Monday, June 11, 2018

Hawai`i data shows CO2 at record levels in atmosphere: and growing faster than ever


Annual CO2 growth rate. Source: NOAA, Scripps
Carbon dioxide levels in the atmosphere continue to grow at a record rate, promising that climate change will continue long beyond our lifetimes.

That's from data collected in Hawai`i—at the Mauna Loa Observatory, which has been collecting atmospheric CO2 data for 60 years. 

The Scripps release on the milestone is here.

In May, those levels reached a record high of 411.31 parts per million.

The latest tally was released last week by scientists from Scripps Institution of Oceanography at the University of California San Diego and NOAA.

And despite international efforts to control emissions, they appear to not be effectively under control. The level of emissions is not only continuing to grow, but it's growing faster. It was growing at 1.5-1.6 parts per million in the 1980s through 1990s, but during the past 10 years has been growing at 2.2 parts per million.

“Many of us had hoped to see the rise of CO2 slowing by now, but sadly that isn't the case. It could still happen in the next decade or so if renewables replace enough fossil fuels,” said Scripps CO2 program director Ralph Keeling, whose father Charles Keeling started the Mauna Loa CO2 program in 1958.

But while it's possible to reverse the growth trend in CO2, for species of all kinds, including humans, the future isn’t bright.

“Today's emissions will still be trapping heat in the atmosphere thousands of years from now.” Pieter Tans, lead scientist of NOAA’s Global Greenhouse Gas Reference Network.

With Kilauea volcano erupting continually for so long, many ask if that has a significant impact on atmospheric carbon dioxide. Researchers say it's clear that most of the CO2 change is from fossil fuel use, not the volcano.

And the proximity of Kilauea to Mauna Loa is also not a big factor. The high rate of growth in atmospheric CO2 is not only being observed at Mauna Loa but also at other sites in NOAA’s Global Greenhouse Gas Reference Network.

© Jan TenBruggencate 2018

Thursday, June 7, 2018

Rats can open a window on ancient island environments


It may be hard to think of something rats are good for, but a team of scientists has figured out a unique way to look into the history of Pacific islands—using rats.
(Image: A Pacific rat, Rattus exulans, in a New Zealand government photo.)

They looked into the bones of rats from ancient archaeological sites, and it turned out that they could extract information from the marrow of rat bones. They were able to figure out what the rats were eating over time, and from that, make assessments about the changing island environment.

A new study on this work was just published in the Proceedings of the National Academy of Sciences. The authors are Jillian Swift, Patrick Roberts and Nicole Boivin of the Max Planck Institute for the Science of Human History, and Patrick Kirch of the Univeristy of California-Berkeley Department of Anthropology. The paper is entitled "Restructuring of nutrient flows in island ecosystems following human colonization evidenced by isotopic analysis of commensal rats."

Some definitions: Isotopes are forms of the same element that have different numbers of neutrons in the nuclei. Isotopic analysis in this instance is studying changes over time in the mix of isotopes of certain elements—in this case carbon and nitrogen. And commensal means living with something, without causing it any particular help or harm—in this case rats living among humans.

When early Polynesians arrived on Pacific islands, they almost always brought Pacific rats with them. People argue over whether that was intentional or not, but it almost always happened. Pacific rats, or Polynesian rats, are Rattus exulans.

And those rats quickly went out on their own, foraging initially in the virgin environment, and later in the environment that humans had created through bringing new plants, slash and burn agriculture and so forth.

"Stable isotope analysis of commensal animals provides an effective proxy for local human environments because these species are closely associated with human activities without being under direct human management," the authors write.

They studied rat bones from archaeological sites in three Polynesian island areas: Mangareva, Ua Huka in the Marquesas and Tikopia far to the west.

They found that their study of rats was able to track dramatic changes in local environments, demonstrating "human land use, intensification and faunal community restructuring."

More specifically, "Our results highlight the large-scale restructuring of nutrient flows in island ecosystems that resulted from human colonization and ecosystem engineering activities on Pacific islands."

This is complicated stuff, and I won't go into details on how the lab work was done, but you can look it up yourself here.

This is data that the authors say is hard to get from standard analysis of early archaeological remains, and it suggests that this kind of stable isotope analysis can help shed more light on how and how quickly humans changed their environments after arriving on Pacific islands.

It is also true that the rats themselves did a lot of that modification of ecosystems—eating birds and insect and seeds and seedlings. But that's all part of the story, since it was humans who brought the rats to these new environments.

© Jan TenBruggencate 2018

Sunday, May 13, 2018

Dying `Ōhi`a: Lots of research, perhaps some hope







Dead `ohi`a with live trees and uluhe.
Credit: DLNR
Lots of news organizations spread word that a variant of the Rapid `Ōhi`a Death fungus has been found on Kaua`i, but none told the larger story.

That story is the powerful effort that’s going on to save the tree that has been called the mother of the forest.

`Ōhi`a is really a remarkable part of the Hawaiian environment, growing in many environments from sea level to high mountains, and in many cases serving as the dominant canopy tree.

It feeds and houses insects. Those insects and the tree’s nectar feed birds. And it houses birds, both in its branches and in cavities in its trunk.

It is prominent in culture, common in legend, and it’s just plain gorgeous with its crimson and orange puffball flowers and widely varying leaf types. Buds can be reddish or orange or green, and shiny or covered with a frost of silver hairs.

“It is the foundation tree of our watershed,” said Bob Masuda, deputy director of the state Department of Land and Natural Resources.

As a community we despaired when there arrived a fungus, Ceratocystis lukuohia, which began killing trees by the thousands on Hawai`i Island. Many trees were infected and once infected, death was certain often in days to weeks. It was sometimes called `Ōhi`a Wilt, and sometimes more dramatically, Rapid `Ōhi`a Death.

It turns out that a small percentage of trees was also infected with a slower-developing related fungus, Ceratocystis huliohia. It could take months to years to kill a tree, often taking single branch systems before killing off the entire tree. 

That’s the one that has now been found on East Kaua`i. Not nearly as virulent as its spooky cousin, but still a problem for `ōhi`a. Foresters suggest it probably shouldn’t be called Rapid `Ōhi`a Death, because, well, it doesn’t progress so rapidly.

Both are examples of something called a vascular wilt—a fungus that clogs the tree’s ability to transfer water between roots and leaves


There are some interesting things about these diseases, including that they appear to have very different sources. The fast-acting one is most closely related to fungi in Latin America, while the slower one appears to be more closely related to Asian fungi.

And the slower-moving version may spread slowly enough that it was in the Hawaiian Islands first, but wasn’t recognized. There are lots of things that can kill `ōhi`a trees, lots of disease that can attack them—although none as aggressive as Ceratocystis lukuohia.

One of the big unanswered questions about both diseases is whether there is hope. Whether there are any examples of `ōhi`a trees that may be resistant—and thus could be used to repopulate the Hawaiian forest.

To help find that out, lots of research is underway, including aerial surveys on several islands to better understand the outbreak. Here’s one study on the aerial monitoring from the journal Remote Sensing

Pathologist Lisa Keith, of the USDA Pacific Basin Agricultural Research Service, said that researchers are growing seedlings of different varieties of `ōhi`a and infecting them with the fungus. So far, some are still surviving—perhaps a good sign, although they may just be heading downhill slower than others.

She and others are also working with different fungicides, which may not save an infected tree, but might keep a particularly valued tree alive longer. Others are working with other techniques to try to strengthen the trees so they can potentially survive infection.

It’s clear that humans are big carriers. If a tool like an ax, chain saw or machete cuts an infected tree, it can easily spread the disease if you cut into a second tree without disinfecting the tool. Any injury to the tree can be a highway for infection.

Scientists are studying the beetles that may be spreading the disease by boring into the trees.

And they’re trying to determine how effective the fungus is at being spread by wind.

And what if it’s not just those beetles, but other insects. Researchers have chunks of infected tree wood in netted containers, to watch what other insects might emerge over time.

If the disease is spread by wind, then perhaps you could limit the spread by cutting down a swath of trees downwind from an infected patch, to deny the fungus trees to spread to. Kind of like cutting a firebreak.  The state Division of Forestry and Wildlife is working on that technique.

Researchers are studying old photographs of the forest to try to determine what they can about disease in `ōhi`a over the years.

And scientists have developed quarantine measures to reduce the spread—like limiting the movement of infected wood.

The number of organizations working on this issue is impressive. It includes the University of Hawaiʻi at Mānoa College of Tropical Agriculture and Human Resources, the U.S. Pacific Basin Agricultural Research Center, USDA Forest Service Institute of Pacific Islands Forestry, the Department of Land and Natural Resources’ Division of Forestry and Wildlife, University of Hawaiʻi at Hilo, The Nature Conservancy, National Tropical Botanical Garden, Hawaiʻi Association of Watershed Partnerships, Coordinating Group on Alien Pest Species, the Big Island, Maui, Molokai, O'ahu and Kaua'i Invasive Species Committees, USFS Region 5 State and Private Forestry, USGS Pacific Island Ecosystems Research Center, Carnegie Airborne Observatory,  Hawai'i Invasive Species Council and Hawai`i Department of Agriculture -Plant Quarantine Branch.


A sign of hope is that not every tree in a diseased stand dies. But it’s not yet clear whether that’s because surviving trees might be resistant to the disease, or that they simply haven’t been infected yet.

That said, the `ōhi`a is so important to the Hawaiian environment that researchers and foresters hope to be able to identify resistant trees.

If they can find them, then the daunting task will be a massive statewide effort to replant these seminal trees throughout the Hawaiian forest.

© Jan TenBruggencate 2018


Friday, March 23, 2018

Vampire Mice II: Mice changing diet, growing bigger as they attack giant seabirds


 Laysan albatross with mouse injury. Credit: USFWS.
Like characters in some horror movie, house mice are moving up the food chain and getting bigger.

They’re feeding on chicks and now adult seabirds, leaving hundreds of three-foot-tall albatrosses bleeding from their necks, heads and backs, like victims in a vampire flick.


In one case, they are also changing in size—nearly doubling in mass on one Atlantic island where they aggressively eat seabird chicks.
The lowly mouse, Mus musculus, has always been an omnivore, but they’ve never had the reputation of rats as attack rodents. That is changing on islands around the world.

The latest spooky change in their level of aggression came on  a remote Hawaiian Island: Sand Island at Midway Atoll at the remote western end of the Papahānaumokuākea Marine National Monument, which takes up all of the Northwestern Hawaiian Islands and considerable square mileage of the surrounding waters.

On Midway, mice are biting the necks of adult Laysan albatross, chewing down skin and fat and muscle, and drinking blood.  Hundreds of the big birds have been found dead, and more hundreds of abandoned nests suggest other injured parent birds may have died at sea.

Night video of the nesting areas show the tiny gray mice climbing the backs and necks of the albatrosses, repeatedly sipping at gaping wounds they have chewed into the birds’ bodies.

Mice going after big adult birds at Midway started out of the blue in 2015, and this was new. This was another step, something not seen before anywhere. Wildlife officials are now studying ways to wipe out the mouse population, before the predation gets worse.

We wrote about this at Raising Islands here

Efforts to control predation on important seabird nesting islands has previously mainly focused on rats—mainly Pacific rats and black rats, which are also known as roof rats and ship rats. But in the past two decades, mice have stepped up as serious predators of seabirds.

Mice have been caught attacking soft chicks and eggs on bird nesting islands for some time. Here is a Live Science piece on attacks at other islands. 

On Gough Island in the South Atlantic, game cameras recorded swarms of mice attacking nestlings of Tristan albatross (Diomedia dabbenena,) great puffins (Puffinus gravis) and Atlantic petrel (Pterodoma incerta.)

“One video showed up to 10 mice mauling an albatross chick and eating from three open wounds on its body,” wrote Live Science writer Jeanna Byer in 2007.
Puffins and petrels are smaller seabirds, the size of mynah birds or pigeons. Albatrosses, which can be three feet tall with wingspans of six to 11 feet, are huge.  A mouse standing up might reach four inches in height. In climbing an albatross, they are climbing a bird nine times taller than they are.
The authors of a 2012 scientific paper in Animal Conservation on that situation wrote: “mice cannot be ignored as a potential threat to island fauna, and island restoration and management plans should routinely include eradication of introduced mice.” 

Injured albatross at Midway in colony. Credit; USFWS.
A 2016 piece in Smithsonian suggests that mice, fed on a rich diet of seabird flesh, are actually changing in size—getting huge. 

They are nearly twice the weight of standard house mice. The standard house mouse is tiny, weighing only about 16 to 25 grams. On Gough, the average mouse runs more than 35 grams.

“They’re the largest and heaviest mice anywhere in the world,” said Richard Cuthbert of the Wildlife Conservation Society.

Cuthbert was the lead author of a 2016  Journal of Mammalogy  article that suggested that the bird diet is a primary cause of the change in mouse size. 

Of course it is not only adult birds that mice attack when they get established on islands. 

Wildlife officials in New Zealand have noted mice killing not only seabird chicks but native lizards, seedlings and bird eggs. New Zealand has removed rats and mice from several offshore islands.

© Jan TenBruggencate 2018

Thursday, March 22, 2018

Vampire mice killing hundreds of Laysan albatross on Hawaiian island of Midway


Bloodied albatross. USFWS photo.
The mysterious vampire mice of Midway Atoll have left hundreds of adult Laysan albatross dead, their necks torn open in garish bloody wounds.

These mice are doing something no mice anywhere else in the world are known to do.

Late at night, they climb the necks of nesting seabirds and chew through the skin, apparently feeding on the birds’ blood, skin, fat and muscle.
The albatross’ commitment to protecting their eggs is so strong that they will shake their heads, but will not leave the nests even with a predatory rodent chewing on them.

And the problem has grown since it was first spotted in 2015.

Wildlife officials assess injured Laysan albatross. Credit: USFWS
“It is horribly destructive what they do to those birds,” said Matt Brown, the U.S. Fish and Wildlife Service superintendent for the Papahānaumokuākea Marine National Monument, which includes Midway.

The Fish and Wildlife Service has teamed up with a number of agencies and now hopes to eradicate the mice, which are an alien species to Midway. Among the 10 major atolls, reefs and islets of the Northwestern Hawaiian Islands, mice only occur on Sand Island, one of the three specks of dry land within Midway Atoll.

The mice have been here at least since World War II, but the new vampirish behavior is both new to Midway and apparently new to science. Mice are known to take eggs and nestlings of seabirds elsewhere, but only on Midway do they attack large adult birds.

“This isn’t a behavior that has been observed before, although rodents have been responsible for a number of seabird extinctions and extirpations on islands,” said Megan Nagel, public affairs officer for the Fish and Wildlife Service in Honolulu.
A Fish and Wildlife Service fact sheet quoted Midway Atoll Refuge manager Bob Peyton: “The Service is working against the clock to determine how many birds have been attacked, what the rate of spread is, and how to stop the attacks. Albatrosses lay only one egg a season.” 

The proposal they’ve come up with is to try to eradicate the mice. New Zealand just completed a successful five-year effort to remove mice from the Antipodes Islands, where they were feeding on chicks and eggs of seabirds, apparently including the Wandering Albatross, whose 10 to 11-foot wingspan makes it one of the biggest of birds. 

The Midway approach will be similar to the one used at the Antipodes: a helicopter drop of toxic bait pellets during a period when the nesting seabird population is at its lowest.  That’s also similar to the technique that has been used to remove mice from more than 80 other islands and to remove rats from more than 400 islands around the world.

In Hawai`i it’s much like the system that was used to eradicate Pacific rats from Mokapu Island off Molokai and black rats from Mokoli`i off O`ahu, and which has been used to control rats at Lehua Island off Ni`ihau, a process that is still underway.
Rats were eradicated from Midway’s three islets in 1996.

The environmental assessment for the Midway mouse effort, under the name Midway Seabird Protection Project, describes the issues and the proposed solution. The public comment for the environmental assessment is open through April 20.

The helicopter would achieve a uniform islandwide distribution of specially designed bait pellets that contain the anticoagulant Brodifacoum. Some hand distribution will be employed in sensitive areas such as near the shore. The work would be done in the summer of 2019, during a period when seabirds are comparatively scarce on the island, and when dry weather limits mouse food supplies—making the grain-based bait pellets more appealing.

There are a number of reasons to use a helicopter, including assuring an even bait distribution but also foot traffic in many areas would collapse many of the thousands of nesting burrows of Bonin Petrels, which recovered strongly after rats were removed.

Similar eradication efforts on other islands have usually but not always been successful. In recent years, the success rate has gone up with improvements in technique. The environmental assessment reviews alternative approaches, and looks at the option of doing nothing at all.  The Brodifacoum bait delivered by helicopter at the right time of year, in specific amounts over time, as described in the proposal, is viewed as the best alternative.

The project is estimated to cost $3.5 million. It is not yet clear the source of that money. Many previous eradications have been funded through a combination of government funds, grants from foundations, and money from private institutions like conservation groups.

The Fish and Wildlife Service would be the lead operational agency, with technical support and assistance from Island Conservation and the Midway Restoration Partnership Group. This is a collaboration of the Fish and Wildlife Serfvice and Island Conservation as well as American Bird Conservancy, the National Wildlife Research Center of the U.S. Department of Agriculture’s Animal and Plant Health Inspection Service, National Oceanographic and Atmospheric Agency, U.S Geological Survey and the state Office of Hawaiian Affairs.

© Jan TenBruggencate 2018
What's at risk :Midway albatross colony. Credit: USFWS.