The Southern sea otter population is healthy at the core of its range along the California coast, but the aquatic mammals are still struggling to expand north and south, probably because of predation by sharks, scientists said as they released the results of the latest annual otter survey.
“The population index has exceeded 3,090 for the first time, and that’s encouraging,” said Lilian Carswell, Southern Sea Otter Recovery Coordinator for USFWS, referring to a threshold number for recovery. If the population stays above that number for three years in a row, the U.S. Fish and Wildlife Service could consider a delisting proposal.Sea otters were presumed to be extinct in California in the early 1900s, but a remnant population of 30 animals was discovered and protected in the 1930s near Bixby Bay, north of Big Sur. They were listed as a threatened species in 1977, deemed at risk from oil spills. Continue reading “California sea otter population growing steadily”→
Biologists create historic record of climate change impacts
The shells of California mussels have thinned dramatically in the modern era, probably as a result of ocean acidification, a direct result of increased carbon dioxide in the atmosphere resulting from fossil fuel combustion, say University of Chicago biologists who compared mussel specimens collected in the 1970s with present-day samples.
In the 70s, the shells were on average 32 percent thicker than modern specimens. Going back even farther, the researchers said shells collected by Native Americans 1,000 to 1,300 years ago were also 27 percent thicker than modern shells.
“Archival material provided by past researchers, the Makah Tribal Nation, and the Olympic National Park allowed us to document this intriguing and concerning pattern in shell thickness,” said Cathy Pfister, PhD, professor of ecology and evolution at the University of Chicago and lead author. The study was published June 15, 2016, in the Proceedings of the Royal Society B. Continue reading “Climate: California mussel shells thinning as oceans acidify”→
A new draft wolf management plan for California aims to conserve biologically sustainable populations of the predators in areas where there is adequate habitat, while minimizing conflicts with livestock.
The California Department of Fish and Wildlife developed the plan in the past few years after wolves recolonized the far northeastern corner of the state. Wildlife managers say they will communicate to the public that natural dispersal of wolves into and through California is reasonably foreseeable given the expanding populations in the Pacific Northwest. Continue reading “California releases draft wolf management plan”→
Findings leave little doubt that marijuana growers are key threat to rare mammals
A new study presents more evidence that illegal marijuana growers are speeding the demise of a rare forest critter in California. After studying hundreds of forest-dwelling fishers, researchers concluded that the annual rate of poisoning deaths rose 233 percent compared to a study in 2012.
“This study further solidifies the need for continuing to remediate and remove these threats to fishers and other species of conservation concern within our public lands,” said Dr. Mourad Gabriel, executive director of the Integral Ecology Research Center, lead author of the study published in PLOS One.
The Pacific Ocean’s El Niño-La Niña cycle may become a dominant factor in West Coast weather by the end of this century and lead to more frequent weather extremes, according to a new study published in Nature Communications. Based on the findings, California could see the number of extreme droughts and floods by 2100, the researchers found.
Latest study suggests giant trees can persist along central coast, at least for a while
Redwood trees in California face an uncertain climate future, but some of the latest research suggests they’ll be able to persist in the coastal mountains south of San Francisco. And suitable climate conditions for the giant trees may expand northward in to Oregon, according to a new study published in Global Change Biology.