DOI: 10.5061/dryad.g4f4qrfr5
title: Data for: A database of West European headwater macroinvertebrate stoichiometric traits

description: Motivation: Ecological stoichiometry investigates the equilibrium and the
 fluxes of chemical elements and energy between organisms and their
 environment. Several studies pointed out the value of integrating
 stoichiometric traits for a better understanding of the mechanisms behind
 community and ecosystem processes. Especially in the light of globally
 changing nutrient levels in freshwater systems, the link of stoichiometric
 traits to nutrient cycling and trophic interactions can improve our
 investigations of a species or community response to these changes.
 Benthic macroinvertebrate assemblages are widely used for biomonitoring in
 freshwaters, providing a large number of data sets gathering information
 about their taxonomic diversity at many different spatial and temporal
 scales. Likewise, an increasing number of large databases gives ready
 access to information on a variety of macroinvertebrate biological traits.
 The addition of stoichiometric traits to this pool of available
 information could thus expand the application of trait approaches and
 facilitate the study of the links between nutrient cycling and ecosystem
 functioning. Main types of variables contained: The database contains
 information on elemental content of 188 taxa, in terms of the major
 nutrients %C, %N and %P and the corresponding molar ratios C:N, C:P and
 N:P. We provide calculated taxon mean values as well as the underlying raw
 data on individual level that was obtained from field sampling,
 supplemented by a literature research (n=1555, 174 taxa). Major taxa and
 level of measurements: The database contains information on 188
 macroinvertebrate taxa, available at species (n = 33), genus (96), tribe
 (9), subfamily (6), family (42), order (1) or class (1) levels. Software
 format: .csv file
description: <strong><i>Data
 acquisition and compilation</i></strong> The data originate mainly from
 field samplings we conducted with the aim of constructing a database of
 stoichiometric information for headwater macroinvertebrates (~64% of data
 presented in our database, n = 998). The sampling campaigns took place
 from May 2019 to January 2020 in small streams located in North-Eastern
 France and the Vosges mountains. We additionally integrated data from
 previous field campaigns done by our lab in the same region and similar
 stream types (~27%, n = 424) and data from the literature (~9%, n = 133).
 The literature research was not exhaustive and not filtered by sampling
 region, but tried to gather information on the most common
 macroinvertebrates in Western Europe. As a result, the stoichiometric
 information was gathered mainly from studies conducted within Western
 Europe, but sometimes completed by information from studies in the
 US.<br> For some taxa the provided values have been exclusively
 based on literature, but those values have only extended the number of
 taxa within groups (mainly family) we had already found in the field.
 Additionally, we graphically verified that literature values (and
 therewith also those from different regions) did not substantially
 increase the range of values associated to a given taxon. The information was gathered at
 the finest taxonomic level of identification possible (mainly genus), or
 taken as provided by the literature. Data were included when at least
 information for one stoichiometric variable (%C, %N, %P, C:N, C:P, N:P)
 was available for one individual or taxon. Mass ratios were transformed to
 molar ratios if necessary. Details on the
 sampling sites and the laboratory nutrient analyses are provided in the
 supplementary material of the corresponding data paper (Appendix
 S1+S2). <strong><i>Data
 curation</i></strong> The molar ratio values (C:N, C:P,
 N:P) were calculated for each individual from the corresponding elemental
 stoichiometric values. When measurements were done on a pool of
 individuals, they were treated like individuals in the following
 calculations. To construct the stoichiometric database,
 the mean of elemental contents and ratios was calculated for each taxon
 and several coarser taxonomic levels, up to the family level (genus,
 sub-family, family). For a given taxonomic level (e.g. family) and a given
 stoichiometric variable, we averaged the information provided by all the
 individuals belonging to this taxonomic group, independently of their
 identification level. For example, if for a given family and a given
 stoichiometric variable, values were available for five individuals of a
 first genus and three individuals of a second genus, these eight values
 were averaged to provide the value of this family for this stoichiometric
 variable. If information was available for one genus (four individuals)
 and two species (three and four individuals), the family value was
 calculated as the mean of these eleven individuals. The geometric mean was
 used for all the stoichiometric variables, as suggested by Isles
 (2020). Here we provide both the calculated mean values
 ("StoichioDB") as well as the underlying raw data
 ("StoichioDB_rawdata").
description: <strong>StoichioDB_rawdata</strong><br> Taxon:
 Name of the taxon<br> %C: Carbon mass content (%)<br> %N:
 Nitrogen mass content (%)<br> %P: Phosphorous mass content
 (%)<br> C:N_molar: molar C:N ratio<br> C:P_molar: molar C:P
 ratio<br> N:P_molar: molar N:P ratio<br> Biomass: Dryweight
 per individual in mg (when available; when a pool of individuals has been
 analyzed, the overall weight has been divided by the number of individuals
 to obtain the individual weight). Note that values for Bivalvia and
 Gastropoda include the shell<br> Sample: Indicates wether the sample
 analysed was a pool of organisms or a single individual<br>
 Reference: Indicates whether the value was obtained from the literature
 giving the corresponding reference, or from fieldsampling
 Class, Order, Family, Subfamily, Genus, Species: Indicates for
 each taxon the taxonomic group it belongs to Stream:
 Stream/ site name<br> Long(E)/ Lat(N): Sampling site coordinates;
 when not available and value was not obtained from the literature, the
 sampling site was in the Vosges mountains (France).
 <br> <strong>StoichioDB</strong><br>
 Taxon: Name of the taxon<br> %C: averaged carbon mass content (%),
 using the geometric mean<br> %N: averaged nitrogen mass content (%),
 using the geometric mean<br> %P: averaged phosphorous mass content
 (%), using the geometric mean<br> C:N_molar: averaged molar C:N
 ratio, using the geometric mean<br> C:P_molar: averaged molar C:P
 ratio, using the geometric mean<br> N:P_molar: averaged molar N:P
 ratio, using the geometric mean sd_X: Standard
 deviation for each taxon and stoichiometric value, using the geometric
 standard deviation<br> range_X: Minimum and maximum value for each
 taxon and each stoichiometric variable<br> n_X: Sample size used in
 the calculation for each taxon and stoichiometric variable
 Reference: Gives the reference when literature values were
 integrated in the calculation; the number in parentheses indicates the
 number of values from this source. Details of references can be found in
 the reference list of the data paper.<br> Class, Order, Family,
 Subfamily, Genus, Species: Indicates for each taxon the taxonomic group(s)
 it belongs to