Gulf of Maine Council

The U.S. Fish and Wildlife Service Gulf of Maine Project has identified important habitats for a variety of plants, invertebrates, fishes and birds, in the lower Casco Bay watershed of Southern Maine. Habitat identification was based on species occurrences and also was projected from environmental parameters favorable to those species, such as suitable vegetation, water depth, or presence of food resources. Numerical scores were assigned to each habitat, reflecting level of use and apparent environmental quality for the evaluation species. Scores were adjusted according to the relative abundance of each habitat within the study area, and the relative ranking of the evaluation species on the Gulf of Maine Council regional listing. Habitat maps for the individual species were aggregated into a final map highlighting areas important to one or several species. This information is being used in an analysis of threats to important habitats from development activities, performed in cooperation with the Casco Bay Estuary Project.

The digital data described in this report are available as geo-referenced compressed binary raster files. These files may be downloaded for use in a number of GIS programs and viewers by accessing the documentation page from several places in this report <Download *.bil files of themes> The figures in this report depict these same data themes.

Table of Contents

Introduction

Chapter 1.Summary of the Analysis (Study Area, Themes, Methods For Habitat Characterization and Scoring)

Chapter 2. Summary of Environmental Data Layers

Chapter 3. Landcover of Casco Bay

Chapter 4. Eelgrass, Cordgrass Habitats

Chapter 5. Shellfish, Marine Worm Habitats

Chapter 6. Loon Habitats

Chapter 7. Black Duck Habitats

Chapter 8. Canada Goose Habitats

Chapter 9. Bald Eagle Essential Habitats

Chapter 10. Roseate Tern Habitats

Chapter 11. Seabird Habitats

Chapter 12. Shorebird Habitats

Chapter 13. Wading Bird Habitats

Chapter 14. Freshwater and Anadromous Fish Habitats

Chapter 15. Funding Opportunities for Habitat Protection

Literature Cited

List of Tables

Table 1. Calculations to Combine Habitat Scores for the Evaluation Species

Table 2. Assignment of NWI Designations to "Class"

Table 3. Results of Comparison Between Upland Classes in Final Grid LCNEW17 and Actual Field Sites

Table 4. Polygon Types Included as Suitable Nesting or Foraging Habitats for Least Terns and Piping Plovers

Table 5. Comparison of Observed Wading Bird Use of Inland Wetlands and Wetland Ranking Criteria

Table 6. Wetland Types Found in Casco Bay and Their Relative Suitability for Wading Birds, Based on National Wetland Inventory Attributes

List of Figures

Figure 1. Casco Bay Study Area

Figure 2. Casco Bay Wetlands

Figure 3a. Casco Bay Landcover

Figure 3b. Casco Bay Bathymetry

Figure 4. Eelgrass Concentration Areas

Figure 5. Cordgrass Habitats

Figure 6. Shellfish Harvest Areas

Figure 7. Marine Worm Harvest Areas

Figure 8a. Loon Habitats

Figure 8b. Black Duck Habitats

Figure 8c. Canada Goose Habitats

Figure 9. Bald Eagle Nesting Locations

Figure 10. Roseate Tern Habitats

Figure 11. Seabird Habitats

Figure 12. Shorebird Habitats

Figure 13. Wading Bird Habitats

Figure 14. Freshwater and Anadromous Fish Habitats

Figure 15. Aggregated Scores for all Evaluation Species

Appendix A: Identification of Species for Priority Habitats (Gulf of Maine Council Ranked List of Evaluation Species)

Appendix B: List of Acronyms

Introduction

As with most areas of the country, the Casco Bay watershed faces the prospect of decline in natural resources with increased development. Residential and commercial development of natural areas may simply replace important fish and wildlife habitats. Land use change may also degrade habitats by affecting water quality, fragmenting a landscape, or disturbing wildlife by introduction of domestic animals and increased human activities. It is possible to reduce the extent of these losses by conservation efforts directed at important habitats remaining in the watershed. We see two components for the success of such initiatives: enthusiasm and support for conservation measures, and a clear depiction of important habitats in the area. This report focusses on the latter aspect, offering maps of known and likely habitats for an assortment of species and species groups significant in the Gulf of Maine, and particularly in Casco Bay. The final chapter lists funding opportunities which local conservation interests may use to protect habitats.

The important habitats identified by this analysis are being incorporated into another analysis which will identify natural resources at risk from future development. This relies on a build-out analysis, estimating the extent to which development may occur in Casco Bay area under present zoning, wetland regulation, and land ownership patterns. This analysis will be the subject of a second report, also by the U.S. Fish and Wildlife Service (FWS), and by the Casco Bay Estuary Project (CBEP). Digital products from the analyses will be available through the CBEP, and also from the FWS Gulf of Maine Project.

Organization of this Report:

The first Chapter of this report summarizes the purpose, materials and methods, and the findings of the biological investigations. Subsequent chapters provide detailed accounts of the individual themes, and explain the basis for the habitat maps.

Acknowledgments:

For Information:

Maine Office of GIS, Augusta ME (digital coverages of roads, streams, lakes, coast)

Maine Geological Survey (MGS), Augusta ME (coastal features, digital bathymetry)

National Wetland Inventory (NWI), Hadley, MA (digital wetland maps)

Maine Department of Inland Fisheries and Wildlife (MDIF&W), Augusta ME (digital and paper versions of fish and wildlife databases and habitat maps)

Maine Department of Marine Resources, Boothbay Harbor ME (digital coverages of marine resources)

Maine Audubon Society, Falmouth ME (digital and paper wildlife databases)

For Assistance:

We greatly appreciate technical input from the following persons: John Atwood, Ralph Andrews, and Katherine Parsons (Manomet Observatory for Conservation Sciences), Brad Allen and Pat Corr (MDIF&W), Seth Barker and Lew Flagg (MDMR), Jane Arbuckle, Jeff Spendelow (Patuxent Research Center), Steve Kress (National Audubon Society), Jerry Longcore and Jed Wright (FWS). This report benefitted from review and comment by the Gulf of Maine Project staff, particularly Richard Smith, Lois Winter and Robert Houston.