China is using satellites to police the protection of nature — but will it work?

China’s government is the first to use satellites to monitor land set aside for conservation to ensure its protection from illegal development. Scientists hope that the move will safeguard ecologically important habitats and provide a model of remote-sensing use for conservation that other countries could follow. But they also have questions about how the nation has decided which areas to protect and where the boundaries, known as the ecological redlines, lie.

“The decision makers have made a really bold step forward,” says Chi-Yeung Choi, an applied ecologist at Duke Kunshan University in Suzhou, China. He says that having a national system to protect ecologically important areas will stop provincial governments from prioritizing development over conservation. The policy “has really huge potential to conserve biodiversity hotspots”, he says.

As a vast nation, China spans diverse habitats such as grasslands, forests, deserts and mountains. It is home to iconic species including the giant panda (Ailuropoda melanoleuca), south China tiger (Panthera tigris tigris) and snub-nose monkeys (Rhinopithecus spp.), as well as tens of thousands of lesser-known species. The International Union for Conservation of Nature (IUCN) counts it as the third most-biodiverse country in the world.

On 22 April, China’s Ministry of Natural Resources announced that its ecological-redline map was finalized. Conservation areas in each mainland province are now organized into a central system managed by the ministry. Previously, China’s conservation zones included 2,750 nature reserves and thousands of other areas protected by different levels of government.

According to the announcement, the protected zones cover 3 million square kilometres of land — approximately 30% of mainland China — and 150,000 square kilometres of sea. That’s in line with the 2022 Kunming–Montreal Global Biodiversity Framework target to have at least 30% of terrestrial and inland water areas conserved by 2030. Zhijun Ma, a conservation biologist at Fudan University in Shanghai, China, says that the redline map doubles the area that is legally protected from development.

Lack of transparency

Four days after the redline map was finished, the Ministry for Ecology and Environment announced the launch of a monitoring platform to police the network of zones. It said that a fleet of 30 satellites has been launched to capture high-resolution images, with an algorithm designed to automatically detect changes to forest cover and land use within the redlines.

The satellites are the space component of a three-layered monitoring network, referred to as ‘space, sky and land’, says Fangyuan Hua, a conservation biologist at Peking University in Beijing. Sky and land refer to drones and on-ground personnel that investigate human activity in the protected zones. The aim is to enable authorities to act swiftly if they detect illegal activity, such as land clearance for new mines or real-estate developments.

But environmental scientists keen to research how effective the zoning will be are frustrated by a lack of transparency from the government. “Even though the map has been finished across the country, we actually don’t know what the map looks like,” says Hua. Without a public record of the conservation boundaries “there’s a possibility that the local governments might be able to shift their redlines to accommodate future [development] needs”, making it impossible for the public to monitor what’s going on, she says.

Last year, Choi and his colleagues used a draft of the map to show that three times as many coastal sites that were important for waterbird conservation — around 75% of 172 sites — would be protected by the new plan than under its predecessor, the national nature reserve system. “Assuming that things will go as planned, then there’s actually a huge increase in the number of sites and the amount of areas that can be protected,” he says. But Hua says that without access to final versions of the map, few studies like Choi’s will be able to assess redline protections.

Alice Hughes, a conservation biologist at the University of Hong Kong, says that other nations could follow China’s example, but “China also should take steps to make the data it is collecting more available.”

China’s Ministry of Natural Resources did not respond to Nature’s request for comment on when the maps will be publicly available.

Ecosystem services

China’s approach to defining its redlines differs from how many countries set aside protected land. Generally, decisions are based on an area’s value to wildlife or plants. The IUCN divides protected areas into seven categories that differ in size and level of protection. China’s redline map includes habitats that are identified as being important for protecting vulnerable species and ecosystems, but also draws on assessments of ecosystem services, a measure of an area’s benefits to humans. For example, the metric attributes value to areas with ecosystems that sequester carbon (such as trees), store or purify water, prevent soil erosion or desertification, and protect biodiversity. Including ecosystem services as a criterion for protection “is a very uniquely Chinese thing”, says Hua.

Using these measures to justify land protection might be appealing to local governments, says Hughes, because preventing events such as landslides or sedimentation in waterways brings financial benefits. Overlapping conservation and economic priorities can lead to “mutual benefits”, she says.

But areas worth protecting for their human benefit might not overlap with areas worth protecting for their biodiversity, says Hua. And whereas ecosystem services can be readily assessed using remote-sensing data — to evaluate canopy cover for carbon sequestration, for example — the same isn’t true for mapping biodiversity, she says. That requires greater on-the-ground assessments, which are more expensive to conduct.

Hughes says that more ecological surveys are needed anyway, because detailed data on species vulnerability and distribution are lacking in China. As a result, conservation areas tend to favour large, charismatic animals such as the panda and snow leopard (Panthera uncia), and overlook less-celebrated species, especially in the southern parts of the country, for which the data are limited.

Unlike most of the IUCN categories of protected areas, which strictly limit human activity, the redline zones often allow some human activity within the borders, says Hua. For example, people might be permitted to live or cultivate crops in certain areas. “The network of redlines is mostly intended to prevent large-scale developments, like mining and construction,” she says.

The satellite monitoring system will be “a very powerful and effective system, if it can be done properly,” Choi says. And if the information on it is made open, researchers will also be able to interrogate land-use changes across the country.