Friday, November 17, 2006
ConsCom ponders wildlife habitat protection near vernal pool
Dr. John Rockwood of EcoTec Consulting offered a mini-seminar on recent amendments to the Massachusetts Wetland Protection Act (WPA) at the October 8 Carlisle Conservation Commission meeting. Listening intently were the commissioners, current applicant Niels Larsen, Stamski and McNary engineer George Dimakarakos, B&C Wetland Scientist David Crossman, plus interested neighbors.
Rockwood had been retained to review a Wildlife Habitat Evaluation drafted by Crossman as part of a project site plan covering four acres of wooded land off Concord Street with 1.6 acres of wetland resource area, 2.2 acres of wetland buffer zone and small areas of upland. Within the wetland is a large, certified vernal pool. A vernal pool is defined as a basin depression which contains water for a minimum of two months during the spring/summer and is free of adult fish populations. Such features are essential breeding habitats for several species of salamanders, tree frogs and other invertebrates.
Speaking as peer reviewer for the habitat evaluation only, Rockwood explained that the WPA amendment in question has added wildlife habitat as an eighth "statutory interest" to be protected whenever alteration of a Bordering Vegetated Wetland (BVW) is proposed. Although vernal pools as such do not have a 100-foot buffer zone, a vernal pool located within a BVW does, and under the new provisions, the feature requires a Wildlife Habitat
Rockwood was careful to add that the vernal pool has a 100-foot buffer zone only within the wetland itself, but that zone of protection does not extend into any portion of the BVW's own 100-foot buffer zone that includes upland territory. Because scientists consider the uplands surrounding vernal pools to be critical to the species that use them as breeding areas, Rockwood said many towns have passed local wetland protection bylaws that impose stringent vernal pool setbacks. However, Carlisle is not one of those communities. (If the reader is wondering why the vernal pools on the Benfield Land have such an extensive habitat protection zone, it is because the salamander found there is rare and protected by the state as "a species of special concern.")
After explaining that the Wildlife Habitat Protection Guidance document declares, "Applicants must certify, and commissions must find, that project alterations [to the wetland itself] will have no adverse effect on wildlife habitat," in order to gain approval, Rockwood went on to say this does not mean that the wetland cannot be altered, if adverse impacts on its habitat status are "sufficiently avoided, mitigated or minimized."
New wildlife habitat
to be provided
Since the Concord Street project involves a 700-foot access road, and since this road must cross, and hence alter the wetland system containing the vernal pool, the WPA specifies that any lost wetland territory must be replaced by a replication area of equal or greater size. That man-made feature must meet seven strict performance standards which, it is hoped, will result in a successful habitat graft. Rockwood concluded that, based upon his review of the plans and mitigations submitted by Stamski and McNary, and assuming that the recommendations made in his own review will be included in the specifications, he would find that Crossman's certification that the Concord Street project "will not substantially reduce the wetlands' capacity to provide important wildlife functions" is a reasonable conclusion.
The environmental complexity of a project of this nature is suggested by the number (29) and the specificity of Rockwood's recommendations. They range from a required stabilization and revegetation regimen to be instituted immediately after completion of the clearing and contouring operations implicit in construction of the roadway and preparation of the proposed dwelling site, to a requirement that six logs of varying condition, from green to decaying, at least eight to ten feet in length and six to ten inches in diameter be placed in the seasonally flooded portion of the replication area. The substrate (floor) must have at least 12 to 16 inches of mixed loam and composted leaf matter, and a qualified wetland scientist must monitor development and maintenance of the replication area to assure that it will promote a healthy level of moisture, both during and for two years following, its construction. There is also the familiar prohibition against present and future use of fertilizers, herbicides and pesticides on the lawn and all other areas of the site (but, as noted by the commissioners, with no suggestion as to how the mandate can be policed in the future).
Given the sensitivity of the construction site and the scope of Rockwood's recommendations, which pertain only to the Wildlife Habitat Evaluation portion of the overall project plan, the commission requested and was granted a continuation of the hearing to November 30 at 8:30 p.m. Rockwood will attend.
© 2006 The