The widely held assumption that any important scientific information would be available
in English underlies the underuse of non-English-language science across disciplines.
However, non-English-language science is expected to bring unique and valuable scientific
information, especially in disciplines where the evidence is patchy, and for emergent
issues where synthesising available evidence is an urgent challenge. Yet such contribution
of non-English-language science to scientific communities and the application of science
is rarely quantified. Here, we show that non-English-language studies provide crucial
evidence for informing global biodiversity conservation. By screening 419,679 peer-reviewed
papers in 16 languages, we identified 1,234 non-English-language studies providing
evidence on the effectiveness of biodiversity conservation interventions, compared
to 4,412 English-language studies identified with the same criteria. Relevant non-English-language
studies are being published at an increasing rate in 6 out of the 12 languages where
there were a sufficient number of relevant studies. Incorporating non-English-language
studies can expand the geographical coverage (i.e., the number of 2 degrees x 2 degrees
grid cells with relevant studies) of English-language evidence by 12% to 25%, especially
in biodiverse regions, and taxonomic coverage (i.e., the number of species covered
by the relevant studies) by 5% to 32%, although they do tend to be based on less robust
study designs. Our results show that synthesising non-English-language studies is
key to overcoming the widespread lack of local, context-dependent evidence and facilitating
evidence-based conservation globally. We urge wider disciplines to rigorously reassess
the untapped potential of non-English-language science in informing decisions to address
other global challenges.
Please see the Supporting information files for Alternative Language Abstracts.