Session: : Communities: Disturbance And Recovery 8
COS 166-6 - CANCELLED - Temporal resource variability and its constituent effects on aquatic biodiversity: tests with protist communities from pitcher plants
Faculty, Chair of EEB Department Cornell University, New York, United States
Abstract: Most ecosystems have permeable boundaries and are influenced by spatial and temporal variability in the supply of resources. Sudden extreme deviations in resource availability are known as resource pulses and can have profound impacts on consumer community structure. Different modes of resource pulse variation – such as the magnitude, frequency, and duration of resource availability – often covary in nature. However, pulse characteristics can strongly influence community structure, leading to uncertainty about how changing patterns of resource variability will affect communities in the future. To elucidate how pulse characteristics differentially impact community organization, we conducted a series of experiments manipulating the magnitude and frequency of resource pulses to protist communities that inhabit pitchers of the purple pitcher plant Sarracenia purpurea.
Increasing resource pulse magnitude led to convergence in community structure among replicates and reduced temporal variation in community structure. Resource pulse frequency altered the persistence of rare taxa: contrary to expectation, high frequency pulses supported more speciose communities than low frequency pulses. Distribution and variability of protist functional traits likely explain how pulse magnitude and frequency drive patterns of community variability. Both large magnitude and low frequency pulses led to communities dominated by fast-moving protists, while small magnitude and high frequency pulses led to increased representation of slow-moving protists. Variation in the density of fast-moving protists may explain why large resource pulses led to convergent patterns of community structure. Understanding how pulse characteristics differentially affect consumer community organization may better enable us to anticipate the ecological consequences of changes in resource variability in the future.
