Beyond boundaries: Global natural lands connectivity
This study presents a new global map of connectivity across all natural lands that accounts for human modification, revealing that most highly connected areas lie outside protected zones and demonstrating how this whole-landscape data can better guide conservation planning, restoration, and protection efforts under the Kunming-Montreal Global Biodiversity Framework.
Original paper licensed under CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). This is an AI-generated explanation of the paper below. It is not written or endorsed by the authors. For technical accuracy, refer to the original paper. Read full disclaimer
To understand how life persists on Earth, we must look beyond the borders of individual parks and reserves. For decades, conservationists have focused on protecting specific patches of land, hoping that if these islands of nature are large enough and close enough together, species can move between them. This idea of connectivity—the unimpeded movement of species and the flow of natural processes—is now recognized as a lifeline for biodiversity in a changing world. However, a critical question remains: does focusing only on the connections between protected areas tell the whole story? Many scientists worry that by looking only at the gaps between these designated zones, we might miss the vast, unprotected landscapes that actually allow animals to travel, or conversely, that we might overlook the hidden barriers that stop them. The reality is that nature does not respect political lines, and the ability of a species to move depends on the condition of the entire landscape, not just the protected bits.
A new global analysis by a team of researchers from organizations including The Nature Conservancy and independent consulting firms challenges the traditional way we map these connections. Instead of drawing lines only between protected areas, the team created a map of the entire planet's natural lands, treating every patch of wild vegetation as a potential starting point for a journey. They used a method that simulates how species might move across a landscape, accounting for the cumulative weight of human activity. In this model, human modification—such as cities, roads, agriculture, and industry—acts as a resistance, slowing down or blocking movement. The researchers applied this approach to the whole world at a resolution of one kilometer, allowing them to see how the pressure of human development shapes the paths available to wildlife, regardless of whether the land is officially protected or not.
The results reveal a world where the story of connectivity is far more complex than a simple map of protected corridors. The team found that roughly two-thirds of the world's natural lands still allow for what they call "diffuse" movement. In these areas, species have many redundant options for travel; the landscape is open enough that an animal does not need to follow a single narrow path to get from one place to another. These high-connectivity zones are most common in the tundra, boreal forests, and conifer forests, regions that often lie outside the current network of protected areas. Conversely, about 29 percent of the world's terrestrial areas show low connectivity, where movement is heavily impeded by intense human modification. These areas of high resistance are prevalent in Asia, Europe, and North America, as well as in temperate and tropical forested biomes.
Perhaps the most significant finding is that relying solely on protected areas to measure connectivity misses the mark. The researchers compared their new global map with existing indicators that measure connections between protected zones and found very little overlap. This suggests that current conservation strategies, which often prioritize linking protected parks, might be overlooking vast areas of unprotected land that are crucial for movement. For instance, in regions like the Appalachian Mountains in the United States or parts of Southeast Asia, traditional models might show low connectivity because there are few large protected areas nearby. However, this new analysis shows that these areas still contain vital, narrow pathways where wildlife can move, even if the surrounding land is heavily used by people. These pathways are not just gaps between parks; they are the remaining arteries of a landscape that has been largely altered.
The study goes further by categorizing these landscapes into distinct types to help guide action. They identified "channelized" areas, where movement is forced into narrow corridors because the surrounding land is too modified to allow travel elsewhere. While these corridors are critical, the researchers caution that they are fragile; if a single link in these narrow chains is broken, the entire connection can collapse. They also identified "impeded" areas where movement is effectively blocked, and "diffuse" areas where movement is free and robust. This distinction is vital for conservation planning. It suggests that in some places, the priority should be protecting the last remaining narrow corridors. In others, the focus should be on restoring the landscape to turn impeded areas back into open, diffuse zones, giving species the redundancy they need to survive climate change and other threats.
This work provides a new tool for implementing global conservation goals, such as the Kunming-Montreal Global Biodiversity Framework, which aims to maintain and restore the connectivity of all ecosystems. By showing where connectivity is strong, where it is channeled, and where it is broken, the map helps decision-makers see the full picture. It reveals that many countries with high levels of natural connectivity have low levels of protection, while others have protected areas surrounded by landscapes that are too modified to allow movement. The data suggests that to truly protect biodiversity, we must look beyond the boundaries of parks. We need to protect the wide-open spaces that allow for free movement, restore the broken links in heavily developed regions, and carefully manage the narrow corridors that remain. The study does not offer a final solution, but it provides a clearer, more honest view of the terrain, showing that the path forward requires a whole-landscape approach that values the natural world everywhere, not just where it is fenced off.
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