Life history and reproductive capacity of Gammarus fossarum and G-roeseli (Crustacea : Amphipoda) under naturally fluctuating water temperatures: a simulation study

摘要

1. Mathematical functions developed in long-term laboratory experiments at different constant temperatures were combined with daily water temperatures for 1991 - 93 in eight Austrian streams and rivers to simulate the complex life histories and reproductive capacities of two freshwater amphipods: Gammarus fossarum and G. roeseli. The functions describe brood development times, hatching success, times taken to reach sexual maturity, growth, and fecundity. The sex ratio was assumed to be 0.5 and an autumn - winter reproductive resting period was based on observations of six river populations. Simulations included summer-cold mountain streams, summer-warm lowland rivers, watercourses fed by groundwater or influenced by heated effluents, and varying amplitudes of change within each year.