Data from: Realm specific adaptations lead to contrasting global patterns in submerged and emergent aquatic plant height

Aim: This study aims to evaluate whether the trait-environment
relationships known for terrestrial plant height extend to freshwater
macrophytes, and to identify the primary environmental factors influencing
global height patterns in emergent and fully submerged aquatic plants.
Location: Global. Time Period: Species occurrence records and height
measurements compiled from 1931 to 2022. Major Taxa Studied:
Freshwater plant species. Methods: We compiled a global dataset of maximum
plant height records for 1,735 aquatic plant species, categorized by
life form (partially emergent vs. submerged). Using generalized
additive models, we tested how plant height varied along
latitudinal gradients and how it was related to environmental predictors
including temperature, relative inorganic carbon supply, and water
depth (indicated by habitat availability). We explicitly
analyzed whether these relationships differed between the two life forms,
and validated these patterns using site-scale species and environmental
data from northern temperate lakes and streams. Results: Species with
emergent growth increase in height with warmer temperature. On
the contrary, fully submerged species exhibit increased height
with higher inorganic carbon availability and
colder climates. At the local scale, submerged plant height was
positively associated with relative inorganic carbon supply in lakes and
streams of the northern temperate zone. Main Conclusions:
The relationships between environmental variables and plant
height differ between partially emergent to completely
submerged life forms, consistent with realm-specific patterns
in trait-environment correlations. These differing patterns
highlight that trait-environment coupling in freshwater systems may not
parallel those in terrestrial ecosystems and suggest that life form
mediates species’ responses to environmental variation.