking an apparent expansion of breeding mourning warblers (Oporornis philadelphia) into the higher elevations of the forest using ad-hoc surveys and point counts. With this species and others -- including the Eastern towhee (Pipilo erythrophthalmus), New England cottontail (Sylvilagus transtitionalis), and smooth green snake (Opheodrys vernalis) -- in mind, we recently created more early successional habitat in two five acre patches near the top of the Taconic Range; we intend to monitor these sites to track any changes in the numbers of these and other species of interest.

Hopkins Forest and its surrounding wooded tracts have been identified by the Nature Conservancy and the Commonwealth of Massachusetts as priority core forest habitat through their BioMap program. In terms of forest stand level research, we have been monitoring 400 permanent vegetation plots, some going back to the 1930s (originally established by the U.S. Forest Service). These plots are all surveyed on an approximate 15 year rotation and this allows us to detect changes in the forest composition over time; track declines and gains on the species level; and make climate related correlations with these and other biometric variables. Additionally, annual breeding bird point counts in June allow us to monitor trends in many species of forest interior (and edge) songbirds; we have identified more than 50 breeding species in the forest and in excess of 125 bird species that use the forest on a year-round basis. In collaboration with local birding groups, we conduct annual Christmas bird counts and spring migration counts that help us to keep track of avian populations beyond the breeding season.

In terms of invasive species: we have a long-term study that targets the population dynamics of garlic mustard (Allaria petiolata) at three sites in the forest. We are looking at the interplay between this introduced biennial and some native herbs that grow in its midst. In some cases, where it does not interfere with ongoing research and is deemed manageable, we have taken measures to remove invasive species, primarily Asian shrub honeysuckles (Lonicera spp.), Japanese barberry (Berberis thunbergii), buckthorns (Rhamnus spp.) and Eurasian bittersweet (Celastrus orbiculatus). We are also keeping our eye on apparent incipient invaders, most notably Norway maple (Acer platanoides); we are determined to keep this weedy tree away from native stands of sugar maple where feasible. On the ecostystem level, we have identified several sensitive or locally uncommon habitats -- including a dry chestnut oak stand, rich marble outcrops, high elevation heaths, and the aforementioned wooded pools and fen. In some cases we have begun to target these areas for management or protection, e.g. prescribed fire on the oak site, and possible control of Phragmites near the fen. Indeed, the main impetus for a recent ten acre land acquisition along our southern boundary was the protection of two wetlands of high value for Jefferson salamanders and other breeding amphibians. We certainly have a keen interest in maintaining and enhancing the biodiversity of Hopkins Forest and are poised to take the steps necessary to do so.