Guwahati: Global bird populations have steadily declined over the last three decades, says new research.
The continued growth of human footprint on the natural world – which has led to the degradation and loss of natural habitats – and over exploitation of many species are the key threats to avian biodiversity, says research published on May 5, in the Annual Review of Environment and Resources.
Climate change is also identified as an emerging driver of bird population declines in the study, led by Manchester Metropolitan University.
The new review State of the World’s Birds found that approximately 48% of existing bird species worldwide are known or suspected to be undergoing population declines. This is compared to trends in 39% of species remaining stable, just 6% showing increasing population trends, and 7% still unknown.
Dr Alexander Lees, Senior Lecturer at Manchester Metropolitan University, and lead author of the study, said, “Avian diversity peaks globally in the tropics and it is there that we also find the highest richness of threatened species. We know a lot less about the fortunes of tropical bird species than we do about temperate ones, but we are now witnessing the first signs of a new wave of extinctions of continentally-distributed bird species which has followed the historic loss of species on islands like the Dodo.”
The study, which involved scientists from Manchester Metropolitan, Cornell University, Birdlife International, University of Johannesburg, Pontifical Xavierian University and Nature Conservation Foundation, India, reviewed changes in avian biodiversity using data from the International Union for Conservation of Nature’s Red List to reveal the changes in fortunes of the globe’s 11,000 bird species.
Results of the State of India’s Birds (SoIB) report released by a partnership of 10 government and non-governmental organizations in February 2020 directly fed into this global assessment.
Dr Ken Rosenberg, Conservation Biologist at the Cornell Lab of Ornithology, Cornell University, added: “After documenting the loss of nearly 3 billion birds in North America alone, it was dismaying to see the same patterns of population declines and extinction occurring globally. Because birds are highly visible and sensitive indicators of environmental health, we know their loss signals a much wider loss of biodiversity and threats to human health and well-being.”
Alongside tropical forests, natural grasslands emerge as a particularly threatened habitat, with strong declines in grassland birds observed in North America, Europe and India.
Dr Ashwin Viswanathan, a researcher at Nature Conservation Foundation, India, said, “If unique ecosystems like grasslands are to retain their diverse birdlife in the future, both governments and research groups must prioritize such landscapes and their inhabitants for conservation and ensure that they do not become plantations or woodlands.”
“To save our birds and their habitats, facilitating easy focused and extensive research of threatened species is key. The more we understand about these birds, the better our chance of saving them.”
Dr Stuart Butchart, Chief Scientist at BirdLife International, said, “The world’s birds are in trouble, with their populations being rapidly reduced by a range of different threats. This is alarming because of their key role in ecosystems and because their trends signal broader environmental losses. It is not too late to save our natural heritage, but substantial action is urgently needed. The world’s birds point the way to the steps required for a nature-positive future.”
The study says lack of progress in conserving these species usually reflects a lack of
resources or political will, rather than a lack of knowledge of what needs to be done. For declines in commoner species, there is often greater uncertainty in the relative importance of sometimes dozens of threats and their often-interlinked drivers, hampering efforts to identify the most cost-effective interventions that can be applied at landscape scales.
“Nevertheless, we have sufficient information to determine the key actions required to slow down and ultimately reverse avian biodiversity loss. The growing footprint of the human population represents the ultimate driver of most threats to avian biodiversity, so the success of solutions will depend on the degree to which they account for the social context in which they are implemented, and our ability to effect changes in individual and societal attitudes and behaviours,” the study says.
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