The Nantucket Conservation Foundation (NCF) is expanding habitat management work within its Middle Moors properties on Nantucket Island, MA to incorporate disk harrowing and native seed addition as a sandplain grassland restoration technique. NCF is a private, non-profit land trust formed in 1963 that currently protects 9,010 acres (or approximately 1/3 of the Nantucket Island land area) through direct ownership. For many years, residents and visitors have enjoyed the wide-open vistas across a portion of NCF’s Middle Moors property known as The Serengeti, thanks to grassland restoration work initiated here in 1998. The next steps for management in this important conservation area came about through adaptive lessons learned over the past 25 years.
Grassland restoration efforts initiated at this site in 1998 consisted of growing and dormant season brushcutting, which has continued at least every 1-3 years since then. Although this repeated, prolonged management resulted in a dramatic reduction in the height of scrub oak and other woody shrubs, there has been very slow colonization by grasses and wildflowers. Past research conducted by the NCF’s Science and Stewardship Department provided a better understanding of the factors limiting grassland restoration: 1) the seed bank at sites overgrown with tall, dense shrubs contains very few seeds of key sandplain grassland wildflowers and grasses; 2) disturbing the duff and mineral soil layers and breaking up the roots of woody species facilitates establishment of native grasses and other herbaceous species through seeding. Lessons learned from this past research as well as feedback provided by colleagues at the Massachusetts Natural Heritage & Endangered Species Program has been incorporated into a new project utilizing brushcutting combined with expanded disk harrow management and native seed addition to restore patches of sandplain grassland habitat within this area.
Disk harrowing in action to restore grassland
The Serengeti area has been subdivided into fifteen designated units, with overall mowing management staggered across a 3-year rotation period, including a mix of summer growing season (after August 1st, to avoid impacting nesting birds) and dormant season management. This revised mowing management regime is expected to maintain these open habitats while creating a mosaic of different stages of vegetative growth across the site to benefit rare moths, shrubland bird species, native bees and pollinators and other wildlife.
Winter 2020-2021 management plan
Additionally, experimental disk harrow subunits (< 2.5 acre each) will be incorporated within units managed with mowing. These harrow subunits will be irregularly shaped and strategically located adjacent to established patches of native grasses that can serve as a seed source. Disk harrowing will be a one-time treatment. In total, approximately 10% (or ~ 47 acres) or less of the entire Serengeti area will be harrowed across a 3-5-year period beginning this winter. When available, seed of locally collected, common native sandplain grassland/heathland associated graminoids and forbs will be added via patch seeding to assist with grassland habitat restoration.
Unit F before harrowing
These changes in management will be accompanied by research and monitoring to provide future learning opportunities. This project is taking advantage of the long history of previous restoration work, utilizing results from successful research and incorporating newer management techniques. Additionally, restoration of sandplain grassland habitat at this inland location will assist in mitigating for loss of this habitat due to coastal erosion at established sites along the southern shoreline of Nantucket. The results of this research and management will contribute to the efforts and knowledge of the Sandplain Grassland Network, of which NCF is a founding partner.
Post-harrowing results