A group of scientists released a report last week claiming that climate change will have a dramatic effect on future bird populations. The authors of the study are calling on lawmakers to decrease greenhouse gas emissions and improve conservation efforts to protect the birds.
The study, sponsored by Audubon California, paints a bleak picture of dwindling potential habitat, or ranges, for birds.
A majority of U.S. birds have moved farther north and inland over the last 40 years, according to data in the report. The authors found a correlation between this movement and the temperature fluctuations related to global warming.
Audubon scientists predict as many as 110 of California’s 310 bird species will experience “significant reductions” in their geographic range in the coming decades due to climate change.
Using known climate information and bird distributions from more than 40 years of data, Audubon scientists created spatial models for how birds would move as greenhouse gases increase.
Bill Monahan, senior geographic information scientist at Audubon California, said the models showed lower emissions in the future correlated with a smaller loss of birds.
“[This suggests] that there’s this opportunity, if we can curb our greenhouse gas emissions, to help conserve birds,” Monahan said.
For example, the Bay Area native Chestnut-backed Chickadee could lose as little as 16 percent or as much as 49 percent of its range. The Yellow-billed Magpie, which lives in California’s Central Valley and Coast ranges, could lose from 9 to 75 percent of its range.
Audubon California’s report proposes policies to limit the impact of climate change, including reducing dependence on oil and supporting alternative energy.
Yet controlling emissions won’t completely stop climate change, Monahan said.
“We have to think about taking steps to help species adapt to that change.“
Locally, the Yolo Bypass Wildlife Area provides a full and protected habitat for nearly 200 bird species. The area consists of 25 square miles of wetland between Davis and Sacramento.
Wildlife area manager Dave Feliz said protecting habitat is one of the most important steps toward maintaining bird populations.
Loss of habitat affects wildlife populations most adversely – approximately 10 percent of the wetlands that existed in the Valley prior to 1850 have been developed or destroyed, and effective habitats must remain free from urban impacts, Feliz said.
“As more and more land becomes developed, the wildlife populations continue to suffer,” he said. “Other factors such as pollution and human disturbance pale in comparison to the massive loss of habitat.“
In general, the effects of habitat alterations on bird ranges are poorly understood.
The complexity of ecosystems makes it difficult to predict what will happen to bird populations in the future, said Andrew Engilis, Jr., curator of UC Davis‘ Museum of Wildlife and Fish Biology.
For example, even minimal human intrusion such as the use of bird feeders can impact ranges significantly, Engilis said.
Hummingbirds, Wood Worblers and several species of Orioles have been known to remain in California throughout the winter season by feeding from bird feeders and ornamental landscape plantings such as Eucalyptus trees, which flower on a southern hemisphere cycle, Engilis said.
Though Engilis believes in habitat and maintenance restoration particularly in California, “where habitat fragmentation is reaching a critical level,” recent studies have suggested that behavior cues, such as the presence of singing male birds, are as important as the habitat’s structure in attracting populations, he said.
“In a human managed world … to expect that we can return systems to ‘normal‘ or even historic conditions may not be realistic,” Engilis said. “What is realistic is to try to stem the tide of biodiversity decline.“
Conservation, habitat restoration and continued research are vital to preserve ecosystem diversity in California, which is considered North America’s biodiversity hotspot due to its abundance of unique bird species, he said.
“There are more endemic [bird] species present in California than anywhere else in North America,” Engilis said. “If we lose California’s endemic species, then they cannot be recovered – ever.“
Regarding the importance of conservation, Engilis compared the ecosystem to an airplane, and the rivets of the wing to the species which inhabit the ecosystem.
“If one rivet is lost, maybe it’s no big deal. Maybe even a few others could be lost with no perceivable impact,” he said. “But how many rivets must be lost before the wing falls off and the ecosystem crashes?”
AARON BRUNER can be reached at city@theaggie.org.
