Between-species differences in demographic responses to temperature of coexisting cladocerans

Abstract

In this work we report on the seasonal trends of abundances in terms of temperature exposure for four coexisting cladoceran species (Daphnia ambigua (Daphniidae), Ceriodaphnia dubia (Daphniidae), Diaphanosoma chilense (Sididae) and Moina micrura (Moinidae)) from a Chilean temperate lake. In order to compare the demographic response to temperature, we used life table experiments to parameterize matrix models for the four species at four fixed temperatures. From these life table response experiments we assessed the effects of temperature, species and their interaction on the variation in growth rate, as well as the contribution of juvenile survival, adult survival, fertility and age at first reproduction to the changes in growth rate. Our results showed interspecific differences in the effect of temperature on the growth rate. Species that present higher field abundance at lower temperature also exhibited, under controlled experiments, higher growth rates at low temperature and lower growth rates at high temperature, relative to the additive model. Conversely, species with higher abundances during the warmer seasons exhibited higher growth rates at higher experimental temperatures and lower growth rates at lower temperatures, relative to the additive model. The vital rates that most contributed to the variation in growth rate were age at first reproduction and fertility. Our growth rate estimates matched predictions of the metabolic ecology model.