Computing functional diversity indices and community weghted means for macroinvertebrates.

The fwtraits access the freshwaterecology.info database that contains several ecological parameters, traits and indicators used in biogeographical modeling, fuunctional diversity and taxonomic assessments, and ecological monitoring. These are grouped based on the taxonomic groups, including macroinvertebrates, fishes, phytoplankton, phytobenthos, and macrophytes. Therefore, in this workflow we demonstrated the use of ecological parameters from the database in assessing functional diversity.

NOTE

• We demonstrated using simulated the datasets to illustrate the use of the package and thus no ecological conclusions can be derived from the analysis.

library(fwtraits)
library(ggplot2)

Simulate the data used in the analysis

set.seed(1135)

sites1 <- rep(c("A","B", "C", "D", "E"), c(7,10, 8, 13, 4))

mv <- c("Margaritifera margaritifera","Pseudunio auricularius","Musculium lacustre",
        "Musculium transversum","Corbicula fluminea","Congeria leucophaeata",
        "Dreissena polymorpha", "Dreissena rostriformis bugensis",
        "Parastenocaris germaica", "Branchiobdella balcanica",
        "Branchiobdella hexadonta","Branchiobdella parasita","Branchiobdella pentadonta")

sp <- c(sample(mv, 7), sample(mv, 10),sample(mv, 8),sample(mv, 13),sample(mv, 4))
abun <- rnorm(length(sp), 1.3, 0.12)

macrodf <- data.frame(sites = sites1, species = sp, abund = abun)

Retrieving the ecological parameters from the database

We considered two ecological references for macroinvertebrate species: stream zonation preference and feeding type. These were selected because most species have records, reducing missing values that might have required imputation.

It should be noted that imputing for missing traits is outside the scope of this package. So, species that do not have records were dropped when computing the functional diversity indices or community weighted means.

traitsdf <- fw_fetchdata(data =  macrodf,
                           organismgroup = 'mi',
                           taxonomic_column = 'species',
                           ecoparams = c("stream zonation preference", "feeding type"),
                           inform = FALSE)

1. Compute functional diversity indices

These are computed by setting FD to TRUE and abund parameter must be provided. They the indices are computed using the FD package (Laliberté & Legendre 2010). The indices tested included Functional richness (FRic), species richness (SRic), Functional evenness (FEve), Functional diversity (FDiv), Funtional dispersion (FDis), and Rao quotient (Rao Q).

#fd indices calculated when abundance  is provided.

fdindices <- fw_fdcompute(fwdata = traitsdf, 
                        sitesdata = macrodf,
                        sites = 'sites',
                        species = 'species',
                        abund = 'abund',
                        FD = TRUE)

#functional richness only: when abundance is not provided.
fdric<- fw_fdcompute(fwdata = traitsdf, 
                        sitesdata = macrodf,
                        sites = 'sites',
                        species = 'species',
                        FD = TRUE)

Visualisation of the ecological paramter for each index.

df <- fdindices |> tidyr::gather('fdind', "vals", -site)
                                 
ggplot(data = df, aes(site, vals, fill = fdind))+
  geom_bar(stat = 'identity')+
  scale_fill_viridis_d()+
  theme(legend.position = "none")+
  facet_wrap(~fdind, scales ='free_y')+
  labs(x='sites', y='FD indices')

#Functional richness

dffric <- fdric |> tidyr::gather('fdind', "vals", -site)
                                 
ggplot(data = dffric, aes(site, vals, fill = fdind))+
  geom_bar(stat = 'identity')+
  scale_fill_viridis_d()+
  theme(legend.position = "none")+
  facet_wrap(~fdind, scales ='free_y')+
  labs(x='Sites', y='FD indices')

1. Compute community weighted means.

Community weighted means measures how traits vary with environmental change (Guy-Haim & Bouchet 2025).

cwmdata <- fw_fdcompute(fwdata = traitsdf, 
                        sitesdata = macrodf,
                        sites = 'sites',
                        species = 'species',
                        abund = 'abund',
                        FD = FALSE)

1. Compute community weighted means.

cwmdata <- fw_fdcompute(fwdata = traitsdf, 
                        sitesdata = macrodf,
                        sites = 'sites',
                        species = 'species',
                        abund = 'abund',
                        FD = FALSE, dummy = FALSE)

Refereences

1. Laliberté, E., & Legendre, P. (2010). A distance‐based framework for measuring functional diversity from multiple traits. Ecology, 91(1), 299-305.

2. Guy-Haim, T., & Bouchet, V. M. (2025). Beyond taxonomy: A framework for biological trait analysis to assess the functional structure of benthic foraminiferal communities. Marine Pollution Bulletin, 213, 117699.