Historical and current black tern habitat relationships in the Great Lakes region

Principal Investigator: Francesca Cuthbert.

Student: Katherine Wyman.

The overall goal of this project is to inform regional planning for black tern conservation through a better understanding of historical causes of colony site abandonment and through refinement of an index to predict current landscape suitability for black tern nesting. Historical causes of colony site abandonment may include changing lake levels, spread of invasive wetland plants, and encroachment of human development or agriculture. Aerial photographs and remote sensing data provide a historical record of site conditions before and after breeding colony sites were abandoned.

Study of current black tern habitat relationships is being conducted through validation and refinement of a landscape suitability index for black terns. The existing index was developed by the regional Joint Venture in 2007 as part of its Waterbird Habitat Conservation Strategy and has not been tested previously. Surveys were conducted in June and July of 2013 and 2014 at sites with a range of landscape suitability index scores. Results of the 2013 surveys suggested that the existing index was basically correct in structure, but that re-scaling and incorporation of additional landscape variables would lead to an index with greater predictive ability. An alternative index was developed in the winter of 2014, and 2014 field surveys occurred at sites with a range of suitability scores according to the new index as well as the old. The final products of this project will include publications on the findings, as well as a map depicting spatial variation in landscape suitability for black tern nesting that can be used as a tool for conservation planning.