Lissa Strohecker — Page 13 — Maui Invasive Species Committee (MISC)

And then the pollinator wasp arrived…

Posted on October 17, 2013 by Lissa Strohecker Leave a Comment

Bo tree, Ficus religiosa, is an attractive ornamental that was once safe to plant in Hawaii. Now the pollinator wasp for the bo tree is in Hawaii and this prolific seeder threatens watersheds. Photo by Forest and Kim Starr

Lori Buchanan, manager of Moloka‘i/Maui Invasive Species Committee (MoMISC), was in downtown Kaunakakai recently when she saw something strange sprouting out of the storm drain. It was a 3-foot tall seedling of a ficus—the very same tree she and her crew are working to remove from Moloka‘i.

Called the bo, peepul, or bodhi tree, Ficus religiosa is planted throughout Asia, Africa, and North America. According to legend, the Buddha sat beneath this species of tree when he meditated and attained enlightenment, hence it’s name. The Hindu deity Vishnu is reputed to have been born under a bo tree. These trees are often planted at Buddhist and Hindu temples. There is a bo tree at the Foster Botanical Garden on Oahu that is said to be a descendant of the tree under which Buddha sat.

Not that long ago, the bo tree couldn’t reproduce on its own in Hawai‘i; it only grew via cuttings. As a member of the Ficus family, it needs a specific wasp to pollinate its flowers in order to produce seeds. That wasp, Blastophaga quadraticeps, was not in Hawai‘i. The wasp crawls inside the minute flower to fertilize it. In 2007, when seedlings sprang up under the bo tree at Foster Garden, Hawai‘i entomologists knew the pollinator wasp had arrived.

Bo tree seedlings springing up out of a sidewalk crack on Molokai

Bo tree seedlings, like this one springing up out of a sidewalk crack on Molokai, indicate the pollinator wasp has arrived. Birds can easily spread seeds into the watershed. Photo by Forest and Kim Starr

The arrival of Blastophaga quadraticeps means that Hawai‘i has joined a relatively small list of places where Ficus religiosa can produce viable seed: India (where it’s native), Israel, and Florida. In Israel, the pollinator wasp fully invaded and Ficus religiosa now ranks alongside other Ficus as invasive and messy. Now that they produce fruit in Israel, purple figs stain the sidewalks, stick to shoes, and splatter cars left in the shade of a tree. Motorcyclists dodge slippery piles of fruit and beachgoers clean gummy residue off their gear.

On Moloka‘i, Buchanan isn’t worried about sidewalk saplings—she’s worried about the forests. “Birds spread the seeds and they [Ficus trees] can get into the forest and threaten the watershed,” she says. “They are prolific seeders and seedlings pop up wherever.” Bo tree could start to take over the native forest on Moloka‘i.

Ficus religiosa, like most Ficus, can grow almost epiphytically: a seedling doesn’t need soil initially but roots reach down until the find earth. Bo tree is technically more of a “splitter” than a strangler fig. Rather than smothering its host in roots, the seeds that sprout in the fork of a tree will send roots through the stem of the support tree, splitting it from the inside. It can find a home in sidewalks and drain sprouts, splitting those apart as well.

MoMISC is actively controlling this species on Moloka‘i, where less than a dozen trees

Bo tree can be recognized by the “tail” or drip-tip on the distinctive heart-shaped leaves. Photo by Forest & Kim Starr

were planted. Only one site with mature trees remains, and Buchanan and her crew are busy hunting down seedlings until the landowner agrees to have the plant removed. On other islands bo tree is planted widely enough that resources are too limited to remove it. But choosing to not plant this tree will slow its spread.

You can help MoMISC by keeping an eye out for bo tree seedlings in Central Moloka‘i, specifically in Kala‘e and Kaunakakai. The bo tree has distinctive heart shaped leaves that extend at the tip. According to Buchanan, the plant most closely resembles the Polynesian “canoe plant” milo, which also grows in the same areas on Moloka‘i. Bo tree has more dark green to grey glossy leaves. Any sightings of bo tree on Moloka‘i should be reported to MoMISC, 954-6585.

By Lissa Fox Strohecker. Originally published in the Maui News, October 13th, 2013 as part of the Kia‘i Moku Column from the Maui Invasive Species Committee.

“Devil weed” sneaks into Hawaii

Posted on September 9, 2013 by Lissa Strohecker Leave a Comment

They saw the pitchfork leaf pattern and knew something was amiss. The unmistakable smell

Devil weed, or Chromolaena odorata growing along a trailside in the Kahuku Motocross Riding Area. This invasive plant is new in Hawaii and only known to be in the Kahuku area. Photo courtesy of Oahu Army Natural Resources Program.

of turpentine in a crushed leaf only added to concern. In January of 2011, a field crew with the O‘ahu Army Natural Resources Program (OANRP) was searching roadsides of the Kahuku training area on the north shore of O‘ahu. They noticed an unusual plant they had not seen before. Could it be devil weed? They sent a sample to specialists with the O‘ahu Invasive Species Committee. Their suspicions were confirmed. Devil weed, or Chromolaena odorata, lives up to its name: it has earned a place on the Invasive Species Specialist Group’s list of the worlds’ 100 worst invaders, alongside coqui frogs and brown tree snakes. The diabolical weed has already invaded Southeast Asia, parts of Africa, and Guam, and has now made to Hawai‘i.

The pitchfork pattern found in the veins on the leaf of devil weed is a key feature of the plant. Photo courtesy of Oahu Army Natural Resources Program.

Native to North America, devil weed is not a pest in its home range, possibly kept in check by natural enemies. Found throughout Florida, Texas, Mexico, and the Caribbean, it attracts butterflies and bees with its fragrant flowers and goes by the much more innocent name of Jack-in-the-bush or blue mistflower. But elsewhere around the world, devil weed causes despair.

A pest in fields, pastures, and wilderness areas, this tangled shrub is fast growing and fertile, covering a foot each week a day. A single plant can make 800,000 seeds. Not surprisingly, it quickly smothers crops and native vegetation. Toxic to animals, it takes over pastureland as well. The bitter oils in the plant that render it toxic are volatile and infestations of this pest fuel wildfires. As devil weed rapidly invades disturbed areas, a fire cycle begins. In Hawai‘i , where ecosystems are not adapted to regular fires and native plants do not regenerate as fast as some invasive species a cycle of fire can mean the end of native habitat, particularly on the leeward sides of the islands.

Best estimates indicate that devil weed is a recent arrival; surveys in the area in 2009 and 2010 did not detect it. Today it is scattered over 900 acres of the Kahuku training area. Julia Parish, the manager of the O‘ahu Invasive Species Committee (OISC), says it’s possible to eradicate Kahuku populations, “But there’s a high risk for reintroduction on private vehicles coming in from across the Pacific region. [U.S.] Customs regularly intercepts Chromolaena on contaminated equipment and vehicles.”

OISC, along with OANRP, Hawai‘i Department of Agriculture, the University of Hawai‘i , and Hawai‘i Department of Land and Natural Resources have teamed up to address devil weed in Hawai‘i .

A single devil weed plant can produce up to 800,000 tiny seeds that are easily spread in mud and equipment. Photo courtesy of Oahu Army Natural Resources Program.

The Kahuku training area is the weekend home of the KahukuMotocrossPark, and 400 acres of trails weave through the area. Kahuku is also popular with hunters and dirt bikers. OISC has been working closely with the Hawai‘i Motocross Association to get the word out about this demon to prevent further spread. According to Parish, “There is an extremely high likelihood of Chromolaena being on other islands.” Bikes move between islands for competitions. The tiny seeds can easily move in the mud on tires or boots.

Finding devil weed early can be tricky, as it resembles other plants. Look for a shrubby plant,

Flowers of devil weed can be lilac to white in color and often have a tangled appearance. Photo courtesy of Oahu Army Natural Resources Program.

sometimes sprawling, with very-triangular leaves, serrated at the edge. The leaf veins form a distinguishable pitchfork pattern and have a turpentine-like smell when crushed. The stems are covered in short soft hairs and older stems are woody. Single flowers resemble a tangled lilac puffball and flowers grow in clusters. The Seeds have a feathery parachute to carry them on the wind.

You can help prevent the introduction of devil weed and other invasive plants. Always clean hiking and sports equipment, and vehicles and gear before bringing them interisland–even between different areas of the island–particularly if covered in soil or mud. Not only will you help prevent the spread of invasive species, your gear will last longer. If you suspect you may have seen devil weed on Maui, call MISC at 573-6472 or email miscpr@hawaii.edu. On other islands call your island-based invasive species committee.

By Lissa Fox Strohecker. Originally published in the Maui News, August 8th, 2013 as part of the Kia‘i Moku Column from the Maui Invasive Species Committee.

The public health threat of invasive species-mosquitoes and dengue

Posted on August 23, 2013 by Lissa Strohecker Leave a Comment

Aedes aegypti is famous the world over for spreading dengue. This species is not established statewide, but it has shown up at the Honolulu International Airport five times since January of 2012. Photo by Muhammad Mahdi Karim

Back in 2001, several East Maui residents started reporting fever, body aches, and rashes. One of the people sickened had just traveled in French Polynesia during a dengue fever outbreak. The Department of Health eventually confirmed 20 cases of dengue fever in East Maui and a crew hired with funds allocated for environmental emergencies went to work removing mosquito habitat. What made this outbreak interesting was that it was spread by the tiger mosquito, Aedes albopictus, common in Hawai‘i.

“We may be the only place in the world to confirm [that] dengue could be spread by the albopictus mosquito. It’s not an efficient carrier of the disease,” explains Gary Gill, Deputy Director of the Environmental Health Administration with the Hawai‘i Department of Health. “In places where dengue is endemic [regularly occurring], it is the aegypti mosquito that is the carrier.”

The invasive mosquito, Aedes aegypti, is famous for spreading dengue. Neither the mosquito nor dengue is widespread in Hawai‘i. Both periodically appear, but luckily not at the same time. Though conditions are prime as Hawai‘i is a global hub for tourism and commerce..

Dengue outbreaks in Hawai‘i are rare and typically occur when someone travels to an infested area, returns to Hawai‘i and is bitten by a mosquito, as happened in 2001. According to Gill, immediate family members and neighbors are at risk, but the common tiger mosquitoes rarely eat from more than one source. The female mosquito finds a person (or animal), and, given the chance, feeds until her belly is about to burst.

In contrast, Aedes aegypti flit from person to person, taking a blood meal from multiple people and spreading any disease carried by the bloodsuckers. Aedes aegypti is not normally found on O‘ahu. “We have not, up until last year, identified any aegypti since the 1940s,” says Gill.

In January of 2012, a Department of Health entomologist collected a trap containing what was later identified as Aedes aegypti at the Honolulu International Airport. “We’ve found aegypti five times in the last year. Every indication is that this mosquito is either living and breeding at the airport, or it is regularly being reintroduced,” Gill says. Mosquitoes can survive in the cabin, cargo hold, or underbelly of an airplane coming from an infested area. Aedes aegypti are originally from Africa but have spread to tropical and sub-tropical regions of the world including Mexico, Asia, and Australia.

Dengue fever is a widespread subtropical disease that is continuously present in areas with established population of Aedes aegypti. This map shows the distribution of Aedes aegypti (blue) and Aedes aegypti and dengue fever (red). Image from Centers for Disease Control

From a public health standpoint having a thriving population of dengue-spreading mosquitoes at the airport is a worst case scenario according to Gill. “A person carrying the virus walks through the airport, and then it spreads to any number of people at the airport who will then take it to wherever they are going. A single population of aegypti could easily spread dengue throughout the state. A dengue-carrier mosquito would be a concern for people who come here as much as for people who live here.” If Aedes aegypti became established throughout Hawai‘i, it would set the stage for a consistent presence of dengue, like does in parts of Central and South America, India, Southeast Asia, and Africa.

Ongoing surveys for mosquitoes are the best way to ensure early detection of this species. The Department of Health continues to monitor mosquitoes at Honolulu International Airport, but surveys are limited to that airport and don’t include surrounding areas. Funding cuts in 2009 gutted the Department of Health. At one point 40 people worked on O‘ahu on environmental health but now only seven positions remain. Staff cuts throughout the state have left no capacity for mosquito monitoring elsewhere. “What’s at Kahului? We have no idea,” worries Gill.

The Department of Health is working with Hawai‘i’s Departments of Agriculture Transportation to explore options for mosquito surveys at airports and harbors statewide. They are working to reduce mosquito habitat at the airport, removing bromeliads and dark undergrowth and replacing it with less mosquito-friendly landscaping. Gill encourages homeowners to do the same, along with removing or changing water in outside open containers every week. For now it’s our best hope. Unless and until capacity is restored at the Department of Health, early detection of this devastating mosquito is up to the public.

By Lissa Fox Strohecker. Originally published in the Maui News, August 11, 2013 as part of the Kia‘i Moku Column from the Maui Invasive Species Committee.

Hawaiian land snails– a tale of evolution worthy of protection

Posted on July 22, 2013 by Lissa Strohecker Leave a Comment

The tale of Hawaiian land snails began millions of years ago as the first plants and animals began to colonize the islands. Researchers don’t know exactly how snails arrived – perhaps stuck to the feathers of a bird or on a floating tree trunk. But in a remarkable story of evolutionary radiation, some 21 or more of those first species that arrived over the millennia gave rise to more than 750 distinct species. Of those, 99% are endemic to Hawai‘i – found here and nowhere else.

This species of Newcomb’s tree snail used to be widespread on Maui but today is only known from a handful of places in the West Maui Mountains thanks to habitat loss and invasive predators-rats and the rosy wolf snail. Baby snails, like this one riding on mom, are rare. Photo courtesy of Hank Oppenheimer

Famously varied in color and shape, Hawaiians called them pūpū kuahiwi, or high-hill snails. Early Europeans collected these jewels of the forest, selling them as lei or to collectors. These snails are still highly valued. Current efforts focus on saving remaining species; high-elevation snail refuges are built to protect them.

Often native snails are found only on one island, or in a single valley or ridge, teetering on extinction because of habitat destruction, shell collection, and invasive species. Adding to the challenges, many Hawaiian land snails reproduce at what is truly a snail’s pace: some species are 3-7 years old at first reproduction and have only 4-7 young per year. They grow slowly—only 0.2 to 0.4 cm a year. Compare this to the invasive giant African snail (Achatina fulica) which reproduce at one year of age, lays up to 600 eggs annually, and grows about 2.5 cm per year.

One species of snail endemic to Maui, Newcomb’s tree snail or Newcombia cumingi, was once found from Lahaina to Makawao, but like most land snails, has become increasingly rare during the latter half of the 20^th century. It was last seen in 1938 by Bishop Museum researchers then rediscovered in 1994 by resource managers with the Maui Land and Pineapple Company’s Pu‘u Kukui Watershed Preserve (PKW).

“One hundred years ago they [native snails] were everywhere,” explains Dr. Kenneth Hayes, a University of Hawai‘i researcher who, along many others, has been working to find out how many West Maui snails remain. Today, 50 percent or more are gone, many turned into escargot for invasive predators—rats, Jackson’s chameleons, and the rosy wolf snail. According to Hayes, the remaining native snails have mostly been relegated to the few areas that still contain native forest, but even these refuges won’t last long if we don’t stem the tide of invasive species. Native snails dine primarily on the fungi that grow on native plants. Invasive plants change the way water moves through Hawaiian watersheds altering the ecosystem by changing what plants, animals, fungi or microbes can live there. The snails’ preferred fungi may not grow in altered habitats.

Pomaikai Kaniaupio-Crozier, conservation manager with PKW, is leading efforts to protect the Newcombia. With US Fish and Wildlife Service funding and partner help they are planning an exclosure in the native forest of West Maui to keep hungry predators from munching native snails.

The West Maui “snail refuge” will be modeled after similar exclosures on O‘ahu, where the O‘ahu Army Natural Resources Program has enclosed three areas to keep out rats, chameleons, and even the predatory rosy wolf snail. A 4-foot tall sheet metal fence topped by a curved lip deters rats and chameleons. Predatory snails face sheet metal at an impossible-to-scale 10 degree angle– if they do manage they hit an electric wire. One fence is equipped with an electronic sensing system that alerts managers via text message if debris falls on the fence.

The first step in protecting Newcombia is a population survey. “They are the size of a pinky fingernail and very cryptic,” says Kaniaupio-Crozier. “It’s like finding the needle in the haystack, looking for something that small in 8,600 acres. Up until a couple months ago we were getting pretty demoralized.”

Then they made a remarkable discovery. They found a new population, in totally unexpected habitat. The existing Newcombia population inhabited a wet area with lots of ‘ōhi‘a; the new population was found on ‘ākia, in much drier terrain. “There’s hope there may be another population somewhere else.”

From survey to construction, building the snail refuge will take several years. You can help. PKW is welcoming people interested in habitat restoration, monitoring, even joining in the brainstorming. Contact Kaniaupio-Crozier at pkaniaupio-crozier@mlpmaui.com or by phone, 870-4225. To learn more about the native and non-native land snails of Hawai‘i, contact Ken Hayes, khayes@hawaii.edu, Norine Yeung, nyeung@hawaii.edu, or visit the Hawaiian Land Snail Conservation Facebook Page.

As with many conservation projects, the snail exclosure at Pu‘u Kukui involves many agencies and partners: US Fish and Wildlife Service, National Science Foundation, University of Hawai‘i Mānoa, O‘ahu Army Natural Resources Program, Department of Land and Natural Resources, Plant Extinction Prevention Program, and more.

By Lissa Fox Strohecker. Originally published in the Maui News, July 14th, 2013 as part of the Kia‘i Moku Column from the Maui Invasive Species Committee.

Predator proof fences: Creating “islands” of protection in the Hawaiian Islands

Posted on July 1, 2013 by Lissa Strohecker Leave a Comment

Sometimes, fences bring freedom.

In Hawai‘i, habitat loss and invasive species have left little room for native plants and animals. And feral cats and dogs attack seabirds. Rats and mice steal eggs from endangered birds and snack on the seeds of rare plants. Introduced snails and chameleons have munched rare native tree snails close to oblivion.

Albatross chicks, like this one on Midway, are becoming an increasingly common sight on O‘ahu at Ka‘ena Point now that a predator-proof fence protects them.

At Ka‘ena Point on the northwest tip of O‘ahu, the Department of Land and Natural Resources tried to protect nesting habitat for seabirds. They closed off the area to motor vehicles and began trapping rats and other predators. It helped—Laysan albatross (mōlī) and Wedge-tailed shearwaters (‘ua‘u kani) began nesting among the native plants and in the dunes of this coastal ecosystem.. In 2011 over 3,000 shearwaters chicks hatched; and by 2012, 61 pairs of albatross took turns sitting atop their single egg. Unfortunately, control efforts only reduced the number of predators; it didn’t stop them. In a typical year, 15% of seabird hatchlings were killed. Periodically, stray dogs wandered into the reserve with catastrophic results. In 2006, 113 shearwaters were killed in a single night. The Department of Land and Natural Resources decided to build a fence.

Predator-proof fencing has been used extensively in New Zealand, but has only recently gained favor in Hawai‘i. It offers a promising solution for ongoing struggles like those at Ka‘ena. Rather than ongoing trapping to remove predators, resource managers can create protected “islands” where native plants and animals have a chance to recover.

The Hawaiian Petrel or ‘ua‘u is one of several species that cold benefit from a predator proof fence on West Maui. Photo by Jay Penniman

On Maui, two fenced enclosures are currently being built on the windward side of the West Maui Mountains at Makamaka‘ole. One is for Newell’s shearwaters, or ‘a‘o, and the other is for Hawaiian petrels, or ‘ua‘u. Both species nest in underground burrows and are vulnerable to attack by rodents, mongoose, and feral cats. The fences are designed to keep these hungry creatures out. First Wind, which built Kaheawa wind farm, is creating the four-acre enclosures as part of their seabird mitigation program to address impacts caused by the towers.

The Makamaka‘ole fences will be similar to the one at Ka‘ena. The mesh on these predator-proof fences is so small that even two-day old mice can’t crawl through. The fence will be topped with a metal hood to keep any animals from climbing over, and a skirt extends along the base to keep animals from burrowing under.

Once the first enclosure at Makamaka‘ole is complete, invasive animals will be removed and sound systems will be installed that broadcast seabird calls to attract prospecting birds. If they land to investigate, they may find home in one of the 50 artificial burrows. Erica Thoele, supervisor of habitat conservation plan compliance with First Wind, says, “Hopefully they’ll think this is a safe place and build a nest,” says Thoele. Crews will trap for predators along a 100 yard perimeter outside the fence in case any seabirds decide to nest nearby. Ongoing monitoring will help evaluate whether seabirds are using the artificial burrows or digging their own nests in the enclosure.

Monitoring at Ka‘ena Point has shown promising results. The 700 yard fence was completed in March 2011 and protects 59 acres of coastline from predators. There have been dramatic increases in seabird productivity now that the rats have been removed- a 25% increase in the number of albatross nesting at Ka‘ena, and a doubling of the number of Wedge-tailed shearwater chicks fledging. Native plants are also showing signs of recovering with more abundant fruits, seeds and seedlings than had been observed prior to removing predators. The fences may keep the hungry critters out, but well-behaved humans are still welcome at Ka‘ena. Double-door gates along the fence allow access to the reserve.

Fencing projects elsewhere in the state are in the works. The Oahu Army Natural Resources Program built “snail” fences to protect rare native snails from rats, mice, Jackson’s chameleons, and the invasive rosy wolf snail. A new fence will be built next year at Kīlauea Point National Wildlife Refuge to enclose nearly eight acres of habitat for six different species of breeding seabirds. Plans are in process for a fence on Lāna‘ihale to protect ‘ua‘u nesting habitat. Learn more about predator proof fencing at Ka‘ena by visiting the website hawaii.gov/dlnr/chair/pio/nr/2011/NR10-225.pdf

By Lissa Fox Strohecker. Originally published in the Maui News, June 9th, 2013 as part of the Kia‘i Moku Column from the Maui Invasive Species Committee.

Mullein and Milk Thistle-Some Medicinal Plants are a Bad Prescription for the Environment

Posted on May 29, 2013 by Lissa Strohecker Leave a Comment

Humans have always relied on plants for medicine and many modern remedies are still derived from plants.

Blessed milk thistle, or Silybum marianum, isn’t so holy when it forms prickly, invasive thickets. Conservationists quick to eradicate it from Maui pastures. Photo courtesy of Maui Invasive Species Committee

The active ingredient in aspirin, salicylic acid, is now synthesized in a lab but used to be obtained from the bark of willows, or plants in the genus Salix. Digitalis, a drug for heart conditions, is one of a group of medicines extracted from the foxglove plant, Digitalis purpurea. An Alzheimer’s treatment, galantamine, is either produced in the lab or extracted from daffodils. Present-day herbalists harvest or grow plants to treat everything from acne to weight loss.

But while they may have health benefits for people, some medicinal plants may sicken our environment. Mullein, notable for its use as a respiratory aid and a remedy for skin problems, is one example. Common mullein, or Verbascum thapsus, thrives on bare soil at mid to high elevations—think the painted landscape of Haleakalā crater. It can monopolize the habitat of native plants, such as the iconic silversword. Mullein is not established on Maui, but the cinder slopes of Mauna Kea and Mauna Loa on Hawai‘i Island are now covered with this highly invasive plant.

Blessed milk thistle, or Silybum marianum, is renowned to herbalists for protecting the liver from poisons. This thorny thistle is equally famous for its invasiveness. Darwin commented on the impacts of this European native as he rode through the pastures of Argentina: “When the thistles are full-grown, the great beds are impenetrable…” He continued to describe the murderous robbers who hid amongst the thistles. Blessed milk thistle has been found in a Makawao pasture, and is on track for removal. At one time this plant was in cultivation on Maui for its medicinal properties. Fortunately that is no longer the case.

Mullein, or Verbascum thapsus, invades on the open slopes of Mauna Loa and Mauna Kea. This medicinal plant is not a good prescription for the environment. Photo by Forest and Kim Starr.

There is much to be learned from studying plants. The practices of herbalism in naturopathy, traditional Chinese medicine, or lā‘au lapa‘au, Hawaiian plant medicine, all stem from living close to nature. Knowing when to harvest plants and what parts to use is an impressive skill. So too is knowing which plants to grow and where.

Hawai‘i is home to a diversity of plants and animals found nowhere else in the world, some with healing properties. When non-native, invasive species become established, they disrupt the interdependent relationships that characterize healthy, intact native ecosystems. Growing medicinal plants can be a way to revive and retain ancient types of knowledge. It can be an avenue to connect with your natural surroundings. And, with a little forethought, it can be done in balance with the environment.

If you are going to grow your own medicinal plants, choose species that are not invasive or otherwise harmful. The common artichoke, for example, has the same liver-supporting compounds as blessed milk thistle, without the invasive characteristics.

How can you determine whether a plant is problematic? The Hawai‘i Pacific Weed Risk Assessment is a screening tool that evaluates plant species’ biological characteristics and their potential for becoming invasive. Check it out at www.plantpono.org.

By Lissa Fox Strohecker. Originally published in the Maui News, May 12th, 2013 as part of the Kia‘i Moku Column from the Maui Invasive Species Committee.

The “yellow dragon disease” is perched on Hawaii’s doorstep

Posted on April 30, 2013 by Lissa Strohecker 2 Comments

Tangerines, oranges, lemons, limes, pummelo and grapefruit— sharing a box of citrus just picked from the backyard is part of life in Hawai‘i, much as leaving your slippers outside the front door.

But imagine walking outside to find your trees covered in bitter, misshapen fruit: no more fresh lemons, tangerines, or oranges from your yard. Backyard gardeners and commercial growers across the mainland are scrambling to protect their citrus in the face of one of the most serious citrus diseases in the world, a disease perched on Hawai‘i’s doorstep.

Citrus greening disease, also known as huanglongbing or yellow dragon disease, originated in Asia. It was first detected in the United States in Florida in August of 2005. By July of 2008 it had spread across the state. It has since sprung up in backyards and farms throughout the Southern United States. Once infected, plants don’t recover and thousands of trees throughout the Southeast have died. The impacts to the citrus industry in Florida have been profound. California citrus growers are bracing themselves after the disease popped up in a Los Angeles suburb last summer.

A tiny, gnat-sized insect, the Asian citrus psyllid (Diaphorina citri), is responsible for spreading citrus greening disease. These psyllids feed on the stems and leaves of citrus and must feed on an infected tree to spread the bacterial disease. Currently, citrus greening is not present in Hawai‘i, but we do have sizeable populations of non-native Asian psyllid. Across the mainland the trend has been for the arrival of the psyllid to be followed by the disease.

The Asian citrus psyllid was first detected on the Big Island in 2006. Monica Tauyan is a plant pest

The pattern of “blotchy mottle” on this citrus leaf is an classic sign of a citrus greening infection. Photo courtesy of the University of Florida Institute of Food and Agricultural Sciences-Citrus Canker.

control technician with the Hawai‘i Department of Agriculture. She is part of a team that regularly surveys citrus across the state for citrus greening. Tauyan has no problem finding the Asian psyllid living on a variety of different citrus. “The psyllid causes leaf curl,” she says, “but the major concern is the disease.” If citrus greening arrives, the psyllids will carry the disease from tree to tree. Tauyan conducts surveys on Maui several times a year, and on Moloka‘i and Lāna‘i annually. Her efforts have been focused on farms, nurseries, and residences, and to date, have come up empty handed.

She’s looking for blotchy mottling on the leaves in an asymmetric pattern, “It’s the classic symptom.” according to Tauyan. When she finds this, or other indicators—such as yellowing leaves or misshapen, bitter fruit that don’t ripen—she collects samples and sends them to the University of Hawai‘i for testing. “We’ve been doing surveys since 2009. So far we’ve had no positives.”

If citrus greening makes it to Hawai‘i, Tauyan thinks it will likely arrive in the form of an infected psyllid. Psyllids carry the disease for life. A miniscule psyllid slipping undetected into Hawai‘i could spell big trouble for our citrus and inspectors with the Hawai‘i Department of Agriculture are on the lookout.

Malformed fruit also indicate and infection of citrus greening. Photo courtesy of the University of Florida Institute of Food and Agricultural Sciences-Citrus Canker.

You can help. First, don’t bring citrus plant material into Hawai‘i from the mainland or other parts of the world without first checking with the Hawai‘i Department of Agriculture. Secondly, regularly check your citrus. If the leaves are blotchy and mottled unevenly, or the fruit is misshapen and not ripening correctly your citrus could be infected. Confirming the diagnosis requires lab work, as there are also mineral deficiencies that resemble a greening infection. Contact Tauyan at the Department of Agriculture on O‘ahu 808-973-9528 if you are concerned about your citrus plants, or collect a sample yourself and submit it to the local extension office of the College of Tropical Agriculture and Human Resources in Kahului or Ho‘olehua on Moloka‘i. Submission guidelines are online at www.ctahr.hawaii.edu/dnn/yellowdragon/SampleSubmission.aspx. Learn more about the disease and find an app for reporting possible cases of citrus greening at www.saveourcitrus.org

By Lissa Fox Strohecker. Originally published in the Maui News, April 14th, 2013 as part of the Kia‘i Moku Column from the Maui Invasive Species Committee.

The crown-of-thorns starfish–despite the prickly reputation, this species is native to Hawai‘i, and beneficial to the reef

Posted on April 15, 2013 by Lissa Strohecker 10 Comments

The crown-of-thorns starfish does munch on coral, but new research is showing that this species, native to Hawai‘i, benefits the reef. Photo courtesy of the National Oceanic and Atmospheric Administration[/caption]A single crown-of-thorns starfish is impressive. This unusually large, sinister-looking sea star grows to three feet in diameter with as many as 19 spiny arms. It’s hard to miss on the reef, where it munches on coral. Crown-of-thorns have the highest fertilization rate of any invertebrate: each female can produce up to 60 million eggs during a single spawning season. When too many of these survive, it’s considered an “outbreak.” An overabundance of crown-of-thorns can spell trouble for Pacific reefs. It’s an unusual case of a native animal acting invasively in the marine environment. But it’s not clear that all outbreaks are bad or how environmental changes might exacerbate the problem.

Proliferations of the spiny creatures can destroy 90 percent of a reef, as past outbreaks in Saipan, the Marshall Islands, and Guam have shown. In situations where the reef is stressed, an abundance of coral-eating starfish can trigger a cascade of changes. First the corals go, replaced by algal overgrowth. The resulting shift in fish populations can take years to recover. In Hawai‘i and Australia, concerns about crown-of-thorns outbreaks have focused on the reduced aesthetic value of the reef, and consequently, a decline in tourism. For some communities the reef is the icebox, and crown-of-thorns outbreaks can leave it empty.

But outbreaks rarely occur in Hawai‘i. Many crown-of-thorns starfish larvae die off, while adults are eaten by triton’s trumpet snails, stripebelly pufferfish, and harlequin shrimp. A healthy reef can support small numbers of prickly stars, and it’s probable that they benefit the reef in some way. According to Russell Sparks, aquatic biologist with the Department of Land and Natural Resources Division of Aquatic Resources, “In Hawai‘i, crown-of-thorns starfish feed on fast-growing, quick-to-settle corals, such as rice and cauliflower coral. These corals can overrun other species like lobe and finger coral, so a periodic bloom of crown-of-thorns could be an important way for reefs to maintain coral diversity.”

In 2004, marine biologists observed a crown-of-thorns outbreak in ʻĀhihi Kīna‘u. “Although the coral cover impacts were dramatic, the recovery seems to be well on its way,“ says Sparks. “It may increase overall coral diversity, which should make the reef more resilient to future disturbances.”

Until recently scientists hypothesized that crown-of-thorns outbreaks in remote locations such as Hawai‘i, Guam, and French Polynesia resulted from an influx of larvae from elsewhere in the Pacific. In Australia, massive starfish outbreaks spread south along the reef in waves, seeded from larvae upstream. But new research indicates that Hawaiian blooms occur within the native population. A team of scientists from the University of Hawai‘i-Manoa looked at the genetics of crown-of-thorns starfish and found that these supposed “invaders” were actually locals—they weren’t some rogue population from across the Pacific. What does this mean?

Crown-of-thorns outbreaks are not fully understood. The species may be acting invasively because of human interference. Some biologists theorize that heavy rainfall and coastal nutrient runoff contribute to a higher than normal survival rate for larvae, resulting in a larger number of adults. Over-harvesting of the species’ natural predators could be another potential trigger. Researcher Dr. Rob Toonen recommends that marine wildlife managers “seriously consider the role that environmental conditions and local nutrient inputs play in driving crown-of-thorns outbreaks.”

You can help scientists learn more. The citizen-monitoring project Eyes of the Reef relies on reports from regular reef users to monitor reef health. Crown-of-thorns sea stars are one species of focus. Early detection of outbreaks is critical to protecting the reef. Report any occurrence of 20 or more crown-of-thorns starfish through the Eyes of the Reef monitoring project at reefcheckhawaii.org/eyesofthereef.html

By Lissa Fox Strohecker. Originally published in the Maui News, March 10th, 2013 as part of the Kia‘i Moku Column from the Maui Invasive Species Committee.

Conservation: Helping the Economy and the Environment

Posted on March 26, 2013 by Lissa Strohecker Leave a Comment

Darryl “Kanamu” Tau‘a was an East Maui tour bus driver who lost his job during the decline in tourism post September 11, 2001. Imi Nelson, a recent Hāna High graduate, was looking for work that would keep him close to his family. That fall, in response to the economic downturn, the Hawai‘i state legislature appropriated $1.5 million to create an emergency environmental workforce that put 450 people back to work. Kanamu got a temporary job controlling miconia, a South American tree invading the East Maui watershed. Imi joined the dengue fever response crew, helping to eliminate the environmental conditions that foster disease-spreading mosquitoes. Later, when the Maui Invasive Species Committee (MISC) had openings on its Hāna miconia control crew, both Kanamu and Imi had the necessary field experience. They landed permanent jobs—hard to come by in rural Hāna.

Conservation means jobs and those jobs mean new skills. Kona Ball and Darrell Aquino of MISC prepare to rappel down a cliff while Robert Vincent of East Maui Watershed Partnership looks on.

Conservation means boots on the ground and fingers on the keyboard. In Hawai‘i, it means jobs for thousands of people throughout the state, from Hāna to Honolulu, Hilo to Hanalei. Local suppliers and contractors provide goods and services for conservation projects, further multiplying the benefits of dollars spent. Natural resource work in Hawai‘i brings an estimated $456.6 million to the economy as wages, goods, and services, according to a report on the Green Industry from the University of Hawai‘i Economic Research Organization. Funding comes from a variety of federal, state, county, and private sources, with the bulk spent employing an estimated 3,275 people working in the field or office. In addition to wages, these jobs as technicians, researchers, hunters, construction workers, data managers, grant writers and accountants, educators, and managers often provide extensive training and skill-set development opportunities.

University research highlights other economic benefits of conservation work, which protects our water supply, food, beaches and reefs, and makes Hawai‘i a great place to live and visit. Natural resource management safeguards more than just native birds, plants, and insects. Almost all of the water Maui County uses is captured from rainfall, and a healthy watershed is key to maintaining adequate and safe water supplies. Economists estimate that if the Ko‘olau watershed on O‘ahu was rendered unusable and no longer contributing to the aquifer, the loss would be between $4.57 and $8.52 million.

A conservation worker learning to attach an external load to a helicopter.

Conservation jobs have been somewhat insulated from the turmoil of employment in the tourism sector. Despite a decline in state job growth of 1 percent over the last five years, jobs in natural resources have increased 1.5 percent. People working in natural resources think that jobs will increase modestly, an opinion likely shaped by concerns about the current state of the economy. In Hawai‘i, where we rely on the environment for so many things, there is plenty of work to be done. Approximately 800,000 acres across the main Hawaiian Islands are in some kind of active conservation management, though there are an estimated 1,900,000 acres of healthy native ecosystem needing protection.

Nelson and Tau‘a continue to live in a rural community, in part because they have jobs in conservation and have learned skills during their employment. Investments spent protecting our environment translate into jobs today and healthy resources for future generations. To find out more about green industry in Hawai‘i check out the Green Growth Report by the University of Hawai‘i Economic Research Organization online at www.uhero.hawaii.edu.

By Lissa Fox Strohecker. Originally published in the Maui News, Feburary 10th, 2013 as part of the Kia‘i Moku Column from the Maui Invasive Species Committee.

Plants Out of Place-Native to Hawaii but Invasive Somewhere Else

Posted on December 6, 2012 by Lissa Strohecker Leave a Comment

The native Hawaiian ecosystem is often described as fragile and prone to invasion, so it may come as a surprise to find that some of our island species on the most unwanted list of invasives in other parts of the world.

Native to Hawaii, naupaka, or Scaevola taccada , invades a beach in Fort Lauderdale, Florida. Naupaka chokes out plants native to Florida and may alter nesting habitat for sea turtles. Photo courtesy of Forest & Kim Starr.

In Hawai‘i, beach naupaka decorates miles of coastline, but in Florida this attractive plant is listed as a state noxious weed. Known as Scaevola taccada to the scientific community, naupaka outcompetes the endangered Scaevola plumieri native to Florida. In the Caymen Islands in the Carribean, where naupaka is also invasive, there is some concern that sea turtles may not be able to access nesting sites with mounds of naupaka blanketing the coasts. Naupaka was introduced to Florida as a landscaping option.

Pōhinahina is another Hawaii coastal native that’s proven invasive elsewhere. Crews on the coast of North Carolina remove this dune-destroying shrub. Photo courtesy of beachvitex.org

In Hawai‘i, pōhinahina, Vitex rotundifolia, sometimes known as beach vitex, grows alongside naupaka but it’s wreaking havoc elsewhere. Pōhinahina is a sprawling coastal shrub with small purple flowers. Landscapers introduced pōhinahina to the Southeastern and Mid-Atlantic States, where it now smothers coastlines, choking out native plants like the endangered sea beach amaranth. Pōhinahina is a noxious weed in North Carolina. Virginia has enacted a statewide quarantine in hopes of stopping its spread. Communities gather regularly to fight back this kudzu of the coastline.

This ‘a‘ali‘i grows on the slopes of Haleakalā, but it has also taken over rangeland in Kenya. Photo courtesy of Forest & Kim Starr.

‘A‘ali‘i, or Dodonaea viscosa, is another hardy Hawaiian native that’s problematic elsewhere. This drought tolerant plant grows in central Maui and up the slopes of Haleakalā. It’s a tough shrub with distinctive winged seedpods, and, as it turns out, doesn’t taste so great–at least to the cattle of Kenya and Uganda, where ‘a‘ali‘i takes over rangeland.
Like many of Hawai‘i‘s native plants, these species are indigenous to Hawai‘i, meaning that they are native to Hawai‘i as well as other places. Naupaka is native throughout the Pacific and India, growing on coastlines from Okinawa to Oman and from Micronesia to Madagascar. Pōhinahina’s native range stretches across the Pacific Rim and into Southern Asia. And ‘a‘ali‘i is a cosmopolitan species found from Florida to the Sonoran deserts into Mexico and across the Pacific to New Zealand and Australia.
These three plants have developed ways to spread their keiki far and wide: plentiful seeds that float and survive a long bath in salt water. ‘A‘ali‘i seeds spread inland by catching the wind and by sticking to the feathers of birds. These strategies help explain why these plants are native to such a huge area, and how they were able to reach Hawai‘i. But when these plants are released from the checks and balances found in their native habitat–competition with other species, predation by insects, even climate and geography–there’s a possibility of a problem.
An invasive plant is not inherently bad; it has developed strategies necessary for its survival. In Hawai‘i these three plants play an important role–protecting beaches from erosion and providing habitat for native animals. However, what constitutes a means to survive in one place can translate into an invasive characteristic elsewhere. It’s just a matter of the right plant in the right place.

By Lissa Fox Strohecker. Originally published in the Maui News, November 11th, 2012 as part of the Kia‘i Moku Column from the Maui Invasive Species Committee.
You can find all the articles in the Kia‘i Moku series http://www.hear.org/misc/mauinews/

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