Fish community trait dissimilarity dampens synchronizing effect of environmental fluctuations
Data files
May 05, 2026 version files 1.84 MB
-
08a_data_for_models.csv
1.78 MB
-
08a_tidy_analysis_cortemp.R
50.10 KB
-
README.md
4.08 KB
Abstract
Spatial synchrony, defined as the synchronized temporal fluctuations in species or community abundances across different locations, has implications for ecological persistence and stability and has received renewed attention in the context of rapid environmental changes. It is shaped by both biotic and abiotic drivers, with shared environmental fluctuations expected to promote synchrony in population dynamics, and dissimilarity in species composition expected to enhance asynchrony. Exploring spatial synchrony using trait-based approaches may provide new insights into the underlying drivers of community dynamics. Here, we investigated the drivers of spatial synchrony in the thermal affinity of fish communities (i.e., thermal community synchrony) within river basins in Europe, Australia, and the United States using multi-membership mixed models accounting for spatial, environmental and community dissimilarity. Our results show that synchrony in fish community thermal affinity decreases with watercourse distance, similar to spatial decays documented for spatial synchrony in population abundance. Thermal community synchrony also increases with synchrony in air temperature, emphasising the role of environmental forcing. However, community composition moderated this forcing, such as greater trait dissimilarity dampened the synchronizing effect of temperature. These findings highlight the interconnected influence of environmental synchrony and community trait composition and the importance of integrating both environmental and community-level factors to better understand metacommunity responses to spatially synchronized environments.
Dataset DOI: 10.5061/dryad.np5hqc08z
Description of the data and file structure
This dataset includes the variables to run the statistical analysis. Variables are as follows –
Details of structure and analysis given in adjoined R script
Thermal Community Synchrony
A standardized metric that quantifies synchrony in temporal fluctuations of thermal CWMs between site pairs. Values range from 0 (asynchronous) to 1 (perfect synchrony), accounting for unequal community variances.
Thermal Niche Distance
Measures the relative difference in long-term average CWM between two sites, reflecting dissimilarity in dominant thermal traits.
Thermal Niche Overlap
Quantifies the similarity in the full distribution of thermal preferences between communities as the area of overlap between their thermal preference density curves (0 = no overlap, 1 = full overlap).
Environmental Temperature Synchrony
Estimated via Pearson correlations of mean annual air temperature between each pair of sites over 2004–2013. Air temperature serves as a proxy for stream temperature due to its high correlation with aquatic thermal conditions.
The modeling analyses were based on standardized fish abundance time-series data sourced from the global RivFishTIME database (Comte et al., 2021), comprising 616 freshwater sites surveyed annually between 2004 and 2013 across Europe, the United States, and Australia. These surveys included 151 fish species and were conducted using electrofishing methods. To ensure consistency and comparability across sites with varying field protocols (e.g., reach length, number of passes), species abundances were converted to relative abundances.
Sites were only included if they had at least eight of the ten years of data available; missing values (1–2 years) were interpolated using the median of adjacent years. Sites with fewer than four species were excluded following a sensitivity analysis to avoid artificially inflated synchrony estimates.
Trait-based metrics were derived using species-specific thermal preference values, sourced from Comte et al. (2021), and used to compute annual Community Weighted Means (CWMs) of thermal preference per site. These CWMs served as the foundation for calculating thermal community synchrony, while watercourse distance, thermal niche distance, and thermal niche overlap described spatial and compositional dissimilarity among community pairs. Environmental temperature synchrony was estimated from mean annual air temperature using the TerraClimate dataset (Abatzoglou et al., 2018), serving as a proxy for stream temperature.
Together, these processed data, relative species abundances, trait-derived CWMs, environmental temperature time series, and spatial linkages formed the core input for the hierarchical multi-membership mixed modeling framework applied in this study.
Files and variables
File: 08a_data_for_models.csv
Description: the input data into multi membership model
Variables
· Sync: thermal community synchrony
· distance: thermal niche distance
· overlap: thermal niche overlap
· annual_avg: synchrony in annual air temperature
· Region: geographical region
· Pair: site-pair synchrony is calculated
· Connectivity: within a basin or not
· WCDistkmsqrt: watercourse distance (km sq rt)
· ZTempCor: z score - synchrony in annual air temperature
· ZDistance: z score - thermal niche distance
· ZOverlapScaled: z score thermal niche overlap
File: 08a_tidy_analysis_cortemp.R
Description: R script to run multi membership models
Access information
Other publicly accessible locations of the data: