We have enough evidence to tackle the most prevalent threats
This blog post was written by Dr Manuela Gonzalez-Suarez, Associate Professor at the University of Reading, UK
Human activities drive many of the pressures facing nature today. We alter habitats and reshape ecological communities. We overexploit species and have even contributed to global climate change. Our footprint is deep.
But humans can also be a positive force. Conservation practitioners sit at the heart of this effort, making decisions every day to develop and implement actions that remove, reduce and manage threats to biodiversity. All done with limited budgets and little time. Tools like Conservation Evidence have been created to help practitioners navigate some of the complexity of deciding which actions are most likely to result in the desired outcomes, offering a searchable database of evidence of what has worked and what didn’t. We know that there are gaps in the evidence and that available evidence is not perfect, but is the available evidence enough? Do we know what works against the biggest threats?
In our recent study, we explored this question in depth. By linking information on the threats affecting more than 35,000 species of tetrapods (amphibians, reptiles, birds and mammals) with the conservation actions tested and reported in the Conservation Evidence synopses (amphibians, reptiles, birds, bats, primates, marine and freshwater mammals, terrestrial mammals), we set out to understand whether evidence is accumulating where it is most needed, and where the biggest gaps still lie.
The answer is encouraging, but there is room for improvement.
Evidence aligns with major threats… mostly
The IUCN Red List identifies a wide range of threats to biodiversity, but ‘Agriculture and aquaculture’ and ‘Biological resource use’ are the most prevalent each affecting >30% of all tetrapods. Encouragingly, actions tackling these widespread threats are also the ones most commonly tested and documented within the conservation evidence base. This means practitioners are likely to find relevant, tested actions when concerned about the most (globally) pressing threats.
And that IS good news, but we do have some “blind spots”.
Information on conservation actions is sparse for some threats that affect large numbers of species. The most striking example is ‘Energy production & mining’. Despite the rapid expansion of mining activities and their significant ecological footprint, relatively few conservation actions specifically addressing this threat have been tested and published. Actions mitigating against ‘Residential & commercial development’ and ‘Climate change’ also remain under-studied. And gaps matter, because without evidence, practitioners must rely on intuition or experience alone, increasing the risk of ineffective or even harmful actions.
Where we test actions also matters
It’s not just what we study, but where. For each documented test of a conservation action, we identified its location and compared it against maps of predicted threat risk for six major threats to see if actions were tested in places where threats were more likely.
Overall, we found that actions tend to be carried out in areas where threats are more prevalent. More good news! We are testing actions where species are most likely to experience those threats. However, important geographic gaps remain. For instance, there are no studies testing the impact of agriculture on birds in Africa, a region where 12% of the land is classed as high risk from agriculture to birds. And this is a problem because the success of actions tested to address impacts of agriculture in Europe may not be transferable to the different species, environmental and socioeconomic conditions of Africa.
Global distribution of studies testing actions to tackle the threat of agriculture (black circles) mapped with the probability of impact from agriculture predicted in each land region for amphibians, reptiles, birds and mammals. The probability of impact is represented in quartile groups we used for comparisons (grey regions are areas where probability of impact could not be predicted). Figure from González-Suárez et al. 2026 (CC BY 4.0).
A word of caution: more evidence does not always mean “better” evidence
While we found more evidence for actions targeted at mitigating more prevalent threats, actions were not found to be more effective or have more certain outcomes than those tackling less common threats. Even for prevalent threats, the effectiveness of some actions had only been tested by one or two studies, which limits our understanding of how well they work under different conditions.
We need more studies testing actions targeted at mitigating prevalent but understudied threats, but we also need replication for already-tested actions. Only by testing the same actions across diverse habitats, species and social contexts can we build a reliable evidence-base.
Four priorities for the future
Our findings point to clear opportunities for strengthening the conservation evidence base and improving its value to practitioners:
1. Support practitioners to test actions and publish results. Many practitioners already test actions in the field but lack resources or incentives to publish their results, and do not always have experience in designing robust tests. Building and supporting partnerships between practitioners and academics could help bridge this gap and increase the amount of robust evidence available.
2. Target evidence gaps strategically. How to best tackle threats like ‘Mining and energy production’ and ‘Urban development’ remains unclear. Funders and practitioners should prioritise testing actions mitigating against threats that impact many tetrapods but for which we have relatively little evidence to understand effectiveness.
3. Embrace replication and context-testing. Actions tested only once or twice offer limited guidance. Replicating tests of actions across regions and taxa can uncover context dependencies and improve confidence in decisions.
4. Reduce geographic biases. Building evidence in understudied regions, particularly in areas where threats are more prevalent, is essential. Supporting local capacity, encouraging publication of grey literature and fostering international collaborations could all help.
A hopeful message for practitioners
The Conservation Evidence database provides substantial coverage of actions addressing the most prevalent threats for tetrapods. Yes, there are still some gaps, but our study shows that the evidence base can broadly support decision making for actions where species need it most.
The challenge ahead is to fill the persistent gaps and ensure the future conservation practice is guided by an even stronger, more inclusive, and more globally representative evidence base.
