It can be easy to think that efforts to save our planet’s wealth of species is a lost cause. Even as scientists, conservationists and governments pour billions of dollars and lifetimes worth of work into staunching the loss of biodiversity, the list of endangered species and ravaged habitat grows ever longer.

So it’s welcome news to hear that all this money and effort is making a measurable difference on a global scale. That’s the takeaway from the first ever planet-wide scientific analysis of whether conservation programs ranging from wildlife reserves to killing invasive species are accomplishing their goals.

“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,” said Penny Langhammer, the executive vice president of the conservation group Re:wild, who took part in the new study. “What we show with this paper is that conservation is, in fact, working.”

The new research offers some encouragement, as well as more detailed insights about which strategies perform well, and which might be avoided.

You might be thinking, “Wait, this is the first time they studied whether all these conservation measures are really working?” When it comes to a planet-wide summing of major conservation strategies, the short answer is, “Yes.”

Scientists have tried to gauge the results from individual initiatives or a handful of similar measures. I wrote about one last week, when researchers found that government-sponsored wolf-killing helped slow declines of woodland caribou in western Canada. But no one had tried an accounting of the effectiveness of all those different initiatives. Until now.

With funding from the International Union for the Conservation of Nature—an alliance of governments and NGO’s that is a leading international organization tracking biodiversity—33 scientists affiliated with universities, governments and conservation groups sat down to scrutinize the track record of conservation initiatives.

The move comes at a big moment in the conservation world. Countries recently made major new commitments to try to stem biodiversity losses. In 2022, 196 nations agreed on the Kunming-Montreal Global Biodiversity Framework, which includes promises to protect 30% of the Earth’s land and ocean, restore 30% of degraded ecosystems and halt species extinctions by 2030. But the world’s track record has been less than stellar. A 2019 studyfound moderate or good progress on fewer than half the 2020 targets established under a previous international accord.

To figure out whether different conservation measures worked, the team of researchers looked at the results from 186 different studies that scrutinized different strategies and compared the results to circumstances where nothing was done. All told there were 665 different metrics to grade the outcome, because each study could have multiple measurements to gauge the effect on biodiversity (for example, the changes in populations for several species).

They found that 45% of those metrics showed an improvement in biodiversity, and another 21% found an intervention had at least slowed the decline, the scientists reported last week in Science.

45% of those metrics showed an improvement in biodiversity, and another 21% found an intervention had at least slowed the decline

“Our study shows that when conservation actions work, they really work. In other words, they often lead to outcomes for biodiversity that are not just a little bit better than doing nothing at all, but many times greater,” said Jake Bicknell, a conservation scientist at the United Kingdom’s University of Kent, who took part in the study.

targeting invasive and “problematic” species showed the biggest effect

Overall, targeting invasive and “problematic” species showed the biggest effect. For instance, removing raccoons and wild pigs that feasted on turtle and bird eggs translated into big gains for loggerhead turtles and least terns in two Florida islands.  Restoring habitats and stopping their loss generally performed well. So did trying to manage ecosystems in a sustainable way, such as putting forest management plans into logging contracts in Africa’s Congo Basin.

Restoring habitats and stopping their loss generally performed well

The creation of protected areas showed benefits, although they were smaller. Meanwhile. trying to encourage the sustainable use of species—such as managed hunting—showed signs of gains, but they weren’t statistically significant.

The scientists also found their share of flops. More than 20% of the time, attempts at conservation seemed to do more harm than good. And in another 12%, things improved more without the human meddling. In just one example in India, efforts to control an invasive algae went awry because when the people grabbed the algae it broke into smaller pieces, spreading still further.

Given the overall positive results, the researchers say a major barrier to success is expanding work to a scale that meets the need. That could mean spending between $178 billion and $524 billion on biodiversity protection each year, the scientists estimate, compared to recent spending levels of around $120 billion.

“We need to invest more in nature and continue doing so in a sustained way,” said Claude Gascon, a study co-author with the Global Environment Facility, which funds conservation efforts in the developing world. “This study comes at a critical time where the world has agreed on ambitious and needed global biodiversity targets that will require conservation action at an entirely new scale.”

Whether world leaders, particularly from the richest nations, are willing to make good on their promises this time remains to be seen.

Langhammer, et. al. “The positive impact of conservation action.” Science. April 25, 2024.