Wet years now dry: the transition to an ever more arid Hawai`i

While El Nino events often mean winter drought in the Islands, it has long been understood that the counterpart, La Nina, brought increased rainfall.

But that balance, which helped restore depleted groundwater reservoirs, appears to have been broken, according to Hawai`i and China researchers.

La Nina—the cold cycle that often occurs between El Nino warm cycles—now no longer brings additional rain, according to a paper in the Journal of Climate. 

The paper is entitled. “Variability of Hawaiian Winter Rainfall during La Niña Events since 1956.” Its authors are Christopher F. O’Connor and Pao-Shin Chu, of the University of Hawai`i Department of Atmospheric Sciences, School of Ocean and Earth Science and Technology, Pang-Chi Hsu, of China’s Nanjing University, and Kevin Kodama, of the Honolulu National Weather Service.

“Rainfall in Hawaii during La Niña years has undergone abnormal variability since the early 1980s. Traditionally, Hawaii receives greater-than-normal precipitation during the La Niña wet seasons. Recently, La Niña years have experienced less-than-normal rainfall,” they write.

The reason seems to be that La Nina itself is changing, they said.

"Variations in tropical sea surface temperatures and circulation features in the northern Pacific Ocean have changed during La Niña wet seasons, thus changing La Niña–year rainfall.”

A lot of our moisture in winter comes in the form of storm systems that blow through. They’re not blowing through as consistently, the authors write.

“A storm-track analysis reveals that the changes … are creating a less favorable environment for the development of Kona lows and midlatitude fronts in the vicinity of Hawaii.”

The fact that the Islands are drier than they used to be is not news. This latest El Nino work helps explain the mechanics of why rainfall is dropping. 

The National Climate Assessment of 2014 reviewed some of the bad news. 

“Freshwater supplies are already constrained and will become more limited on many islands,” that report said. “On most islands, increased temperatures coupled with decreased rainfall and increased drought will reduce the amount of freshwater available for drinking and crop irrigation.”

RaisingIslands has been covering this dryness trend for years. 

Here is a report on weakening tradewinds and their impact on rainfall. 

Here is a report reviewing reduced rainfall on Haleakala over the past quarter-century. 

Here is a report on the increasing frequency of El Nino andLa Nina events.

© Jan TenBruggencate 2015

Biochar: naturally increasing soil fertility, sequestering carbon

Increasing evidence suggests that biochar—the residue of burning plant matter in an oxygen-starved environment—can be extremely important in improving fertility of poor soils.

Hawai`i researchers have worked on ways of producing the material from macadamia husks and other local products, including sewage sludge. It comes out as shards, splinters, chunks and powder that some have called agriculture’s black gold.

More and more, that evidence is coming down on the side of char. University of Hawai`i researcher Michael Antal has a great deal of information at this website.

Biochar has been promoted as a valuable soil amendment for any farming system, including organic, backyard, third world, conventional and more. 

The US Department of Agriculture reports extensively on biochar, and says that studies with numerous crops showed significant increases in production with many of them. 

Field tests in the African nation of Burkina Faso have shown that soils treated with biochar produce heads of lettuce that weigh more than those grown in untreated soils, all other things being equal. The Urban FoodPlus project, outlined in the magazine Rubin, showed that not only was the soil better at growing crops, but the biochar locked up carbon in the soil, serving to counter CO2 buildup in the atmosphere.

Biochar may help with water retention and may also promote better nutrient uptake. It also sequesters carbon, reduces soil acidity.

A lot of the early work on biochar in soil is built on the discovery in the Amazon area of vast areas of dark soils called terra preta, in which early peoples have introduced charcoal into the soil, ostensibly to improve crop potential.

But there are caveats with this process. One of them involves the availability and loss of the plant materials that are burned to produce biochar. Some researchers are working on other feedstocks for biochar, including livestock manure and even sewage.

Spanish researchers at the University of Madrid used cattle, pig and chicken manure to produce biochar.

Another group used sewage sludge, and had good results. “The obtained results so far are quite encouraging as they show how the addition of biochar to soil can enhance its quality (for example, its ability for moisture retention, pH or biological activity) and therefore, to enhance crop yields,” wrote Science Daily on the work.  

The International Biochar Initiative celebrates the benefits of this material. On its website, the IBI crows about Brazilian soils into which the biochar was introduced hundreds of years ago: “These soils continue to ‘hold’ carbon today and remain so nutrient rich that they have been dug up and sold as potting soil in Brazilian markets.”

The IBI website has extensive information on how to go about the process.

For Hawai`i-specific information see Hawaiibiochar.com and Pacificbiochar.com.

© Jan TenBruggencate 2015

Organic farming in Islands up 60 percent since 2008

Organic farming in Hawai`i is going gangbusters, according to a new federal organic survey.

The 2014 Organic ProductionSurvey of the U.S. Department of Agriculture reports that there are now 166 organic farms in the Islands, and that they’re tilling 3,505 acres.

Hawai`i State Statistician Kathy King has worked through the national numbers.

If you’ve been under the impression that most organic farmers are selling at farmers’ markets or directly to local consumers, you’d be wrong. It’s a much bigger business than that. 

Only about a third sell directly to consumers. Another third sells to retailers, and the third group to wholesalers. (The actual percentages are 28 consumer, 37 retail and 35 wholesale.)

It appears that if you like local food, organics are pretty significant players in that market. But they also have a big export role.

The survey shows that 49 percent of organic products are sold within 100 miles of the farm—which pretty much means on the same island as where they’re grown. Another 16 percent are sold within the state of Hawai`i. 

That said, a big proportion, 35 percent of organic crops, are shipped out of state. (The 35 percent breaks down to 30 percent shipped within the country and 5 percent internationally.)

Most of the value in organics is in vegetables, although more growers are producing organic fruits. Sixty-one farms produce $8.7 million in vegetables. One hundred twenty-six farms produce $3.4 million in organic fruits. That makes the industry worth $12.1 million.

And that’s a big increase since a survey in 2008, when the total was $7.6 million. That represents a 60 percent increase in organic farming value over six years.

In addition to crops sold fresh, 44 of the islands’ 166 farms made value added products, which had a total value of $1.8 million.

A release from the National Agricultural Statistics Service Hawaii Field Office reviews some of the production practices of the organic farmers of the Islands:

“The majority of organic farmers in Hawaii used the following production practices: organic mulch/compost, green or animal manures, no-till or minimum till, maintained buffer strips, and water management practices. 

“Other production practices utilized were biological pest management, maintaining beneficial insect or vertebrate habitat, selecting planting locations to avoid pests, releasing beneficial organisms, choosing pest resistant varieties, and planning plantings to avoid cross-contamination.”

An overview of Hawaii anagriculture as a whole finds that there are 7,000 farms in the Islands, covering 1.12 million acres. 

Coffee has the highest value at $54.3 million, followed by macadamia nuts at $40 million, bananas at $11.8 million and papayas at $11.3 million. 

Taro stands at $1.9 million and avocado at $1.6 million.

 

Perhaps the most significant numbers are about the primary operators of Hawaiian farms. Only 52 percent, 3,642 of 7,000 of Hawaiian farmers do it full-time. And of those farmers, 2,666 are 55 or older. Of those, 1,445 are 65 years old or older.

© Jan TenBruggencate 2015

Kapa plant Wauke confirms Polynesian migration theories

When Polynesians cane across the Pacific, a 5,000-year migration, they brought familiar products with them.

A new paper tracks genetically one of those products, paper mulberry, which is known in Hawai`i as wauke (Broussonetia papyrifera). 

(Image: An indication of the wide range of the wauke plant, this one was photographed within the volcanic crater of Rano Kau on Rapa Nui or Easter Island. Credit: Kuo-Fang Chung.)

And its genetic makeup in different locations across the ocean confirms modern theories of  migration from the island now known as Taiwan, through New Guinea, and eventualy into the Eastern Pacific and Hawai`i.

The paper, entitled “A holistic picture of Austronesian migrations revealed by phylogeography of Pacific paper mulberry,” was written by by Taiwan and Chile researchers Chi-Shan Chang, Hsiao-Lei Liu, Ximena Moncada, Andrea Seelenfreund, Daniela Seelenfreund and Kuo-Fang Chung.
The paper was printed in the Proceedings of the National Academy of Sciences

Various theories start the migration of the people who would be the Polynesians in South China, Taiwan, Vietnam or elsewhere in southeast Asia. 

“We test these propositions by studying phylogeography of paper mulberry, a common East Asian tree species introduced and clonally propagated since prehistoric times across the Pacific for making barkcloth, a practical and symbolic component of Austronesian cultures,” the authors write.

Wauke, whose inner bark was converted into bark cloth for clothing, ornament and other uses, may be the most widely distributed fiber product of early prehistory, the authors write.

“We demonstrate a tight genealogical link between its populations in South China and North Taiwan, and South Taiwan and Remote Oceania by way of Sulawesi and New Guinea, presenting the first study, to our knowledge, of a commensal plant species transported to Polynesia whose phylogeographic structure concurs with expectations of the “out of Taiwan” hypothesis of Austronesian expansion,” they write.

A commensal relationship is one in which two different things—in this case humans and wauke—work together to the benefit of both. Humans got clothing, and the paper mulberry got to dramatically expand its range.

The authors studied 600 or so samples of wauke tissue collected from across the Pacific, and looked at genetic variation in them. They were able to track the migration of the wauke, and thus the Polynesians, across the ocean. 

Separately, they were able to show that the earliest Taiwan residents may have brought a predecessor plant from southeast China.

© Jan TenBruggencate 2015

Ancient insects, lost in time, in Kaua`i's amazing Makauahi Cave

Deep in the sediments of Kaua`i’s Makauahi sinkhole is evidence of an entire collection of insects, lost in time and now extinct.

They represent some of the diverse life forms of the Hawaiian lowland forest that once spilled from the foothills of Ha`upu mountain. 

The beetles are in the genus Blackburnia, and help fill in missing pieces in the evolution of the Islands, according to anarticle in the journal Invertebrate Systematics, by James K. Liebherr and Nick Porch, of Cornell University and Australia’s Deakin University, respectively.   

 “The addition of extinct Kauai species to clades previously known only from extant species on Maui Nui and Hawaii Island reinforces the biogeographic pattern of progressive colonization by Blackburnia beetles from older Hawaiian islands to younger,” they write.

The paper is entitled “Reassembling a lost lowland carabid beetle assemblage (Coleoptera) from Kauai, Hawaiian Islands.”

The new findings link known species of beetles from ancient Laysan Island to young Hawai`i Island.

Scientists had some fun with naming the new species. They are Blackburnia burneyi, B. cryptipes, B. godzilla, B. menehune, B. mothra, B. ovata and B. rugosa. 

Several of the newly named species are significantly larger than any of the living relatives on Kauai, which explains their names. B. godzilla is the biggest of all, and mothra is another big one. 

The first, B. burneyi, is named for David A. Burney, who led the excavation of the famous south Kaua`i limestone feature known as Makauahi. His wife and partner, Lida Pigott Burney helps manage the cave reserve. 

For more information on the amazing sinkhole and associated caves, and the program to re-establish many of the native plant species that once existed on this landscape, see http://cavereserve.org/. (If you like what they'd doing, please consider sending a donation.)

The beetles are believed to have gone extinct largely because of human-caused destruction of their habitat. The beetle parts were found in sediments dated to before the arrival of Polynesians in the Islands, and they disappear from sediments soon after.

“Seven of the species discovered in these deposits are not known  from  any  historically  collected  specimens,  supporting the conclusion that these species suffered extinction through the agencies of Polynesian agricultural land conversion and introduction of invasive predators such as the Pacific rat,” the paper says.

The authors of the paper don’t believe they have yet collected enough material to be able to describe all of the insects of this prehistoric South Kaua`i habitat, but there’s a suggestion more may be learned.

“We do not claim to have an accurate representation of the lowland carabid fauna of Kauai that was destroyed through the agencies of man. But now that there are fossils, there are some interesting tales to tell,” they write. Carabids are part of a global family of fast-moving ground beetles.

© Jan TenBruggencate 2015