 Despite ongoing loss of diversity in freshwater ecosystems, it is still not clear what ecological drivers underlie lotic biodiversity due to confounding factors, such as correlation between oxygen and temperature. A systematic review was conducted using both qualitative and quantitative analyses to disentangle these two drivers. The qualitative analysis did not show strong consistent effects of either dissolved oxygen concentration or temperature on diversity, but the meta-analysis showed a positive relationship between taxonomic richness and dissolved oxygen concentration, while a negative correlation with temperature was found. These results highlight the strength of systematic reviews and meta-analyses over conventional reviews without a meta-analysis, showing no pattern with the qualitative analysis, but a strong pattern with the quantitative analysis. This article was authored by L. Kroigmans, J. F. De Jong and H. H. T. Prince. We are article.tv, links in the description below.