Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Global bird populations face dramatic decline in coming decades

14.12.2004


Ten percent of all bird species are likely to disappear by the year 2100, and another 15 percent could be on the brink of extinction, according to a new study by Stanford University biologists. This dramatic loss is expected to have a negative impact on forest ecosystems and agriculture worldwide and may even encourage the spread of human diseases, according to the study published in the Online Early Edition of the Proceedings of the National Academy of Sciences (PNAS) in December.




"Our projections indicate that, by 2100, up to 14 percent of all bird species may be extinct and that as many as one out of four may be functionally extinct-that is, critically endangered or extinct in the wild," said researcher Cagan H. Sekercioglu of the Stanford Center for Conservation Biology (CCB) and lead author of the PNAS study. "Important ecosystem processes, particularly decomposition, pollination and seed dispersal, will likely decline as a result."

These findings come on the heels of the November 2004 Global Species Assessment by the World Conservation Union (IUCN), which found that 12 percent of all bird species are already threatened with extinction, along with nearly one-fourth of the world’s mammals, one-third of the amphibians and 42 percent of all turtles and tortoises.


"Even though only 1.3 percent of bird species have gone extinct since 1500, the global number of individual birds is estimated to have experienced a 20 to 25 percent reduction during the same period," wrote Sekercioglu and CCB co-authors Gretchen C. Daily and Paul R. Ehrlich. "Given the momentum of climate change, widespread habitat loss and increasing numbers of invasive species, avian declines and extinctions are predicted to continue unabated in the near future."

Future scenarios

The study was based on a painstaking analysis of all 9,787 living and 129 extinct bird species. Eight researchers spent a year collecting data on the conservation, distribution, ecological function and life history of every species-more than 600,000 computer entries in total. "The result is one of the most comprehensive databases of a class of organisms ever compiled," Sekercioglu said.

To forecast probable rates of extinction, he and his colleagues entered the data into a computer program designed to simulate best-case, intermediate-case and worst-case scenarios for the future. The best case was based on the assumption that conservation measures in the next 100 years would be sufficient to prevent additional bird species from becoming threatened with extinction.

For the worst case, the researchers assumed that the number of threatened species will increase by about 1 percent per decade-that is, 1 percent in 2010, 2 percent in 2020, 3 percent in 2030, etc. "These assumptions are conservative, since it is estimated that, every year, natural habitats and dependent vertebrate populations decrease by an average of 1.1 percent," the authors wrote.

For the intermediate scenario, the scientists used statistics from 1994 through 2003 as a basis for calculating the likelihood that a non-threatened species would become threatened after a decade. The results of the three future scenarios were dramatic. The computer forecast that between 6 and 14 percent of all bird species will be extinct by 2100, and that 700 to 2,500 species will be critically endangered or extinct in the wild. Even the middle-of-the-road intermediate scenario revealed that one in 10 species will disappear a century from now, and that approximately 1,200 species will be functionally extinct.

The study cited several reasons for the expected decline in bird populations, including habitat loss, disease, climate change, competition from introduced species and exploitation for food or the pet trade. "Island birds are particularly at risk," the authors said, noting that one-third to one-half of all oceanic island species will be extinct or on the brink of extinction by 2100. Birds with highly specialized diets are predicted to experience more extinctions than average, they wrote, adding that some plant species also face extinction if their primary pollinators and seed-dispersers vanish.

"It’s hard to imagine the disappearance of a bird species making much difference to human well-being," said Daily, an associate professor (research) in Stanford’s Department of Biological Sciences and director of the CCB Tropical Research Program. "Yet consider the case of the passenger pigeon. Besides mail becoming a lot less fun to receive, its loss is thought to have made Lyme disease the huge problem it is today. When passenger pigeons were abundant-and they used to occur in unimaginably large flocks of hundreds of millions of birds-the acorns on which they specialized would have been too scarce to support large populations of deer mice, the main reservoir of Lyme disease, that thrive on them today."

Scavengers and insectivores

More than a third of all scavengers and fish-eaters are extinction-prone, according to the study, yet little is known about the potential consequences of their widespread disappearance. "Since most scavenging birds are highly specialized to rapidly dispose of the bodies of large animals, these birds are important in the recycling of nutrients, leading other scavengers to dead animals and limiting the spread of diseases to human communities as a result of slowly decomposing carcasses," the authors wrote.

As an example, the researchers pointed to India, where the collapse of the vulture population in the 1990s was followed by an explosion of rabid feral dogs and rats. In 1997 alone, more than 30,000 people died of rabies in India, more than half of the world’s total rabies deaths that year.

Insect control is another important ecosystem service performed by birds, yet the study found that more insect-eating bird species are prone to extinction than any other group. "Exclusions of insectivorous birds from apple trees, coffee shrubs, oak trees and other plants have resulted in significant increases in insect pests and consequent plant damage," the authors wrote, adding that the extreme specializations of many insectivorous birds, especially in the tropics, make it unlikely that other organisms will be able to replace the birds’ crucial role in controlling pests.

"The societal importance of ecosystem services is often appreciated only upon their loss," the authors wrote. "Disconcertingly, avian declines may in fact portray a best-case scenario, since fish, amphibians, reptiles and mammals are 1.7 to 2.5 times more threatened [than birds]." Invertebrates, which may be even more ecologically significant than animals, also are disappearing, they noted. Therefore, "investments in understanding and preventing declines in populations of birds and other organisms will pay off only while there is still time to act," the authors concluded.

Mark Shwartz | EurekAlert!
Further information:
http://www.stanford.edu
http://www.birdlife.net
http://www.redlist.org

More articles from Ecology, The Environment and Conservation:

nachricht Successful calculation of human and natural influence on cloud formation
04.11.2016 | Goethe-Universität Frankfurt am Main

nachricht Invasive Insects Cost the World Billions Per Year
04.10.2016 | University of Adelaide

All articles from Ecology, The Environment and Conservation >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Significantly more productivity in USP lasers

In recent years, lasers with ultrashort pulses (USP) down to the femtosecond range have become established on an industrial scale. They could advance some applications with the much-lauded “cold ablation” – if that meant they would then achieve more throughput. A new generation of process engineering that will address this issue in particular will be discussed at the “4th UKP Workshop – Ultrafast Laser Technology” in April 2017.

Even back in the 1990s, scientists were comparing materials processing with nanosecond, picosecond and femtosesecond pulses. The result was surprising:...

Im Focus: Shape matters when light meets atom

Mapping the interaction of a single atom with a single photon may inform design of quantum devices

Have you ever wondered how you see the world? Vision is about photons of light, which are packets of energy, interacting with the atoms or molecules in what...

Im Focus: Novel silicon etching technique crafts 3-D gradient refractive index micro-optics

A multi-institutional research collaboration has created a novel approach for fabricating three-dimensional micro-optics through the shape-defined formation of porous silicon (PSi), with broad impacts in integrated optoelectronics, imaging, and photovoltaics.

Working with colleagues at Stanford and The Dow Chemical Company, researchers at the University of Illinois at Urbana-Champaign fabricated 3-D birefringent...

Im Focus: Quantum Particles Form Droplets

In experiments with magnetic atoms conducted at extremely low temperatures, scientists have demonstrated a unique phase of matter: The atoms form a new type of quantum liquid or quantum droplet state. These so called quantum droplets may preserve their form in absence of external confinement because of quantum effects. The joint team of experimental physicists from Innsbruck and theoretical physicists from Hannover report on their findings in the journal Physical Review X.

“Our Quantum droplets are in the gas phase but they still drop like a rock,” explains experimental physicist Francesca Ferlaino when talking about the...

Im Focus: MADMAX: Max Planck Institute for Physics takes up axion research

The Max Planck Institute for Physics (MPP) is opening up a new research field. A workshop from November 21 - 22, 2016 will mark the start of activities for an innovative axion experiment. Axions are still only purely hypothetical particles. Their detection could solve two fundamental problems in particle physics: What dark matter consists of and why it has not yet been possible to directly observe a CP violation for the strong interaction.

The “MADMAX” project is the MPP’s commitment to axion research. Axions are so far only a theoretical prediction and are difficult to detect: on the one hand,...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

ICTM Conference 2017: Production technology for turbomachine manufacturing of the future

16.11.2016 | Event News

Innovation Day Laser Technology – Laser Additive Manufacturing

01.11.2016 | Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

 
Latest News

Closing the carbon loop

08.12.2016 | Life Sciences

Applicability of dynamic facilitation theory to binary hard disk systems

08.12.2016 | Physics and Astronomy

Scientists track chemical and structural evolution of catalytic nanoparticles in 3-D

08.12.2016 | Materials Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>