Biogeography of Submerged Aquatic Vegetation (SAV) in the Pontchartrain Basin: Species Salinity Zonation and 1953–2016 Lake Pontchartrain Trends

• Published in: Southeastern geographer 2017-09, Vol.57 (3), p.273-293
• Main Authors: POIRRIER, MICHAEL A., CAPUTO, CLAIRE E., FRANZE, CAROL D.
• Format: Article
• Language: English
• Subjects: Analysis; Aquatic ecosystems; Aquatic plants; Barrier islands; Biogeography; Canals; Coverage; Dredging; Drought; Ecosystem services; Ecosystems; Environmental aspects; Erosion; Fisheries; Flowers & plants; Grasses; Habitats; Hurricanes; La Nina; Lakes; PART I: PAPERS; Plants (botany); Saline water; Salinity; Salinity effects; Sea level rise; Sediments; Shoreline protection; Species; Trends; Turbidity; Urbanization; Vegetation; Water shortages; Wetlands; Zonation
• ISSN: 0038-366X; 1549-6929; 1549-6929
• DOI: 10.1353/sgo.2017.0025

A biogeographic study of submerged aquatic vegetation (SAV) in the Pontchartrain Basin of southeastern Louisiana was conducted. These plants provide numerous essential ecosystem services. Eighteen species occurred in different salinity zones ranging from freshwater to the saline waters of the Gulf of Mexico. Lake Pontchartrain SAV coverage was reduced by 70 percent from 1953 to 1990 due to increased turbidity from urbanization and shell dredging. A La Niña drought (1998–2001) increased SAV to 80 percent of the 1953 coverage, but declines occurred after the drought and there was extensive damage from Katrina and other hurricanes between 2005 and 2012. Coverage in 2016 is about 10 percent of the 1953 level. In these subtropical waters, some species were abundant during the winter and spring, but declined during the summer. Lower Basin SAV is also changing due to high rates of relative sea level rise and erosion of marsh and barrier islands. Se realizó un estudio biogeográfico de la vegetación acuática sumergida (SAV) en la cuenca de Pontchartrain, en el sureste de Luisiana. Estas plantas proporcionan numerosos servicios esenciales del ecosistema. Dieciocho especies se produjeron en diferentes zonas de salinidad que van desde agua dulce hasta las aguas salinas del Golfo de México. El lago Pontchartrain SAV cobertura se redujo en un 70 por ciento de 1953 a 1990 debido al aumento de la turbidez de la urbanización y la concha de dragado. Una sequía de La Niña (1998–2001) aumentó el SAV al 80 por ciento de la cobertura de 1953, pero los descensos ocurrieron después de la sequía y hubo daños extensos de Katrina y otros huracanes entre 2005 y 2012. La cobertura en 2016 es alrededor del 10 por ciento de la de 1953 nivel. En estas aguas subtropicales, algunas especies fueron abundantes durante el invierno y la primavera, pero disminuyeron durante el verano. Lower Basin SAV también está cambiando debido a las altas tasas de aumento relativo del nivel del mar y la erosión de las islas pantano y barrera.