44% of Earth’s land surface must receive conservation attention to stop the biodiversity crisis

The minimum land area requiring conservation attention to safeguard biodiversity

James R. Allan, Hugh P. Possingham, Scott C. Atkinson, Anthony Waldron, Moreno Di Marco, Stuart H.M. Butchart, Vanessa M. Adams, W. Daniel Kissling, Thomas Worsdell, Chris Sandbrook, Gwill Gibbon, Kundan Kumar, Piyush Mehta, Martine Maron, Brooke A. Williams, Kendall R. Jones, Brendan A. Wintle, April E. Reside, James E. M. Watson. 

Summarized by Michael Hallinan

What data were used? No new data was generated for this study, instead already existing data from different sources was combined in a new way. Spatial data about existing protected areas, key biodiversity areas, and ecologically intact areas was taken from the World Database on Protected Areas from February 2020 and 2017. In addition, data from the September 2019 version of the World Database of Key Biodiversity Areas was used, as well as animal distribution data from IUCN Red List and the BirdLife International Handbook. All this data was then merged to create an existing guide to important conservation areas as well as biodiversity. This is necessary to determine the existing species health and eventually predict future species health.

Methods: Using the animal distribution data, targets were set for what percentage needs to be conserved based on the range and quantity of each of the groups such as freshwater crabs, terrestrial mammals, and birds. Following this, an analysis on each species range and the determined important conservation areas was performed to identify what additional range may be needed as well as a potential lack of species in those areas. Then, a series of optimization analyses was performed on 30 x 30 km land units to determine which land would need to be conserved to reach those targets. Factors like cost, historical inquiry, human development, and the inability to perform agriculture as a result of conservation were also estimated. Finally, after all these considerations, potential areas for future conservation efforts were identified and outlined as different components. There are four components: Protected areas, which are areas outlined for general conservation; Key Biodiverse areas, which is land labeled for conservation of specific biodiversity; Ecologically Intact communities are ecological land which contain all the expected species within the ecosystem; and Conservation Priorities, which is land that requires conservation attention.

Results: Ultimately, the study estimates that the minimum land area that needs conservation attention to safeguard biodiversity is 64.7 million square kilometers (~24.9 million square miles), or roughly 44% of Earth’s terrestrial area. This 64.7 million comprises 35.1 million km of ecologically intact areas, 20.5 million of already existing protected areas, 11.6 million of key biodiversity areas, and 12.4 million km of additional land needed to promote species wellness in the smallest range possible. As for specific regions, this means 64% of the land in North America, and at least 33.1% of Europe’s land needs to be protected.

In addition to these spatial statistics, it’s also found that currently 1.87 billion people live on land that needs conservation attention, or approximately 24% of the world’s population with Africa, Asia, and Central America being the most affected due to high population density.  Approximately 55% of this land is located in developed economies such as Canada or Germany. As for the animal targets themselves, amphibians, reptiles, and freshwater animals were found to be below even half the target population . On the other hand, birds and mammals were found to be between 50 and 75% of the target population.

A map of the world, where terrestrial land is marked with protected areas, key biodiversity areas, ecologically intact areas, and additional conservation priorities identified. North America features many areas of key biodiversity with much of the United States being labeled as additional conservation priorities, specifically along the coast and the south-east. Canada is overwhelmingly labeled as ecologically intact with some already protected areas and some key biodiversity areas. Central America is heavily labeled as in need of conservation priorities with a relatively-high quantity of key biodiversity areas. South America consists of heavily protected areas in the Amazonas with many areas of additional conservation priorities along the coasts, and some key biodiversity areas. Large parts of identified areas in Europe are already protected, with some new conservation priorities near coastal regions and eastern Europe such as Belarus. Africa is mainly ecologically intact with the Sahara desert in the north, anda diverse mixture of protected areas, additional conservation priority areas, and key biodiversity areas across the whole continent. Next, Oceania has a large quantity comprising mostly protected areas and ecologically intact areas in central Australia with additional conservation priorities identified around the coast and neighboring island nations. Lastly, Asia is heavily ecologically intact towards the northern part of Russia, and becomes a mixture of protected areas, ecologically intact, and a heavy quantity of conservation priority areas as you go from the southern part of Russia through the rest of the continent. It’s also notable that China contains a large amount of the protected areas in the Himalayas.
This graph shows the protected areas (light blue), Key Biodiversity Areas (purple), and ecologically intact areas (dark blue), as well as new conservation priorities (green). The Venn Diagram to the left shows proportional overlap between features, showing that the majority of both the ecologically intact areas as well as the key biodiversity areas are currently not yet protected.

Why is this study important?: Land loss and conversion is one of the biggest threats to biodiversity. As climate change increases and human development expands, plants and animals become increasingly threatened and infringed upon leading to potential permanent damage, loss of life, and possibly even extinction. By performing studies like these, we can identify what areas are especially valuable, create action plans to remediate damage and support existing animal biodiversity.

This study identifies not only the amount of land needed, but also suggests where specific conservation attention needs to be focussed, as well as economic and social considerations that should be taken into account. In addition it needs to be kept in mind that historically, some conservation actions have adversely affected Indigienous people, Afro-descendants, and other local communities such as forcible removal of native populations off land in the name of conservation. By considering all of the social, economic, scientific, and historical factors that affect this issue, we can support the world around us better. 

The Big Picture: To safeguard biodiversity throughout future years, conservation attention needs to be given to an estimated minimum of 64.7 million square kilometers or roughly 44% of the Earth’s terrestrial land. This was estimated through mapping and data analysis of existing protected areas and existing species distribution data, which was then viewed on a global scale. Amphibians, reptiles, and freshwater animals are the furthest from the targets they need to meet to survive in the long run.The majority of the land which needs the most conservation efforts appears in developed nations. 

Citation: Allan, J.R., Possingham, H.P., Atkinson, S.C., Waldron, A., Di Marco, M., Butchart, S.H., Adams, V.M., Kissling, W.D., Worsdell, T., Sandbrook, C. and Gibbon, G., 2022. The minimum land area requiring conservation attention to safeguard biodiversity. Science376(6597), pp.1094-1101.

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