A standardized protocol and basic ecological findings to include charophytes in functional trait studies.

Area of Science:

• Ecology
• Botany
• Aquatic Plant Biology

Background:

• Charophytes are ecologically important freshwater benthic macroalgae.
• They are often excluded from functional trait research, underestimating ecosystem diversity.
• A standardized protocol for charophyte functional traits is needed.

Purpose of the Study:

• To develop a standardized protocol for measuring charophyte leaf functional traits.
• To compare charophyte functional traits with common vascular macrophyte life forms.
• To assess the contribution of charophytes to aquatic plant functional diversity.

Main Methods:

• Identified functional units in charophytes (whorls, branchlets, internodes).
• Measured leaf area, specific leaf area, dry matter content, chlorophylls, carotenoids, and nutrient content (N, P, C) for 9 charophyte species.
• Validated the protocol by comparing charophyte traits with 5 macrophyte groups using a multidimensional niche approach.

Main Results:

• Trait measurements were comparable between charophytes and vascular macrophytes.
• Charophyte functional traits aligned with ecological expectations regarding depth and light gradients.
• Charophytes exhibited high intraspecific variability and occupied a unique functional niche, overlapping with submerged narrow-leaved plants.

Conclusions:

• Charophytes significantly expand the functional diversity of aquatic plants.
• The developed protocol enables better integration of charophytes into ecosystem functional assessments.
• Future research should apply the protocol to Characeae genera and explore trait variability drivers.