Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Jeepers Creepers! Climate Change Threatens Endangered Honeycreepers

28.05.2009
Deadly Diseases May Move Up Hawaiian Mountains to Birds’ Refuges

As climate change causes temperatures to increase in Hawaii’s mountains, deadly non-native bird diseases will likely also creep up the mountains, invading most of the last disease-free refuges for honeycreepers – a group of endangered and remarkable birds.

A just-published U.S. Geological Survey (USGS) review discusses the likelihood of a forthcoming “disease invasion” by examining the present altitudinal range of avian malaria and pox, honeycreeper distribution, and the future projected range of diseases and honeycreeper habitat with climate change.

At one time, the Hawaiian Islands had no mosquitoes – and no mosquito-borne diseases. But, by the late 1800s, mosquitoes had set up permanent housekeeping, setting the stage for epidemic transmission of avian malaria and pox. Honeycreepers – just like people faced with novel viruses such as swine flu – had no natural resistance against these diseases.

Before long, Hawaii’s native honeycreepers significantly declined in numbers and geographic range. It was likely that malaria swept rapidly across all of the lower Hawaiian Islands after the disease was introduced, leaving few survivors. Today, native Hawaiian birds face one of the highest rates of extinction in the world. Of 41 honeycreeper species and subspecies known since historic times, 17 are probably extinct, 14 are endangered, and only 3 are in decent shape.

Pox and malaria transmission in Hawaii depends on climatic conditions, especially seasonal changes in temperature and rainfall that increase or decrease mosquito populations. “Without question, the one factor that prevented widespread and rapid extinction of virtually all of Hawaii’s native honeycreepers after the introduction of avian pox and avian malaria was the presence of high-altitude disease refuges on Kauai, Maui and Hawaii,” said lead study author Dr. Carter Atkinson, a USGS microbiologist based at the USGS Pacific Islands Ecosystems Research Center in Hawaii.

These cool, high-elevation – above 4,000 feet (1,200 meters) -- mountains not only provided habitats that mosquitoes didn’t thrive in, but they also had habitat that honeycreepers liked, wrote the authors. While birds in those areas find refuge from the diseases – dispersing juvenile birds and adults that follow seasonal flowering of native plants to lower elevations are exposed to disease.

“Unfortunately,” said study co-author, USGS scientist Dr. Dennis LaPointe, “this seasonal movement happens at the same time that mosquito populations soar at mid-elevations, which fuels high disease-transmission rates there. There’s a continuous source of disease-susceptible birds each fall.”

Although most disease transmission now occurs in these mid-elevation forests, this will change if the projected 3.6 degrees Fahrenheit (2 degrees Centigrade) raise in temperature occurs.

“With this kind of temperature change, about 60 to 96 percent of the high-elevation disease refuges would disappear,” said Atkinson. For example, available high-elevation forest habitat in the low-risk disease zone would likely decline by nearly 60 percent at Hanawi Natural Area Reserve on Maui to as much as 96 percent at Hakalau Forest National Wildlife Refuge on Hawaii Island. On other islands, such as Kauai, with lower elevations and no low-risk zones even now, predicted temperature changes would likely be catastrophic for remaining honeycreeper species.

“Right now, disease transmission in the mountains of Kaui is highly seasonal, but with temperature increases, disease would be able to be transmitted throughout most of the year,” said Atkinson.

In addition, the tropical inversion layer – often visible as a thin cloud layer around high peaks -- may play a more significant role than temperature in determining tree line and the upper extent of forest bird habitat, the authors wrote. The inversion layer forms as cool, dry air meets warm, moist air, creating an inversion layer that caps moisture and cloud development between 5,900 and 7,900 feet (1,800 and 2,400 meters). Over the past 24 years, the height of this layer has remained fairly stable in spite of warming trends but has increased in how often it occurs.

“This could have a tremendous adverse effect on the continued existence of high-elevation disease refugia,” said Atkinson. “Remaining bird populations could be squeezed between expanding disease transmission from lower elevations and the upper limits of suitable forest habitat. Such changes would likely push remaining populations of threatened and endangered honeycreepers to extinction, and cause severe declines in other honeycreepers not now endangered but susceptible to avian malaria.”

Given the likelihood of global warming, the authors suggested that management of mid-elevation habitats to reduce disease transmission will become increasingly vital. The best opportunities for doing this, they wrote, will be through reducing habitat for mosquito larvae, habitat that is often created by introduced feral pigs, goats and cattle in forests.

“The survival of these species into the next century may ultimately depend on our ability to remove or offset introduced threats and restore native forests from sea level to tree line,” Atkinson said.

Honeycreepers rival Darwin’s finches in the Galapagos Islands in terms of their bill types and number of species that descended from a common founder. The birds specialize on food that includes nectar, fruits and insects. Before people came to the islands, as many as 56 kinds of honeycreepers probably occurred.

Avian malaria is caused by a protozoan parasite, and avian pox is a viral infection that typically causes tumor-like swellings on exposed skin of the feet, legs, beak and eyelids of infected birds. Malaria often results in appetite and weight loss, anemia, and massive enlargement of birds’ liver and spleen.

The article, Introduced avian diseases, climate change, and the future of Hawaiian honeycreepers, was published in the Journal of Avian Medicine and Surgery.

Carter Atkinson | EurekAlert!
Further information:
http://www.usgs.gov

More articles from Ecology, The Environment and Conservation:

nachricht Upcycling of PET Bottles: New Ideas for Resource Cycles in Germany
25.06.2018 | Fraunhofer-Institut für Betriebsfestigkeit und Systemzuverlässigkeit LBF

nachricht Dry landscapes can increase disease transmission
20.06.2018 | Forschungsverbund Berlin e.V.

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: First evidence on the source of extragalactic particles

For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.

To rule out other origins with certainty, the team led by neutrino physicist Elisa Resconi from the Technical University of Munich and multi-wavelength...

Im Focus: Magnetic vortices: Two independent magnetic skyrmion phases discovered in a single material

For the first time a team of researchers have discovered two different phases of magnetic skyrmions in a single material. Physicists of the Technical Universities of Munich and Dresden and the University of Cologne can now better study and understand the properties of these magnetic structures, which are important for both basic research and applications.

Whirlpools are an everyday experience in a bath tub: When the water is drained a circular vortex is formed. Typically, such whirls are rather stable. Similar...

Im Focus: Breaking the bond: To take part or not?

Physicists working with Roland Wester at the University of Innsbruck have investigated if and how chemical reactions can be influenced by targeted vibrational excitation of the reactants. They were able to demonstrate that excitation with a laser beam does not affect the efficiency of a chemical exchange reaction and that the excited molecular group acts only as a spectator in the reaction.

A frequently used reaction in organic chemistry is nucleophilic substitution. It plays, for example, an important role in in the synthesis of new chemical...

Im Focus: New 2D Spectroscopy Methods

Optical spectroscopy allows investigating the energy structure and dynamic properties of complex quantum systems. Researchers from the University of Würzburg present two new approaches of coherent two-dimensional spectroscopy.

"Put an excitation into the system and observe how it evolves." According to physicist Professor Tobias Brixner, this is the credo of optical spectroscopy....

Im Focus: Chemical reactions in the light of ultrashort X-ray pulses from free-electron lasers

Ultra-short, high-intensity X-ray flashes open the door to the foundations of chemical reactions. Free-electron lasers generate these kinds of pulses, but there is a catch: the pulses vary in duration and energy. An international research team has now presented a solution: Using a ring of 16 detectors and a circularly polarized laser beam, they can determine both factors with attosecond accuracy.

Free-electron lasers (FELs) generate extremely short and intense X-ray flashes. Researchers can use these flashes to resolve structures with diameters on the...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Leading experts in Diabetes, Metabolism and Biomedical Engineering discuss Precision Medicine

13.07.2018 | Event News

Conference on Laser Polishing – LaP: Fine Tuning for Surfaces

12.07.2018 | Event News

11th European Wood-based Panel Symposium 2018: Meeting point for the wood-based materials industry

03.07.2018 | Event News

 
Latest News

Global study of world's beaches shows threat to protected areas

19.07.2018 | Earth Sciences

New creepy, crawly search and rescue robot developed at Ben-Gurion U

19.07.2018 | Power and Electrical Engineering

Metal too 'gummy' to cut? Draw on it with a Sharpie or glue stick, science says

19.07.2018 | Materials Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>