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° × 2° 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.

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 419,680 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, and can expand the geographical (by 12-25%) and taxonomic (by 5-32%) coverage of English-language evidence, especially in biodiverse regions, albeit often 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.

Protected areas in Guatemala provide habitat for diverse tropical ecosystems, contain ancient archeological sites, sequester carbon, and support economic activity through eco‐tourism. However, many of the forests in these protected areas have been converted to other uses or degraded by human activity, and therefore are considered “paper parks”. In this study, we analyzed time series of satellite data to monitor deforestation, degradation, and natural disturbance throughout Guatemala from 2000 to 2017. A recently developed methodology, Continuous Degradation Detection (CODED), was used to detect forest disturbances of varying size and magnitude. Through sample‐based statistical inference, we estimated that 854 137 ha (± 83 133 ha) were deforested and 1 012 947 ha (±139 512 ha) of forest was disturbed but not converted during our study period. Forest disturbance in protected areas ranged from under 1% of a park's area to over 95%. Our estimate of the extent of deforestation is similar to previous studies, however, degradation and natural disturbance affect a larger area. These results suggest that the total amount of forest disturbance can be significantly underestimated if degradation and natural disturbance are not taken into account. As a consequence, we found that the protected areas of Guatemala are more affected by disturbance than previously realized.

Despite the mounting threats that tropical ecosystems face, conservation in the tropics remains severely under‐researched relative to temperate systems. Efforts to address this knowledge gap have so far largely failed to analyze the relationship between an author's choice of study site and that author's country of origin. We examined factors that motivate both foreign and domestic scientists to conduct research in tropical countries, based on a sample of nearly 3000 tropical conservation research articles. Many barriers that have historically deterred foreign research effort appear to have been overcome, although US scientists still respond negatively to safety concerns and distance. The productivity of local scientists is affected by corruption and lack of institutional support. Both foreign and in‐country scientists are increasingly working in places with more listed threatened species, but many regions still lack adequate conservation research. Although foreign scientists could be attracted to less‐studied areas through targeted grants, the long‐term solution must be to train and employ more local scientists.

The biodiversity crisis necessitates a global implementation of effective, equitable, and feasible conservation strategies. Public land acquisitions (PLAs) for watershed protection can produce co-benefits for basic human needs and biodiversity, but there are concerns that acquiring land is not scalable or may not protect threatened biodiversity. PLA programs are rare, allowing for limited opportunities to assess these concerns. We investigate a unique policy that has legally mandated PLAs in the Colombian Andes, a tropical biodiversity hotspot, since 1993. Using a novel dataset of >7000 PLAs, along with surveys and inperson interviews, we study the scale, spatial allocation, and constraints on PLA implementation, and examine its potential conservation benefits. More than 300,000 ha were acquired through PLAs, but economic and institutional factors such as land cost, government income, and land tenure informality were main drivers in the degree of PLA implementation. Acquisitions were thus directed mostly toward cheaper, less threatened ecosystems.