Tuesday, June 11, 2019

Controlling rats doubles `elepaio nesting success, and other conservation success stories

Hawai`i `elepaio, Image: Kelly Jaenecke, USGS

A new study, published this year in the journal The Condor, found that removing black rats from a forest environment quickly improves the ability of the native `elepaio to bounce back.
It is part of a growing body of evidence that removing rats from environments where they are not native can significantly improve bird survival and forest recovery. 
And unexpected benefits can happen. As when black rats were removed from Palmyra Atoll. While it was mainly intended to protect seabirds and native crabs, the removal also wiped out the Asian tiger mosquito, Aedes albopictus, which carried disease. It turned out the mosquitoes needed the rats as a blood source.
And with rats gone, suddenly the Palmyra forest floor burgeoned with seedlings of native trees.
The new `elepaio study is entitled, "Increased nesting success of Hawaii Elepaio in response to the removal of invasive black rats." You can find it here. Authors are Paul C. Banko, Kelly A. Jaenecke, Robert W. Peck and Kevin W. Brinck.
It's not news that rats are toxic to the natural environment in the Islands. They eat everything--seeds, seedlings, eggs, adult birds, insects and lots more. What's new here is clear proof of the direct impact on one important deep forest species.
"In Hawaii and other oceanic islands with few native land mammals, black rats (Rattus rattus) are among the most damaging invasive vertebrate species to native forest bird populations and habitats, due to their arboreal behavior and generalist foraging habits and habitat use," the authors wrote.
There are models that suggest that growth rates for native bird species populations should respond well to removing rats, but there hasn’t been a lot of evidence—mainly because that evidence is hard to get. Many of the critical native forest birds are rare, their nests are hidden and hard to observe and they can be high in trees.
One reason black rats are a special problems is that they climb trees, and will take females and eggs right off the nest. There are wildlife video images of it.
"Lower female survival rates have been attributed to nest predation by rats for a number of Hawaiian species," the authors write.
"Hawaiian forest bird nesting studies have indicated that rats are an important cause of nest failure for at least the Oahu Elepaio in lowland mesic forests dominated by invasive fruit-bearing tree species and for the Puaiohi in wet montane ‘ōhi‘a forests." O`ahu `elepaio are known to science as Chasiempis ibidis, and puaiohi or small Kaua`i thrush as Myadestes palmeri.
In the paper's study, researchers used rodenticide to reduce rat populations by 90 percent in two Hawai`i Island forest areas, each 120 acres in size, along the Mauna Loa Strip Road in Hawai`i Volcanoes National Park. They also trapped rats, catching thousands of them.
Their finding: Once the rat populations were reduced, for the Hawai`i puaiohi or Chasiempis sandwichensis, nesting success doubled, from 33 to 62 percent, and female survival also increased dramatically.
"The rapid response of Hawaii Elepaio to rat removal indicates that predator management could be a powerful tool for restoring the entire forest bird community. Hawaii Elepaio are representative of other forest bird species because they nest in a variety of widespread, abundant tree species and they build their nests throughout the forest canopy," they wrote.
And one of the benefits of keeping the bird numbers elevated, they argue, is to give the species time. Time to evolve natural resistance to one of the other critical threats, mosquito-borne avian malaria.
It's good news for conservation. 
Another bit of positive news from a couple of years ago was that native forest birds like the `elepaio quickly inhabit newly established native forest areas.
It's another case of, if you build it, they will come.
© Jan TenBruggencate 2019

Thursday, June 6, 2019

Bee swarm visits, leaves a pristine waxen gift

Itʻs June and that means the beehives are overfull with bees--swarm season.

Iʻve had two swarms come through my yard this week. One took up residence in an old empty hive box, but the other was just passing through.

A basketball sized bunch of bees hung under a loulu palm frond for a few hours this morning.
They were not aggressive. I could walk right up and photograph them. 

And then they seemed to get message--perhaps scout bees had found a likely home. 

A bunch of them left the clump and swirled up into the air. And then the swarm came apart, fist-sized clumps of bees falling off and flying up into the air.

They swirled up in a great buzzing storm, right above the palm tree on which they had perched.
The cloud of bees began extending itself to the south, and in another minute, they were gone.

Swarm hangs under loulu frond
The only evidence that they had been there was a cell-phone-sized pristine white wax comb.

Swarm starts to break up, leaving the palm.

All the remains is a bit of wax comb.

Friday, May 24, 2019

Walking isnʻt just for your heart any more. Also the liver, the brain, diabetes...

The link between exercise and heart health is will understood, but new data suggests other organs, notably the liver, also benefit, and dramatically.

This doesnʻt mean you need to run marathons or go to other physical extremes. Walking is sufficient to reduce risks pretty dramatically.

The Harvard Medical School makes the point clearly: "Walking improves cardiac risk factors such as cholesterol, blood pressure, diabetes, obesity, vascular stiffness and inflammation, and mental stress.

"And if cardiac protection and a lower death rate are not enough to get you moving, consider that walking and other moderate exercise programs also help protect against dementia, peripheral artery disease, obesity, diabetes, depression, colon cancer, and even erectile dysfunction."

The article that quote comes from is a valuable lesson for the sedentary. 

The latest bit of data to support going out on regular hikes is a study that looked at 26 years of data on the exercise habits of 117,000 people. Thatʻs a big study.

The study notes that cirrhosis of the liver is increasing along with the nationʻs obesity crisis, but that regular exercise, like walking, can reverse the trend.

"Our findings show that both walking and strength training contribute to substantial reductions in risk of cirrhosis-related death, which is significant because we know very little about modifiable risk factors," said Dr. Tracey Simon, of Harvard Medical School and lead researcher on the study, which was  presented at a conference of Digestive DiseaseWeek

Their study found that those in the top fifth in terms of amount of walking reduced their likelihood of cirrhosis-related death by 73 percent. And those who added strength training cut their risk even more.

Simonʻs study was published in the May 2019 edition of the journal Gastroenterology.  Her co-authors were Edward Giovannucci, Kathleen E. Corey, Xuehong Zhang and Andrew T. Chan. The paper is entitled: Physical activity, including walking and strength training, are associated with reduced risk of cirrhosis-related mortality: Results fromtwo prospectice cohors of U.S. men and women.

They followed 68,000 women and 49,000 men in the Health Professionals Follow-up Study, who reported their walking, other aerobic activities and resistance exercise over a period from 1986 to 2012. And they looked at the ones who died during the period, and whose deaths were attributable to cirrhosis.

"Compared to adults in the lowest quintile of physical activity, those in the highest quintile had a 73% lower risk for cirrhosisrelated death," the report said.

The authors said thereʻs still need for more research into the best kind of exercise, amount of exercise and intensity of exercise. But it seems clear that getting out and moving it has significant benefits for long-term health.

© Jan TenBruggencate 2019

Tuesday, May 21, 2019

Forget 3 feet, Hawaii should be planning for 6 feet of sea level rise, new research says

Melting Greenland ice sheet. Credit: NOAA
Hawai`i may be planning for only half the sea level rise that is possible within the lives of todayʻs newborns.

A new study from British, American, Dutch and German climate researchers argues that sea levels could be more than 6 feet higher than now in 80 years, wiping out many of the worldʻs most important cities and coastlines.

Many of those coastal areas would be inundated far sooner than that. That includes much of Honolulu. 
Most of the worst-case planning in Hawai`i assumes a 3-foot or one-meter rise, but this study suggests we should be planning for twice that.

One planning organization in the Islands, Honoluluʻs city Climate Change Commission, is on board with the 6-foot recommendation by 2100. Commisson member Victoria Keener said 3 feet is possible much earlier, by mid-century.

The authors of the new paper are cautious about their numbers because the science is very complex. But they say that if the worldʻs great ice reservoirs—the immense Greenland and Antarctic ice sheets—melt as many climate models suggest, the world will be a very, very different place.

Imagine all cargo needing to be offloaded from ships at anchor, because all the harbor facilities are submerged. Imagine the most valuable property in Hawai`i underwater. Imagine no coastal road access—meaning many Hawaiian communities could be reached only by boat.

Part of the problem is that many researchers have been focused on keeping warming to 2 degrees Centigrade, but warming of as much as 5 degrees by the end of the century now seems possible. That is because fossil fuel use is rising instead of falling, global carbon dioxide levels are rising at faster pace rather than stabilizing, and the global ice sheets canʻt help but respond by melting.

The authors of this daunting report are some of the worldʻs premier researchers. They include Jonathan L. Bambera of the UKʻs University of Bristol School of Geographic Science, Michael Oppenheimer of Princeton University, Robert E. Kopp of Rutgers University, Willy P. Aspinall of the University of Bristol School of Earth Sciences, Roger M. Cooke of the Dutch Delft University of Technology Department of Mathematics. The paper was edited by Stefan Rahmstorf, of Germanyʻs Potsdam Institute for Climate Impact Research. They consulted with climate scientists in America and Europe.

It is entitled, " Ice sheet contributions to future sea-level rise from structured expert judgment," and was published this week in PNAS, the Proceedings of the National Academy of Sciences.

The authors are cautious, but they are clear that the world should stop focusing on the lower range of sea level rise estimates. Many nations are already planning and building structures to protect their shorelines from near-term sea level rise.

"Adaptation measures accounting for the changing hazard, including building or raising permanent or movable structures such as surge barriers and sea walls, enhancing nature-based defenses such as wetlands, and selective retreat of populations and facilities from areas threatened by episodic flooding or permanent inundation, are being planned or implemented in several countries," the authors write.

But it might not be enough.

"Our findings support the use of scenarios of 21st century global total (sea level rise) exceeding 2 m for planning purposes," they write. That translates to more than 6 feet, at the upper level of the estimates.

It doesnʻt stop there. Temperatures at those levels will progressively melt ice sheets, and the world in 2200 could see as much as 7.5 meters in sea level rise above todayʻs levels, the authors say. That represents a 25-foot rise.

Many of the best estimates of sea level change before now have not included the impacts of the ice sheets, because they are so extraordinarily difficult to model. They have not gotten easier to model, but both the Antarctic and Greenland ice sheets have been losing mass at an increasing rate, and the authors say melting ice sheets have now exceeded mountain glaciers in their contributions to sea levels.

In response, there has been "a focused effort by the glaciological community to refine process understanding and improve process representation in numerical ice sheet models." As scientists learn more, they also learn how much they still donʻt know, and the uncertainty about the future rises, the authors said.

The most common estimate of 1 meter of sea level rise by 2100 comes from the 5th International Panel on Climate Change report from 2013. Numerous studies since then have indicated that its estimates are significantly too conservative, and that temperatures and sea levels are rising and are expected to continue rising far faster than that study estimated.

Is there enough water on Earth for sea levels to rise as much as they suggest? There is. NOAA and others have calculated that if all the planetʻs ice melted, there is enough water and ice to increase sea levels by more than 200 feet. National Geographic mapped what that might look like. https://www.nationalgeographic.com/magazine/2013/09/rising-seas-ice-melt-new-shoreline-maps/

But much of the polar ice would remain frozen, so such catastropic sea levels are unlikely.

Still a possible 6-plus feet by 2100 is catastrophic enough for a coastal state like Hawai`i, and it is a level that most planning has not considered.

The Hawai‘i Climate Change Mitigation and Adaptation Commission last year recommended government and other agencies plan for 3.2 feet or 1 meter of ocean rise.

The Hawai`i Sea Level Rise Vulnerability and Adaptation Report of December 2017 also targets that level, but indicates it could come far earlier than 2100: "this magnitude of sea level rise could occur as early as year 2060 under more recently published highest-end scenarios." Thatʻs only 40 years out.

Some of the most aggressive estimates have come from the City of Honoluluʻs Climate Change Commission, which last year adopted numbers closest to those suggested by the new paper. That recommendation, adopted by the City, recommends the 6-foot number be used in planning for projects with long lifespans. Its sea level rise guidance is here.

You can view the impacts of 3 feet of rise a this site from the University of Hawai`i School of Ocean and Earth Science and Technology: 

There is extensive information on sea level rise in the Islands at the Pacific Islands Ocean Observing System website: 

© Jan TenBruggencate 2019

Sunday, May 19, 2019

Higher, Hotter, Faster, More Acid: Climate Change is Speeding Up

The Mauna Loa Keeling Curve, which indicates how much carbon-dioxide is in the atmosphere, has crossed into new high territory—more than 415 parts per million.

But perhaps more dangerously, the rate of rise has locked in a new trajectory—meaning itʻs going higher faster.

Climate researchers are seeing all the secondary impacts of that—rising temperatures, rising seas and rising ocean acidity are also going up.

Climate change is coming far faster than we ever anticipated. It used to be that activists could guilt us by saying we were leaving a climate mess to our grandchildren. But it appears most of us will see dangerous changes not in our grandchildrenʻs lifetimes, but in our own.

The Keeling Curve is a measurement that started being taken at Hawai`iʻs Mauna Loa Observatory in 1958 by Charles Keeling, and it has been taken steadily since then. It is a jagged line because the amount of CO2 in the atmosphere goes up and down with the seasons. But the overall path has been up.

And more worrisome, it is angling steeper with time. We have long known that an atmosphere with higher CO2 and other greenhouse gases traps more heat than one with lower levels.

The image to the upper right is from the latest Keeling Curve (May 18, 2019) from the Scripps Institution of Oceanography, University of California at San Diego. The colored lines are my alteration, showing how the trajectory has changed. The lower orange line is the rate of rise during the 1960s. The upper red line is the rate of rise during recent years. 

It means weʻre still dumping fossil fuel emissions into the atmosphere, and despite all the talk about conservation and efficiency and renewables and electric cars, weʻre doing it at an increasing rate.

Is there a statistic for that? Of course there is. World oil production 50 years ago—when the Keeling Curve was young—was way under 50 million barrels a day. Now itʻs 100 million barrels a day, and rising. 
Temperatures are going up with the increased production of greenhouse gas. If you look at this NASA chart, and check the graph from 1960 onward, you can see that temperature trends follow the Keeling Curve. The source of this graph is this NASA site

Live near the ocean? In Hawai`i we all do. If itʻs not your home that will be threatened, it may be your work place, but it will certainly be your beach park and your coastal roadway. Like temperatures, sea levels are rising and seem to be rising faster in recent years.  

If you look carefully, youʻll see that it also has that increasingly upward slant in recent years, suggesting that sea levels are coming up way faster than it seemed they would a few years ago.

Ocean acidity changes the fundamental chemistry of the seas. Increasing acidity dissolves the shells of marine mollusks, weakens reefs and has all kinds of other global impacts. The acidity of the ocean is rising, along with sea levels and temperatures and carbon-dioxide.

Here is a great resource, aimed at students in grades 10-12, on understanding the chemistry and impacts of acidification of our seas. 

So with all that additional carbon-dioxide in the atmosphere, some of it dissolves into the ocean. Here's an EPA graph from 2016 showing carbon dioxide dissolved in ocean water in Hawai`i, Bermuda and the Canary Islands. And here's where that came from, another resource for students. 

Scientific American reviewed some of the latest data, which indicates that climate change is coming faster than was anticipated. It’s a sobering outlook. 

It can be useful to remember that every time you take a trip to the West Coast or Vegas, your portion of the fuel required represents roughly a full 55-gallon barrel, and burning it produces about half a ton of carbon-dioxide.

Every time you take an extra drive to the store, or fly to another island to shop, or go cruising in your pickup, you're choosing to add to the problem.

© Jan TenBruggencate 2019