Data for: Functional trait variability supports the use of mean trait values and identifies tradeoffs for marine macroalgae

Trait-based ecology (TBE) has proven useful in the terrestrial realm and
beyond for collapsing ecological complexity into traits that can be
compared and generalized across species and scales. However, TBE for
marine macroalgae is still in its infancy, motivating research to build
the foundation of macroalgal TBE by leveraging lessons learned from other
systems. Our objectives were to evaluate the utility of mean trait values
(MTVs) across species, to explore the potential for intraspecific trait
variability, and to identify macroalgal ecological strategies by
clustering species with similar traits and testing for bivariate
relationships between traits. To accomplish this, we measured thallus
toughness, a trait associated with resistance to herbivory, and tensile
strength, a trait associated with resistance to physical disturbance, in
eight tropical macroalgal species across up to seven sites where they were
found around Moorea, French Polynesia. We found interspecific trait
variation generally exceeded intraspecific variation across species.
Further, MTV within species varied across sites, suggesting future
research should focus on whether these traits are influenced by
site-specific differences in biotic and abiotic drivers. Species grouped
into three clusters representing different ecological strategies: species
that were defended against herbivores but not strong, species that were
strong but not defended, and species that were neither. Intraspecific
Standardized Major Axis regressions revealed five species exhibited
significant or marginally significant positive relationships between these
two traits, suggesting trait syndromes within species. Only one species
exhibited a significant intraspecific tradeoff, as indicated by a negative
regression slope. Synthesis: Our results point to three key takeaways that
should provide a foundation to rapidly advance development of TBE for
macroalgae in the future. First, our evidence supports the use of MTVs for
macroalgae. Second, we identified significant spatial variability in
macroalgal traits may indicate an ability to respond to shifting
environmental drivers. Third, measuring even a few traits can be a
powerful tool to identify different ecological strategies to resist
disturbances such as herbivory and removal by wave action.  We
hope these novel findings motivate future research into a wider suite of
macroalgal traits, functions, and strategies to further develop
trait-based approaches for marine macroalgae.