Data from: Flow intermittence shapes fish metacommunity variability in a Neotropical ecoregion
Data files
Jan 06, 2026 version files 17.43 KB
-
Cube_fish_env_2021.csv
9.78 KB
-
Cube_fish_spp_2021.csv
5.13 KB
-
README.md
2.53 KB
Abstract
Drying River Networks (DRNs) comprise intermittent reaches that cease to flow or dry, and these networks are becoming more prevalent with ongoing climate change. However, their distribution, constituent species, and ecological processes remain underexplored in the Neotropics, limiting our ability to predict future scenarios for freshwater biodiversity. Drying is a strong environmental filter, leading to low α-diversity at intermittent reaches as taxa lacking adaptations to resist and recover from drying are lost. Additionally, because drying creates a complex mosaic of lotic and lentic habitats that change through time, β-diversity (variability in community composition) is high in intermittent reaches. To explore these dynamics, we analyzed the influence of local and regional factors on the spatio-temporal variability of a fish metacommunity in the Chocó Biodiversity hotspot in Northwestern Ecuador. Fish α-diversity was lower in intermittent reaches during both seasons, while temporal β-diversity was higher at perennial reaches. Distinct fish assemblages were indicative of intermittent and perennial reaches, with community composition being stable in intermittent reaches but more variable in perennial reaches. Lastly, metacommunity analysis suggests that environmental filtering was the primary community assembly process, with species being replaced along the environmental gradient of the river network. Physical distance was important in structuring communities but only for fish species with low dispersal abilities, indicating that for these species, dynamics may be controlled by hydrological connectivity. Our findings suggest that variability in fish communities results from seasonal intermittence and species-specific habitat preference, partially confirming previous hypotheses regarding the determinants of fish diversity in DRNs.
https://doi.org/10.5061/dryad.3tx95x6rj
Description of the data and file structure
This dataset contains two separate files: one with environmental data and one containing fish abundance data from samples collected at perennial and intermittent reaches of a drying river network (DRN) in the Cube River basin, western Ecuador, across wet and dry seasons. Both files are in comma-separated values format.
- Cube_fish_env_2021.csv refers to environmental variables collected in two sampling seasons of 2021
- Cube_fish_spp_2021.csv refers to the species collected in two sampling seasons of 2021
The environmental dataset file (Cube_fish_env_2021.csv) is organized with sampled environmental variables as columns and samples (reach IDs) from both seasons as rows.
- Alti = Elevation (m)
- Slope = Slope
- Width = Average wetted width (m)
- Velo = Avg velocity macroinvertebrates (m/s)
- Depth = Maximum depth (cm)
- Temp = Temperature (°C)
- Ph = pH
- Cond = Conductivity (µS/cm)
- Specific_c = Specific conductivity (µS/cm)
- DO = Oxygen (mg/l)
- Oxygen_Sat = (Oxygen saturation %)
- Disch = Discharge (L/s)
- Chla = chlorophyll a
- AFDM = biofilm ash-free dry mass (mg/L)
- Luse = Land use, 1: surrounded by forest, 0: surrounded by crops/pastures
- F⁻ = Fluoride (mg L⁻¹)
- SO₄²⁻ = Sulfate: mg L⁻¹
- PO₄³⁻ = Phosphate: mg L⁻¹ (unless reported as P; then mg P L⁻¹)
- SS = Suspended Solids (TSS) (mg L⁻¹)
- TOC = Total Organic Carbon (mg L⁻¹)
- Ba²⁺ = Barium (µg L⁻¹)
- Ca²⁺ = Calcium (mg L⁻¹)
- K⁺ – Potassium (mg L⁻¹)
- Mg²⁺ = Magnesium (mg L⁻¹)
- Na⁺ = Sodium (mg L⁻¹)
- Pb²⁺ = Lead (µg L⁻¹)
- Zn²⁺ = Zinc (µg L⁻¹)
- Season = Wet or Dry
- Flow = The classification of the sampled reach based on its flow regime, indicating whether it is perennial (flowing year-round) (Per) or non-perennial (temporal or intermittent, with periods of no flow) (Int).
The fish abundance dataset file (Cube_fish_spp_2021.csv) is organized with species identities as columns and sampled reaches (reach IDs) from both seasons as rows; values represent species abundances, and zeros indicate that no individuals of a given species were detected at that reach.
Code/software
All R packages and functions used for data processing are specified in the associated publication.