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At least one species has been lost on more than half of Earth’s land area

  • A study published in the journal Frontiers In Forests And Global Change last week largely supports the conclusions of the IPBES report released last month, determining that there is less intact habitat harboring its original community of life than has previously been estimated. And the authors of the study say their findings show that methods used to determine the most important areas for wildlife conservation using remote sensing and global datasets may not be accurately assessing faunal intactness.
  • Researchers found that at least one species has gone extinct on 54.7 percent of our planet’s land area (not including Antarctica), with some sites losing as many as 52 species. Even many forests identified as being intact because they have intact canopies have lost species below the canopy, the researchers found.
  • They conclude: “Recent papers have highlighted the small percentage of remaining wilderness or intact sites and yet our results indicate that truly intact sites with a full complement of species are likely to be much rarer still.”

Last month, the U.N.’s Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services (IPBES) released a summary of its extensive research on threats to global biodiversity, finding that species are disappearing more quickly now that at any other point in human history. Some 1 million species of plants and animals are currently facing extinction, according to the report, and that has serious implications for the future of human well-being.

According to the IPBES report, the number of terrestrial species on Earth has declined by 20 percent, primarily over the past 120 years. A study published in the journal Frontiers In Forests And Global Change last week largely supports the conclusions of the IPBES report, determining that there is less intact habitat harboring its original community of life than has previously been estimated. And the authors of the study say their findings show that methods used to determine the most important areas for wildlife conservation using remote sensing and global datasets may not be accurately assessing faunal intactness.

The study was led by Andrew Plumptre, head of the secretariat for the Key Biodiversity Areas (KBA) Partnership, which is comprised of 12 international conservation organizations, including the International Union for the Conservation of Nature (IUCN), Birdlife International, and the Wildlife Conservation Society. Plumptre and a team of researchers found that at least one species has gone extinct on 54.7 percent of our planet’s land area (not including Antarctica), with some sites losing as many as 52 species. Even many forests identified as being intact because they have intact canopies have lost species below the canopy, the researchers found.

“This is one more statistic showing the perilous situation our planet faces,” Plumptre said in a statement. “We need governments to act on the outputs of the recent IPBES report and seriously commit to finding solutions to both biodiversity loss and climate change.”

Plumptre and colleagues assessed the degree of faunal intactness in landscapes around the world by compiling range maps published by the IUCN Red List of Threatened Species showing where species have been lost to extinction. Not every assessor of species’ conservation status for the IUCN Red List maps where species have gone extinct, however, and the Red List only maps species’ ranges going back to the year 1500. The researchers said that these limitations in the data likely mean that they’ve underestimated the extent of extinctions across the planet.

There are a number of approaches to identifying the parts of the world that are globally important for biodiversity conservation measures, and the study looks at two in particular. One of those approaches is the identification of so-called Last of the Wild areas, where the least human influence within biomes has been recorded — though, for the study, the researchers modified the “last of the wild” method to look at ecoregions rather than biomes, and called the new approach Last of the Wild in each Ecoregion (LWE).

Kahuzi-Biega National Park in eastern Democratic Republic of the Congo. Photo Credit: A.Plumptre-KBA Secretariat.

The other approach informing the study is estimates of Intact Forest Landscapes (IFL), which is similar to the “last of the wild” approach but dedicated solely to forest ecosystems.

“With a focus on forested ecosystems, we assessed whether either approach identifies areas of faunal intactness as a preliminary measure of a more comprehensive species intactness,” Plumptre and co-authors write in the study. “LWE and IFL are two approaches in what is now a broad family of techniques to mapping ecological integrity at the global scale, identified through measures of degree of human impact or influence, rather than through mapping of intact faunal communities.”

The researchers compiled range maps for 18 species that rely on forest habitats, are likely to be impacted by human activities, and for which estimates of density or abundance have been made across the entire range of the species. By combining that data with estimates of IFLs and LWEs, the researchers found that many areas considered to be intact have lost one or more of those 18 species, meaning they can no longer be considered to have an intact fauna.

“Our results show that there are few places left on the planet that are faunally intact, a result that corresponds with many assessments of global biodiversity (e.g., Secretariat of the Convention on Biological Diversity United Nations Environment Programme, 2014; Wolf and Ripple, 2017),” the researchers write in the study. IFL and LWE areas encompass “reasonably large areas of the globe,” they note, but “when we look at forest species that might be using the IFLs and LWE areas, for many there are large parts of these ‘intact areas’ where they are absent or at low densities that are not likely ecologically functional.”

More than half of the LWE areas the research team looked at may have had no records of species going extinct, but that wouldn’t be the case if pre-1500 data were available, especially in Europe, “and if extinction records in the IUCN Red List were more comprehensive in general,” the study states.

Plumptre and co-authors say that the main takeaway from their analysis is that “faunal intactness is highly rare in the remaining large areas on earth and that we cannot easily identify this from satellite images of seemingly intact forest canopy and human disturbance (the IFL method) nor from assessments using the [Human Impact Index] (the LWE areas).”

They conclude: “Recent papers have highlighted the small percentage of remaining wilderness or intact sites and yet our results indicate that truly intact sites with a full complement of species are likely to be much rarer still.”

Elephant mother and calf. Photo Credit: A.Plumptre-KBA Secretariat.

CITATION

• Plumptre, A. J., Baisero, D., Grantham, H., Jędrzejewski, W., Kühl, H., Maisels, F., … & Wich, S. A. (2019). Are we capturing faunal intactness? A comparison of intact forest landscapes and a first scoping of Key Biodiversity Areas of Ecological Integrity. Frontiers In Forests And Global Change. doi:10.3389/ffgc.2019.00024