Similar physical, geographic, and historical factors shape fish species richness in lakes across Ontario and Northern and Western Europe

Species diversity patterns and their drivers are essential for understanding and mitigating threats to freshwater ecosystems worldwide. We examined limnetic fish biodiversity across 9350 lakes in Ontario and 1824 lakes in northern and western Europe, using data on lake glacial history and environmental conditions to identify the main factors influencing species richness. We applied log-log linear mixed-effects models (LMM) and generalized linear mixed-effects models (GLMM) with a Poisson distribution to assess relationships between fish species richness and climatic, geographic, physical, and historical variables. Local variation in diversity was further explored using beta diversity and nested ‘temperature’ analyses based on sub-basins defined by the HydroBASINS database. Across both regions, lake area emerged as the strongest predictor of species richness, with additional influences from lake elevation, morphometry, age, and longitude. LMM and GLMM results were broadly consistent, and..., , , # Data from: Similar physical, geographic, and historical factors shape fish species richness in lakes across Ontario and Northern and Western Europe

[https://doi.org/10.5061/dryad.2547d7x1m](https://doi.org/10.5061/dryad.2547d7x1m)

## Description of the data and file structure

For Ontario lakes, fish species richness data was collected from the Aquatic Habitat Inventory Program through the Ministry of Natural Resources in Ontario. In addition to presence-absence data for the fish species, measurements of lake area, maximum lake depth, latitude, and longitude were included. For fine scale data, please reach out to the OMNR ([https://www.ontario.ca/feedback/contact-us?id=26930&nid=65620](https://www.ontario.ca/feedback/contact-us?id=26930&nid=65620)). For European lakes, fish species richness measurements were collected for the European Water Framework Directive, assembled by the European project WISER (Water Bodies in Europe) collected between 1990 and 2010. Lake characteristic measu..., ,