Counteracting effects of recruitment and predation shape establishment of rotifer communities under climate change

• Published in: Limnology and Oceanography
• Main Authors: Zhang, Huan, Ekvall, Mattias, Xu, Jun, Hansson, Lars-Anders
• Format: Article in Journal/Newspaper
• Language: English
• Published: ASLO 2015
• Subjects: Ecology; Copepods; Rotifer
• Online Access: https://lup.lub.lu.se/record/8227141; https://doi.org/10.1002/lno.10122

To assess how synergies between climate warming and increased concentrations of humic substances ("brownification") will affect rotifer community establishment in spring, we conducted a mesocosm experiment where we combined a 3 degrees C temperature increase with a doubling in water color, changes corresponding to modeled projections for the coming 25-75 yr. We also performed a complementary predation experiment to separate the effects of predation from climate-driven changes. We show that recruitment from the sediment is crucial for shaping the rotifer community and that an elevated temperature will likely advance the recruitment peak resulting in an earlier rotifer peak abundance in spring. However, increased predator abundances, also resulting from elevated temperatures, counteracted the climate driven increase in rotifer recruitment and thereby hampered the pelagic establishment of rotifers. We show further that different rotifer genera respond differently to these increased predation pressure due to selective predation by copepods and taxa-specific protection morphologies and behaviors of rotifers. However, with the exception of one taxon, the effects from brownification were negligible, compared to effects imposed by elevated temperatures. We conclude, therefore, that future rotifer dynamics will be affected both directly through elevated temperatures and indirectly by increased predation.