Foreseeable global warming will differentially affect Chara vulgaris populations from different altitudes

Abstract A 2–4 °C increase in temperature is foreseen for the Mediterranean region by the end of the 21st century due to climate change. This warming is expected to occur as heat waves, and will be particularly important for shallow water bodies which are the main freshwater ecosystems in the Mediterranean. We subjected four populations of Chara vulgaris to a common garden experiment. Each population came from locations at different altitudes, hence living at different mean temperatures. Individual charophyte cultures were initiated with specimens from four origins and acclimatized at 20 °C in a controlled environment for 3 weeks. After this, all the populations were incubated under 3 water…