Monitoring Habitat Restoration for Floodplain and Upland Forest Birds in Michigan

The North Oakland Headwaters Land Conservancy (NOHLC) has 47 years of experience preserving and stewarding land in northwest Oakland County, Michigan. In 2019, we initiated a study to measure the effectiveness of restoration at two NOHLC preserves (79 total acres). The parcels are dominated by floodplain and upland forest along high-quality streams in the Upper Clinton River Watershed. However, both properties have become degraded due to an increase in the abundance of invasive plant species. Our ongoing restoration methods include manual removal and herbicide treatment of invasives and planting perennial native plants. Among our management goals is to improve habitat for six focal bird Species of Greatest Conservation Need (SGCN) in Michigan (cerulean warbler, hooded warbler, Louisiana waterthrush, prothonotary warbler, red-headed woodpecker, and red-shouldered hawk). In spring and summer 2019, we conducted surveys of invasive stems at random locations in each square-acre of the preserves and surveyed birds twice at each site using an area-search method. Based on estimates from the invasive surveys, the density of invasive stems ranged from 0 stems/acre in high-quality areas to >20,000 stems/acre in heavily degraded areas. The most common invasives were glossy buckthorn and common buckthorn. Bird surveys in the first year of the study did not detect our focal SGCNs. Several forest specialists were observed, including wood thrush and scarlet tanager. We will continue to document vegetation and bird species in 2020. We hope that our monitoring methods can be a model for other land conservancies and conservation organizations.