First comprehensive meta-analysis shows conservation action contributes to reversing and halting biodiversity loss
By Eleanor Momberg
A new study published in the scientific journal Science provides the strongest evidence yet that environmental conservation is not only successful, but that scaling up conservation interventions will contribute to reversing and halting biodiversity loss.
“We have shown that across a full suite of conservation actions and intervention types, multiple levels and metrics of biodiversity, and over a century of action, conservation has improved the state of biodiversity—or at least slowed its decline—compared with no conservation action,” the report states.
The findings of the first-ever comprehensive meta-analysis of the impact of conservation action are critical as more than 44,000 species are listed as being at the risk of extinction. This holds tremendous consequences for ecosystems that stabilise the climate and which provide millions of people worldwide with a number of ecosystem services, including clean water and supporting livelihoods.
The research, funded through the International Union for Conservation of Nature (IUCN) by the Global Environment Facility, points to the recent adoption by government of the Global Biodiversity Framework aimed at reversing and halting biodiversity loss adding this made it even more critical to understand whether conservation actions are working.
Lead author of the study and executive vice president of Re:wild, Penny Langhammer, said: “If you look only at the trend of species declines, it would be easy to think that we’re failing to protect biodiversity, but you would not be looking at the full picture. What we show with this paper is that conservation is, in fact, working to halt and reverse biodiversity loss. It is clear that conservation must be prioritised and receive significant additional resources and political will globally, while we simultaneously address the systemic drivers of biodiversity loss, such as overconsumption and production.”
The report in Science indicates that although many papers look at individual conservation projects and interventions and their impact compared to no action taken, these papers have never been pulled into a single analysis to see how and whether conservation action is working overall.
Lauren Waller, the EWT’s Regional Planning Coordinator in the Conservation and Science Planning Unit said a meta-analysis of 186 case studies, including more than 665 trials, was conducted to determine the impact of the various conservation interventions undertaken globally. These were compared with what would or could have happened without any conservation interventions.
“The study showed that conservation improved the state of biodiversity, or slowed the decline in biodiversity loss. It also showed that species-targeted interventions were particularly effective,” said Waller, who is also the IUCN SSC Conservation Planning Specialist Group (CPSG) Regional Resource Centre Convenor for Southern and East Africa.
Among the key findings are that in two-thirds of cases, conservation either improved the state of biodiversity or at least slowed declines and that interventions targeted at species and ecosystems, such as invasive species control, habitat loss reduction and restoration, protected areas, and sustainable management, are highly effective and have large effect sizes. This provides the strongest evidence to date that conservation actions are successful but require transformational scaling up to meet global targets, the report states.
Robust impact assessment using a counterfactual approach revealed that conservation action has prevented extinctions and reduced extinction risk for species across taxonomic groups compared with an absence of conservation action. There has been an increase over the last decade in studies evaluating the impact of specific conservation actions from global to local scales using counterfactual comparisons, including effects of protected areas, payments for environmental services, invasive alien species (IAS) eradications and sustainable management of ecosystems.
“This paper is not only extremely important in providing robust evidence of the impact of conservation actions. It is also extremely timely in informing crucial international policy processes, including the establishment of a 20-year vision for IUCN, the development of an IPBES assessment of biodiversity monitoring, and the delivery of the action targets toward the outcome goals of the new Kunming-Montreal Global Biodiversity Framework,” Thomas Brooks, IUCN chief scientist and co-author of the study, said.
The paper also argues that there must be more investment specifically in the effective management of protected areas, which remain the cornerstone for many conservation actions. Consistent with other studies, this study finds that protected areas work very well on the whole. And what other studies have shown is that when protected areas are not working, it is typically the result of a lack of effective management and adequate resourcing. Protected areas will be even more effective at reducing biodiversity loss if they are well-resourced and well-managed.
Protected areas have been shown to be effective in reducing conversion of natural land cover, terrestrial habitat loss, coral loss, tropical forest fires, species extinction risk, and in increasing biomass and density of marine organisms. The results, however concur that while their effectiveness is not universal, protected areas are an important tool for achieving conservation outcomes. Well-resourced and well-managed protected areas are needed to effectively reduce biodiversity loss, the paper states.
Dr Sam Ferreira, SANParks large mammal ecologist said at the South African National Satellite Event of the World Species Congress, that the global biodiversity crisis, driven primarily by human activity, was accelerating at unprecedented rates.
Human-driven threats such as poaching, habitat destruction, and human-wildlife conflict are increasing with growing human populations, leading to alarming declines in animal populations and ranges. This crisis, irreversible in nature, poses one of the most serious environmental threats to the planet. The interconnectedness of species within ecosystems underscores the significance of biodiversity, with the extinction of one species disrupting the delicate balance of entire ecosystems. For instance, the decline of bee pollinators due to habitat loss, pesticide use, and climate change threatens not only plant species but also other species dependent on them, illustrating the cascading effects of species loss on the web of life, including humans.
“Urgent action is needed to mitigate these threats and preserve biodiversity for the health of ecosystems and human well-being,” said Ferreira.
The meta-analysis adds that although the state of biodiversity is declining across the globe in absolute terms, conservation actions work most of the time. The challenge now is to expand these to the scale necessary to reverse the global biodiversity crisis. That is, conservation interventions are working but there are simply not enough conservation actions implemented or in the right places.
Realising the highly ambitious vision of the GBF will require ongoing assessment of the impact of specific conservation interventions to inform adaptive management with evidence. Importantly, it will require substantially scaled-up funding and commitment for implementation of demonstrably effective conservation interventions—a real transformational change—which in turn depends on increased political will and investment.
Such an increase in conservation action and associated outcomes will require expanded implementation and significant additional investment across many sectors of society, particularly beyond the traditional conservation sector, the report said.
The authors of a meta-analysis contend that more and better counterfactual studies are needed for a wider range of conservation interventions and geographic regions. Particular gaps include assessments of pollution control, climate change adaptation, sustainable use of species, habitat loss reduction (beyond protected areas), actions targeting species and genetic diversity, and conservation actions in the Global South.