DOI: 10.5061/dryad.n5tb2rc5w
title: Invertebrate abundance and river drying data from Europe and South America: family and genus-level taxonomic resolution for perennial and non-perennial reaches

description: Drying river networks include non-perennial reaches that cease to flow or
 dry, and drying is becoming more prevalent with ongoing climate change.
 Biodiversity responses to drying have been explored mostly at local scales
 in a few regions, such as Europe and North America, limiting our ability
 to predict future global scenarios of freshwater biodiversity. Locally,
 drying acts as a strong environmental filter that selects for species with
 adaptations promoting resistance or resilience to desiccation, thus
 reducing aquatic α-diversity. At the river network scale, drying generates
 complex mosaics of dry and wet habitats, shaping metacommunities driven by
 both environmental and dispersal processes. By repeatedly resetting
 community succession, drying can enhance β-diversity in space and time. To
 investigate transferability of these concepts across continents, we
 compiled and analyzed a unique dataset of 43 aquatic invertebrate
 metacommunities from drying river networks in Europe and South America. In
 Europe, α-diversity was consistently lower in non-perennial than perennial
 reaches, whereas this pattern was not evident in South America.
 Concomitantly, β-diversity was higher in non-perennial reaches than in
 perennial ones in Europe but not in South America. In general, β-diversity
 was predominantly driven by turnover rather than nestedness. Dispersal was
 the main driver of metacommunity dynamics, challenging prevailing views in
 river science that environmental filtering is the primary process shaping
 aquatic metacommunities. Lastly, α-diversity decreased as drying duration
 increased, but this was not consistent across Europe. Overall, drying had
 continent-specific effects, suggesting limited transferability of
 knowledge accumulated from North America and Europe to other biogeographic
 regions. As climate change intensifies, river drying is increasing and our
 results underscore the importance of studying its effects across different
 regions. The importance of dispersal also suggests that management efforts
 should seek to enhance connectivity between reaches to effectively
 monitor, restore, and conserve freshwater biodiversity.
description: Aquatic invertebrate metacommunity datasets from Europe and South
 America were identified and compiled. Selection was based on four
 criteria. Drying was the main source of environmental variation and
 sampled rivers were minimally or least impacted with moderate to high
 water quality. For each metacommunity, each reach was sampled at least
 once before and once after drying to capture the local effects of the
 drying on metacommunity dynamics. Sampling methods were quantitative or
 semi-quantitative. Nine datasets were compiled, spanning 12 countries, 41
 rivers, 43 metacommunities, and 2505 samples from 696 unique reaches and
 249 sampling campaigns. Communities were sampled between 2004 to 2022 and
 covered a wide environmental gradient across both continents, ranging from
 first-order gravel-bed headwater streams to fifth-order sand-bed rivers.
 DRN catchment areas ranged between 13 and 1076 km². Datasets included 3–8
 environmental variables from stream velocity, wetted width, maximum depth,
 temperature, pH, conductivity, dissolved oxygen, and discharge.
description: # Invertebrate abundance and river drying data from Europe and South
 America: family and genus-level taxonomic resolution for perennial and
 non-perennial reaches
 [https://doi.org/10.5061/dryad.n5tb2rc5w](https://doi.org/10.5061/dryad.n5tb2rc5w) ## Description of the data and file structure This dataset contains three separate files, two with invertebrate abundance and environmental data from different samples collected at perennial and non-perennial reaches of drying river networks (DRNs) in Europe and South America, and one containing water-course distance matrices of each DRN analyzed in this study. Invertebrate abundance files are separated by taxonomic resolution: one at the family level and the other at the genus level. Both files are in Excel format, with one sheet containing the sampled data and another sheet providing the explanation of each column. Specifically, environmental sampled variables, which are reported in the first sheet are explained in the second sheet. 'N/A' (not applicable) appears in environmental variables or metadata to indicate missing information, which may vary by dataset depending on whether it was not collected or was lost. This dataset combines information collected by coauthors, either specifically for this study or from previously published research. Details about data sources are provided in the 'authors' column. The water-course distance file contains distance matrices for each site within the analyzed DRN. Each sheet in this file corresponds to a different DRN. This file includes the distance matrices for all 43 DRNs analyzed in this study. ### Files and variables All metadata can be found in the second tab in each file. Below is only a sampling of variables.  #### File: invert\_meg\_data\_dryad.xlsx **Description:** Macroinvertebrate data at family level resolution.  ##### Variables * Avg velocity macroinvertebrates (m/s) * Average wetted width (m) * Maximum depth (cm) * Temperature (C) * Ph * Conductivity (µS/cm) * Oxygen (mg/l) * Discharge (l/s) * Basin Area km2 * Elevation (m) * Reach type: The classification of the sampled reach based on its flow regime, indicating whether it is perennial (flowing year-round) or non-perennial (temporal or intermittent, with periods of no flow). #### File: EU\_Genus\_data\_dryad\_.xlsx **Description:** Macroinvertebrate data at genus level resolution. ##### Variables | TotFlow | Total duration (in days) that the water was flowing at the sampled reach throughout the monitoring period. | | :----------- | :---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | TotDur | Total duration (in days) of drying events experienced by the sampled reach throughout the monitoring period. | | TotNum | Total number of drying events that occurred throughout the monitoring period. | | Stream\_type | The classification of the sampled reach based on its flow regime, indicating whether it is perennial (flowing year-round) or non-perennial (temporal or intermittent, with periods of no flow). | #### File: Water\_course\_distances\_.xlsx **Description:** This file includes the distance matrices for all 43 DRNs analyzed in this study. Each sheet in this file corresponds to a different DRN. This file does not contain variables. ## Code/software All R packages and functions used for data processing are specified in the manuscript. ### **Version Changes** **Jan-2025:** Added additional data from rivers in France and Italy to the invertebrate abundance files at the family and genus taxonomic levels. Additionally, an Excel file containing watercourse distance matrices was included.