Rapid ʻŌhiʻa Death – a new threat to our watersheds

This ohia tree shows one of the characteristic symptoms of Rapid Ohia Death - the tree looks frozen or burnt, leaves still in place. Photo by J.B. Friday

This ohia tree shows one of the characteristic symptoms of Rapid Ohia Death – the tree looks frozen or burnt, leaves still in place. Photo by J.B. Friday

Five years ago, people living in the Puna district on Hawaiʻi Island started seeing native ʻōhiʻatrees in their yards dying. First, the leaves on a single limb or the whole tree would start to yellow and brown. Within days or weeks, the tree would be dead. “Trees look burnt or frozen,” explains Dr. Flint Hughes, a research ecologist with the USDA-Forest Service. He’s one of several scientists investigating the cause of Rapid ʻŌhiʻa Death, an apt description for a disease causing ʻōhiʻa to die so fast they don’t have time to drop their leaves.

Symptoms can appear in a single branch or the entire canopy of a tree. Pruning the affected brance will not save the tree since the Ceratocytis fungus is already established in throughout the tree. Photo by J. B. Friday

Symptoms can appear in a single branch or the entire canopy of a tree. Pruning the affected brance will not save the tree since the Ceratocytis fungus is already established in throughout the tree. Photo by J. B. Friday

The disease spreads across landscapes nearly as fast. In 2012, it had killed ʻōhiʻa across about 1000 hectares (nearly 2500 acres). By last summer, it covered 6000 hectares. Healthy trees, young trees, old trees–it doesn’t matter—once symptoms appear, the tree will be dead within weeks.

A disease this virulent is potentially catastrophic for native species and watersheds. ʻōhiʻa are a keystone species for a Hawaiian rainforest. Like the uppermost stone in an arch, ʻōhiʻa is critical to the structure and function of the forest, both as refuge for native birds and other species, and as an effective way to transform what falls as rain into what comes out of the tap.

Last year, Hughes and his colleagues began to research what was happening. They knew it was a new phenomenon and not related to any previously known problems in ʻōhiʻa, such as ʻōhiʻa dieback or ʻōhiʻa rust. Within six months they had isolated the pathogen causing Rapid ʻŌhiʻa Death. The disease is caused by a fungus, Ceratocytis fimbriata. It gets into the sapwood of ʻōhiʻa, stopping the tree’s ability to transport water and sugars. “The fungus essentially strangles the tree,” says Hughes.

The ceratocytis fungus responsible for killing ohia accross 15,000 acres on Hawaii Island can be seen as a dark staining in the sapwood. Photo by J.B. Friday

The ceratocytis fungus responsible for killing ohia accross 15,000 acres on Hawaii Island can be seen as a dark staining in the sapwood. Photo by J.B. Friday

Isolating the cause of Rapid ʻŌhiʻa Death, also called Ceratocytis wilt of ʻōhiʻa, is the first step. Ceratocytis has been present in Hawaiʻi for decades. In the Islands, it’s known only as a pathogen on sweet potato and taro, never before attacking ʻōhiʻa. In other parts of the world, Ceratocytis infects sycamore, eucalyptus, mango, coffee, cacao, citrus, poplar, fig, and rubber trees.

Researchers have yet to determine the origin of this recent outbreak—more than likely a new, more virulent strain of Ceratocytis was introduced but it is possible the existing strain jumped to ʻōhiʻa.

One of the researchers’ top priorities is determining how the disease is spreading. Other places

The Ceratocytis fungus spreads throughout the sapwood or vascular system of the ohia, eventually strangling the tree. The dark staining in this cross-section of an ohia is a symptom of infection  by the Ceratocytis fungus. Photo by J.B. Friday

The Ceratocytis fungus spreads throughout the sapwood or vascular system of the ohia, eventually strangling the tree. The dark staining in this cross-section of an ohia is a symptom of infection by the Ceratocytis fungus. Photo by J.B. Friday

in the world, insects and contaminated equipment are vectors for spreading Ceratocytis, and that could be the case in Hawaiʻi. Until that’s determined, Hughes urges people not to move ʻōhiʻa—logs or seedlings. The fungus can survive in dead logs for a year or more. He suggests that it’s even possible that Ceratocytis spores may land on plants growing near ʻōhiʻa and movement of those plants may spread the disease

On Hawaiʻi Island some of the nicest stands of low-elevation ʻōhiʻa are gone, but researchers are not giving up. “One of the hopes is that we’ll see some genetic resistance in ʻōhiʻa, or there may be environmental constraints,” says Hughes. On Hawaiʻi Island, Ceratocytis has been found as high as about 1,400’ elevation in Mountain View, but that may reflect the relatively recent introduction rather than the full extent of its potential range.

Fungal spores of Ceratocytis on a dead log. The fungus can survive in dead logs for a year or more, and the disease can infect the plants for 2-3 months before symptoms appear. Help stop the spread by not moving ohia-logs or seedlings. Photo by J.B.Friday

Fungal spores of Ceratocytis on a dead log. The fungus can survive in dead logs for a year or more, and the disease can infect the plants for 2-3 months before symptoms appear. Help stop the spread by not moving ohia-logs or seedlings. Photo by J.B.Friday

They do know that the fungus can be present for months before any symptoms appear. During pathogenicity testing, ʻōhiʻa trees showed symptoms two or three months after inoculation. Pruning a symptomatic branch will not necessarily protect the tree as the fungus may have already spread throughout the tree and possibly to nearby trees.

Researchers have much to learn about Ceratocytis wilt on ʻōhiʻa. For now, they encourage people to clean boots and equipment after working on infested trees and caution against interisland movement of ʻōhiʻa logs and seedlings.  Rapid ʻŌhiʻa Death is only known to occur on Hawaiʻi Island. If you are on Maui or elsewhere in the Islands and see symptoms:  leaves quickly turning yellow or brown, dead trees looking burnt or frozen with leaves still in place, or tell-tale brown streaking on the dead wood, contact Hughes by phone, 808-854-2617, or e-mail fhughes@fs.fed.us Learn more online at http://www2.ctahr.hawaii.edu/forestry/disease/ohia_wilt.html

Lissa Strohecker is the public relations and education specialist for the Maui Invasive Species Committee. She holds a biological sciences degree from Montana State University. Kia’i Moku, “Guarding the Island,” is prepared by the Maui Invasive Species Committee to provide information on protecting the island from invasive plants and animals that can threaten the island’s environment, economy and quality of life.

Originally published in the Maui News, May 10th, 2015 as part of the Kia‘i Moku Column from the Maui Invasive Species Committee.

Now accepting nominations for the 2015 Malama i ka Aina Award

Varez imageNominations are now being accepted to honor invasive species prevention efforts within Maui County.  The Malama i ka Aina Award is presented annually to a landscaper, plant provider (retail and wholesale nurseries and garden shops), or commercial/agricultural property owner/manager to recognize their efforts to keep invasive species out of Maui County.

The award is a cooperative effort of the Maui Association of Landscape Professionals, the Maui Invasive Species Committee, and the County of Maui.

The winner will be announced Saturday, June 20th at the Maui Association of Landscape Professionals’ Lawn & Garden Fair at the Maui Mall.  The winner will receive a plaque, a glass sculpture by artist Jupiter Nielsen, a one-year free membership with the Maui Association of Landscape Professionals and local media recognition.

Applicants are requested to explain how the nominee’s activities or decisions have contributed to keeping Maui free from invasive species. Examples include: not selling or using invasive plants; steps taken to learn about invasives; and efforts to reduce the use of invasive species by other customers.

Applications are due by May 30th, 2015 and are available via this link: 2015 Malama i ka `Aina Award On-line Application-2

You may submit completed nominations via  email to miscpr@hawaii.edu, fax to 573-6475, or mail to MISC at P.O. Box 983, Makawao, HI 96768. There is no fee to apply. Self-nominations are welcome.  For more information, call 573-MISC (6472), or e-mail miscpr@hawaii.edu.

Past Malama i ka Aina Award recipients were recognized for meaningful steps taken to prevent the spread of invasive species, including incorporating codes-of-conduct in business practices, educating the public and clients about invasive species, and encouraging the use of native species in landscape design. Actions of award recipients are steps in the right direction!

Invasive species can sting aloha

Photo courtesy of Forest and Kim Starr.

Photo courtesy of Forest and Kim Starr.

Aunty Penny Martin is a lei-maker on Molokaʻi. She was talking story one day with a friend visiting from Hawaiʻi Island, and the conversation turned as it often does, to lei-making.  The friend had a lime-green hydrangea growing in her yard and offered to bring her some. “As a lei maker, the hydrangea are the best for making lei po‘o (lei for the head),” said Aunty Penny. “I was really excited to see.”

At their next meeting, her friend had brought the beautiful flowers from Hawaiʻi Island. “I was overcome by the hydrangea,” she said. “I was ooh-in and ahh-ing,” Then she noticed her friend must have picked them on the go, bagging them before leaving to go to the airport so they would be fresh.  While the lei-maker was touched by the gesture, the sight of the freshly bagged hydrangea triggered a thought.  “It was like an epiphany—I’m thinking fire ants, coqui. I really wanted it….my hands were just itching to make that lei.”

The lime-green hydrangea ended up double bagged to contain any pests and buried at the Molokaʻi landfill. “It would have been easy to stop thinking responsibly,” said Aunty Penny.

As every malahini (newcomer) soon learns, the expansive aloha spirit also celebrates the bounty

The aloha spirit celebrates the bounty of the land, but invasive species threaten to change the practice of bringing gifts from our homes.

The aloha spirit celebrates the bounty of the land, but invasive species threaten to change the practice of bringing gifts from our homes.

of the land. Sharing in that bounty goes beyond good manners–it’s culture. Bringing gifts from your home, be they avocados or citrus, flowers or orchids, even cream puffs or manapua from a local bakery, is part of our way of life.

But as devastating pests like little fire ants become established on some islands and not others, our culture may change. “That kind of sharing and exchanging—pretty soon not going to be the norm, ‘cause you’re going to be worried about things,” says Aunty Penny.

Concerns about invasive species affect even the most traditional of cultural practices. Last summer, a group of students on Big Island helped place lei on every known burial site at Kalaupapa on Molokaʻi to remember those who lived and died there.  The lei brought from the Big Island were made of ti leaves, chosen in part because they could withstand freezing to kill any little fire ants.

Invasive species have affected cultural practices in other ways:  apple snails munch taro throughout much of the state, scale insects on hala can ruin the leaves for weavers in East Maui, and mites threaten the coconut groves planted for King Kamehameha V on Molokaʻi.

Lei-makers often share material between islands. Increasing concerns about transporting pests is beginning to hamper that practice. Photo courtesy of Maui Nui Botanical Garden.

Lei-makers often share material between islands. Increasing concerns about transporting pests is beginning to hamper that practice. Photo courtesy of Maui Nui Botanical Garden.

“I grew up with the tradition of bringing lei from island to island,” says Aunty Penny. “It just crushes me that now I have to think about fire ants and coqui.” Hawaiʻi residents don’t have to stop sharing plants and flowers with friends, but taking a few minutes to check that the gifts are free of unintentional hitchhikers will help keep the natural environment and native culture intact. “I loved that hydrangea,” says Aunty Penny, “but I love Molokaʻi more.”

Lissa Strohecker is the public relations and education specialist for the Maui Invasive Species Committee. She holds a biological sciences degree from Montana State University. Kia’i Moku, “Guarding the Island,” is prepared by the Maui Invasive Species Committee to provide information on protecting the island from invasive plants and animals that can threaten the island’s environment, economy and quality of life.

Originally published in the Maui News, March 8th, 2015 as part of the Kia‘i Moku Column from the Maui Invasive Species Committee.

Got Guano?

This albatross colony on Midway Atoll is representative of what the historic density of seabirds may have been throughout Hawaiʻi. Declines in the seabird population  have an impact throughout the ecosystem. Photo by Forest and Kim Starr.

This albatross colony on Midway Atoll is representative of what the historic density of seabirds may have been throughout Hawaiʻi. Declines in the seabird population have an impact throughout the ecosystem. Photo by Forest and Kim Starr.

When horticulturalists at Maui Nui Botanical Gardens want to give an extra boost to their most sensitive and critically endangered Hawaiian plants, they bring out the seabird and bat guano. Why guano? It’s the natural nutrient-packed fertilizer that Hawaiian plants are used to.

Prior to the first canoe reaching Hawaiian shores, taloned and feathered beasts ruled these Islands. Scientists estimate that seabird populations on the main Hawaiian Islands were equivalent to what the 18th century explorers found on the Northwest Hawaiian Islands–in other words, plentiful. Some accounts indicate seabirds were so abundant they blackened the sky. And if they could darken the sky with their wings, they were certainly capable of whitening the ground with their poop, aka guano.

Bird droppings may not be welcome on your car, but plants benefit from the splattered remains of a seabird’s meal. Guano is a gift for growing seedlings: high in nitrogen, phosphate, and potassium–nutrients essential for plant development. The more guano drops from the sky, the more plants sprout from the ground. This growth affects the entire ecosystem. As plants decompose, they provide plentiful and nutritious food for insects, nematodes, snails, and assorted detritivores, as well as soil bacteria and fungus.

An ʻuʻau chick in a burrow. Once plentiful, the ground nesting Hawaiian petrel is critically endgangered, threatened by feral cats, mongoose, and barn owls. Photo by Jay Penniman

An ʻuaʻu chick in a burrow. Once plentiful, the ground nesting Hawaiian petrel is critically endangered, threatened by feral cats, mongoose, and barn owls. Photo by Jay Penniman

Hawaii’s seabird populations are only a fraction of what they once were. The ‘ua‘u, or Hawaiian petrel, was once the most abundant seabird in the Islands. Today this burrowing resident is endangered. In Maui County, remnant populations exist atop the summits of Haleakalā on Maui and Lānaʻihale on Lānaʻi. The reason for the species’ decline is simple, yet irreversible. They were gobbled up by people, rats, mongoose, and barn owls; the hillsides where the birds nested are now pastures, golf courses, farms, and shopping centers. Other seabirds, such as the wedge-tailed shearwater, Newell’s shearwater, and Bulwer’s petrel once filled the air with their cries; these species now live in scattered, isolated populations.

If efforts to restore seabird colonies on the main Hawaiian Islands are successful, this may be a site any resident or visitor to Hawaii can see. For now, you have to visit Midway to see Laysan albatross this dense. Photo by Forest and Kim Starr.

If efforts to restore seabird colonies on the main Hawaiian Islands are successful, this may be a site any resident or visitor to Hawaii can see. For now, you have to visit Midway to see Laysan albatross this dense. Photo by Forest and Kim Starr.

Fewer seabirds mean fewer plant fertilizers. We may never fully understand how declines in pelagic bird populations impact the environment in Hawaiʻi, but research on islands in New Zealand offers some insight into what happens when avian populations crash due to introduced predators. Comparing islands that had been invaded by rats with those still dominated by seabirds, researchers found that the soil on rat-infested islands had a much different nutrient composition and pH. Additionally, the types and abundance of insects and other invertebrates varied, possibly due to differing rates of plant growth and nutrient uptake. The scientists concluded that reducing the seabird population triggers effects that cascade through entire ecosystems, down to the smallest microorganism.

Back in Hawaiʻi, there’s an opportunity to find out what happens in reverse–how a seabird-based ecosystem can recover when the invaders are removed. At Kaʻena point on Oʻahu, rats have been eradicated A predator-proof fence now prevents rodents from re-entering the 59-acre protected area. The resurgence of seabirds, with their increasing deposits of poop, will soon boost nitrogen and stimulate the recovery of native plants.

The loss of a single species has implications for the entire ecosystem. In this case, it’s just about the birds, it’s about what they leave behind, what lives off that, and on and on, all the way down.

You can support the restoration of Hawaiian seabird populations. Visit websites for Maui Nui Seabird Recovery Project (www.mauinuiseabirds.org/restoration/) and Hawaiʻi Offshore Islet Restoration Committee to learn more (http://www.hawaiioirc.org/about-us/).

Lissa Strohecker is the public relations and education specialist for the Maui Invasive Species Committee. She holds a biological sciences degree from Montana State University. Kia’i Moku, “Guarding the Island,” is prepared by the Maui Invasive Species Committee to provide information on protecting the island from invasive plants and animals that can threaten the island’s environment, economy and quality of life.

Originally published in the Maui News, February 8th, 2015 as part of the Kia‘i Moku Column from the Maui Invasive Species Committee.

Look close—the endemic insects of Haleakalā

Flightless moth

The flightless moth of Haleakalā is one of the more dramatic examples of evolution in Hawaiian insects. Photo courtey of Forest & Kim Starr

The flightless moth of Haleakalā is one of the more dramatic examples of evolution in Hawaiian insects.  Known to science as Thyrocopa apatela, this moth lives only on the barren slopes of Maui’s highest peak. As caterpillars, they spin webs in rock crevices to catch dead leaves blowing past for food. Adult moths hop like grasshoppers across the ground – up to 10 times their body length. Though its evolutionary ancestors could fly, the adults of this species have only partial wings. This unique behavior may have evolved as a result of environmental conditions: high winds and cold may have meant that flight was not an advantage for the moths.

In Hawaiʻi, the climate varies dramatically from one area to another within a short distance. Even if the drizzle never lets up at your house, it could be sunny all day a half mile away. These microclimates create a variety of habitat types that plants and animals have evolved to take advantage of, the tiniest residents included. Native insects and spiders often specialize to survive in their tiny piece of paradise, resulting in the amazing adaptations seen among Hawaiʻi’s insects and spiders.

Of the native Hawaiian insect species, an estimated 98 percent are endemic—meaning they are found nowhere else in the world. Arachnids (spiders) follow suit; an estimated 96 percent of Hawaiian spiders are endemic. The changes that the crawling and flying critters have undergone after arriving in the islands have been dramatic, in part because there are so many varied environmental conditions in a limited area. An ecological niche may be left open that an insect species rapidly adapts to fill.

Researchers have been evaluating potential control measures for the invasive Argentine ant. Photo by Forest and Kim Starr.

Researchers have been evaluating potential control measures for the invasive Argentine ant. Photo by Forest and Kim Starr.

But today, exotic predators prove to be one of the greatest threats to the flightless moth and other creatures in the alpine environment.  The Argentine ant, Linepithema humile, arrived in Hawaiʻi in 1940, most likely by hitching a ride in military cargo. First detected at Fort Schaffer on Oʻahu, people then unwittingly spread Argentine ants throughout the state; by 1967 ants had been carried to Hosmer’s Grove. Hawaiʻi has no native ants and his alien ant is one of 50 plus ant species accidentally introduced to Hawaiʻi but while most ants live in lower elevations, the Argentine ant prefers the cooler climates of higher elevations

The insects and spiders found in the alpine ecosystem belong to a greater system: the yellow-faced bee and a Hawaiian noctuid moth pollinate silverwords; the silverswords in turn provide habitat for the Hawaiian long-horned beetle, a plant hopper, and the tephritid fly. Extremely rare carabid beetles scavenge a meal from whatever comes their way-researchers only recently rediscovered some of these species, once thought extinct, on the slopes of Haleakalā. The predatory Argentine ant could wipe out this food web shaped over millions of years of evolution. Regular monitoring of Argentine ant populations in Haleakalā National Park has shown that in areas where the invasive ant is present, insect diversity drops by 50 percent and overall insect abundance drops by 65 percent.

Since people first introduced the Argentine ant o Haleakalā, it has spread quickly from the small infestation in Hosmer’s grove. In 1982, a second infestation was found near the Kalahaku overlook on the crater rim. Since Argentine ants don’t have a mating flight, the ants most likely hitched a ride when people inadvertently moved nest material. In Haleakalā National Park the Argentine ant has spread at rates exceeding 150m per year; left unchecked, the ant could cover 75 percent of the subalpine shrubland and Haleakalā crater—critical habitat for many native Hawaiian species.

Researchers have been evaluating potential control measures within the park, particularly for source infestations, such as campgrounds, from which people may unintentionally spread the ant. You can help by making sure your gear and picnic supplies are clean and free of all ants, Argentine or not, that you may have picked up elsewhere in your travels.

Learn more about the native insects on Haleakalā and how the Argentine ant threatens them at http://www.hoikecurriculum.org/unit/good-critters-bad-critters/

Lissa Strohecker is the public relations and education specialist for the Maui Invasive Species Committee. She holds a biological sciences degree from Montana State University. Kia’i Moku, “Guarding the Island,” is prepared by the Maui Invasive Species Committee to provide information on protecting the island from invasive plants and animals that can threaten the island’s environment, economy and quality of life.

Originally published in the Maui News, January 11th, 2015 as part of the Kia‘i Moku Column from the Maui Invasive Species Committee.

Christmas berry’s unwelcome presence

Christmas berry, is also a pest in the pastures of Hawaii. Photo by Forest and Kim Starr

Christmas berry, is also a pest in the pastures of Hawaii. Photo by Forest and Kim Starr

Covered in glossy green leaves and bedecked with red berries, the invasive shrub, Schinus terebinthifolius, is commonly known by the appropriate moniker of Christmas berry.  But the presence of this Brazilian species in Hawaiʻi hardly inspires festive spirit in the hearts of island resource managers.

Christmas berry was introduced to Hawaiʻi sometime before 1911 to spruce up yards. Before long this hardy shrub escaped backyards and began to spread across Hawaiʻi .  Drought-tolerant, fire-resistant, and even capable of withstanding flooding for up to six months, Christmas berry thrives in dry and mesic climate zones across the archipelago.

The Hawaiian mesic forest found in Kaupō Gap is one of the most diverse ecosytems found in the state. Photo by Woody Mallinsin

The Hawaiian mesic forest found in Kaupō Gap is one of the most diverse ecosytems found in the state. Photo by Woody Mallinsin

The mesic forest zone is characterized by a moderate amount of rain and no extended droughts—ideal conditions for many plants. Hawaiian mesic forests are one of the most varied ecosystems in the islands, home to a diverse assemblage of endemic plants found nowhere else on earth. Dominated by koa, this forest is also home to sandalwood, māmane, tree lobelias, and species of native hibiscus. This is critical habitat for native insects, birds, and the ʻōpeʻapeʻa, or Hawaiian hoary bat, yet the mesic forest is one of the most threatened and consequently most rare ecosystems

Today, Maui’s mesic zone is where the farmland, pasture, and houses that make up Makawao, Kula, and ʻUlupalakua can be found.  Unfortunately, native forest not lost to development is being gobbled up by feral deer and goats and infested by fast-growing, non-native weeds, such as Christmas berry.

Christmas berry, is also a pest in the pastures of Hawaii. Photo by Forest and Kim Starr

Christmas berry, is also a pest in the pastures of Hawaii. Photo by Forest and Kim Starr

Crews from Haleakalā National Park are trying to reverse that trend. After fencing goats out of Kaupō Gap, crews began removing some of the worst invasive plants in the area. Capable of establishing in shady conditions and releasing chemicals that inhibit the growth of other plants, Christmas berry is one of the most significant threats to endangered plants.

Christmas berry is not only a pest to pristine native forest; it has a well-deserved reputation as a pasture weed. Cattle pass over the turpentine-scented leaves, but birds savor the plentiful seeds, helping to spread the plant to new areas. With high germination rates, Christmas berry quickly chokes out pastureland.

Christmas berry is also a problem in Florida where it’s known as Brazilian pepper. This invader has taken over an estimated 700,000 acres, threatening riparian areas and unique ecosystems of Everglades National Park.

Like other established invaders, Christmas berry is a target for biological control.  With hopes of checking the spread and vigor if Christmas berry, the Hawaiʻi Department of Agriculture introduced several insects that attack the plant in its native range In the 1950s and 60s the Hawaiʻi  Department of Agriculture brought in three insects, a beetle and two moths from Brazil. The beetle and one moth became established but have only caused minor damage.  Another beetle, an unintentional import from Australia, attacks the plant’s seeds.  Currently, research is underway on the efficacy of a sawfly, a wasp-like insect that feeds on the leaves of the plant, for biological control in Hawaiʻi.

You can help. If you live near sensitive natural areas, please do not plant Christmas berry. You can find information from the University of Hawaiʻi s College of Tropical Agriculture and Human Resources about how to control Christmas berry at ww.ctahr.hawaii.edu/invweed/WeedsHI/W_Schinus_terebinthifolius.pdf

A chance to see some of the last remaining intact mesic forest in Hawaiʻi is only a hike away on the Kaupō trail. Before you go you, learn more about the plant communities of Kaupō through the Haleakalā National Park website: www.nps.gov/hale/naturescience/upload/Kaupo-Gap-Mesic-Forest-2.pdf

By Lissa Fox Strohecker. Originally published in the Maui News, December 14th, 2014 as part of the Kia‘i Moku Column from the Maui Invasive Species Committee

Pueo or barn owl: here’s the difference

A pueo chick peers out from its nest. Ground nesting birds, like this native owl, are vulnerable to predation by introduced rats and mongoose.

A pueo chick peers out from its nest. Ground nesting birds, like this native owl, are vulnerable to predation by introduced rats and mongoose. Photo by Forest & Kim Starr

In Hawai‘i , owls are creatures of myth.  Owls are said to rescue lost souls from the underworld and guide armies to safety. Hawaiian legends say the god Kāne took the form of an owl in battle to protect his people. Seeing an owl is always exciting, and it’s easy to overlook the fact that today there are two species of owls in Hawai‘i : the native pueo and the introduced barn owl.

The pueo, known to scientists as Asio flammeus sandwichensis, is a subspecies of the short-eared owl; it’s found only in Hawai‘i . For many Hawaiian families, both ancient and modern, pueo are ‘aumakua, ancestral guardians that protect the family from harm. Pueo are skilled hunters, dining on mice, insects, and small birds. Scientists believe they arrived in Hawai‘i  after the Polynesians and it’s possible that introduced rats helped the population establish. Unlike many owls, pueo hunt during the day but like the fate of many birds native to Hawai‘i , their population levels are now low and they are rarely seen.

A pueo perches on a tree branch in Ulupalakua. The native pueo are darker in color than the introduced barn owl.  Photo by Forest & Kim Starr

A pueo perches on a tree branch in Ulupalakua. The native pueo are darker in color than the introduced barn owl. Photo by Forest & Kim Starr

Pueo can be distinguished from the introduced barn owl (Tyto alba) by appearance as well as hunting behavior. Pueo are smaller, stockier, and darker in color than the barn owl with brown streaking and a brown, round face whereas barn owls are lanky and light in color with a nearly white, heart-shaped face. Pueo nest on the ground, making them more vulnerable to introduced mammals like rats, mongoose, and cats, whereas barn owls nest in tree cavities. Pueo are more active during the day than the barn owl.

Most owl sightings today are likely to be barn owls. Between 1958 and 1963, the Hawai‘i Board of Agriculture

Introduced barn owls are the owl most often seen in Hawaii. Photo by Forest & Kim Starr

Introduced barn owls are the owl most often seen in Hawaii. Photo by Forest & Kim Starr

and Forestry imported 86 barn owls to Hawai‘i Island, Moloka‘i, O‘ahu, and Kaua‘i ­­to control rats in cane fields. The population took off and today this generalist predator is common on all the main Hawaiian Islands and has also been seen in the Northwest Hawaiian Islands. Unfortunately, there is no evidence that the barn owl has had a significant impact on rat populations.

This introduced species may start hunting around dusk, but mostly stalks its prey under the cover of darkness. Its nocturnal habits raise concerns for resource managers working to protect native birds as barn owls can take advantage of species that may be naïve to a nocturnal raptor.

Jay Penniman of the Maui Nui Seabird Recovery Project has seen the impacts first hand. His project works to protect ‘ua‘u, or Hawaiian petrel, an endangered ground-nesting seabird. On Lanai, crews regularly recovered carcasses from ‘ua‘u killed by barn owls. “In the area we were working, we’d find a half dozen kills in a year,” says Penniman. “This indicates it’s a relatively common occurrence.” They know pueo are not the culprit as pueo are active during the day and the ‘ua‘u only return to their burrows at night.  Additionally pueo are slightly smaller than the ‘ua‘u, making the native seabird an unlikely target. Penniman suspects that the barn owls learn to specialize on seabirds and once that happens, become very effective. Other native birds are vulnerable as well: barn owls have been known to snatch Newell’s shearwaters, Hawaiian stilts, Bulwer’s petrels, brown noddies, Hawaiian ducks, and nēnē goslings. Barn owls are protected under the migratory bird act, but exemptions are allowed to remove these predators in critical refuge areas.

Meanwhile, pueo populations have declined dramatically. At the end of the 19th century, pueo were widespread and often seen throughout the islands. But despite being active during the day, these owls are rarely seen today. Besides predation, other possible causes include disease, collisions with vehicles and habitat loss.

You can help. If you find an injured pueo, the Hawai‘i  Wildlife Center on Hawai‘i  Island can help rehabilitate it. Find out more information on their website: www.hawaiiwildlifecenter.org

By Lissa Fox Strohecker. Originally published in the Maui News, November 9th, 2014 as part of the Kia‘i Moku Column from the Maui Invasive Species Committee

Hawaiian Hoary Bat-Our Only Native Land Mammal

Hawaiian_hoarybat_Kokee_AFS_Kauai_May_2010-1-2

Opeapea is a subspecies of the North American hoary bat and is the only terrestrial mammal native to the Hawaiian Islands.

Under the cover of night a skilled hunter twists and turns in the Hawaiian sky, darting and dodging trees with acrobatic skill to catch dinner.  Little is known about this hunter: scientists don’t have an estimate of its population size, and outside of the scientific community, few people even realize that Native Hawaiian bats exist.

Prior to the arrival of humans, other species traveled to Hawai‘i one of three ways: on the wind, via water, or by wing (either flying here themselves or being carried by a winged creature). It follows that the only native land mammal would bear wings.

‘Ōpe‘ape‘a is a subspecies of the North American hoary bat. Found only in Hawai‘i , it’s listed as a federally endangered species. Its Hawaiian name means “half-leaf,” and refers to the bat’s open wing, which resembles the bottom half of a taro leaf.

‘Ōpe‘ape‘a are more common than most people realize, but researchers have only recently begun to study this species more closely. Genetic evidence indicates that bats colonized the Hawaiian Islands in the not-too-distant past—first arriving approximately 10,000 years ago with a second colonization as late as 800 years ago.

An opeapea, sleeps hanging from a tree branch. Little is known about the Hawaiian hoary bat in part because of their tendency to roost alone in trees. Photo courtesy of Forest and Kim Starr

An opeapea, sleeps hanging from a tree branch. Little is known about the Hawaiian hoary bat in part because of their tendency to roost alone in trees. Photo courtesy of Forest and Kim Starr

Like all bats, ‘ōpe‘ape‘a are nocturnal but you won’t find them roosting in caves. These bats are solitary tree roosters, attaching themselves to the tips of branches on a tall tree.  Weighing in at only ½ oz, these little acrobats are hard to find and even harder to study. Mist nets, the kind used to catch and study songbirds, are not very effective when catching bats, as the tiny mammal quickly learns to avoid the net.

The most effective way to detect ‘ōpe‘ape‘a is with ultrasonic bat detectors that pick up the bats’ vocalizations as they travel and hunt. Recent improvements in ultrasonic detection technology have made bats easier to study, and researchers in Hawai‘i  are working to find out more about these mysterious mammals.

On Hawai‘i Island, researchers detected ‘ōpe‘ape‘a more frequently during the summer at lower elevations, possibly because food is abundant during the summer at lower elevations or because the warmer temperatures mean less stress for newborns and lactating mothers. Mother ‘ōpe‘ape‘a  give birth to pups, typically one set of twins, in May or June and stay with the pups until they are 6-7 weeks old. When the pups are young, the mother will carry them with her on her nightly hunts. When they are old enough to hold on to the roosting site themselves, she will leave them safe in the tree until they are old enough to fly with her and learn to hunt. ‘Ōpe‘ape‘a’s diet is mostly moths, but includes mosquitoes, beetles, crickets, and termites.

When temperatures began to cool, researchers on Hawai‘i  Island found increased bat activity at higher elevations. Whether that means they “migrate” up and down the mountain is still uncertain. Even movement between islands is unknown, but bats are on all the main Hawaiian Islands so inter-island movement occurred at some time in the past.

Researchers studying the opeapea are learning  more about this federally endangered species. It has been seen throughout Maui, from sea level to the top of Haleakala as it swoops through the sky. Photo by Forest and Kim Starr

Researchers studying the opeapea are learning more about this federally endangered species. It has been seen throughout Maui, from sea level to the top of Haleakala as it swoops through the sky. Photo by Forest and Kim Starr

On Maui, researchers know ‘ōpe‘ape‘a are in Haleakalā National Park, both at the summit and in the crater. The flying insectivores are often spotted at sea level as well. There is a good chance they are in your neighborhood.

Look for bats at twilight, particularly along pasture edges pastures and clearings. Bats dart back and forth as they catch insects, whereas the rare birds returning to roost take a direct path.

The threats to ‘ōpe‘ape‘a not yet clear but one cause of death is collisions with man-made objects such as communication towers, wind turbines, and barbed wire. This may happen as the bats catch an insect and “turn off” their echolocation for a few seconds to eat.

You can help protect this endangered species. If you know you have ‘ōpe‘ape‘a in your area, protect roosting sites–don’t cut tall trees until after the summer pupping season.  If you are installing a fence in a pasture, consider using barbless wire on the top strand to prevent snagging a hunting bat. If you find a dead bat on Maui, contact Fern Duvall, Wildlife Biologist with the Department of Land and Natural Resources, at 873-3502. You can help scientists learn more about the genetics and habits of this cryptic creature—far more spectacular than spooky.

By Lissa Fox Strohecker. Originally published in the Maui News, October 12th, 2014 as part of the Kia‘i Moku Column from the Maui Invasive Species Committe

Pacific Cooperative Studies Unit: the fingers on the keyboards that get the boots on the ground

Crew  with the West Maui Mountains Watershed Partnership build fence in some of the most difficult terrain imagnable. This and other resource managment efforts are possible thanks to the work behind the scnese at the Pacific Cooperative Studies Unit. Photo by Chris Brosius

Crew with the West Maui Mountains Watershed Partnership build fence in some of the most difficult terrain imagnable. This and other resource managment efforts are possible thanks to the work behind the scnese at the Pacific Cooperative Studies Unit. Photo by Chris Brosius

On any given day, there are hundreds of people at work throughout Hawaii to protect the āina.

Fence crews pound ungulate-proof fences into place in thickly forested terrain, spending weeks away from their families. Botanists scale cliff faces, tracking down the last populations of rare and endangered plants. A researcher on Hawai‘i Island loads gallons of peanut butter into a ceiling spackler testing new ways to control little fire ants in trees.

These people all have one thing in common: the Pacific Cooperative Studies Unit, based out of the Botany Department at the University of Hawai‘i at Mānoa. The unit’s staff works behind the scenes, helping project managers buy helicopter time, hire staff and pool funds from different sources so that conservation crews can stay in the field and focused on their work.

The Pacific Cooperative Studies Unit began 40 years ago when the University of Hawai‘i was providing scientific services to the state’s national parks.

Today, the unit facilitates funding for many of the “boots on the ground” projects throughout the state. It enables multiple funders and agencies to work together. In Maui County, the unit administers three watershed partnerships, two bird projects, one seabird project and two invasive species committees. Each of these projects has field staff, baseyards or offices, vehicles and equipment to maintain, safety concerns and multiple funding sources.

They work on land that falls under various types of management, from private to public and county to federal. A project might have funds from 10 different sources in one year, each with different deadlines and contract requirements. Having a single organization to pool and manage these resources allows the project to remain effective.

Despite supporting 350 staff across five islands and an annual budget of approximately $12 million per year, the unit is a surprisingly low-key organization, an approach mirrored in the philosophy of Unit leader David Duffy, a professor of botany with UH- Mānoa.

“We’re not top down. We try to give projects as much autonomy as possible,” he said.

So, the unit’s role in protecting natural resources in Hawai‘i may be overlooked.

One of the main benefits the unit offers its projects is flexibility. “We can do things that other people can’t, and we can do them faster,” Duffy said. State and federal organizations can be limited by mandates and jurisdiction, whereas a unit project may work wherever the need is.

Need drives the continued presence of the unit. If invasive species were no longer a threat, or endangered plants were safeguarded across the archipelago, it could go by the wayside. “In the best of worlds, we would go away,” Duffy said. “We continue to exist because we’re useful.”

The unit’s efforts mean that researchers and field crews can get the funding needed to continue monitoring and preserving rare native ecosystems across the āina.

To learn more about PCSU and the projects it manages, visit manoa.Hawai‘i .edu/hpicesu/pcsu.htm.

By Lissa Fox Strohecker. Originally published in the Maui News, September 14th, 2014 as part of the Kia‘i Moku Column from the Maui Invasive Species Committe