Dune vegetation fertilization by nesting sea turtles

• Published in: Ecology (Durham) 2007-04, Vol.88 (4), p.1053-1058
• Main Authors: Hannan, Laura B., Roth, James D., Ehrhart, Llewellyn M., Weishampel, John F.
• Format: Article
• Language: English
• Subjects: allochthonous input; Animal and plant ecology; Animal nesting; Animal reproduction; Animal, plant and microbial ecology; Animals; barrier island ecology; Beaches; Biological and medical sciences; Caretta caretta; Chelonia mydas; coastal dune soils; Conservation of Natural Resources; Dunes; Ecology; Ecosystem; Eggs; endangered species; facilitation; Female; Flowers & plants; Fundamental and applied biological sciences. Psychology; General aspects; green turtle; habitat conservation; islands; leaves; loggerhead; Marine; Marine ecology; nesting; Nesting Behavior - physiology; Nitrogen; nitrogen deposition; Nitrogen Isotopes - analysis; nutrient availability; nutrient transport; Oats; Oviposition - physiology; Plant Development; Plant nutrition; refuge habitats; Reptiles & amphibians; sea oats; Sea turtles; Seas; Silicon Dioxide - analysis; soil fertility; soil nutrients; Soils; species differences; stable isotopes; threatened species; trophic relationships; Turtles; Turtles - physiology; Uniola paniculata; Vegetation; wildlife habitats; Zoology
• ISSN: 0012-9658; 1939-9170
• DOI: 10.1890/06-0629

Sea turtle nesting presents a potential pathway to subsidize nutrient-poor dune ecosystems, which provide the nesting habitat for sea turtles. To assess whether this positive feedback between dune plants and turtle nests exists, we measured N concentration and δⁱ⁵N values in dune soils, leaves from a common dune plant (sea oats [Uniola paniculata]), and addled eggs of loggerhead (Caretta caretta) and green turtles (Chelonia mydas) across a nesting gradient (200—1050 nests/km) along a 40.5-km stretch of beach in east central Florida, USA. The δⁱ⁵N levels were higher in loggerhead than green turtle eggs, denoting the higher trophic level of loggerhead turtles. Soil N concentration and δⁱ⁵N values were both positively correlated to turtle nest density. Sea oat leaf tissue δⁱ⁵N was also positively correlated to nest density, indicating an increased use of augmented marine-based nutrient sources. Foliar N concentration was correlated with δⁱ⁵N, suggesting that increased nutrient availability from this biogenic vector may enhance the vigor of dune vegetation, promoting dune stabilization and preserving sea turtle nesting habitat.