Wednesday, May 27, 2015

Hurricanes this year a near slam dunk: Be ready

NOAA’s Central Pacific Hurricane Center is predicting an El Nino this summer, and that means a much higher chance of hurricanes in our part of the Pacific.

And we’re due. More on that later.

(Image: This is a satellite image of the eastern Pacific from today, May 27. The storm system with the red X shows strong signs of developing into a more powerful storm. Credit: NOAA.)

This year, the NOAA numbers make hurricanes a statistical slam dunk. Nearly 20-1 odds that we’ll see big storms before December.

That’s not a guarantee, but the odds are looking spookier for hurricanes than they have in a very long time. 

The part of NOAA’s package of statistics that is most concerning is not so much that we are likely to have a more active hurricane season. They predict that in any El Nino year.

What’s concerning this year is that there’s only a 5 percent chance of a less-than active hurricane season. And a 95 percent chance of a normal to higher season. That’s weighted strongly (70% to 25%) in favor of more than normal.

Although the average year sees 4 to 5 tropical depressions, tropical storms and hurricanes in our part of the ocean, there have been years when there have been virtually none. And we’ve been quiet for what seems like a very long time.

The last time the state took a direct hit was Hurricane Iniki in 1992—23 years ago.

Before satellites, it was hard to identify major storms in the Pacific unless a ship ran into one, or it hit an island. But in terms of storms that have caused damage, there were Nina in 1957, Dot in 1959, Iwa in 1982, Estelle in 1986, Iniki in 1992.

That’s five big storms in 35 years, or one every seven years on average.

And the longest time between them was Dot to Iwa, 23 years. Same as the time from Iniki to 2015.

This may be the year to pay attention. Says NOAA:

“This outlook is based upon the expectation of El Niño continuing and possibly strengthening as the hurricane season progresses. 

“El Niño decreases the vertical wind shear over the  tropical central  Pacific, favoring the development of more and stronger tropical cyclones. 

“El Niño also favors more westward tracking storms from the eastern Pacific into the central Pacific.

“This combination typically leads to an above-normal Central Pacific hurricane season.”

The Central Pacific Hurricane Center  is careful to say it can’t guarantee one or more of those storms will actually hit the Islands, but it does encourage families to sign up for emailed weather alerts, to sit down and talk about what they’ll do in the event of a storm, and to put together a hurricane kit. 

If you have a phone book, there are instructions in the front pages. If not find hurricane preparedness tips online.

You can join NOAA’s central Pacific hurricane page on Facebook 
Oh, and while the hurricane season doesn’t start until June 1, there is already a weather system headed this way. See the image above.

It’s still off Mexico, but has an 80 percent chance of developing into a tropical depression in the next two days, and 90 percent in the next five days.

© Jan TenBruggencate 2015

Tuesday, May 26, 2015

Superweeds and pesticide resistance in Hawai`i

The diamondback moth, a major pest of Hawaiian watercress, cabbages and other crucifers, has repeatedly developed resistance to pesticides used to control it.

There has been a lot of discussion in the Islands about weeds gaining resistance to pesticides used on genetically modified crops, but pesticide resistance has been an issue for farmers since long before genetic modification became prevalent. 

(Image: Diamondback moth larvae feeding on cabbage. Credit: Doug Wilson, USDA.)

Almost every pest control method—organic and synthetic pesticides, and even cultural techniques like crop rotation, have been defeated by persistent pests. 

The message of pesticide resistance is that there’s no magic bullet. Farmers need to use a range of techniques to control their pests—they can’t simply count on a single chemical spray to solve all the problems.

In the case of the diamondback moth, Plutella xylostella, it became resistant to pyrethroid pesticides in Hawai`i in 1992, and when farmers switched to using another natural pesticide product, Bacillus thuringiensis, the bugs began developing resistance to it in three years.

And not just in Hawai`i—the resistance appears everywhere

Farmers have switched to other pesticides and have fine tuned their applications to try to defeat it, but are increasingly depending on biological controls—other insects that feed on the various life stages of the moth. Researchers are looking at increasing the effectiveness of viruses that attack the moths, and there's some genetic modification of moths underway in hopes of improving control.

But with respect to pesticide use, there’s still a concern, as consumers insist on food crops that look nice: “In food crops where damage to vegetables must be minimal, chemical control has not been eliminated by biological control,” wrote Ronald F.L. Mau and Jayma L. Martin Kessing of the University of Hawai`i at Mānoa.

How pesticide resistance develops is pretty simple to explain. In every population, there are a few individuals that will be tolerant of a new pesticide—will survive it. The few who survive will be the only ones to reproduce—and their offspring are far more likely to be tolerant. Soon, if you keep using the pesticide, most of the population will be resistant to it and your bug spray will no longer be effective.

Resistance is found for fungicides, insecticides and herbicides as well as for some cultural techniques. There is a bug that responded to farmers switching to a different crop every other year, by going dormant for the intervening year so they’d be ready when the original crop was again available.

But while pests are resilient, so are farmers. There are numerous techniques to overcome pesticide resistance.

“Growers can help delay the development of resistance by applying pesticides only when they are needed, by rotating between different chemical classes, and by using rates of pesticides within the labeled range. Integrating non-chemical approaches such as pheromone mating disruption and cultural controls can also help delay resistance,” wrote the authors of Fruit Crop Ecology and Management, a publication of Michigan State University. 

So, some of the techniques to combat resistance:

Use pesticides that biodegrade rapidly, so subsequent generations of pests aren’t exposed and don’t further increase resistance.

Use combinations of pesticides—some may be resistant to one or the other, but few to both.

Plant “sacrificial” crops—either in nearby fields or even every other row—so there are always non-resistant bugs for resistant bugs to mate with, reducing the overall resistance. Alternatively, leave some areas untreated.

Learn more about the pests and use a tighter target—in the case of a bug, attack only a specific life stage rather than trying to kill the larvae, the adults and the rest all at once.

Experiment with non-pesticide techniques to reduce bug numbers—remove plants they require to complete their life cycle, rotate crops to reduce buildup of crop-specific pests, use baits and attractants to draw pests away from the crops.

And there are other techniques. 

One that doesn’t work well is a homeowner’s solution of simply using more pesticide in hopes of getting ALL the pests.

“Deceptively reasonable on first inspection, this approach rarely works in practice. The reason is that pesticide residues are usually deposited very unevenly in most field situations, even when very high rates are used. Uneven deposition of pesticides allows resistant pests to survive in greater proportions than susceptible pests, thereby increasing resistance,” says Washington State University’s online pamphlet on pesticide resistance. 

The popular press likes to write about Roundup-resistant "superweeds." But they are, of course, not super in any way other than Roundup resistance. They're still susceptible to mulching, to other herbicides, to hoes and mowers, and to techniques that restore their Roundup sensitivity.

Pesticide resistance is not the end of the world—but its management is a significant and normal part of modern farming. 

The Washington State paper says integrated pest management, including moderate, targeted pesticide use, has been shown to work. Key missions for the farmer, Washington State says:

They must monitor pests regularly, carefully manage (not overuse) their treatments, and “make full use of nonpesticidal methods, such as biological and cultural control, sanitation and host plant resistance.”

The whole issue of resistance is complex—stacks of scientific papers and many very dense books have been written about it. Included above are just a few insights into the issue.

Missouri farmer Blake Hurst was quoted in the New York Times:

"The war between man and weed goes on. No different than it has since the beginning of time,"

© Jan TenBruggencate 2015

Tuesday, May 19, 2015

Native Hawaiian ducks repopulating the island chain

Okay, not much cuter than a mama duck and her ducklings.

Laysan ducks, the most geographically isolated duck species in the world, has now leapfrogged across the Hawaiian archipelago, from its Laysan home to Midway in 2004 and last year to Kure Atoll.

(Image: Laysan duck and her clutch. Credit: DLNR.)

Laysan ducks, Anas laysanensis, which are sometimes called Laysan teals, were once found throughout the Hawaiian Islands, up and down the chain from the high islands to the tiny atolls to the northwest. 

But under pressure from humans, other predators like rats, habitat loss and other issues, they finally were only present on Laysan. Laysan is a sandy island with a central marsh that’s located about halfway up the archipelago from Kauai to Kure.

The species is currently the rarest species of duck in the northern hemisphere, with the smallest range of any 

In 1911, under pressure from introduced predatory rats and from rabbits that ate much of the island’s vegetation, the population at Laysan was down to 20 birds. But with rabbit and rat removal, the population began expanding. 

Eventually, with numbers on Laysan at several hundred birds, wildlife officials felt the population was healthy enough to try to develop new populations. The risk of the entire population being on one small island was too great. 

The first move was to take a bunch of the birds and shift them to Midway, where wildlife officials are stationed and could keep an eye on them. 

And here at RaisingIslands, we take some small credit for the survival of these birdies. We were aboard the voyaging canoe Hokule`a in 2004, before Laysan ducks were transplanted from Laysan to Midway. 

The crew of the canoe dug up plants of the native sedge, makaloa, which ducks particularly like. We transported the plants aboard the canoe as it sailed up the Hawaiian archipelago, and we delivered them to Midway, where they were planted alongside ponds dredged for the benefit of the ducks.

That original transplanting of ducks to Midway had its problems, from disease to tsunami, but 11 years later, the Midway flock of Laysan ducks is doing well. Here is a 2007 RaisingIslands post on the duck boom.

In 2008, a botulism outbreak killed many of the Northwestern Hawaiian Islands ducks, including a quarter of the Midway population.

Today, the population of Laysan ducks on Midway is in the neighborhood of 400 birds. They’re doing so well that 28 of the Midway birds were transplanted last year to Kure Atoll, the westernmost island in the Hawaiian archipelago. 

As occurred with Midway, the transfer followed the removal of rats, the digging of ponds and the transplanting of native plants to the island, to provide the ducks with the best habitat possible. 

The translocation was a joint project of the state Department of Land and Natural Resources' Division of Forestry and Wildlife, the U.S. Fish and Wildlife Service's National Wildlife Refuge System, the U.S. Geological Survey, Hawaii Wildlife Center, Kure Atoll Conservancy and Papahānaumokuākea Marine National Monument,. (The Monument is managed by the NOAA, USFWS, and the State of Hawai’i._

And the ducks have done well on Kure.

“We documented that all 28 founder birds translocated to Kure in the fall of 2014 had survived six months after their translocation and release,” said Cynthia Vanderlip, Kure Atoll state wildlife sanctuary manager. 

In the spring season of 2015 on Kure, the 28 birds produced 19 ducklings, bringing the population to more than 40—an auspicious beginning.

“Everyone working on this project to help save an endangered species is thrilled that this reintroduction may reduce extinction risk of this rare Hawaiian endemic duck. We all feel like proud parents,” Vanderlip said.

You can see a video of the ducks here.

Here is the state Department of Land and Natural Resources’ press release on the ducks and ducklings. 

© Jan TenBruggencate 2015

Sunday, May 17, 2015

Comet's clues critical in solar system origin probe.

Okay, you expect to find weird stuff if you go digging on comets.

But this weird?

(Image: Three rocks [left] and fine-grained dust [right] from Wild 2. Credit: R. Ogliore & Z. Gainsforth.)

Geophysicist Ryan Ogliore, of the University of Hawai`i Institute of Geophysics and Planetology, looked into the comet Wild 2, and found a bizarre assemblage of materials.

“The comet's nucleus today is made up of small rocks and ice, separated by fractions of an inch, that originally formed billions of miles apart. Some rocks have seen temperatures above 2500 degrees Fahrenheit, but adjacent ice has been kept close to absolute zero for billions of years. Every tiny grain we look at has its own fascinating story to tell.”

Here is the University of Hawai`i press release on their findings.

Ogliore and his team studied samples from the comet that were collected by the NASA Stardust mission. Wild 2 is a comet that used to travel outside Neptune’s orbit, but was diverted to nearer Earth’s orbit in 1974, when it got too close to Jupiter’s gravitational zone.

The team’s findings were printed in the journal Geochimica et Cosmochimica Acta. The citation: Ogliore, R.C., Nagashima, K., Huss, G.R., Westphal, A.J., Gainsforth, Z., Butterworth, A.L., Oxygen Isotopic Composition of coarse- and fine-grained material from Comet 81P/Wild 2, Geochimica et Cosmochimica Acta (2015), doi:

They found both tiny dust particles and larger rock bits, but the evidence suggest that different particles were formed in vastly different places in the solar system. Some, as Ogliore said above, had at some point gotten very hot. Others have been beyond icy cold for immensely long periods of time.

Some of the larger rocks appear similar to rocks found in primitive meteorites. But the tiny dust particles, strangely for something orbiting out in Jupiter’s zone, looks like the dust that you’d expect from the inner solar system.

What could be going on?

“Does the fine-grained dust from comet Wild 2 represent a diverse sampling of many inner-solar-system objects that were transported to the outer solar system, or in fact, the raw starting materials of the solar system?” said Ogliore.

They’ll be looking into that. It may provide clues to how the Solar System developed. Wild 2 has some interesting clues for us.  

“The comet, in an orbit beyond Neptune since its formation, retains an intact a record of early-Solar-System processes,” Ogliore and his team wrote. 

It may be, they write, “A window into the birth of the solar system."

© Jan TenBruggencate 2015.