CHESAPEAKE BAY LOWLANDS ECOREGIONAL PLAN Conservation Science Support—Northeast and Caribbean The Chesapeake Bay Lowlands Plan is a first iteration. The draft report that was distributed in hardcopy for review on 6/27/2002 is included on the CD. No updates were made to that version. CSS is now developing a standard template for ecoregional plans, which we have applied to the CBY ecoregional plan report. Some of the CBY results have been edited or updated for this version. Click on index in the navigation plane to browse the report sections. Note: The Bibliography (still slightly incomplete) contains the references cited in all report sections except for the Marine references, which have their own bibliography. What is the purpose of the report template? The purpose of creating a standard template for ecoregional plans in the Northeast and Mid-Atlantic is twofold: — to compile concise descriptions of methodologies developed and used for ecoregional planning in the Northeast and Mid-Atlantic. These descriptions are meant to meet the needs of planning team members who need authoritative text to include in future plan documents, of science staff who need to respond to questions of methodology, and of program and state directors looking for material for general audience publications. — to create a modular resource whose pieces can be selected, incorporated in various formats, linked to in other documents, and updated easily. How does the template work? Methods are separated from results in this format, and the bulk of our work has gone into the standard methods sections. We have tried to make each methods section stand alone. Each section includes its own citation on the first page. All documents are in PDF format. Some sections of the template have no counterpart in the CBY first iteration. For the most part we have left these empty, although we have added some material. We have modified CBY results sections only to streamline the remaining text and to reflect any divergence from or elaboration of the standard methods. This CD Guide takes advantage of the template's features. Throughout, you will find links to modules of the standard template in different contexts. Draft: Chesapeake Bay Lowlands Ecoregional Plan The Nature Conservancy EXECUTIVE SUMMARY* Description of the Ecoregion The Chesapeake Bay Lowlands (CBY) ecoregion is centered on the Chesapeake Bay and includes most of Delaware, all of the coastal plain in Maryland and the District of Columbia, and coastal Virginia south to the James River. The ecoregion ends at the Atlantic Ocean on the east and the Piedmont to the west, where Interstate 95 follows the Fall Line through much of Maryland and Virginia, closely approximating the western boundary of the ecoregion. The landscape of the ecoregion east of the Bay – the Delmarva Peninsula - is dominated by agriculture and characterized by low, flat sandy plains cut by wide, slow-flowing rivers bordered by extensive swamp forests and tidal marshes. To the west of the Bay, a broad plain with generally low slopes and gentle drainage divides is dissected by a series of major rivers – the Patuxent, the Potomac, the Rappahannock, the York and the James – that form a series of large, parallel peninsulas running into the Bay. The western shore in Maryland (especially the northern portion) is dominated by urban/suburban development around and between Washington, D.C., Baltimore and Annapolis. The western shore in Virginia is a lightly-developed, heavily forested area impacted by urban/suburban development near Richmond and Newport News-Hampton. The CBY ecoregion also includes 140 miles of Atlantic coastline along the Delmarva Peninsula characterized by a complex and dynamic patchwork of barrier islands, salt marshes, tidal flats and large coastal bays, with significant development impacts at Ocean City, Maryland and several beach towns in Delaware. Subdivided by the Conservancy from the much larger Outer Coastal Plain Mixed Forest Province mapped by Bailey, CBY grades into the North Atlantic Coast ecoregion on the south shore of the Delaware Bay, and with the Mid-Atlantic Coastal Plain below the mouth of Chesapeake Bay. Conservation Targets Five major types of conservation targets were identified in the CBY ecoregion: 1) matrix forest blocks; 2) aquatic ecosystems; 3) “significant conservation areas” in tidal waters (for estuarine, coastal and marine targets); 4) natural communities, and; 5) species. Matrix forest blocks fell into six block-groupings, as defined by Ecological Land Units. Streams and rivers were classified into 11 different system types, based on their geological, hydrological and biological characteristics. Ten species and four habitat types were included as estuarine, coastal and marine targets in Significant Conservation Areas. At least 113 natural community targets in 18 vegetation groups were identified in the ecoregion. Fifty eight plant and animal species were selected as Primary targets in CBY, including 15 federally listed as Endangered or Threatened. Occurrences of 46 Secondary species targets were also evaluated at portfolio sites. Ecoregional Portfolio The full ecoregional portfolio includes 20 matrix forest blocks, 51 aquatic ecosystem occurrences (37 Tier 1, 14 Tier 2), 18 Significant Conservation Areas (14 Tier 1, 4 Tier 2) for estuarine, coastal & marine targets, and 274 sites for species (303 viable occurrences) and natural communities (233 viable occurrences). * Samson, D.A., M.G. Anderson et al. 2003. Chesapeake Bay Lowlands Ecoregional Conservation Plan; First Iteration, Edited. The Nature Conservancy, Mid-Atlantic Division, Charlottesville, VA 6/27/02 – Edited 7/2003 EXEC-1 Draft: Chesapeake Bay Lowlands Ecoregional Plan The Nature Conservancy Excluding the aquatic ecosystem occurrences, the total area of the ecoregion encompassed by all portfolio sites combined is about 2,461,000 acres, with 966,00 ac in matrix forest blocks, 1,276,986 ac in SCA’s, and 218,000 ac in sites harboring species and natural community targets (i.e., named in Natural Heritage Program BCD’s). This represents 22.7% of the total area (land and water) of the ecoregion. The total portfolio area for only matrix forest blocks and Natural Heritage sites combined (i.e., terrestrial sites only), represents 15.7% of the land area only of the ecoregion. Conservation Goals The current portfolio includes just 25% of the natural community occurrences needed to meet goals set for CBY, based on community patch size and rangewide distribution. Among the 18 vegetation groups, success ranged from below 10% to above 80 percent. Among individual natural community association across groups, only nine met or exceeded the numerical goal set for that community type. The overall success rate for portfolio occurrences of Primary species was about 38%, varying among species from as low as zero to as high as 200%. Conservation goals were met or exceeded for only three animal and five plant species targets. Many species targets had fewer than half of the number of portfolio occurrences that were set as the conservation goal for that species in the ecoregion. Threats Not surprisingly, many of the species and natural community targets in this ecoregion occur in aquatic, wetland or shoreline habitats. Direct threats to these conservation targets were judged to be minimal, given their location in areas not suitable for development or natural resource extraction. Many of these sites, however, are threatened by poor water quality, due to agricultural runoff (esp. on Delmarva Peninsula) and urban/suburban runoff on the western shore (esp. in MD). Future threats to water quantity at these sites may be of greater concern, due to depletion of both surface and deep groundwater aquifers from domestic and municipal wells, crop irrigation, and climate change. Threats to upland sites and matrix forest blocks vary across the ecoregion, depending on their location in the human landscape. Sites and matrix forest blocks located in rural areas and/or with high proportions of low, wet woods (esp. on Delmarva and in VA), are lightly impacted by agriculture, logging and roads, while sites and blocks in southern MD are seriously threatened by all of the impacts associated with encroaching urban/suburban development. The Chesapeake Bay has been seriously degraded by excessive runoff of nutrients, sediments and toxic chemicals from millions of acres of farm land and developed land in the watershed. Poor water quality in the Bay is both the cause and the consequence of severely diminished submerged aquatic vegetation (SAV) beds and oyster reefs. Overfishing of both finfish and shellfish stocks have depleted a number of the species characteristic of the Bay. The coastal bays along the Atlantic, especially the northern bays in Delaware and Maryland, have been, and continue to be, degraded by many of the same threats affecting the Chesapeake Bay. Probably the single greatest threat to all of these tidal systems, and to many of the freshwater aquatic sites further upstream, is significant sea level rise. An increase in the intensity and frequency of Atlantic storms and other regional weather events as a result of global climate change would also damage many natural areas and ecological systems in the ecoregion. 6/27/02 – Edited 7/2003 EXEC-2 Draft: Chesapeake Bay Lowlands Ecoregional Plan The Nature Conservancy Conservation Implementation The Delaware, Maryland/DC and Virginia chapters have committed to work on a suite of 10 Year Action sites in the ecoregion that includes 13