World over, the Red List published by the International Union for Conservation of Nature (IUCN) is seen as the Magna Carta in the wildlife conservation and all conservation programmes are designed based on the recommendations of threat. However, for the first time ecologists have disputed the IUCNs Red List and with their independent studies along the Western Ghats have proved that IUCN had underestimated the threat status of about 17 species of birds. Out of the 18 endemic species of birds that the ecologists studied belonging to various threat statuses, 15 species requires to be uplisted further on the list suggesting that they are at even more danger!
Focussing on the geographic range size adopted by the IUCN to predict threat status of species, group of ecologists from the US based Cary Institute of Ecosystem Studies, Duke University, Cornell University and Columbia University revealed that IUCN had overestimated the geographic range sizes of several species resulting in the underestimation of threat perception. According to ecologists, they created accurate maps using data made available by the citizen science database (eBird) that excluded unsuitable habitat for the species. The finding of the ecologists has been published in the international journal ‘Biological Conservation’ last week.
Vijay Ramesh, lead author of the paper told BM that IUCN considers the geographic range of every species while preparing the Red List every year. “The IUCN relies on accuracy of the geographic range size estimate for that species. Range maps used to assess threat status often contain large areas of unsuitable habitat and thereby overestimating range and underestimating the threat,” Vijay explained.
Elaborating further Vijay said, “Global range size of any species is an important parameter for assigning IUCN threat status. Estimating the threat status of birds, IUCN relies on red listing authorities like Bird Life International (BLI) to provide them with the latest maps. Hence the onus falls on BLI to provide an error free datasheet.” The team found that these data sheets comprising large areas of unsuitable habitat have overestimated their geographical range that resulted in the underestimation of threat status of birds. “Range over-estimation not only introduces inaccuracies to threat status estimation, but it also makes it difficult to track changes in habitat or modify ranges to incorporate effects of climate change, and migratory patterns of hundreds of species worldwide,” a researcher from the team said.
According to researchers, previously too there have been efforts by the experts to highlight discrepancies in IUCN list. “A global paper by Ocampo-Penuela et al attempted to address the issue in 2016. However, their approach was analogous to the one taken by BLI. As their approach was not completely data-driven, their conclusions were flawed. Contrary to previous findings, ours was data-driven study. We used freely available data from the Citizen Science database—eBird to actually show that the ranges are much smaller than previously thought off. Meticulous and through studies by our team, we realised that the BLI ranges are just based on the knowledge of a few experts, who tell you where a species is found. This will lead to erroneous estimates since, the distribution of these birds are governed by a multitude of factors - land cover, temperature, precipitation, elevation etc. We took all of this data into consideration and allowed the data to tell us where these birds are found today,” Vijay explained.
Even though the studies by the ecologists’ group confined only to 18 endemic species of birds along the Western Ghats, it will have far reaching impact on assessing the threat status of other species across the world. “While the IUCN ensures that their criteria can uniformly be applied across taxa, using inaccurate data in the process will result in designating the wrong threat status for many species. The IUCN and its agencies must switch over to data-driven methods in the future as much of such data is freely available today,” the researchers opined. “Findings by our team have larger implications in conservation world. BLI makes maps for all bird species across the world. If their methods are erroneous, it would only affect the threat perception of many species. An accurate data-driven method like ours has to be adopted for preparing a scientific list,” Vijay explained.
The ecologists’ team also makes it a point that they are not disputing the IUCN Red List or attacking IUCN over incorrect findings. “Our only wish is that IUCN needs to be stringent with data-quality checks. Our finding is not an attack on the IUCN and its adopted criteria but the quality of the data that goes into IUCNs assessment. When you are preparing a universal Red List, you cannot rely on just one person to finalise over the map of a region. You need variety of data that are accurate and latest to help you map the distribution of the species. Conservationists in India are aware that the ranges for these birds are shrinking. But if one continue to rely on BLI range maps which underestimate threat and overestimate habitat, the right protection measures are not issued for different species,” Vijay revealed.
Considering the endemic avifauna that WG has, the team chose to study the threat status of birds. “Species in WG varies in habitat preference from general species in orchards, tea plantations to specialist species that exist only in high elevation shola forests and grassland patches. “The WG species also differ in their IUCN threat status from endangered to least concern. It also has species that are not recognised and not evaluated. Hence, eliminating all hurdles that may come on the way of our study we chose to study 18 species of endemic bird species,” Vijay justified.
The BLI maps used by IUCN had overestimated the ranges of 17 out of 18 species. While the Nilgiri pipit has the highest range overestimation by IUCN (88%), the White-bellied blue flycatcher had the least overestimation (1%). “Based on our scientific findings we propose that the threat status of Western Ghats endemic bird species must be reassessed and in many cases must be uplisted as majority of these species lack supplementary information regarding population size estimates,” Vijay explained.