Project Description
The Nyanza Natural Resource Trustees provided funding to the non-profit New England Wild Flower Society (renamed the Native Plant Trust in 2019) to restore native wild rice populations in the the Sudbury, Assabet, and Concord (SuAsCo) River Watershed. Wild rice is an important food source for waterfowl, moose, muskrats and other organisms. The dense stalks provide roosting areas, brood cover and nesting habitat for many species of birds. Wild rice also improves water quality by trapping sediment and removing excess nutrients. Large stands were once common throughout the watershed but have since declined, likely due to the spread of invasive plants and herbivory from carp and Canada geese. During the first phase of the project, surveys were conducted by canoe, kayak or motorboat to map the distribution of wild rice in the SuAsCo River Watershed and collect data such as number of plants, phenology, and preferred habitat. Wild rice was found at approximately 128 locations, with only 30 containing stands of 25 or more individual plants. Larger stands were generally found in shallow, open water areas along the Assabet River, often near conserved land. In the Concord Impoundments at the Great Meadows National Wildlife Refuge (GMNWR), wild rice was observed in low numbers but may be limited by the dense foliage of American lotus, a fast spreading aquatic plant that is not believed to be native to New England. Smaller stands of wild rice were found in the Sudbury River but they may be limited by the spread of invasive water chestnut.
In late September 2015, seed was collected from two stands for a small-scale restoration experiment. The seed was broadcast sown onto four plots with suitable habitat along the Sudbury River to evaluate planting techniques and germination rates. Several years after the seeds were spread, one site had no plants, two plants were observed at another, and there were hundreds of plants at the other two sites. Between 2016 and 2019, a four year experimental restoration project was conducted to further understand the habitat requirements of wild rice and refine methods for restoration in the watershed. Twenty exclosures were constructed to run experiments at several locations along the Sudbury River and in the Concord Impoundments to examine herbivory by birds, fish and rodents, and germination rates and plant growth in areas impacted by invasive plants. The experiments found that herbivory was present but did not influence wild rice survival to a significant degree though grazing waterfowl can inhibit plant growth during the early stages of the growing period. Invasive plants were found to compete with wild rice for habitat and nutrients as seed germination and the growth of stems and reproductive structures were slowed in the presence of dense infestations of water chestnut and American lotus. The highest survival rates were in areas where invasive plants were removed. In 2018 and 2019, the exclosures were removed and the invasive plants around them were disposed of. Seed was broadcasted in areas along the Sudbury River that had suitable habitat and not been infested with invasive plants. In September 2019, seed was also broadcast sown in areas where active invasive species management had taken place.
Restoration Land Ownership
County or Municipal; Fish and Wildlife Service; State
DOI Project Representatives
Fish and Wildlife Service