Tag: biodiversity

Will global warming lead to a battle of the birds?

Mountain bluebird.
Mountain bluebird. @bberwyn photo.

Migration changes could affect competition for nesting sites

Staff Report

As global warming speeds up the springtime northward migration of swallows, it could spell trouble for mountain bluebirds.

Both species are cavity nesters; at times they compete for the same habitat. Historically, mountain bluebirds have arrived in the breeding territories earlier than the swallows, giving them a chance to defend their nests. But if the swallows arrive first, the bluebirds may have a harder time finding a safe spot to lay eggs, according to new research published in The Auk: Ornithological Advances.

The scientists from the University of Saskatchewan acknowledged that the outcomes of interspecies battles for nest sites depend on a number of factors, but wanted to study what happens when tree swallows and mountain bluebirds compete for nest sites. So they set up side-by-side pairs of nest boxes in grassland habitat in central British Columbia.

When bluebird and swallow pairs moved in next door to each other, they would either block the entrance to one box and let the two pairs of birds compete for the one that remained, or remove both boxes and replace them with a fresh one.

“I became interested in this topic after watching many competitive interactions over natural tree holes during a long-term study of Northern Flickers in central British Columbia,” said researchers Karen Wiebe. “In early spring when the birds are trying to claim a nest site, these disputes can be intense and really grab your attention. Because bluebirds and swallows readily use nest boxes, I was motivated to try some experiments in a system where I could have more control over the spacing of nests and settlement patterns of the birds.”

Wiebe found that when Tree Swallows were defending their previously owned box or when the two species were competing over a new box, Tree Swallows won 65-70 percent of the time. Bluebirds got a boost when they defended a box they already occupied, however, fending off swallows 77 percent of the time.

Climate change may bring the two species into direct competition more often and reduce bluebirds’ ability to claim and defend nest sites.

“This is a nice set of clever and simple experiments that show that species are not the same when it comes to the importance of being the first one to occupy a nest site,” according to ecologist Hanna Kokko of the University of Zurich, an expert on interspecies competition in birds. “The one that currently tends to arrive first, the bluebird, relies more on this, which could easily cause problems if the arrival order changes on a changing planet.”

Florida’s latest invasive species is a potential man-eater

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Nile crocodiles may be spreading out Florida. Photo courtesy MathKnight and Zachi Evenor, via Wikipedia and the Creative Commons.

Scientists say Nile crocs may be thriving in Sunshine State swamps

Staff Report

The latest non-native species to invade Florida’s subtropical clime is a man-eater, according to University of Florida researchers who say they’ve genetically identified Nile crocodiles living in the swamps of the Sunshine State.

The aquatic reptiles can grow as long as 18 feet and weigh as much as a small car, and in their native habitat eat everything from hippos and zebras to humans. In Florida, they could eat native birds, fish and mammals, as well as the state’s native crocodile and alligators, said the researchers, have confirmed the capture of multiple Nile crocodiles in the wild, using DNA analysis.

Crocodylus niloticus, as they’re known scientifically, were blamed for at least 480 attacks on people and 123 fatalities in Africa between 2010 and 2014. Three juveniles, likely released by humans, have been found in South Florida, swimming in the Everglades and relaxing on a house porch in Miami. Continue reading “Florida’s latest invasive species is a potential man-eater”

Biodiversity: Frog-killing fungus turns up in Africa

boreal toad
The frog-killing chytrid fungus, which has all but wiped out species like boreal toads, has now been found in Africa. @bberwyn photo.

Researchers track chytrid in mountains of Cameroon

Staff Report

Africa’s frogs may also be succumbing to the chyrid fungus that has wiped out species around the world, researchers reported this week in the journal PLOS ONE.

Tracking frogs on Cameroon’s Mount Oku and Mount Manengouba over a span of more than 12 years, University of Florida herpetologist David Blackburn and colleagues at the Museum für Naturkunde in Berlin have linked declines of at least five frog species linked with chytrid — possibly exacerbated by habitat destruction, pollution and climate change. Continue reading “Biodiversity: Frog-killing fungus turns up in Africa”

Environment: Can dams be operated without killing rivers?

Glen Canyon Dam. Image courtesy NASA Earth Observatory.
Glen Canyon Dam. Image courtesy NASA Earth Observatory.

New study eyes impacts to aquatic insects

Staff Report

Using a vast sample of data collected in a citizen science project, researchers say they’ve been able to discern how hydropeaking affects aquatic insects that form the base of river food chains. The information could help resource managers develop alternative hydropower practices that aren’t as harmful to ecosystems, according to a new study published in the journal BioScience.

Hydropeaking refers to the practice of increasing river flows at times of peak demand, generally during the day. This study shows how abrupt water level changes affect aquatic insects in every stage of life. The research was done by scientists with the U.S. Geological Survey, Oregon State University, Utah State University and Idaho State University. Continue reading “Environment: Can dams be operated without killing rivers?”

Wildlife: Court settlement compels feds to complete recovery plan for Mexican gray wolves in the Southwest

Mexican gray wolfWolf advocates hope for more releases of captive-bred wolves

Staff Report

The U.S. Fish and Wildlife Service this week agreed to prepare a recovery plan for Mexican gray wolves by 2017. The court settlement will compel the federal agency to finally meet its legal obligation to ensure that the wolves can establish a healthy, sustainable population. The settlement may speed up the slow-going conservation and recovery effort.

The settlement came in response to a lawsuit filed by a coalition of wolf-conservation groups, environmental organizations and a retired federal wolf biologist. Less than 100 Mexican gray wolves exist in the wild, making it one of the most endangered mammals in North America. The settlement follows a September 2015 ruling by a federal judge in Tucson that rejected the government’s effort to dismiss the case.

The recovery effort has long been mired in politics, with conservative Republican lawmakers setting roadblocks at every turn, pressuring the USFWS from the state level and trying to make end runs around the Endangered Species Act in Congress. Continue reading “Wildlife: Court settlement compels feds to complete recovery plan for Mexican gray wolves in the Southwest”

Milkweed shortage not the only reason for monarch decline

Monarch butterflies during migration. PHOTO COURTESY GENE NEIMINEN/USFWS.
Monarch butterflies at their overwintering grounds in Mexico. Photo courtesy Gene Neiminen/USFWS.

‘We have to get the science right’

Staff Report

The decline of milkweed may not be the main factor driving monarch butterflies toward oblivion, according to a new study by Cornell University scientists. Weather, habitat fragmentation and dwindling sources of nectar in the autumn are also critical, the new study reports.

“Thanks to years of data collected by the World Wildlife Fund and citizen-scientists across North America, we have pieced together the monarch life cycle to make inferences about what is impacting the butterflies,” said Cornell University Prof. Anurag Agrawal.

“Given the intense interest in monarch conservation, the blame being put on herbicide use and the national dialog about potentially listing monarchs under the endangered species act, we have to get the science right,” Agrawal said. Continue reading “Milkweed shortage not the only reason for monarch decline”

Watchdog group keeps door open for endangered species petitions

Two of the five lynx dens documented this spring by CDOW are in Summit County. PHOTO BY TANYA SHENK, COLORADO DIVISION OF WILDLIFE.
Two of the five lynx dens documented this spring by CDOW are in Summit County. Photo by Tanya Shenk/Colorado Division of Wildlife.

Feds dial back proposed regs that would have made it harder to seek endangered species protection

Staff Report

Many plants and animals that are protected as endangered species in the U.S. got that status because conservation groups — representing concerned citizens — petitioned the federal government. It’s a process that’s explicitly mandated by the Endangered Species Act, but that has led to serious frustration among government biocrats and various extractive industries that specialize in exploiting public land resources.

In an attempt to try and cripple citizen groups, the U.S. Fish and Wildlife Service recently proposed making the petitioning process much more difficult by requiring pre-clearance from state agencies and limiting petitions to a single species. All in all, the proposal was aimed at trying to avoid giving protection to species that need it. Continue reading “Watchdog group keeps door open for endangered species petitions”