Mass mortality of a dominant invasive species in response to an extreme climate event: Implications for ecosystem function

Autor: William G. McDowell, William H. McDowell, James E. Byers
Rok vydání: 2016
Předmět:
Zdroj: Limnology and Oceanography. 62:177-188
ISSN: 0024-3590
Popis: Impacts of invasive species on ecosystems are often context dependent, making empirical assessments difficult when climatic baselines are shifting and extreme events are becoming more common. We documented a mass mortality event of the Asian clam, Corbicula fluminea, an abundant invasive clam, which has replaced native mussels as the dominant filter-feeding bivalve in the southeastern United States. During an extremely hot and dry period in the summer of 2012, over 99% of Corbicula died in our 10-km study reach of the Broad River, Georgia. Because Corbicula were the only filter-feeding organism in the ecosystem with substantial biomass, their death led to the nearly complete cessation of ecosystem services provided by filter-feeding bivalves. We estimate that following the mass mortality event, turnover time within the sampling reach (reach volume/total filtration) rose from approximately 5 h to over 1200 h. In addition to the loss of filtering capacity, concentrations of total dissolved phosphorus (TDP) and soluble reactive phosphorus (SRP) were also higher in areas where die-off was occurring than in an upstream area without mortality. Mass balance calculations and a manipulative mesocosm experiment predicted TDP and SRP concentrations much higher than our observed values, suggesting that rapid biotic or abiotic uptake of phosphorus may have occurred. Our study demonstrates that climate change can increase the temporal variability of populations of aquatic organisms that provide key ecosystem functions, and highlights that even pulsed, short-lived events can markedly affect systems of reduced diversity.
Databáze: OpenAIRE
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