Pacific sea otters and nuclear bombs


This Associated Press video says about itself:

(7 Nov 1971) Protest demonstrations in Washington, Toronto, and Tokyo against the US American five megaton nuclear bomb test on Amchitka.

By Bethany Brookshire in the USA, 11:30am, November 7, 2018:

50 years ago, atomic testing created otter refugees

When the [Atomic Energy Commission] first cast its eye on the island of Amchitka as a possible site for the testing of underground nuclear explosions, howls of anguish went up; the island is part of the Aleutians National Wildlife Refuge, created to preserve the colonies of nesting birds and some 2,500 sea otters that live there…— Science News, November 9, 1968

Update

The commission said underground nuclear testing would not harm the otters, but the fears of conservationists were well-founded: A test in 1971 killed more than 900 otters on the Aleutian island.

Some otters remained around Amchitka, but 602 otters were relocated in 1965–1972 to Oregon, southeast Alaska, Washington and British Columbia — areas where hunting had wiped them out. All but the Oregon population thrived, and today more than 25,000 otters live near the coastal shores where once they were extinct.

This 2015 video says about itself:

The Sea Otter’s Enchanted Forest | America’s National Parks

Endangered sea otters protect the kelp beds by preying on small undersea life, which would otherwise overpopulate.

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Arctic wolf spiders and climate change


This video says about itself:

29 May 2009

Identifying spiders in Alaska requires looking for the American house spider, which is bulbous and splotched, or the wolf spider, which has long, slender, hairy legs. Watch out for Alaskan spiders with helpful facts from an entomology student in this free video on arachnids.

Expert: Lauren Saldana

Bio: Lauren Saldana is an entomology student at Fresno State University in California who specializes in arachnid studies.

Filmmaker: Brandon Payan

From Washington University in St. Louis in the USA:

Warming alters predator-prey interactions in the Arctic

Spiders could buffer some effects of warming on decomposition

July 23, 2018

Summary: Under warming conditions, Arctic wolf spiders’ tastes in prey might be changing, according to new research — initiating a new cascade of food web interactions that could potentially alleviate some impacts of global warming.

Wolf spiders are so abundant that they outweigh real wolves in the Alaskan Arctic by several orders of magnitude. Their sheer numbers make them one of the important predators on the tundra. They may also be important in buffering some effects of climate change.

Under warming conditions, arctic wolf spiders’ tastes in prey might be changing, according to new research from Washington University in St. Louis, initiating a new cascade of food web interactions that could potentially alleviate some impacts of global warming.

The surprising result of this chain reaction is described in a new paper by Amanda Koltz, a postdoctoral researcher in biology in Arts & Sciences, published July 23 in the Proceedings of National Academy of Sciences.

The ways in which animals interact with each other will be affected by climate change, scientists generally agree. But few studies have explored the larger picture of how these changes will alter not just individual species, but concurrently impact all of the biological and physical interactions in a given environment.

“We often think about how warmer temperatures might strengthen or weaken interactions between predators and their prey”, Koltz said. “But in this case we show that when warming alters those interactions, it can also lead to changes in ecosystem-level processes like decomposition rates.”

Koltz and her team study wolf spiders. They are less than half an inch long, but in a warming future, they might be both larger and more prolific (so don’t say we didn’t warn you).

Wolf spiders don’t make webs. This type of spider hunts on the ground and can eat almost anything smaller in size, from plant-eating bugs to other predators.

But they really love to eat Collembola — the small arthropods commonly called springtails. It’s this spider snack that connects them to the belowground environment. Springtails eat both decaying plants and fungus. And, in wet tundra, the fungus in the ground largely controls how quickly dead plant matter is decomposed and its nutrients released into the soil and air.

Arctic wolf spiders are thus said to have an “indirect” effect on decomposition. The spiders eat animals (springtails) that eat fungus; if more fungus-eaters get eaten, then fungus grows unchecked. When there is a lot more fungal activity, there is faster decomposition.

Decomposition is usually positive for plants, in that it releases more nutrients to the soil. Some of these nutrients, such as nitrogen, are sought-after fertilizers that enhance plant productivity. But decomposition is a double-edged sword for the environment. As microbes eat dead plants, they also respire carbon dioxide and methane — powerful greenhouse gases.

Between one-third to one-half of the global pool of soil organic carbon is frozen in Arctic permafrost, currently locked away from decomposers but vulnerable to warming.

To test the effects of warming on the spider/fungus-eater/soil system, Koltz and her team installed a series of experimental enclosures in an area of arctic tundra in Northern Alaska over two summer seasons. These mini-ecosystems were 1.5 meters in diameter and separated all of the regular tundra inhabitants — including belowground animals and fungus — from their surroundings in a space where temperature and densities of spiders could be manipulated.

At the end of the study period, the scientists surveyed everything inside the enclosures. They counted springtails and mites, measured microbial biomass (fungus and bacteria), and tallied the other tiny animals that could either eat the springtails themselves or serve as alternative food sources for the wolf spiders.

What they discovered was surprising. At ambient temperatures, there were fewer springtails left in the high-spider-density plots, and decomposition of leaf litter had happened faster. This was expected since wolf spiders love to eat springtails. But in the warmed plots with high spider densities, the researchers found significantly more of the springtail prey, and less evidence of decomposition of the leaf litter in the soil.

What’s going on here? The researchers believe that under warming conditions, the wolf spiders are developing a taste for different prey. Instead of springtails, they could be eating more of the intermediate predators, like smaller spiders.

That’s good news for springtails — and maybe for the climate, too.

In a warming future, if wolf spiders eat fewer springtails, such that the springtails are able to eat more microbes, then there may be less decomposition — and less carbon released from the permafrost.

“The way that organisms interact with one another can influence important ecosystem functions like how much carbon stays fixed by plants, how quickly decomposition happens, and how nutrients are cycled within that ecosystem”, Koltz said. “Controls on nutrient cycling in the Arctic are very important for us to understand, because this region plays a disproportionately large role in the global carbon cycle.

“Spiders are not going to save us from climate change, but we found that decomposition is slower under warming when there are more wolf spiders present”, Koltz added. “This suggests that under some circumstances, they could be alleviating some of the effects of warming on carbon losses from the tundra. It’s a good thing.”

Plants in the Arctic are growing taller because of climate change, according to new research from a global scientific collaboration led by the University of Edinburgh: here.

The United Nations Intergovernmental Panel on Climate Change (IPCC) released a special report Monday calling for “rapid, far-reaching and unprecedented changes in all aspects of society” in order to limit human-induced global warming to 1.5 degrees Celsius above pre-industrial levels: here.

How bears help small mammals


This 2014 video says about itself:

Grizzly Bears Catching Salmon | Nature’s Great Events | BBC

It’s the time of year when the salmon make their annual pilgrimage upstream to spawn, but leaping past the waiting hungry bears is no easy task.

From Oregon State University in the USA:

Berry-gorging bears disperse seeds through scat and feed small mammals

July 5, 2018

New research shows that mice and voles scurry to bear scats to forage for seeds, finding nutritional value in the seeds and in some cases further dispersing them.

The study is published in the journal Ecosphere by researchers at Oregon State University and the Alaska Department of Fish and Game. The research builds on an OSU study that determined that bears are the primary seed dispersers of berry-producing shrubs in Alaska.

In southeastern Alaska, brown and black bears are plentiful because of salmon. Bears frequently supplement their salmon-based diet with fruit as they build their fat stores for winter hibernation. As a result, their seed-filled scats are found throughout the landscape.

“Salmon can have a far greater impact on the ecosystem than we thought”, said study lead author Yasaman Shakeri, an Oregon State University graduate now with the Alaska Department of Fish and Game. “Our study shows how small mammals can benefit indirectly from salmon through high bear densities that salmon support and the resulting seed-filled scats on the landscape. Not only are small mammals spending months feeding and fighting for the seeds in scats, they’re also scattering the seeds on the landscape, which allows some of the seeds to become future fruiting plants.”

The researchers placed motion-triggered cameras near bear scats in the upper Chilkat Valley, 30 miles north of Haines, from June to October in 2014 and 2015. They recorded visits to the scat made by small mammals and birds.

Northwestern deer mice made 4,295 total visits to the scats — an average of 8.5 a day. Northern red-backed voles visited 1,099 times at an average of 2.2 times a day. In addition to the cameras, the researchers also live-trapped and tagged small mammals to estimate their abundance and population densities.

The team collected bear scats on roads and trails within the study area from July-September in 2014 and 2015 and analyzed the nutritional characteristics found in the 12 species of fruit found in the scats, including gross energy, total dietary fiber, crude protein and crude fat. From those samples, they estimated digestible energy per seed.

The energy within the seeds in bear scats can be a significant portion of the energy budget of rodents. For example, a single bear scat contained 73,230 devil’s club seeds, which was capable of meeting the daily energy requirements of 91 deer mice. In coastal Alaska riparian areas, bears are potentially capable of indirectly subsidizing the energy needs of 45-65 percent of local deer mouse populations, Shakeri said.

In addition to consuming the seeds at the site, the mice appear to scatter-hoard the seeds in much the same way that gray squirrels scatter-hoard acorns, said Taal Levi, an ecologist in OSU’s College of Agricultural Sciences and co-author on the study. Scatter-hoarding is creating a large number of small hoards, as opposed to a large hoard found in a single place.

“This process is called secondary seed dispersal and forgotten seeds can have much higher survival than unburied seeds”, Levi said.

The study was also co-authored by Kevin White, a wildlife biologist with the Alaska Department of Fish and Game. The M.J. Murdock Charitable Trust and OSU’s Department of Fisheries and Wildlife provided funding for the study.

Whiskered auklets, new study


This video from Alaska says about itself:

Pelagic birding in the Aleutian Islands, 2012

Laysan Albatrosses were in view almost constantly. We encountered a few Black-footed Albatrosses during the Attu tour, but they were more common near Dutch Harbor. We saw over 15 Short-tailed Albatrosses, one of the major targets of the tours, over the course of both tours. On the way to Attu, two or three were seen between Buldir and Shemya Islands. There were three or four at Stalemate Bank, and on the return to Adak, we saw at least three more. Between Adak and Dutch Harbor, we saw five or more in Seguam Pass and four or more west of Herbert Island.

Other highlights included Whiskered Auklet (scattered throughout the islands, but the largest numbers were in Little Tanaga Strait east of Adak); hundreds of thousands of Least and Crested Auklets with the biggest concentration at the nesting colony at Sirius Point, Kiska Island; Red-legged Kittiwakes between Buldir and Shemya Island and at Stalemate Bank; Northern Fulmars, which like Laysan Albatross, were almost constantly in view, and we saw hundreds of thousands at Chagulak Island, one of their largest nesting colonies. We also saw 10 other species of alcids, Fork-tailed and Leach’s Storm-Petrels, Long-tailed Jaeger, and other pelagic species.

Mammals seen included many sperm and killer whales, one humpback whale, and a pod of Baird’s beaked whales, and Dall’s porpoises.

From the American Ornithological Society Publications Office in the USA:

Whiskered auklets lack wanderlust, are homebodies instead

May 30, 2018

A new study from The Auk: Ornithological Advances presents some of the best evidence that Whiskered Auklets are an outlier in the auklet family by not migrating and instead staying close to “home” (their breeding colonies) year-round. Most migratory birds lead two opposite lifestyles in the same year. During the breeding season a bird’s location is constrained and their habits are repetitive given a nest full of chicks that require food, warmth, and protection. For some birds it is the only time they congregate or otherwise come together. Comparatively, during the non-breeding season their only true task is to survive. Whether migratory or residential, as long as the bird makes it back to the breeding grounds to reproduce, they can go almost wherever they want. Whiskered Auklets are consistent through the year though and don’t wander far at all.

Carley Schacter and Ian Jones of Memorial University of Newfoundland used light-based archival geolocation tags on Whiskered Auklets in Buldir Island, Aleutian Islands, Alaska, to determine the locations of their full annual life cycle. The data they collected corroborated what researchers have long suspected. This species is unique in the auklet family for not migrating at all. Most seabirds roost on the water at night, but Whiskered Auklets stay in the vicinity of the breeding colony year-round and consistently return to roost at night on land. Such behavior may not only be unique to auklets, but to the entire seabirds group. How could this unusual adaptation have come about? Whiskered Auklets capitalize on the foraging habitat close to their breeding colony which reduces metabolic costs. Given the influence of tradeoffs on animal behavior and life history strategies, this foraging area could be a large contributor to their residential behavior.

But there are risks to this strategy as well. Lead author Carley Schacter notes, “While this non-migratory behavior is very interesting to us on a theoretical level, there are also important implications for the conservation and management of this most vulnerable of auklet species. Year-round residence near the breeding site (an area of high fishing and shipping traffic) makes Aleutian-breeding Whiskered Auklets even more exposed than previously thought to human threats such as oil/fuel spills and light attraction leading to fatal collisions with vessels. Their nocturnal roosting behavior also makes them especially vulnerable to introduced mammalian predators such as rats and foxes.”

“The authors found evidence for an almost unique adaptation of a seabird in a remote, difficult-to-work-in, and isolated environment”, adds Jeff Williams, Assistant Refuge Manager at the Alaska Maritime National Wildlife Refuge, who was not involved with this research. “We now know that Whiskered Auklets are particularly sensitive to human-caused disturbances (oil spills, light attraction, invasive species introductions etc.) and can incorporate this information into management planning.”

Russian cuckoos invade Alaska


This video is called Common cuckoo (Cuculus canorus).

Unfortunately, after reading about the cuckoo research mentioned in this blog post, I would not be too surprised to soon see smears in the Rupert Murdoch and other corporate media, depicting these beautiful birds as supposedly mechanical clock cuckoos sent by Vladimir Putin to subvert the USA … after all, the Russia! Russia! screamers have already smeared the Black Lives Matter movement, the United States Green party, former Democratic chairperson Ms Donna Brazile, Senator Bernie Sanders, and so many others as ‘tools of the Kremlin’ for thinking independently of the establishment …

From the University of Illinois at Urbana-Champaign in the USA:

Russian cuckoo invasion spells trouble for Alaskan birds

May 7, 2018

Common cuckoos and oriental cuckoos in eastern Russia appear to be expanding their breeding range into western Alaska, where songbirds are naive to the cuckoos’ wily ways, researchers report. A new study suggests the North American birds could suffer significant losses if cuckoos become established in Alaska.

Like brown-headed cowbirds, cuckoos are “brood parasites”, laying their eggs in the nests of other species, said University of Illinois animal biology professor Mark Hauber, who led the new research with Vladimir Dinets of the University of Tennessee, Knoxville. Cuckoos time their egg-laying so that their chicks will hatch first. The chicks then kick the other eggs out of the nest, “thereby eliminating the entire reproductive success of their hosts”, Hauber said.

“Brood parasitism is a rare strategy among birds. Only about 1 percent of birds engage in it”, he said. “Obligate brood parasites do it always. They never build a nest, they never incubate the eggs, they never feed their chicks. Instead, they sneak their eggs into somebody else’s nest, forcing the foster parent to take care of the young.”

Birdwatchers and ornithologists occasionally report seeing oriental cuckoos and common cuckoos in Alaska, and Alaskan natural history museums already contain a handful of cuckoo specimens collected locally, Hauber said. These birds are likely traveling from sites in Beringia, in eastern Russia.

“We don’t have evidence of them breeding in Alaska, but it’s likely already occurring,” Hauber said. “We wanted to know whether the potential Alaskan hosts are ready for this cuckoo invasion.”

In the new study, researchers tested whether more than a dozen Alaskan bird species had evolved defenses to counter the cuckoos’ parasitic ways. Such defenses are common among bird species that frequently encounter brood parasites elsewhere.

“There are strategies such as hiding your nest, nesting at a time when the brood parasite is not around or attacking the brood parasite when it is in proximity to your nest”, Hauber said. “If that doesn’t work, you can abandon the nest with a cuckoo egg in it.”

Some birds will pierce the cuckoo eggs and toss them out of the nest, he said.

For the new study, the researchers put fake eggs in the nests of more than two dozen bird species nesting in Siberia and Alaska — outside the normal breeding range of the cuckoos. The eggs were either pale blue, like those of the redstart host of common cuckoos, or light gray-blue with brown spots, like the eggs of pipits that often are targets of common cuckoos and oriental cuckoos. The researchers tested each nest at least twice, once with each of the eggs, in random order. After losses from predation, the team collected data from 62 nests of 27 bird species.

“What we found was very straightforward,” Hauber said. “Out of 22 experiments that we ran in Siberia, 14 rejected the fake cuckoo eggs. But out of the 96 experiments that we ran in Alaska, only one pair rejected one of the fake cuckoo eggs.”

The Siberian birds are better at rejecting the cuckoo eggs perhaps because they have encountered the brood parasites before, Hauber said.

“But the North American hosts have no defenses against invading cuckoos. They will be parasitized”, he said.

How Alaskan fur seal pups migrate


This video from the USA says about itself:

13 June 2013

This video footage supplements NOAA‘s Northern Fur Seal K-3 Curriculum Activity 1.4, “Walk and Swim Like a Pinniped”, and shows harbor seals and northern fur seals on land and underwater to compare and contrast movement styles of different species of pinnipeds.

From the American Geophysical Union:

Ocean winds influence seal pup migration

February 13, 2018

Scientists have confirmed what native Alaskans have observed for centuries — maritime winds influence the travel patterns of northern fur seal pups. New research presented at the Ocean Sciences Meeting here today shows strong winds can potentially displace seal pups by hundreds of kilometers during their first winter migration.

Most northern fur seals breed on islands in the Bering Sea during the summer and embark on an eight-month-long journey to the North Pacific Ocean to forage for food in November and December of each year. For unexplained reasons, seal births have been declining there since the late 1970s, prompting increased research into the animals’ behavior. Researchers found many pups die during their initial migration from the Bering Sea to the North Pacific Ocean, but the rate at which this happens varies from year to year — and scientists are unsure why.

New research comparing the movements of individual seal pups during their migration with reconstructions of ocean surface winds shows that as wind speed increases, pups increasingly move downwind and to the right. The preliminary findings suggest surface winds could influence an individual pup’s displacement by hundreds of kilometers during their first winter migration.

It is unclear whether being blown downwind is helpful or harmful to the seal pups, but the results offer a new insight into environmental effects on seal survival, according to the researchers.

“They’re at the whims of what’s happening in the environment of the North Pacific Ocean”, said Noel Pelland, a physical oceanographer and National Research Council postdoctoral associate at NOAA’s Alaska Fisheries Science Center in Seattle, Washington, who will present the new research today at the 2018 Ocean Sciences Meeting, co-sponsored by the Association for the Sciences of Limnology and Oceanography, The Oceanography Society and the American Geophysical Union.

Northern fur seals are among the most long-studied marine mammals because of their historical importance to the fur trade. They have been a staple food of native Alaskans for thousands of years and have been commercially harvested for their fur since Europeans arrived in Alaska in the 18th and 19th centuries.

In the new research, Pelland and his colleagues analyzed data from more than 150 seal pups equipped with tags that allow satellites to track their movements. The researchers compared the pups’ movements to models of wind speed and intensity in the North Pacific from 1997 to 2015.

They found differences in the prevailing winds aligned with where the pups ended up. During years when strong winds blew from the west, the pups ended up farther east, in the Gulf of Alaska, by about January 1. But in years where winds were weaker and came from the north, the pups ended up farther south, closer to the Aleutian Islands.

The researchers are unsure which scenario is better for pup survival, but the results confirm anecdotal evidence of seal migration behavior observed by native inhabitants of the Aleutian Islands, Pelland said.

In 1892, the U.S. Secretary of the Treasury sent Captain C. L. Hooper to the Aleutian Islands with instructions to gather as much information as he could about northern fur seals from the Aleuts who lived there and hunted them. The Aleuts consistently told Hooper seals always travel with a fair wind and disliked traveling against the wind.

“What’s cool is that with this project, we have this sophisticated technology that allows us this unprecedented look at the lives of individual animals, and what it allows us to do is quantify things that may have been known for millenia, by the people who’ve lived there and experienced this species”, Pelland said.

How Alaskan bears help plants


This video about Alaska is called The Land of Giant Bears.

From Oregon State University in the USA:

Great scat! Bears — not birds — are the chief seed dispersers in Alaska

January 16, 2018

It’s a story of bears, birds and berries.

In southeastern Alaska, brown and black bears are plentiful because of salmon. Their abundance also means they are the primary seed dispersers of berry-producing shrubs, according to an Oregon State University study.

The OSU team used motion-triggered cameras to record bears, birds and small mammals eating red berries of devil’s club, and retrieved DNA in saliva left on berry stalks to identify the species and sex of the bears. Researchers found that bears, while foraging, can disperse through their scat about 200,000 devil’s club seeds per square kilometer per hour. Rodents then scatter and hoard those seeds, much like squirrels hoard acorns.

The study was published today in the journal Ecosphere.

In most ecosystems, birds generally are thought of as chief dispersers of seeds in berries, said Taal Levi, an ecologist in OSU’s College of Agricultural Sciences and co-author on the study. The researchers found that birds accounted for only a small fraction of seed dispersal.

This is the first instance of a temperate plant being primarily dispersed by mammals through their gut, and suggests that bears may influence plant composition in the Pacific Northwest.

It was well-known that bears were dispersing seeds through their scat, Levi said, but it was not known that they were dispersing more seeds than birds, or the relative contribution of brown and black bears to seed dispersal, or whether the two species bears were eating berries at different times of the year.

“Devil’s club is extremely abundant in northern southeast Alaska, so it didn’t seem plausible that birds were dispersing all this fruit”, Levi said. “Bears are essentially like farmers. By planting seeds everywhere, they promote a vegetation community that feeds them.”

The researchers found that in the study area along the Chilkat and Klehini rivers in southeastern Alaska, brown bears dispersed the most seeds, particularly before salmon became widely available. They also found that after the brown bears switched from eating berries to salmon later in the season, black bears moved in and took over the role as principal seed dispersers. Black bears are subordinate to brown bears and avoid them.

The fruit on a devil’s club stalk is clustered into a cone containing berries. The researchers observed through the camera recordings that brown bears can swallow an estimated 350 to 400 berries in a single mouthful. Birds, on the other hand, consumed on average 76 berries per plant that they visited.

“That’s pretty remarkable,” Levi said. “When birds visit these shrubs, they take a few berries and fly off. They don’t eradicate the cones like a bear.”

Laurie Harrer, Levi’s co-author, swabbed devil’s club to retrieve environmental DNA from residual saliva left by animals and birds that ate the berries. Harrer, a master’s student in OSU’s Department of Fisheries and Wildlife, analyzed the samples to determine that female brown bears ate more berries than male brown bears, female black bears ate more than male black bears and brown bears ate more than black bears.

Brown bears, also known as grizzlies, are extinct in Oregon and California and are nearly extinct in Washington.

“The indirect effect of salmon is that they support abundant bear populations that then disperse a lot of fruit”, Levi said. “We’ve lost the salmon-bear ecosystem that once dominated the Pacific Coast. That has implications for the plant community. These seed dispersal pathways through brown bears are all but eliminated. The degree to which black bears can fulfill that role is not clear.”