The University of Oxford has contributed to a first-of-its kind review on the success of a wide range of conservation actions. The results, published in Science, provide the strongest evidence to date that not only is nature conservation successful, but that scaling conservation interventions up would be transformational for halting and reversing biodiversity loss and reducing the effects of climate change, the University of Oxford claims.
Although many studies have assessed the impact of individual conservation projects, these papers have never before been combined into a single analysis to investigate whether conservation action is working overall. For this new study, the research team conducted the first-ever meta-analysis of 186 studies, including 665 trials, that looked at the impact of a wide range of conservation interventions globally, and over a century, compared to what would have happened without those interventions.
The meta-analysis found that conservation actions—including the establishment and management of protected areas, the eradication and control of invasive species, the sustainable management of ecosystems, habitat loss reduction, and restoration—improved the state of biodiversity or slowed its decline in most cases (66%) compared with no action taken at all, says the University of Oxford.
Examples of highly effective conservation interventions include:
- Management of invasive and problematic native predators on two of Florida’s barrier islands, Cayo Costa and North Captiva, resulted in an immediate and substantial improvement in nesting success by loggerhead turtles and least terns, especially compared with other barrier islands where no predator management was applied.
- In the Congo Basin, deforestation was 74% lower in logging concessions under a Forest Management Plan (FMP) compared with concessions without an FMP.
- Protected areas and Indigenous lands were shown to significantly reduce both deforestation rate and fire density in the Brazilian Amazon. Deforestation was 1.7 to 20 times higher and human-caused fires occurred four to nine times more frequently outside the reserve perimeters compared with inside.
- Captive breeding and release boosted the natural population of Chinook salmon in the Salmon River basin of central Idaho with minimal negative impacts on the wild population. On average, fish taken into the hatchery produced 4.7 times more adult offspring and 1.3 times more adult second-generation offspring than naturally reproducing fish.
THe authors found a correlation between more recent conservation interventions and positive outcomes for biodiversity, suggesting that conservation is getting more effective over time.
In the Congo Basin, deforestation was 74% lower in logging concessions under a Forest Management Plan compared with concessions without one. Image credit: Axel Fassio/CIFOR.
In some other cases where the conservation action did not succeed in benefiting the target biodiversity compared with no action at all, other native species benefitted unintentionally instead. For example, seahorse abundance was lower in protected sites because marine protected areas increase the abundance of seahorse predators, including octopus.
According to the research team, there must be more investment specifically in the effective management of protected areas, which remain the cornerstone for many conservation actions and which this study found to work very well on the whole.
The authors also call for further studies to assess the impact of a wider range of conservation interventions, such as those that look at the effectiveness of pollution control, climate change adaptation, and the sustainable use of species, and in more countries.
Dr Grethel Aguilar, Director General of the International Union for Conservation of Nature (IUCN), stated: “This paper has analysed conservation outcomes at a level as rigorous as in applied disciplines like medicine and engineering—showing genuine impact and thus guiding the transformative change needed to safeguard nature at scale around the world. It shows that nature conservation truly works, from the species to the ecosystem levels across all continents”.
