Finally, a thorough tally of Hawaiian canoe plants, including pa'ihi and kamole.

 Which Hawaiian plants are canoe plants, the plants that Polynesian voyagers carried on their voyaging canoes to support new lives in new islands?

Some folks will say there were as few as 23. Others say as many as 32, Most are in between. Where’s the truth? Come on along for this investigation.

In most parts of the world, plants are conveniently divided into native and introduced. And among the natives, there are the endemics that are found nowhere else and the indigenous, which somehow got here without human assistance, but are also found in other parts of the world.

Canoe plant kukui (left), alongside hala, which might be but was already here. 
Jan TenBruggencate photo.

In Hawai’i, we had another classification: canoe plants or Polynesian introductions—the plants the Polynesian canoe voyagers carried with them to support their lives on newly found islands.

The late Lynton Dove White, in her book Canoe Plants of Ancient Hawai’i, lists 24 canoe plants. 

Art Whistler has more.

“The farther into the Pacific from the center of dispersal (Western Polynesia), the fewer successfully introduced canoe plants there were (e.g., ca. 60 in Tonga, c. 27 in Hawai‘i). Only about six canoe plant species were successfully introduced to New Zealand by the Maoris, mainly because canoe plants are tropical, and did not survive or thrive in temperate New Zealand,” wrote ethnobotanist Art Whistler. He is the author of “Plants of the Canoe People.” 

They are probably both low in their counts.

There were certainly somewhere between two and three dozen of them. 

At a minimum, these: `ape elephant ear, `awa kava, ‘auhuhu wild indigo or fish poison plant,`awapuhi shampoo ginger, ipu Lagenaria gourd vine, kalo taro, kamani Alexandrian laurel, ki ti leaf, ko sugar cane, kukui candlenut, mai`a banana, niu coconut, noni Indian mulberry, `ohe bamboo, `ohi`a `ai mountain apple, `olena turmeric, pia arrowroot, `uala sweet potato, uhi yam, `ulu breadfruit, and wauke paper mulberry.

That’s 21.

Many think hau or sea hibiscus and milo or portia tree were likely canoe plants, but could also have already been on the Islands.

That’s 23

Hala or pandanus used to be on the canoe plant list, but then fossils of hala were found in rocks erupted 100,000 to 500,000 years ago, and later ancient pollen was found in sediments that predate human arrival in the island.

The orange-flowered Kou (Cordia subcordata) also used to be placed on the list, but again, ancient pollen showed there were forests of it already there to greet the first canoes.

That said, the quartet of hala, hau, milo and kou were such valuable plants in Hawaiian and the larger Polynesian culture that they might have been on the first arriving canoes as part of the Polynesian survival kit, even if they turned out to be already in the Islands.

They would make 25.

There are problems with the list we’ve made so far. It is as far as most tallies go, but it is incomplete. For example, it lists banana as mai’a, but there were at least two quite different species of mai’a, and it lists one but there were three species of yam. And there are other plants that are not on the most common lists at all.

The yams: not only the uhi or winged yam, but also the hoi or bitter yam and pi’a Hawai’i, or five-leaf yam, Dioscorea pentaphylla, which is different from the Polynesian arrowroot that is also known as pi’a, Tacca leontopetaloides.

There appear to have been not one but two bananas, the more common mai’a , but also the fe’i banana, he’i, Musa troglodytarum.

The Bishop Museum’s Plants of Hawai'i program lists 32 canoe plants, some of which are so obscure they most people won’t know them. This Bishop Museum botany site seems to be the most thorough list out there, although (as I write this) it is missing the Hawaiian names of a couple of the less common species.

Plants of Hawai’i includes the popolo, or American nightshade, which clearly was an early arrival in the Islands, and is not commonly included in canoe plant lists.

Another canoe plant on its list is the Oxalis corniculata, yellow wood sorrel, has several Hawaiian names, ‘ihi ‘ai, ‘ihi ‘awa, ‘ihi maka ‘ula, ‘ihi mākole. It is edible, used medicinally for several ailments and made a dye.

Plants of Hawai’i cites two canoe plant species without Hawaiian names, although other sources do identify the Hawaiian names of those plants.

One is the Mexican primrose willow, Ludwigia octovalis, which other sources call water primrose, and in Hawaiian kamole or alohalua. It is said to be edible, but seems primarily to have been used medicinally, often in the form of a tea.

Another is pa’ihi, Polynesian cress, Rorippia sarmentosa. It is both edible and medicinal. Plants of Hawai’i lists this cress, as well as the primrose willow and wood sorrel, as possible accidental introductions—which suggests that perhaps seeds were on the canoes, but that they were not intended canoe plants.

The upshot is that while some folks will tell you there were precisely 23 or “more than 24” or 27 or exactly 30, or 32 canoe plants, nobody can be entirely sure. Here’s our comprehensive list—including the ones that might have been canoe plants but were also here already, and the ones that might have hitchhiked on canoes.

‘Ape, ‘auhuhu, ‘awa, ‘awapuhi, hala, hau, hoi, ‘ihi’ai, ipu, kalo, kamani, kamole, ki, ko, kou, kukui, mai’a, mai’a he’i, milo, niu, noni, ‘ohe, ‘ohi’a ‘ai, ‘olena, pa’ihi, pi’a Hawai’i, pi’a, popolo, ‘uala, uhi, ‘ulu, wauke.

And that’s 32 canoe plants.

© Jan TenBruggencate 2024

Fire-prone invasive grasslands need intense work to restore native species

 Invasive grasslands, like those linked to the destruction of Lahaina, are remarkably stable systems, and will be difficult to change.

That’s a conclusion of a new report by federal foresters.

They determined that active and intensive wildland management will be required to restore native-dominated landscapes. The alternative is a continued dominance of fire-prone grasslands.

The study, in the journal Ecology and Evolution, is entitled “Invasive-dominated grasslands in Hawaiʻi are resilient to disturbance.” The authors are Stephanie Yelenik and Eli Rose of the U.S. Geological Survey’s Pacific Island Ecosystem Research Station and  Susan Cordell of the U.S. Forest Service’s Institute of Pacific Islands Forestry.

The conclude that once a native Hawaiian ecosystem is converted to an alien grassland, it becomes difficult to change to another system, such as one dominated by native species that might be less fire-prone.

They did the research by disturbing six 100-square-meter plots with different vegetation mixes.

“We implemented a disturbance experiment to assess how plant communities would reassemble,” they wrote. They included in each plot plantings of two native species, ‘a’ali’i (Dodonea viscosa) and a native bunchgrass known as Hawaiian lovegrass (Eragrostis atropioides.)

The plantings were done on Hawai'i Island, in the Keʻāmuku Maneuver Area of the Army’s Pōhakuloa Training Area.

They found that competitive invasive grasses tended to become dominant after disturbance. They generally do better than native species in disturbed habitats. And once they have taken over, they tend to stay in charge.

“Our results highlight that the altered post-agricultural, invaded grassland landscapes in Hawaiʻi are stable states,” they wrote.

Some of those invasive non-native species they found include buffel grass (Cenchrus ciliaris,) Kikuyu grass (Cenchrus clandestinus,) fountain grass (Cenchrus setaceus,) Natal red top (Melinis repens,) and a toxic daisy called fireweed or Madagascar ragwort (Senecio madagascariensis.)

This study involved bulldozing the land, but the reaction to this disturbance seems similar to that found after fires, they said.

“While the disturbances that we imposed differ significantly from fire, wildfire resulting from invasive grasses are increasing in Hawaiʻi,” they wrote. “Past research in Hawaiʻi shows that fire in invaded grasslands generally results in the return of the same grass species across various ecosystems including those dominated by invasive grasses…”

They conclude that active management is needed if the goal is to return alien-dominated grasslands to native-dominated ecosystems.

“If the desired management goal is native-dominated ecosystems, such stable states will likely take large inputs of time and resources to alter,” they wrote.

© Jan TenBruggencate 2024

Gray-backed terns produce a second keiki at Palmyra since rat removal at the atoll

 A second gray-backed tern chick has been spotted at Palmyra Atoll, several hundred miles south of Hawai`i.

Gray-backed tern chick at Palmyra.
TNC photo.

The first was raised last year.

The birds were killed off on the atoll by rats, but have begun to return since The Nature Conservancy, which manages Palmyra with the U.S. Fish and Wildlife Service, eradicated the invasive rat population.

Many seabirds nest at Palmyra and many of the other remote atolls and islands of the central Pacific. But eight species known to the region were absent from Palmyra, and rats, which take both eggs and chicks, were believed to be the reason.

Rats were wiped out in 2011, and the island’s managers quickly began to see changes in vegetation and wildlife. In 2020, they began experiments to try to attract seabirds that might be flying by, using both recorded calls and decoy birds.

Last year, the first gray-backed terns nested at the atoll, and this year, more did.

 “Our science volunteers Oliver (Dunn) and Cass (Crittenden) saw 5 adults in the last month and three adults in the area near the chick. They also saw an adult feeding a chick. Thanks to their efforts, we have more data to show that our seabird attraction efforts are working,” said Katie Franklin, Island Conservation Strategy Lead for The Nature Conservancy, Hawaiʻi and Palmyra.

Alex Wegmann, lead scientist for The Nature Conservancy’s Island Resilience Strategy, said it is a milestone for TNC’s efforts.

 “It also emphasizes the value of decades of conservation and management by TNC, the US Fish and Wildlife Service and our many partners, as well as the efficacy of seabird social attraction methods,” Wegmann said.

Adult gray-backed terns at Palmyra.
TNC photo.

Gray-backs are one of eight species of seabird now missing but which may once have nested there. The grays are the first to return after the rat eradication. They are known in Hawaiian as pākalakala and their scientific name is Onychoprion lunata.

© Jan TenBruggencate 2024

Gray-backed tern returns to Palmyra Atoll

 The Nature Conservancy has attracted gray-backed terns back to Palmyra Atoll after they were lost to the island, likely due to rat predation.

(Image: Gray-backed tern chick. Credit: The Nature Conservancy.)

Researchers used wooden decoys and recorded bird calls to try to convince the terns--and seven other seabird species--to land and to nest on Palmyra. A single gray-backed tern was raised on this island this season, the first in recent memory.

Gray-backed terns, formerly Sterna lunata and recently recategorized Onychoprion lunata, are pākalakala in Hawaiian. They are one of eight seabirds known to the part of the ocean that contains Palmyra, but which have not been found nesting there in recent years. They likely were preyed on and their breeding colonies removed by rats that came during World War II.

Rats were eradicated from the island in 2011. In 2020, The Nature Conservancy began trying to call the missing seabirds back to the island with loudspeakers playing recorded nesting calls, and with wooden bird decoys. These techniques have successfully called in birds in other projects.

Gray-backed terns are the first to respond.

These birds are speckled as chicks--as shown in the photo above--but as adults they have white bottomsides, gray backs, and a black head with a white stripe over the eye. 

Palmyra Atoll, roughly 900 miles south of Hawai'i, is jointly managed by The Nature Conservancy and the U.S. Fish and Wildlife Service. 

© Jan TenBruggencate 2023

 

New research: Hawaii dramatically drier over past 40 years

 Hawaii has grown drier and browner over the last 40 years.

This won’t be a big surprise to land managers who have faced repeated droughts, more wildfires and lower streamflows. But now there’s data to back up their observations.

A new study in the journal Environmental Management confirms that reduced rainfall has had significant impacts across the state.

That translates to less green, more brown.

The paper, which was published in November 2022, has the title: “A Near Four-Decade Time Series Shows the Hawaiian Islands Have Been Browning Since the 1980s.” 

The lead author, Austin Madson, is with Wyoming Geographic Information Science Center, University of Wyoming. Co-authors, several from Hawai’i, include Monica Dimson, Lucas Berio Fortini, Kapua Kawelo, Tamara Ticktin, Matt Keir, Chunyu Dong, Zhimin Ma, David W. Beilman, Kelly Kay, Jonathan Pando Ocón, Erica Gallerani, Stephanie Pau and Thomas W. Gillespie.

They used satellite measurements to show that Hawai’i’s environment is going in the opposite direction of most of the planet.

“Globally there has been a significant increase in … greenness due to climate warming,” they wrote.

The researchers looked at all eight major Hawaiian Islands, using a system called the Normalized Difference Vegetation Index or NVDI.

Their findings: “Overall, there has been a significant decline in NDVI (i.e., browning) in the Hawaiian Islands from 1984 to 2019.”

Ni’ihau and Kaho’olawe, already the driest of the islands, did not see significant changes, but all the other islands “experienced significant declines,” they wrote.

Kaua’i was a little better off, but the problem was worse on O’ahu and Molokai, and worst of all on Lana’i and Hawai’i.

Native forests, generally in the uplands, suffered some if the worst declines: “Native ecosystems on O’ahu (56%), Moloka’i (70%), and Hawai’i (57%) decreased the most in NDVI from 1984 to 2019.”

That translates, they said, into reduced productivity and reduced biodiversity.

“In the future, if the drying and warming of the climate on the leeward slope of the island of Hawai’i continue, native ecosystems may become increasingly vulnerable to fire and succumb to the expansion of invasive species.”

Whether the drying trend will continue isn’t known, but it’s a worrisome trajectory.

© Jan TenBruggencate 2023

At Palmyra, native forests store more carbon than coconut plantations

There are lots of interesting things about native forests in the Islands, and The Nature Conservancy has just added an important one.

These forests do a better job of capturing carbon than planted forests, at least in the example of Palmyra Island, where the Conservancy and the U.S. Fish and Wildlife Service operate an atoll refuge a few hundred miles south of Hawai’i.

Native Hawaiian forests are excellent at capturing moisture and preventing aggressive, eroding runoff. That is in part due to the complexity of the Hawaiian forest. There are generally canopy trees, and smaller understory trees and shrubs and at the lowest level, ferns and mosses.

So when a heavy rain falls, its downward force is diminished by all the leaves and branches it encounters on the way down, and then the forest soaks it up like a sponge. So mountain streams in native forest areas run clear, not muddy. And they keep running even after weeks of dry weather, as the natural spongy forest floor lets the water seep out slowly.

By contrast, in a forest dominated by alien trees, like eucalyptus or Java plum, there is little understory growth. And heavy rains often lead to muddy runoff, eroded gullies, and sediment-filled streams. And shortly after the rain stops, the soils dry out.

(Image at right: Pisonia forest at Palmyra. Credit: Andrew Wright.)

A new study at Palmyra by The Nature Conservancy has shown that another benefit of native forests is that they also store more carbon than single-species forests like the coconuts that once dominated Palmyra’s coralline ground.

The paper was published in PLOS One by Kate Longley-Wood, Mary Engels, Kevin D. Lafferty, John P. McLaughlin and Alex Wegmann. The title: Transforming Palmyra Atoll to native-tree dominance will increase net carbon storage and reduce dissolved organic carbon reef runoff.

At Palmyra, the Conservancy has been replacing dense coconut stands, which are not native to the island, and were planted to promote a copra industry, with the native forest that once existed there.  They knew there would be impacts of this conversion, but it wasn’t entirely clear what they would be.

“To better understand how this landscape-level change will alter the atoll’s carbon dynamics, we used field sampling, remote sensing, and parameter estimates from the literature to model the total carbon accumulation potential of Palmyra’s forest before and after transformation,” the authors wrote.

Their research showed that the new forest increased carbon storage on the atoll’s land areas by nearly 12 percent, and also reduced the flow of dissolved organic carbon into the island’s lagoon. That, in turn, is expected to result in healthier corals and a strong community of the species reliant on the coral reefs.

“We’ve demonstrated that better stewardship of natural resources can increase their carbon capture ability,” said lead author Kate Longley-Wood, Ocean Mapping Coordinator with TNC’s Protect Oceans, Lands and Waters program. “That native tree species are better for carbon capture and ocean health is the icing on the cake.”

All that said, it takes time for the effect to be seen, and the story will likely change somewhat over time as the restored forest matures. There is a loss of carbon in the standing trees when the coconuts are cut down and allowed to be replaced by native Pisonia grandis (Pu’atea in Tahitian or cabbage tree in English), Heliotropium foertherianum (beach heliotrope), Pandanus tectorius (hala or screwpine) and other species native to the atoll.

The native species are considered to be superior habitats for native seabirds, they store more carbon, and they support a larger native ecosystem.  But the results don’t mean it’s appropriate to go around cutting down all the coconuts elsewhere, as they could be important parts of the human communities on some islands. The scientific name of coconut is Cocos nucifera, sometimes written C. nucifera.

“C. nucifera’s role in human migration and settlement throughout Oceania is notable, and control of C. nucifera to transform native forest should be balanced with the societal value provided by C. nucifera to Pacific Island communities,” the paper said.

© Jan TenBruggencate 2022

COVID-19 conspiracy theories: Hoofbeats and zebras?

Lots of conspiracy theories about the new coronavirus make little sense, and if you actually apply a little scientific rigor to the issue, they fall apart.

They even contradict each other. If it came from a Chinese lab, why? They got hit first. If, as some
Russians say, it came from America, why are we Americans also sick? Whoa, what about the fact that
Russia seemed to be largely free of the disease, isnʻt that suspicious? Well itʻs not, any more--they've got a growing number of cases as well.

The philosopical theory known as Occamʻs Razor suggests that the simplest solution is generally the
right one. There's the old line that if you're in the American west and hear hoofbeats, your first thought should not be zebras.

A group of researchers looked into whatʻs likely and whatʻs not about the origins of COVID-19, also
known as SARS-CoV-2.

1. They found that we know of seven previous cases of this class of disease getting into humans;
2. They found that itʻs highly unlikely that this was a human-engineered virus.

Their study was published in the journal Nature Medicine. The authors are American, Australian and British researchers Kristian G. Andersen, Andrew Rambaut, W.vIan Lipkin, Edward C. Holmes and Robert F. Garry.

"Our analyses clearly show that SARS-CoV-2 is not a laboratory construct or a purposefully manipulated," they wrote.

One clue, they said, is that when you look at the genetics, this virus behaves more like a random
mutation than a purposeful construct. In other wordS, if someone had engineered it, theyʻd have done a better job, or at least would have done it differently.

Which is not to say that labs donʻt work on viruses. They do. But not like this. "The genetic data irrefutably show that SARS-CoV-2 is not derived from any previously used virus backbone," the authors wrote.

The most likely pathway is one of two, Anderson and his co-authors said. Either the virus evolved into its current form in an animal and then was passed to humans, or an earlier form of the virus passed from animals to humans and then evolved into its current form in humans.

You may have heard that many of the early victims of the virus had visited live-animal markets in
Wuhan, China. And that the animal host might have been bats, or pangolins or birds.

So far, none of those animals has been found with a form of the virus that looks close enough to be the source of the COVID-19 pandemic, they said, but they admitted that the animal population has been "massively undersampled." Pangolins seem to have the virus version closest to the pandemic version.

Alternatively, it is possible an early version of the virus jumped repeatedly to humans in a version that did not spread from human to human. Until one evolved the ability to be transmitted between people.

It is not yet possible to determine which of these things actually led to the outbreak, but there is lots of study going on, and at some point, it will be possible.

"We do not believe that any type of laboratory-based scenario is plausible," but more research will doubtless show which of the natural mechanisms was the more likely culprit.

One of the best arguments against a laboratory conspiracy to infect the world: Animal-to-human transfer of disease has been a common source of human misery since long before sophisticated laboratories were set up. There is even a term for it, zoonosis. That link is the Centers for Disease Control site on zoonotic diseases.

We have had lots of zoonotic diseases in Hawai`i, like leptospirosis and dengue, but most of these diseases require an animal-to-human infection path for each sick human. The difference with COVID-19 is that once it crossed the species barrier, it could be transmitted directly human to human.

This has happened repeatedly. Think of bird flu and swine flu. The source of the devastating 1918 "Spanish" flu, is not well known, although it almost certainly didn't come from Spain. It went on to infect a third of the world population and to kill an estimated 50 million people. Some suggest it might have crossed from birds.

Thus, this is neither new nor rare. "More than 60% of the roughly 400 emerging infectious diseases that have been identified since 1940 are zoonotic," wrote the authors of this 2012 paper in the journal The Lancet, which has the ominous title, "Prediction and prevention of the next pandemic zoonosis."

© Jan TenBruggencate 2020

Rat lungworm now in coqui frogs, bufos, even centipedes and crabs.

Coqui frog. Credit: U.S. Fish and Wildlife Service

This may read like something out of a Godzilla movie, but it has now become clear that rat lungworm disease has now teamed up with coqui frogs.

Researchers last year identified rat lungworm in the invasive, incredibly noisy frogs, and last month published a scientific paper on their findings.

Lungworm is spreading throughout the environment. Itʻs not only in rats, and of course humans and now coqui, but the scientists found it is also in centipedes, greenhouse frogs and even bufos.

The paper, "Occurrence of Rat Lungworm (Angiostrongylus cantonensis) in Invasive Coqui Frogs (Eleutherodactylus coqui) and Other Hosts in Hawaii, USA," was published in the Journal of Wildlife Diseases. The lead author is Chris N. Niebuhr of the USDAʻs National Wildlife Research Center Hawai`i Field Station in Hilo. Co-athors are Susan I. Jarvi, Lisa Kaluna, Bruce L. Torres Fischer, Ashley R. Deane, Israel L. Leinbach, and Shane R. Siers.

It still is not yet clear what role the new carriers play in transmitting the disease to humans, but it is clear that the rat lungworm is finding a pliant host in some of them: "In the frogs and toads, multiple tissue types were positive, including stomach and intestine, muscle, liver, heart, and brain, indicating larval migration," the authors wrote.

Rat lungworm is a nematode, a tiny worm that can cause severe neurological symptoms in humans. Here is the Hawai`i Department of Health website on the disease. 

Symptoms can go from nearly unnoticeable to severe pain and even paralysis.

Humans can be infected by, generally accidentally, eating it. Says the state Department of Health: 

"You can get angiostrongyliasis by eating food contaminated by the larval stage of A. cantonensis worms. In Hawaii, these larval worms can be found in raw or undercooked snails or slugs. Sometimes people can become infected by eating raw produce that contains a small infected snail or slug, or part of one. It is not known for certain whether the slime left by infected snails and slugs are able to cause infection. Angiostrongyliasis is not spread person-to-person."

The many source of human infection in the Islands seems to have been from unnoticed infected worms on salad greens, but as the nematode moves into new hosts, there could be new sources of infection.

The new hosts are referred to as paratenic or transport hosts. They are now believed to include frogs, toads, lizards, centipedes, crabs and other species. And while you might not directly eat these things, you or your pets could still be at risk.

The paperʻs authors wrote: " Although the species discussed here are not known to be intentionally consumed by humans in Hawaii, the ingestion of infected hosts could still pose a threat to other animals, because rat lungworm can infect both domestic and wild animals such as dogs (Canis lupus familiaris), horses (Equus caballus), and birds."

Rat lungworm in rats is excreted in their feces, which can be eaten by snails and slugs, as well as other species. Humans have been infected when eating uncooked greens with live slugs on them. 

With the disease now in frogs and toads and centipedes and the rest, new transmission could occur when uninfected rats eat infected specimens of those creatures. And with so many different carriers, it is possible new ways will emerge for humans to be impacted.

This is still an active area of research, the authors say, and more needs to be learned:

"Although our report of rat lungworm infections in frogs and centipedes implicates them as possible disease reservoirs, further investigations are warranted to better understand the role paratenic hosts may be playing in angiostrongyliasis transmission in Hawaii."

©Jan TenBruggencate 2020

You have a pile of yard waste. How best to deal with it?

Walking stick, coulda been a bonfire.

So, youʻve got a pile of yard waste or pruned tree limbs. What to do with it?

1. You could use it; 2. You could let it rot (compost); or 3. You could burn it.

This is an argument for the first and the second, but not the third.

Some yard waste, if it doesnʻt have a bunch of weed seeds in it, can be mulch to keep weeds down and retain soil moisture. Or parts of it can be used as planting material (stick a plumeria stalk or a trimmed hibiscus branch in the ground and theyʻll grow). Chunks of wood can be slabbed up for construction projects, or carved into art objects. Really, you donʻt need to buy a walking stick...itʻs called a stick for a reason.

Composting is magical. It turns waste into a valuable soil amendment. And you can get all scientific about it to get the best, fastest results that produce enough heat to kill weed seeds. Or you can just pile the stuff up and the natural world will break it down in its own time. The crawly bugs and fungi and bacteria, the mesophylic and thermophylic organisms, the worms and the larvae, theyʻll do all the work.

What about the burning option? It gets the volume down fast, and creates wood ash, which has a lot of potash and other micronutrients that you could use in your yard.

There are times when burning is appropriate, but the downsides to burning are compelling. The heat sterilizes the soil under the fire and kills anything living in the greenwaste. If composting is a technique that celebrates life, fire is the opposite. Fire can be a natural process, but weʻre not talking about lightning-lit fires in native forests or savannahs.

(We can concede that for some species fire is a friend—grasses in many cases thrive after fires, both because the competition is killed off and because the ash fertilizes the soil. And we note in passing that a dry compost pile can sometimes catch fire, but thatʻs another discussion.)

What else?

Smoke from fires can be irritating to human (and other species) breathing and to eyes. It can make allergies worse. Sometimes toxic compounds that were locked up in the biological matter can be released into the atmosphere.

Wood smoke contains particular matter as well as chemicals in gas form. Breathing that stuff can have both short-term and long-term health impacts.

Hereʻs a paper on hazards of wood burning. And hereʻs a warning from the Centers for Disease Control and Prevention.

And then, of course, thereʻs the elephant in the room—the whole climate thing. Every time you burn, youʻre dumping a pulse of greenhouse gas into the atmosphere. Itʻs why folks are so exercised about the burning of the Amazon forests.

A few boring statistics: For every pound of wood you burn, you create 1.5 to 1.9 pounds of carbon dioxide (depending on the carbon density of the wood). Carbon dioxide, of course, is a big greenhouse gas. You also produce other greenhouse gases, like nitrogen oxides.

So to go back to the start, weʻre all better off if you make something (compost, mulch, a carved elephant, a picture frame) than if you immediately convert your woody waste to greenhouse gas. Youʻre just locking up that carbon for longer.

It seems clear that keeping that carbon in the soil rather than in the atmosphere is a good thing. And itʻs a good thing for more than just the climate, according to a 2005 article by Canadian researcher Henry H.Janzen. 

"Soil organic matter is far more than a potential tank for impounding excess CO2; it is a relentless flow of C atoms, through... myriad...streams—some fast, some slow—wending their way through the ecosystem, driving biotic processes along the way."

© Jan TenBruggencate 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

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.