Submerged Aquatic Vegetation (SAV) Salinity Zones

<p><b>Open the Data Resource:</b> <a href='https://gis.chesapeakebay.net/ags/rest/services/WIP/SAV_FactSheetSegs/MapServer/3' rel='nofollow ugc'>https://gis.chesapeakebay.net/ags/rest/services/WIP/SAV_FactSheetSegs/MapServer/3</a></p> <p>Also known as underwater grasses, submerged aquatic vegetation, or SAV, are plants that grow in the shallow waters of the Chesapeake Bay and its streams, creeks and rivers. Until 2013, SAV acreage for the Chesapeake Bay were aggregated into three zones: Upper Bay, Middle Bay and Lower Bay. In 2013, it was decided to report the totals by the Bay's four salinity zones:</p> <ul> <li>Tidal fresh, which represents freshwater areas.</li> <li>Oligohaline, which represents salinities of 0.5-5 ppt. </li> <li>Mesohaline, which represents salinities of 5-18 ppt. </li> <li>Polyhaline, which represents salinities of 18-30 ppt. </li> </ul> <p>Approximately 17 species of SAV are commonly found in the Chesapeake Bay, and species diversity increases as salinity decreases. In the Bay's oligohaline and tidal fresh areas, for example, up to a dozen species of SAV have been observed. In the Bay's mesohaline areas, three to five species are normally observed in any one area. Towards the mouth of the Bay, where salinity is highest, only eelgrass and widgeongrass are observed.</p> <p>The more species of SAV that are present in an area, or the higher the diversity in that region, the more resilient that SAV habitat will be. Since different species of SAV are generally found in waters of a specific salinity range, tracking changes in SAV abundance by salinity can help track changes in species abundance.</p>