SIGNIFICANT HABITATS IN THE TOWN OF DOVER, DUTCHESS COUNTY, NEW YORK C. Graham © 2020 Report to the Town of Dover and the Dutchess Land Conservancy By Christopher Graham, Nava Tabak, and Gretchen Stevens February 2020 Hudsonia Ltd. P.O. Box 5000 Annandale, NY 12504 SIGNIFICANT HABITATS IN THE TOWN OF DOVER CONTENTS - I - CONTENTS Page EXECUTIVE SUMMARY .................................................................................. 1 INTRODUCTION Background ........................................................................................................ 3 What is Biodiversity? ........................................................................................ 5 What are Ecologically Significant Habitats? ..................................................... 6 Study Area ......................................................................................................... 7 METHODS Gathering Information and Predicting Habitats .............................................. 12 Preliminary Habitat Mapping and Field Verification ...................................... 13 Defining Habitat Types ................................................................................... 14 Final Mapping and Presentation of Data ......................................................... 15 RESULTS Overview ......................................................................................................... 16 Habitat Descriptions: Upland Habitats Upland Forest ............................................................................................ 21 Cool ravine ................................................................................................ 30 Crest/Ledge/Talus ...................................................................................... 32 Oak-Heath Barren and Rocky Barren ........................................................ 35 Woodlands ................................................................................................. 38 Red Cedar Woodland ................................................................................ 40 Marble Knoll and Red Cedar Barren ......................................................... 42 Upland Shrubland ...................................................................................... 46 Upland Meadow ........................................................................................ 48 Gravel/Cobble Shore ................................................................................ 51 Orchard/Plantation ..................................................................................... 52 Waste Ground ............................................................................................ 52 Cultural Habitats ........................................................................................ 53 Habitat Descriptions: Wetland Habitats Swamp ....................................................................................................... 54 SIGNIFICANT HABITATS IN THE TOWN OF DOVER CONTENTS - II - Acidic Bog ................................................................................................. 58 Intermittent Woodland Pool ...................................................................... 60 Kettle Shrub Pool/Buttonbush Pool ........................................................... 63 Marsh ......................................................................................................... 64 Wet Meadow ............................................................................................. 66 Calcareous Wet Meadow ........................................................................... 68 Fen ............................................................................................................. 69 Springs and Seeps ...................................................................................... 72 Open Water ................................................................................................ 74 Constructed Pond ....................................................................................... 75 Stream, Floodplain Forest, and Riparian Corridor .................................... 76 CONSERVATION PRIORITIES AND PLANNING .................................. 81 Priority Habitats in Dover ............................................................................. 81 Large Forests ...................................................................................... 86 Cool Ravines ...................................................................................... 91 Oak-heath Barrens, Woodlands, and Crest/Ledge/Talus ................... 93 Marble Knolls and Red Cedar Barrens .............................................. 97 Large Meadows ................................................................................ 100 Acidic Bogs ...................................................................................... 105 Intermittent Woodland Pools/Pool-like Swamps/Buttonbush Pools 109 Fens and Calcareous Wet Meadows ................................................ 115 Wetland Complexes ......................................................................... 119 Streams, Floodplain Forests, and Riparian Corridors ...................... 122 Planning for Biodiversity General Guidelines for Biodiversity Conservation ......................... 128 Townwide Planning ......................................................................... 130 Reviewing Site-Specific Proposals .................................................. 131 Enhancement of Developed Areas .......................................................... 133 Enhancing Habitat Characteristics ................................................... 134 Minimizing Disturbance to Resident and Migratory Biota .............. 136 Conservation Areas in Dover .................................................................. 138 Northwestern Meadows ................................................................... 138 West Mountain ................................................................................. 138 Harlem Valley .................................................................................. 139 Great Swamp .................................................................................... 141 East Mountain .................................................................................. 142 Southeastern Hills ............................................................................ 143 CONCLUSION ................................................................................................ 145 SIGNIFICANT HABITATS IN THE TOWN OF DOVER CONTENTS - III - ACKNOWLEDGMENTS ............................................................................... 148 REFERENCES CITED ..................................................................................... 149 APPENDICES A. Mapping Conventions ............................................................................. 159 B. Explanation of Rarity Ranks ................................................................... 162 C. Species of Conservation Concern ............................................................ 168 D. Common and Scientific Names of Plants Mentioned in this Report ....... 173 FIGURES 1. Watersheds ................................................................................................ 10 2. Bedrock Geology ....................................................................................... 11 3. Ecologically Significant Habitats ............................................................... 18 4. Contiguous Habitats ................................................................................... 20 5. Contiguous Forested Patches ...................................................................... 90 6. Crest/Ledge/Talus and other Rocky Habitats ............................................. 96 7. Calcareous Habitats .................................................................................... 99 8. Contiguous Meadow Patches ................................................................... 106 9. Acidic Bogs and Cool Ravines. ................................................................ 108 10. Woodland Pools. ..................................................................................... 111 11. Wetlands .................................................................................................. 121 12. Streams .................................................................................................... 127 13. Conservation Areas ................................................................................. 144 TABLES 1. Ecologically significant habitats in Dover ................................................ 17 2. Species of statewide conservation concern observed in Dover ................. 83 3. Priority habitats, species of concern, and conservation zones ................... 85 SIGNIFICANT HABITATS IN THE TOWN OF DOVER SIGNIFICANT HABITATS IN THE TOWN OF DOVER EXECUTIVE SUMMARY - 1 - EXECUTIVE SUMMARY Hudsonia biologists identified and mapped ecologically significant habitats in the Town of Dover during two periods: September 2008 through December 2010 and May 2016 through December 2017. Through map analysis, aerial photograph interpretation, and field observations we created a large-format map showing the locations and configurations of habitats throughout the town. Some of the habitats are rare or declining in the region or support rare species of plants