Governments and international organisations invest billions of dollars every year in policies intended to protect biodiversity, reduce climate change, and improve people's livelihoods. But surprisingly, answering a seemingly simple question – which policies actually work, for whom, under what conditions, and why? – requires much more than collecting published studies.

Together with colleagues from the International Initiative for Impact Evaluation (3ie), the world's leading organisation for producing and curating rigorous evidence for development and conservation, Senior Research Fellow Claudia Romero from the University of the Sunshine Coast’s Forest Research Institute, spent the last few years answering exactly this question for land management policies in low- and middle-income countries.

The team’s work followed the highest international standards for evidence synthesis. Unlike traditional literature reviews, systematic reviews include only studies that meet strict methodological criteria, reducing the risk that weak evidence leads to poor policy decisions. These standards are well established in fields such as public health and education, where evidence directly informs decisions that affect millions of people. Increasingly, they are becoming equally important for environmental policy.

The first stage of the team’s work was to map the global evidence base. They developed an ‘Evidence Gap Map’ to identify where strong evidence already existed and, just as importantly, where critical knowledge gaps remained. Rather than simply asking whether interventions worked, they examined who benefited, where, under what circumstances, and through which mechanisms.

Evidence Gap Map (2024)

Marion, P., Shafiq, M. Z., Córdova-Aráuz, D. B., Lwamba, E., Lokossou, J., Nabi, A., Khan, L., Lee, S., Leon, M. D. A., Romero, C., Parrao, C. G., & Snilstveit, B. (2024). Mapping the evidence of climate change and biodiversity interventions on environmental and human outcomes in low- and middle-income countries. International Initiative for Impact Evaluation (3ie).

Using this map, they identified the highest-quality studies and developed a peer-reviewed systematic review protocol. Publishing the protocol before beginning the review is a hallmark of best practice, ensuring transparency and preventing researchers from changing methods after seeing the results.

Systematic Review Protocol (2025)

Marion, P., Storhaug, I., Lee, S., Romero, C., Parrao, C. G., & Snilstveit, B. (2025). PROTOCOL: The Effects of Land Management Policies on the Environment and People in Low- and Middle-Income Countries: A Systematic Review. Campbell Systematic Reviews, 21(4), e70062.

Once the protocol was approved, they conducted the systematic review itself. Guided by a theory of change, the team synthesised the strongest available evidence to understand not only whether land management policies produced environmental and social outcomes, but also why they succeeded or failed. They also assessed the costs of implementing these interventions – information that is rarely reported but is essential for making informed policy and investment decisions.

The resulting review, published in Campbell Systematic Reviews, provides one of the most comprehensive and rigorous assessments currently available of the environmental and human wellbeing impacts of land management policies in low- and middle-income countries.

Systematic Review (2026)

Marion, P., Storhaug, I., Lee, S., Sempé, L., Romero, C., Gonzalez Parrao, C., & Snilstveit, B. (2026). The Effects of Land Management Policies on the Environment and People in Low- and Middle-Income Countries: A Systematic Review. Campbell Systematic Reviews, 22(2), 18911803261435887.

Beyond the publications themselves, the impact of this work is that it provides policymakers, practitioners, donors, and researchers with a trusted evidence base for deciding where conservation and climate investments are most likely to deliver measurable benefits. It also identifies where evidence remains insufficient, helping guide future research towards the questions that matter most.