Biodiversity is essential for the entire ecosystem to function properly. Since 1500, humans have disrupted biodiversity so significantly that around 50% of all species have become extinct or are at risk of extinction. A professional study was conducted that came up with this shocking finding. A new survey of 3,331 scientists studying biodiversity across 187 countries has revealed that more species are threatened with extinction than previously thought. The survey was published in the journal Frontiers in Ecology and the Environment.

What results did the research produce?

As scientists from all over the world participated in the research, it was focused on all major species, but also on habitats and ecosystems.

“While considering the types of species and ecosystems they know best, experts estimated that about 30% of species have been globally threatened or driven extinct since the year 1500,” said Forest Isbell, lead author and an associate professor in the College of Biological Sciences at the University of Minnesota. “Experts also acknowledged substantial uncertainty around their estimates, with perhaps as few as 16% or as many as 50% of species threatened or driven extinct over this time.”

Expert estimates of (a) global biodiversity loss and (b, c) its impacts. (a) Medians of estimates and upper and lower bounds for past biodiversity loss (white circles, lines) and future biodiversity loss by 2100 if current trends continue (rightward gray arrows) or if conservation efforts are increased (leftward gray arrows). Where available, IUCN estimates are shown (red lines). (b) Expert estimates (black) as well as lower (blue) and upper (red) bounds for impacts of three levels of biodiversity loss (jittered on the x-axis). (c) Combining estimates of past biodiversity loss (a) and its impacts (b, linearly interpolated) shows the estimated impacts of past biodiversity loss. Sample sizes show the number of responses, which do not always sum to the total because respondents were not required to answer all questions.

Co-author Patricia Balvanera at the University of Mexico noted that the survey results found that women and those in the Global South tended to provide higher estimates of biodiversity loss. “Also, experts who identify as women disproportionately study the taxa that experts estimate are most threatened,” Balvanera added.

Expert estimates of changes in global biodiversity in terrestrial biomes (left column) and marine realms (right column) since 1500 (top row), by 2100 if current trends continue (middle row), or by 2100 if conservation efforts are intensified (bottom row). Values represent medians across all responses received from experts investigating biodiversity in each terrestrial biome and marine realm and are shown for terrestrial biomes and marine realms with at least ten responses (minimum = 11, median = 35, maximum = 470 responses per biome or realm). See WebFigure 2 for additional marine and freshwater habitats.

The study was broad in scope

It was very challenging to get and process information from experts from all over the world. When information on understudied taxa and responses from underrepresented experts were included, global biodiversity loss was found to be much greater than previously thought.

“Since biodiversity is highly regional in nature, the attempt of our study to bring together the opinions of regional experts from around the world is unprecedented,” said co-author Akira Mori of the University of Tokyo in Japan. “From the perspective of social and cultural diversity and inclusiveness, even if they are not necessarily complete, I believe we have presented certain suggestions for future international policy discussions.”

What is the conclusion of this study?

The results found that the loss of ecological diversity will have a huge impact on the ecosystem and the contribution of nature to humans will be greatly reduced. The biggest culprit is, of course, man. Species are dying out en masse mainly due to excessive land use, urbanization, pollution and also due to the introduction of invasive species. The positive news is that such studies are helping to increase the protection of specific endangered species. Experts estimated that greatly increasing conservation investments and efforts now could remove the threat of extinction for one in three species that may otherwise be threatened or extinct by the year 2100.


Image credit: Scientists,