Indicators of Biodiversity and Ecological Services

Biodiversity Conservation

Last Updated on April 4, 2024

This indicator aims to monitor the extent of forests worldwide that are critical for conservation of biodiversity because it is currently not possible to measure changes in forest biodiversity directly at a global scale in a comprehensive way. The indicator considers five categories of forest that are important for biodiversity conservation. These categories are not mutually exclusive (i.e., the same forest area may be included in more than one category) and are therefore estimated individually but not summed.

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How much forest has highly “intact” biodiversity?

As of 2018, 782 million hectares (Mha) of forest were considered to have highly intact biodiversity, meaning that the biodiversity of these forests had been minimally impacted by human activity.See <a href="/gfr/data-and-methods#biodiversityconservation">Data and Methods</a>. Of these forests, 32 percent were legally protected, 67 percent were located in the tropics, and two-thirds were found in only five countries: Brazil, Canada, the Democratic Republic of the Congo, Peru, and Russia.See <a href="/gfr/data-and-methods#biodiversityconservation">Data and Methods</a>. Even though temperate and boreal forests tend to receive far less media attention than forests in the tropics, these forests also possess unique and important biodiversity.      

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How much forest is highly “significant” for biodiversity?

As of 2018, 455 Mha of forest were considered highly significant for biodiversity, meaning these forests were disproportionately important for the concentration of species that they supported.  Of these forests, 24 percent were legally protected, nearly 41 percent were on islands, and 25 percent were found within Australia, Brazil, and Indonesia.  Even though islands only account for 11 percent of forest overall, these forests, and the island nations where they are located, play a disproportionate role in supporting some of Earth’s unique species. Islands have high levels of endemicity, making forest-dwelling species particularly vulnerable to extinction if forest habitat is cleared. 

In 2023, forests that were highly significant for biodiversity had 2.6 million hectares of forest loss, reducing their extent by half a percent.  Of this loss, 29 percent occurred in Australia, Indonesia, and Madagascar.  

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The top five countries with the greatest extent of highly significant forests for biodiversity

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How much forest exists within the habitat ranges of threatened keystone species?

Many keystone species, such as Asian elephants, orangutans, and tigers, are losing their forest habitat at alarming rates. As commercial agricultural tree crops such as oil palm and rubber replace forest, habitats shrink and become fragmented, disrupting mating, reducing food supply, and increasing the risk of human-wildlife conflict, poaching, and illegal trade in wildlife. 

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How much forest exists in sites that are identified as important for the global persistence of biodiversity?

As of 2010, 446.9 Mha of tree cover — 11 percent of global tree cover — fell within Key Biodiversity Areas (KBAs), including Alliance for Zero Extinction (AZE) sites.  In 2023, 1.8 Mha of this tree cover was lost.    

These KBAs are sites of significance for the global persistence of biodiversity. Over 16,000 such areas have been identified in all ecosystems by the KBA Partnership, based on criteria relating to threatened or geographically restricted species and ecosystems, ecological and biological processes, and irreplaceability. Since 2001, tree cover loss in KBAs has increased by an average of 7 percent per year, equivalent to 7 percent of tree cover extent in KBAs in 2000.  

AZE sites are the subset of KBAs holding the last remaining population of one or more species classified as “Endangered” or “Critically endangered” on the International Union for the Conservation of Nature (IUCN) Red List of Threatened Species. If habitats in these sites are destroyed, their highly threatened species will become globally extinct. Since 2001, tree cover loss in AZE sites has increased by an average of 12 percent per year, equivalent to 9 percent of tree cover extent in AZE sites in 2000.  

Tree cover loss in areas of global importance for biodiversity has risen from 2001 to 2023
 

 
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How much forest exists within legally recognized protected areas, which are often protected for the purpose of biodiversity conservation among other reasons?

Some 836 Mha of tree cover — 21 percent of global tree cover — fall within protected areas as mapped by the World Database on Protected Areas.  In 2023, 3.8 Mha of this tree cover was lost, including 0.69 Mha of primary forests and 1.3 Mha in intact forests.  In strict nature reserves, wilderness areas, and national parks (a subset of all protected areas that often have the most importance for biodiversity conservation), tree cover loss has increased since 2001 by an average of 14 percent per year, equivalent to 7 percent of tree cover extent in these areas in 2000. Much of this increase is due Australian wildfires in late 2019 and early 2020, which account for 62 percent of loss in these strict protected areas in 2019 and 2020, as well as Canadian wildfires in 2023, which account for 75 percent of loss in these areas in 2023.  

Tree cover loss within protected areas can result from various causes. Whereas some may be illegal and caused by humans (such as deforestation related to logging or agriculture), other tree cover loss may be due to natural causes (fire) or part of planned management activities. Furthermore, in some cases tree cover loss may be temporary and followed by forest regeneration, such as after a wildfire. 

Tree cover loss in IUCN Categories I and II, 2001–2023
 

 
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Limitations and Future Prospects

Tree cover loss in areas deemed important for biodiversity conservation is a proxy for measuring changes in forest biodiversity directly. Tree cover loss does not capture changes in forest condition that result from forest degradation, such as the impact of invasive species, changes in pollination, partial reductions in canopy cover, and other changes in the understory. Such changes are undetectable by satellites because of the small scale at which they occur, but they have significant impacts on biodiversity. Moreover, the tree cover extent and tree cover loss data exclude landscapes with sparse trees that are not officially defined as “forest.” These trees outside forests are important components of overall biodiversity in these landscapes.

This indicator omits tree cover gain because existing data for the 2001–2020 time period include planted forests, which negatively impact biodiversity, and there is a long lag time between tree cover gain and biodiversity recovery. Additionally, forest gain alone doesn’t capture the degree to which biodiversity will respond to the creation of new habitat as other drivers may be at play. The availability of annual tree cover gain data, which will likely improve in coming years, will present opportunities for evaluating the impact of forest gain on biodiversity.

Future updates will draw on improved and updated versions of the global biodiversity intactness and significance data sets. Biodiversity intactness data will improve as better spatial data on forest type and condition become available. Biodiversity significance data will incorporate a larger sample of taxonomic groups to include all reptiles and plants. 
 

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{"Glossary":{"51":{"name":"agricultural tree crops","description":"Trees cultivated for their food, cultural, or economic values. These include oil palm, rubber, cocoa, cashew, mango, oranges (citrus), plantain, banana, and coconut.\r\n"},"141":{"name":"agroforestry","description":"A diversified set of agricultural or agropastoral production systems that integrate trees in the agricultural landscape.\r\n"},"101":{"name":"albedo","description":"The ability of surfaces to reflect sunlight.\u0026nbsp;Light-colored surfaces return a large part of the sunrays back to the atmosphere (high albedo). Dark surfaces absorb the rays from the sun (low albedo).\r\n"},"94":{"name":"biodiversity intactness","description":"The proportion and abundance of a location\u0027s original forest community (number of species and individuals) that remain.\u0026nbsp;\r\n"},"95":{"name":"biodiversity significance","description":"The importance of an area for the persistence of forest-dependent species based on range rarity.\r\n"},"142":{"name":"boundary plantings","description":"Trees planted along boundaries or property lines to mark them well.\r\n"},"98":{"name":"carbon dioxide equivalent (CO2e)","description":"Carbon dioxide equivalent (CO2e) is a measure used to aggregate emissions from various greenhouse gases (GHGs) on the basis of their 100-year global warming potentials by equating non-CO2 GHGs to the equivalent amount of CO2.\r\n"},"99":{"name":"CO2e","description":"Carbon dioxide equivalent (CO2e) is a measure used to aggregate emissions from various greenhouse gases (GHGs) on the basis of their 100-year global warming potentials by equating non-CO2 GHGs to the equivalent amount of CO2.\r\n"},"1":{"name":"deforestation","description":"The change from forest to another land cover or land use, such as forest to plantation or forest to urban area.\r\n"},"77":{"name":"deforested","description":"The change from forest to another land cover or land use, such as forest to plantation or forest to urban area.\r\n"},"76":{"name":"degradation","description":"The reduction in a forest\u2019s ability to perform ecosystem services, such as carbon storage and water regulation, due to natural and anthropogenic changes.\r\n"},"75":{"name":"degraded","description":"The reduction in a forest\u2019s ability to perform ecosystem services, such as carbon storage and water regulation, due to natural and anthropogenic changes.\r\n"},"79":{"name":"disturbances","description":"A discrete event that changes the structure of a forest ecosystem.\r\n"},"68":{"name":"disturbed","description":"A discrete event that changes the structure of a forest ecosystem.\r\n"},"65":{"name":"driver of tree cover loss","description":"The direct cause of forest disturbance.\r\n"},"70":{"name":"drivers of loss","description":"The direct cause of forest disturbance.\r\n"},"81":{"name":"drivers of tree cover loss","description":"The direct cause of forest disturbance.\r\n"},"102":{"name":"evapotranspiration","description":"When solar energy hitting a forest converts liquid water into water vapor (carrying energy as latent heat) through evaporation and transpiration.\r\n"},"2":{"name":"forest","description":"Forests include tree cover greater than 30 percent tree canopy density and greater than 5 meters in height as mapped at a 30-meter Landsat pixel scale.\r\n"},"3":{"name":"forest concession","description":"A legal agreement allowing an entity the right to manage a public forest for production purposes.\r\n"},"90":{"name":"forest concessions","description":"A legal agreement allowing an entity the right to manage a public forest for production purposes.\r\n"},"53":{"name":"forest degradation","description":"The reduction in a forest\u2019s ability to perform ecosystem services, such as carbon storage and water regulation, due to natural and anthropogenic changes.\r\n"},"54":{"name":"forest disturbance","description":"A discrete event that changes the structure of a forest ecosystem.\r\n"},"100":{"name":"forest disturbances","description":"A discrete event that changes the structure of a forest ecosystem.\r\n"},"5":{"name":"forest fragmentation","description":"The breaking of large, contiguous forests into smaller pieces, with other land cover types interspersed.\r\n"},"6":{"name":"forest management plan","description":"A plan that documents the stewardship and use of forests and other wooded land to meet environmental, economic, social, and cultural objectives. Such plans are typically implemented by companies in forest concessions.\r\n"},"62":{"name":"forests","description":"Forests include tree cover greater than 30 percent tree canopy density and greater than 5 meters in height as mapped at a 30-meter Landsat pixel scale.\r\n"},"69":{"name":"fragmentation","description":"The breaking of large, contiguous forests into smaller pieces, with other land cover types interspersed.\r\n"},"80":{"name":"fragmented","description":"The breaking of large, contiguous forests into smaller pieces, with other land cover types interspersed.\r\n"},"74":{"name":"gain","description":"The establishment of tree canopy in an area that previously had no tree cover. Tree cover gain may indicate a number of potential activities, including natural forest growth or the crop rotation cycle of tree plantations.\r\n"},"143":{"name":"global land squeeze","description":"Pressure on finite land resources to produce food, feed and fuel for a growing human population while also sustaining biodiversity and providing ecosystem services.\r\n"},"7":{"name":"hectare","description":"One hectare equals 100 square meters, 2.47 acres, or 0.01 square kilometers and is about the size of a rugby field. A football pitch is slightly smaller than a hectare (pitches are between 0.62 and 0.82 hectares).\r\n"},"66":{"name":"hectares","description":"One hectare equals 100 square meters, 2.47 acres, or 0.01 square kilometers and is about the size of a rugby field. A football pitch is slightly smaller than a hectare (pitches are between 0.62 and 0.82 hectares).\r\n"},"67":{"name":"intact","description":"A forest that contains no signs of human activity or habitat fragmentation as determined by remote sensing images and is large enough to maintain all native biological biodiversity.\r\n"},"78":{"name":"intact forest","description":"A forest that contains no signs of human activity or habitat fragmentation as determined by remote sensing images and is large enough to maintain all native biological biodiversity.\r\n"},"8":{"name":"intact forests","description":"A forest that contains no signs of human activity or habitat fragmentation as determined by remote sensing images and is large enough to maintain all native biological biodiversity.\r\n"},"55":{"name":"land and environmental defenders","description":"People who peacefully promote and protect rights related to land and\/or the environment.\r\n"},"9":{"name":"loss driver","description":"The direct cause of forest disturbance.\r\n"},"10":{"name":"low tree canopy density","description":"Less than 30 percent tree canopy density.\r\n"},"84":{"name":"managed forest concession","description":"Areas where governments have given rights to private companies to harvest timber and other wood products from natural forests on public lands.\r\n"},"83":{"name":"managed forest concession maps for nine countries","description":"Cameroon, Canada, Central African Republic, Democratic Republic of the Congo, Equatorial Guinea, Gabon, Indonesia, Liberia, and the Republic of the Congo\r\n"},"104":{"name":"managed natural forests","description":"Naturally regenerated forests with signs of management, including logging, clear cuts, etc.\r\n"},"91":{"name":"megacities","description":"A city with more than 10 million people.\r\n"},"57":{"name":"megacity","description":"A city with more than 10 million people."},"56":{"name":"mosaic restoration","description":"Restoration that integrates trees into mixed-use landscapes, such as agricultural lands and settlements, where trees can support people through improved water quality, increased soil fertility, and other ecosystem services. This type of restoration is more likely in deforested or degraded forest landscapes with moderate population density (10\u2013100 people per square kilometer). "},"86":{"name":"natural","description":"A forest that is grown without human intervention.\r\n"},"12":{"name":"natural forest","description":"A forest that is grown without human intervention.\r\n"},"63":{"name":"natural forests","description":"A forest that is grown without human intervention.\r\n"},"144":{"name":"open canopy systems","description":"Individual tree crowns that do not overlap to form a continuous canopy layer.\r\n"},"82":{"name":"persistent gain","description":"Forests that have experienced one gain event from 2001 to 2016.\r\n"},"13":{"name":"persistent loss and gain","description":"Forests that have experienced one loss or one gain event from 2001 to 2016."},"97":{"name":"plantation","description":"An area in which trees have been planted, generally for commercial purposes.\u0026nbsp;\r\n"},"93":{"name":"plantations","description":"An area in which trees have been planted, generally for commercial purposes.\u0026nbsp;\r\n"},"88":{"name":"planted","description":"A forest composed of trees that have been deliberately planted and\/or seeded by humans.\r\n"},"14":{"name":"planted forest","description":"A forest composed of trees that have been deliberately planted and\/or seeded by humans.\r\n"},"73":{"name":"planted forests","description":"A forest composed of trees that have been deliberately planted and\/or seeded by humans.\r\n"},"15":{"name":"primary forest","description":"Old-growth forests that are typically high in carbon stock and rich in biodiversity. The GFR uses a humid tropical primary rainforest data set, representing forests in the humid tropics that have not been cleared in recent years.\r\n"},"64":{"name":"primary forests","description":"Old-growth forests that are typically high in carbon stock and rich in biodiversity. The GFR uses a humid tropical primary rainforest data set, representing forests in the humid tropics that have not been cleared in recent years.\r\n"},"58":{"name":"production forest","description":"A forest where the primary management objective is to produce timber, pulp, fuelwood, and\/or nonwood forest products."},"89":{"name":"production forests","description":"A forest where the primary management objective is to produce timber, pulp, fuelwood, and\/or nonwood forest products.\r\n"},"87":{"name":"seminatural","description":"A managed forest modified by humans, which can have a different species composition from surrounding natural forests.\r\n"},"59":{"name":"seminatural forests","description":"A managed forest modified by humans, which can have a different species composition from surrounding natural forests. "},"96":{"name":"shifting agriculture","description":"Temporary loss or permanent deforestation due to small- and medium-scale agriculture.\r\n"},"103":{"name":"surface roughness","description":"Surface roughness of forests creates\u0026nbsp;turbulence that slows near-surface winds and cools the land as it lifts heat from low-albedo leaves and moisture from evapotranspiration high into the atmosphere and slows otherwise-drying winds. \r\n"},"17":{"name":"tree cover","description":"All vegetation greater than five meters in height and may take the form of natural forests or plantations across a range of canopy densities. Unless otherwise specified, the GFR uses greater than 30 percent tree canopy density for calculations.\r\n"},"71":{"name":"tree cover canopy density is low","description":"Less than 30 percent tree canopy density.\r\n"},"60":{"name":"tree cover gain","description":"The establishment of tree canopy in an area that previously had no tree cover. Tree cover gain may indicate a number of potential activities, including natural forest growth or the crop rotation cycle of tree plantations.\u0026nbsp;As such, tree cover gain does not equate to restoration.\r\n"},"18":{"name":"tree cover loss","description":"The removal or mortality of tree cover, which can be due to a variety of factors, including mechanical harvesting, fire, disease, or storm damage. As such, loss does not equate to deforestation.\r\n"},"19":{"name":"tree plantation","description":"An agricultural plantation of fast-growing tree species on short rotations for the production of timber, pulp, or fruit.\r\n"},"72":{"name":"tree plantations","description":"An agricultural plantation of fast-growing tree species on short rotations for the production of timber, pulp, or fruit.\r\n"},"85":{"name":"trees outside forests","description":"Trees found in urban areas, alongside roads, or within agricultural land\u0026nbsp;are often referred to as Trees Outside Forests (TOF).\u202f\r\n"},"105":{"name":"unmanaged natural forests","description":"Naturally regenerated forests without any signs of management, including primary forest.\r\n"}}}

Citation

“Biodiversity Conservation Indicator.” Global Forest Review, updated April 4, 2024. Washington, DC: World Resources Institute. Available online at https://research.wri.org/gfr/biodiversity-ecological-services-indicators/biodiversity-conservation.