DOI: 10.5061/dryad.nzs7h4502
title: Data from: Quantifying the contribution of community trait mean and diversity to ecosystem functioning

description: Hundreds of experiments conducted over the last decades demonstrate a
 positive relationship between species diversity and ecosystem functions.
 Following good experimental practice, most of these studies have
 manipulated species richness artificially by assembling communities
 randomly. Yet, natural communities along ecological gradients often show
 niche-based responses to selection gradients, and species extinction order
 is generally not a random process. Such responses are commonly
 trait-mediate,d and the effects of communities on ecosystems’ functions
 also depend on species traits. In an effort to disentangle the
 relationship of trait mean value and diversity with ecosystem functioning,
 we revisited a community assembly mesocosm experiment that simulated
 habitat heterogeneity and a typical gradient of productivity to test how
 body size diversity and composition of cladocerans responded to such
 gradients and whether and how such trait responses impacted top-down
 control of unicellular algae, a key ecosystem function in aquatic systems.
 Nutrient addition lead to an increase in average body size (CWMBS), which
 ultimately resulted in an increased zooplankton resource use efficiency
 (RUEZP). This increase in CWMBS acted as a buffer for ecosystems functions
 despite the decline in species richness under high phosphorus levels.
 Habitat heterogeneity modified the response of both richness and size
 diversity (SD) along the nutrient gradient, suggesting that habitat
 structure provided by aquatic plants can modify zooplankton diversity
 under eutrophic conditions. We also show that CWMBS and SD are both
 important and largely independent determinants of variation in RUEZP,
 whereas the explanatory power of species richness was mostly shared with
 SD. Overall, our findings illustrate the potential for a key trait, such
 as body size, to predict top-down control of algae through selection
 effect mediated by differences in trait mean, as well as complementarity
 associated with trait diversity among coexisting species.  
description: # Zooplankton community trait mean value rather than diversity determines
 ecosystem functioning
 [https://doi.org/10.5061/dryad.nzs7h4502](https://doi.org/10.5061/dryad.nzs7h4502) The dataset consist in a subset of the data from a metacommunity assembly experiment performed by Declerck et al. (2007; [https://doi.org/10.1890/07-0048.1](https://doi.org/10.1890/07-0048.1)). In our study, a multifactorial combination of nutrient concentrations and habitat complexity levels was performed using cattle tanks (200-L) under semi-standardized outdoor conditions (ARENA outdoor experimental area, Heverlee, Belgium). The experiment lasted 32 days following a 34-day inoculation/acclimatation period. In the experimental design, for each level of habitat heterogeneity (i.e., with and without artificial macrophytes) by nutrient concentration (i.e., 0, 10, 100, and 1000 µg L-1), five replicates were used, resulting in a total of 40 cattle tanks. For further details about the experimental design, see Declerck et al. (2007; [https://doi.org/10.1890/07-0048.1](https://doi.org/10.1890/07-0048.1)). ## Description of the data and file structure The dataset "Trait-based_CAFE_data" includes data relative to the sampling of zooplankton density (Density_zoo; org L-1), biomass (Biom_zoo; µg L-1), resource use efficiency (RUEzp_D65), richness (S), community average size (CAS_dens; mm), and size diversity (SDshn_dens). The datapoints are identified based on unique sampling identification (Id), habitat heterogeneity treatment (NPL - without macrophytes, or APL - with artificial macrophytes), phosphorus addition levels (0, 10, 100, and 1000), and replicates (A, B, C, E). Note that replicate D was excluded due to missing datapoints.  All diversity metrics were calculated using density matrix and all analyses were done using Chlorophyll-a of day 65.  ## Sharing/Access information Links to other publicly accessible locations of the data: * [https://github.com/lobiouni/Trait-based_CAFE](https://github.com/lobiouni/Trait-based_CAFE) Data was derived from the following sources: * Declerck S., M. Vanderstukken, A. Pals, K. Muyleart, and L. De Meester. 2007. Plankton biodiversity along a gradient of productivity and its mediation by macrophytes. *Ecology* 88: 2199–2210 ([https://doi.org/10.1890/07-0048.1)](https://doi.org/10.1890/07-0048.1). ## Code/Software The R code provided shows the data analyses undertaken to assess how environmental pressures related to eutrophication and loss of habitat heterogeneity influence a key ecosystem function through its impacts on zooplankton community features.