More than 15% of all land has been protected from human development over the past century in an effort to conserve wildlife.

But a new report found that “protected” is a vague term.

In fact, one-third of all protected lands around the world, such as national parks and wilderness areas, are consistently subject to destructive practices like mining, logging, drilling, fracking, road-building, grazing, tourism, and other forms of industry, while 90% of all protected land is being degraded in some way, according to the Guardian.

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The study was published Friday in the journal Science by researchers at the University of Queensland, Wildlife Conservation Society (WCS), and University of Northern British Columbia.

The authors found that 2.3 million square miles, or double the size of Alaska, is being heavily damaged, according to a WCS press release.

While not all protected lands enjoy the same funding and legal status, they’re all meant to conserve wildlife — and industrial practices undermine that purpose, according to the researchers.

They found that protected lands established before 1992 — when the Convention of Biological Diversity called for greater conservation — are more likely to be degraded. 

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The most impacted areas were found in densely populated parts of Asia, Europe, and Africa.

The failure on the part of countries to enforce conservation mandates is accelerating the decline of wildlife around the world, according to the study’s authors.  

Globally, more than 1,500 bird species are endangered and 90% of fish are over-harvested. Over the past few decades, billions of regional animal populations have been lost, and 50% of all individual animals have died.

"A well-run protected area network is essential in saving species,” the paper's lead author, Kendall Jones of University of Queensland, said in a press release. “If we allow our protected area network to be degraded there is a no doubt biodiversity losses will be exacerbated."

The authors found that land managed with the help of organizations like Wildlife Conservation Society are more likely to be protected, suggesting that international protocols and systems can be established for improved conservation.

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"We know protected areas work — when well-funded, well-managed, and well placed, they are extremely effective in halting the threats that cause biodiversity loss and ensure species return from the brink of extinction,” Professor James Watson of WCS and University of Queensland, who worked on the report, said in a release.

Global Citizen campaigns to promote conservation in protected lands and you can take action on this issue here.