DOI: 10.5061/dryad.jd8f99n
title: Data from: Quantifying the importance of functional traits for primary production in aquatic plant communities

description: 1. Aquatic plant meadows are important coastal habitats that sustain many
 ecosystem functions such as primary production and carbon sequestration.
 Currently, there is a knowledge gap in understanding which plant
 functional traits e.g. leaf size or plant height underlie primary
 production in aquatic plant communities. 2. To study how plant traits are
 related to primary production, we conducted a field survey in the Baltic
 Sea, Finland, which is characterized by high plant species and functional
 diversity. 30 sites along an exposure gradient were sampled (150 plots)
 and nine plant morphological and chemical traits measured. The aim was to
 discern how community-weighted mean traits affect community production and
 whether this relationship changes along an environmental gradient using
 structural equation modelling (SEM). 3. Plant height had a direct positive
 effect on production along the exposure gradient (r = 0.33) and indirect
 effects through two leaf chemical traits, Leaf δ15N and Leaf δ13C (r =
 0.24 and 0.18 respectively) resulting in a total effect of 0.28. In plant
 communities experiencing varying exposure, traits such as root N
 concentration and leaf δ15N had positive and negative effects on
 production, respectively. 4. Synthesis: Our results demonstrate that the
 relationship between plant functional traits and community production is
 variable and changes over environmental gradients. Plant height generally
 has a positive effect on community production along an exposure gradient,
 while the link between other traits and production changes in plant
 communities experiencing varying degrees of exposure. Thus, the underlying
 biological mechanisms influencing production differ in plant communities,
 emphasizing the need to resolve variability and its drivers in real-world
 communities. Importantly, functionally diverse plant communities sustain
 ecosystem functioning differently and highlight the importance of benthic
 diversity for coastal ecosystem stability.
description: CWM_traits for aquatic
 plantsData was collected in a
 field survey in August 2014 comprising 30 sites in the Gulf of Finland,
 Northern Baltic Sea. Sampled sites occurred along a wave exposure gradient
 and were divided into outer, middle and inner archipelago areas (see
 article for details). At each site, five replicate plots (1m2 each) were
 sampled. Trait measurements were weighted by the shoot densities of each
 species to retrieve the community-weighted mean trait value and
 standardized to have a mean of 0 and variance of 1. See article for more
 information on the trait measurements. The data was used in constructing
 Structural Equation Models. Abbreviated headlines are as follow: “CWM_SLA”
 = community-weighted mean specific leaf area, “CWM_Root” =
 community-weighted mean root length, “CWM_Hmax” = community-weighted mean
 maximum vegetative height, “CWM_RS = community-weighted mean root to shoot
 ratio, CWM_LeafN = community-weighted mean leaf nitrogen concentration,
 “CWM_RootN” = community-weighted root nitrogen concentration,
 “CWM_Leafd15N” = the community-weighted mean delta 15N of youngest leaves,
 “CWM_Leafd13C” = the community-weighted mean delta 13C of youngest leaves,
 “CWM_Rootd15N” = the community-weighted mean delta 15N of youngest roots,
 “lnSilt” = the ln-transformed silt-fraction and “lnPrimprod” = the
 ln-transformed community primary production.CWM_traits.csv