Selecting functional traits that capture trade-offs for intertidal macroalgae provides a roadmap for future studies.

Area of Science:

• Marine Ecology
• Phycology
• Ecosystem Dynamics

Background:

• Current functional ecology models for marine macroalgae are outdated (1980s functional groups).
• Anthropogenic stressors necessitate new tools to understand ecosystem shifts and community change.
• Trait-based approaches are powerful for other taxa but underdeveloped for macroalgae.

Purpose of the Study:

• To identify a core set of marine macroalgal traits that capture diverse ecological strategies.
• To streamline the application of trait-based ecology for macroalgae in changing ocean environments.
• To provide a foundation for advancing macroalgal trait-based ecology across different ecosystems.

Main Methods:

• Measured and analyzed numerous functional traits across seven diverse macroalgal species in rocky intertidal zones.
• Employed quantitative methods and literature review to select a parsimonious set of core traits.
• Utilized permutational multivariate analyses of variance (PERMANOVA) to compare trait datasets (16 vs. six traits).

Main Results:

• Both 16 and six core traits explained significant differences in species
• A key trade-off was identified between thallus height (for preemptive resource acquisition) and relative surface area (for efficient uptake in low-resource conditions).
• Taller algae require strength to resist drag, while high surface area algae are shorter and weaker.

Conclusions:

• Six core traits are sufficient to capture the ecological strategies of intertidal macroalgae.
• This reduced trait set effectively explains ecological variation and simplifies future research.
• The findings offer a roadmap for applying trait-based ecology to macroalgae in various marine ecosystems.