THERMAL REGULATION OF FUNCTIONAL GROUPS IN RUNNING WATER ECOSYSTEMS

摘要

Upper and lower thermal limits and temperature dependent growth have been determined for a number of organisms (or populations) representing various functional groups of stream ecosystems (microconsumers, producers and macroconsumersshredders, collectors, scrapers and predators). Although temperature functions as an overall control parameter, organic substrate (microconsumers) and inorganic nutrients (microconsumers and producers), light (producers) and food quality (macroconsumers) pan modify thermal responses. Stream microorganisms typically grow below their thermal optima, community composition being determined by those that can manage the maximum growth at a given temperature utilizing a given organic substrate. Producers in first to third order streams are generally light limited (although nutrient availability is also important). Food quality, primarily a function of microbial biomass in the case of detritivores, can compensate for temperature dependent growth in non-predator macroinvertebrate functional groups.