[Dataset] Analysing the contribution of intermittent rivers to beta diversity can improve freshwater conservation in Mediterranean rivers

RSTUDIO (usage notes): 0_FD_functions.R # R functions to estimate functional metrics and perform null models. 0_model_functions # R functions required to run the models and perform null models. 0_quality_funct_space_fromdist.R # R function for computing the quality of functional multidimensional functional spaces.It is required to estimate functional metrics and perform null models. 1_metric_preparation.R # R script to estimate widely used river biomonitoring metrics (i.e. taxonomic richness and standard biological indices) and novel functional metrics, including functional redundancy (i.e. the number of taxa contributing similarly to an ecosystem function, here a trophic function) and response diversity (i.e. how functionally similar taxa respond to natural disturbance and anthropogenic impacts). 2_models.R # R script to run the models assessing the ability of biomonitoring metrics to detect anthropogenic impacts at both perennial and intermittent sites. It was used in both all aquatic-phases dataset and flowing-phases dataset. 3_null_models # R script to run the null models. It was used in both all aquatic-phases dataset and flowing-phases dataset. ############################################################################ Input files: bloc_e # Number of categories of each effect trait. bloc_r # Number of categories of each response trait. effect_traits "# Trophic characteristics of each genus were gathered from the Freshwater Information Platform (http://www.freshwaterecology.info) (Moog, 2002; Schmidt-Kloiber & Hering, 2015): grazers, miners, xylophagous, shredders, gatherers, active and passive filter feeders, predators, parasites and others. Same as with response traits, for genera without traits or for taxa not identified to genus, averaged data from other genera within the same family or from family-level traits were used. This was the case for 24 taxa identified to genus: Atrichopogon, Berdeniella, Chelifera, Chironomus, Dolichopeza, Eristalis, Hexatoma, Hydrellia, Limnephilus, Limnophora, Lispe, Niphargus, Orimarga, Oxycera, Ptychoptera, Satcheliella, Scatella, Selysiothemis, Sepedon, Simulium, Stratiomys, Tipula, Tonnoriella and Wiedemannia, as well as for the Chironomidae and Ceratopogonidae identified to subfamily or tribe. " family_vs_genera # Family names of each used genus. final_set "# Final set of widely used and functional metrics, and a set of the descriptors of flow intermittence and anthropogenic impacts. It is used in both all aquatic-phases dataset and flowing-phases dataset. Hydrological variables were: the hydrological regime of each site (HR; where 0 refers to perennial rivers and 1 to intermittent ones; calculated by using the TREHS software), the number of days in the disconnected pool phase since last sample was taken (DPi; calculated from temperature data loggers), and the total number of zero-flow days (i.e. disconnected pool or dry riverbed) during the 30-week study period (ZFt; calculated from temperature data loggers). Besides, to calculate the ZFt, we used the total number of days in the disconnected pool phase (total_DP) and the total number with dry riverbed (total_dry). The extent of anthropogenic impacts at each site was measured using the number of impacts in the Mediterranean reference criteria (MRC) (Sánchez-Montoya et al., 2009). " response_traits "# Traits related to resilience and resistance strategies to estimate functional richness (FRic, Villéger, Mason, & Mouillot 2008) and functional dispersion (FDis, Laliberté & Legendre, 2010; hereafter, RD) for the whole community and each trophic group. Categories of response traits: asexual reproduction, with resistance forms (i.e. diapause or dormancy, cocoons), aerial respiration (i.e. spiracle, hydrostatic vesicle), flier and burrower (i.e. epibenthic) or interstitial (i.e. endobenthic) locomotion and substrate relation, less than a year life cycle duration, more than one reproduction cycles per year, aerial active and aquatic passive (i.e. drift) dissemination (see Table S1 in Supplementary Information). Response traits were compiled from Tachet, Richoux, Bournaud, and Usseglio-Polatera (2010). Same as with effect traits, for genera without traits or for taxa not identified to genus, averaged data from other genera within the same family or from family-level traits were used. This was the case for 24 taxa identified to genus: Atrichopogon, Berdeniella, Chelifera, Chironomus, Dolichopeza, Eristalis, Hexatoma, Hydrellia, Limnephilus, Limnophora, Lispe, Niphargus, Orimarga, Oxycera, Ptychoptera, Satcheliella, Scatella, Selysiothemis, Sepedon, Simulium, Stratiomys, Tipula, Tonnoriella and Wiedemannia, as well as for the Chironomidae and Ceratopogonidae identified to subfamily or tribe. "

In Mediterranean climate regions, intermittent rivers (IRs) harbor highly dynamic communities with species and trait composition changing over time and space. Simultaneously considering multiple biodiversity facets and a spatiotemporal perspective is, therefore, key to developing effective conservation strategies for these ecosystems. We studied the spatiotemporal dynamics of aquatic macroinvertebrates in rivers of the western Mediterranean Basin by analysing (1) the taxonomic and functional richness and the local contribution to beta diversity (LCBD; measured considering taxonomic and functional facets) of perennial rivers and IRs over five sampling times, and (2) their relation with flow intermittence, local environmental uniqueness, and the number of anthropogenic impacts. Both analyses were also conducted for the subset of data including only IRs to compare values between their flowing and disconnected pool phases. According to our results, taxonomic and functional richness tended to be higher in perennial rivers than in IRs, while taxonomic and functional LCBD tended to be higher in IRs than in perennial rivers. When comparing IR sites over time, higher values of taxonomic and functional LCBD corresponded mostly to their disconnected pool phase. Flow intermittence, the number of anthropogenic impacts and the environmental uniqueness were significant predictors of taxonomic and functional richness, but only flow intermittence was an important predictor of taxonomic LCBD. For the IR-only data subset, disconnected pool permanence was the main predictor explaining spatiotemporal patterns. Our results highlight the importance of IRs to biodiversity conservation of Mediterranean climate rivers, especially during the disconnected pool phase, suggesting that these ecosystems cannot be ignored in conservation planning strategies.

Open Access funding provided thanks to the CRUE-CSIC agreement with Springer Nature. The study was supported by the LIFE+ TRivers (LIFE13 ENV/ES/000341) project. MS was supported by the Scholarship for studies or projects outside Catalonia funded by “Fundació Universitària Agustí Pedro i Pons” and the Iberoamerican Mobility Scholarship funded by “Banco Santander”. CG-C was supported by a Junior Leader Fellowship contract (LCF/BQ/PR22/11920005) funded by “la Caixa” Foundation (ID 100010434). PR-L was supported by a Margalida Comas postdoctoral contract (PD/031/2018) funded by the Government of the Balearic Islands and the European Social Fund and by a Juan de la Cierva-Incorporación fellowship (IJC2019-041601-I).

Peer reviewed