How does a wetland plant respond to increasing temperature along a latitudinal gradient?

Area of Science:

• Ecology
• Plant Biology
• Climate Change Research

Background:

• Global warming impacts plant fitness and ecosystem functions, with wetlands facing particular threats due to their decline.
• Understanding how warming affects plant traits is crucial for predicting ecosystem responses.

Purpose of the Study:

• To investigate the effects of warming on the growth and reproduction of *Caltha palustris*, a common wetland plant, considering population origin along a latitudinal gradient.
• To assess phenotypic plasticity in response to climate change in a key wetland species.

Main Methods:

• A 2-year *in situ* temperature manipulation experiment using open-top chambers on *Caltha palustris* clones across four Swedish regions.
• Measurement of growth (plant height, leaf area, roots) and reproductive traits (flowers, fruits) on 320 plants over two seasons.

Main Results:

• Warming significantly increased plant height, leaf area, number of leaves, and roots.
• High-latitude populations showed a stronger growth response to warming, especially in leaf area.
• Reproductive responses varied: increased flowers in the second year, and increased fruits in low-latitude populations in the first year.

Conclusions:

• Warming promotes growth, particularly in high-latitude wetland plants, potentially altering plant community composition and ecosystem functions.
• Reproductive success under warming is regionally and temporally variable.
• Warming effects are context-dependent, necessitating further research across diverse wetland types and climate gradients.