Climate-influenced changes in flowering, fruiting also affect bird abundance, activities

November 9, 2017, USDA Forest Service

Life cycle changes, such as breeding and molting, along with overall species abundance were found to shift in native Hawaiian birds, such as the 'i'iwi, to coincide with climate-related changes to native vegetation. Credit: US Forest Service/Amanda Uowolo
"You are what you eat" might give way to "you are when you eat," based on a new study tracking shifts in Hawaiian bird abundance, breeding and molting based on climate-related changes to native vegetation.

Researchers with the U.S. Forest Service's Pacific Southwest Research Station recently reviewed extensive climate, vegetation and bird data collected between 1976 and 1982 at a 40-acre monitoring site about 5 miles outside Hawai'i Volcanoes National Park on Hawai'i Island. Their results, "Bottom-up processes influence the demography and life-cycle phenology of Hawaiian bird communities," were recently published in this month's issue of Ecology and has implications for future bird population stability in future projected climates.

"The susceptibility of many Hawaiian birds to climatically-induced changes in their food web is alarming when considering that the archipelago has been subject to an increasingly drier climate during the last 30 years," said Jared Wolfe, a research ecologist and lead author of the study.

Wolfe, along with collaborators C. John Ralph and Andrew Wiegardt, found that three native birds that commonly feed on nectar—'i'iwi, 'apapane and Hawai'i 'amakihi—all timed their breeding season with the availability of 'ōhi'a lehua flowers, which in turn was coincident with periods of heavier rains. Similar correlations were found in select native and non-native bird species, based on their respective flower or fruit food sources and the timing of molting, an energy-taxing period when replace their feathers. Bird species abundance and scarcity also regularly mirrored the availability of their food sources.

"Our results suggest that changes in climate can cascade up the food chain and strongly affect wildlife at higher levels in the chain," Wolfe said.

The relative isolation in which Hawaiian ecosystems developed made it an ideal landscape to study the interaction between and plants, avoiding other factors or influences that might mask climate effects in mainland populations. The inclusion of non-native bird species in the study also helped confirm that patterns detected were irrespective of evolutionary history.

"These types of studies are rare because they depend on long-term data and labor-intensive field work," said Ralph, an emeritus research ornithologist with the Pacific Southwest Research Station. "But findings from long-term studies, such as this one, are critically important because they provide insights into how changes in might affect organisms in seemingly indirect ways."

Explore further: Study looks at how residential yards impact food webs

More information: Jared D. Wolfe et al, Bottom-up processes influence the demography and life-cycle phenology of Hawaiian bird communities, Ecology (2017). DOI: 10.1002/ecy.1981

Related Stories

Study looks at how residential yards impact food webs

October 30, 2017

University of Delaware doctoral student Desiree Narango is researching trees and shrubs planted in the lawns of homeowners throughout the Washington, D.C., Maryland and northern Virginia areas to assess how those choices ...

Birds are on the move in the face of climate change

September 7, 2017

Research on birds in northern Europe reveals that there is an ongoing considerable species turnover due to climate change and due to land use and other direct human influences. The findings are published in Ecology and Evolution.

Native forest birds in unprecedented trouble: researchers

January 19, 2012

Native birds at Hakalau Forest National Wildlife Refuge are in unprecedented trouble, according to a paper recently published in the journal PLoS ONE. The paper, titled "Changes in timing, duration, and symmetry of molt of ...

Climate change blamed for collapse of Hawaiian forest birds

September 7, 2016

Native forest birds on the Hawaiian island of Kauai are rapidly dying off and facing the threat of extinction as climate change heats up their habitat and allows mosquito-borne diseases to thrive, according to a study released ...

Recommended for you

Working lands play a key role in protecting biodiversity

October 18, 2018

With a body the size of a fist and wings that span more than a foot, the big brown bat must gorge on 6,000 to 8,000 bugs a night to maintain its stature. This mighty appetite can be a boon to farmers battling crop-eating ...


Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.