title: Effects of invasive cordgrass on presence of Marsh Grassbird in an area where it is not native.
abstract: The threatened Marsh Grassbird (Locustella pryeri) first appeared in the salt marsh in east China after the salt marsh was invaded by cordgrass (Spartina alterniflora), a non-native invasive species. To understand the dependence of non-native Marsh Grassbird on the non-native cordgrass, we quantified habitat use, food source, and reproductive success of the Marsh Grassbird at the Chongming Dongtan (CMDT) salt marsh. In the breeding season, we used point counts and radio-tracking to determine habitat use by Marsh Grassbirds. We analyzed basal food sources of the Marsh Grassbirds by comparing the δ(13) C isotope signatures of feather and fecal samples of birds with those of local plants. We monitored the nests through the breeding season and determined the breeding success of the Marsh Grassbirds at CMDT. Density of Marsh Grassbirds was higher where cordgrass occurred than in areas of native reed (Phragmites australis) monoculture. The breeding territory of the Marsh Grassbird was composed mainly of cordgrass stands, and nests were built exclusively against cordgrass stems. Cordgrass was the major primary producer at the base of the Marsh Grassbird food chain. Breeding success of the Marsh Grassbird at CMDT was similar to breeding success within its native range. Our results suggest non-native cordgrass provides essential habitat and food for breeding Marsh Grassbirds at CMDT and that the increase in Marsh Grassbird abundance may reflect the rapid spread of cordgrass in the coastal regions of east China. Our study provides an example of how a primary invader (i.e., cordgrass) can alter an ecosystem and thus facilitate colonization by a second non-native species.
authors.affiliation: Coastal Ecosystems Research Station of Yangtze River Estuary, Ministry of Education Key Laboratory for Biodiversity Science and Ecological Engineering, Institute of Biodiversity Science, Fudan University, No. 220 Handan Road, Shanghai, 200433, China.
authors.forename: Zhijun
authors.initials: Z
authors.lastname: Ma
authors.forename: Xiaojing
authors.initials: X
authors.lastname: Gan
authors.forename: Chi-Yeung
authors.initials: CY
authors.lastname: Choi
authors.forename: Bo
authors.initials: B
authors.lastname: Li
mesh_terms: D063147:Animal Distribution; D000818:Animals; D002681:China; D003247:Conservation of Natural Resources; D004032:Diet; D058865:Introduced Species; D006109:Poaceae / Q000502:physiology*; D012098:Reproduction; D020308:Songbirds / Q000502:physiology*; D053833:Wetlands
keywords: Locustella pryeri; Spartina alterniflora; análisis de isotopo de carbono; biological invasion; breeding; carbon isotope analysis; estructura de hábitat; exotic plant; food source; fuente de alimento; habitat structure; invasión biológica; invasor primario; marisma; planta exótica; primary invader; reproducción; salt marsh