Kia’i Moku Column — Page 10 — Maui Invasive Species Committee (MISC)

Pigs and Pampas

Posted on January 12, 2016 by Lissa Strohecker

A spike camp in the East Maui rainforest. Camps like these are home for the crews working to protect and remove invasive species in this remote section of Maui. Photo by Maui Invasive Species Committee.

At about 4000’ elevation, just east of Koʻolau Gap above Keʻanae on the island of Maui, a four foot tall hogwire fence stretches from the cliff edge across ravines and gulches to the next cliff edge at Honomanū. This fence and a rudimentary shelter are the only indications that people have ever set foot up here. It’s a unique section of the mountain; the soil is slow to drain and the ground is boot-sucking wet, even in summer. Clouds drift through the branches of ‘ōhiʻa all day long, leaving everything soggy, though rain may not actually fall.

The fence protects this section of East Maui rainforest from the feral pigs that roam farther down the mountain, but that was not always the case. Pigs are not native to Hawaiʻi. But until a decade ago, they wandered freely up here, miles from the nearest road. Though they weren’t plentiful, they did plenty of damage as they rooted through the soil, leaving patches of bare dirt scattered over hundreds of acres.

Pigs were not the only invaders. Pampas grass, an ornamental once planted in upcountry residents’ yards, sprang up throughout this forest. The tall, clumping grass sends up a feather plume filled with seeds that travel on the wind for miles. Pampas seeds occasionally germinate in mossy tree trunks, but their preferred conditions are bare soil with regular moisture. Pigs in Honomanū cleared and prepped the forest floor for pampas grass. Once a few plants became established, conditions were ideal for spreading. They quickly began to outcompete native species.

Far from the landscaped yards, pampas grass flourishes in the East Maui rainforest, benefiting from the disturbance created by another invader, pigs. Photo by Maui Invasive Species Committee.

Of course it’s not just pampas grass that benefits from the disturbance created by pigs. Many notorious invasives spread into upland forest with the help of wild pigs–strawberry guava and banana poka, for instance. Pigs carry the seeds in their gut, then deposit them with a pile of fertilizer. Their rooting habits create wallows for mosquitoes that spread diseases to native birds. Pigs knock down native hāpu;u tree ferns to reach a starchy meal in the trunk, in the process destroying the fern’s native seedling “nursery.”

In Hawaiʻi, pig impacts are magnified. The rototilling action of a pig is a completely alien force in a forest that evolved for millions of years without a hoof or tusk. “Disturbances to the forest floor from pigs and weed problems go hand in hand,” says Dan Eisenberg, who manages the East Maui Watershed Partnership. His organization built the fence east of Koʻolau Gap and other fences that protect high elevation forest on East Maui.

Fencing out pigs and other hooved invaders is the first step in restoring native Hawaiian ecosystems. When these tusked tillers are removed, plants do better–regardless of whether they are native or introduced. Common native plants recover in under a decade, but rare species often take much longer, and face competition from exotics that became established prior to pig removal. “Invasive plant species are so fast growing compared to most plants in the native forest that our unique native species don’t have a chance without responsible management,” explains Eisenberg.

As pigs dig for roots and grubs, they rototill the soil. Disturbance and bare soil creates gaps in the forest floor opening it up for invasive plants. Photo courtesy of East Maui Watershed Partnership

The East Maui Watershed Partnership completed the fence in Honomanū in 2006, about the same time, crews from the Maui Invasive Species Committee switched from trying to spray pampas from the air to camping in the field while removing pampas on the ground. Weeklong work trips are a less soggy ordeal since the team built a tent platform. When crews find pampas hiding amongst the native foliage, they cut off any seed heads, bury them inside the plant, and then kill the pesky grass in place, being careful to not disturb the soil and open up an area for seeds to germinate again.

During the summer of 2014, crews found and controlled 87 pampas plants, only 4 of which were capable of making seeds. Compare this with the summer of 2008, when crews found 2,029 plants. Pampas grass seeds don’t remain viable for long, perhaps as short as 6 months. Soon the East Maui pampas may disappear entirely and the forest can rebound.

Read more about the efforts to remove pigs and pampas grass on East Maui at www.eastmauiwatershed.org and www.mauiisc.org.

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.

Written by Lissa Strohecker. Originally published in the Maui News on October 11th, 2015 as part of the Kia‘i Moku Column from the Maui Invasive Species Committee.

How did that get here? Strange plants atop Haleakalā

Posted on November 5, 2015 by Lissa Strohecker

High atop Haleakalā winds whip across the summit, frost crystals sparkle in the morning sun – melting as the day progresses. But even in this harsh landscape, native plants and animals can thrive – and so can invasive species.

Pineapple chamomile, a native to the Northwestern US and other places, may have been carried to Haleakala summit via a seed on a boot. Photo courtesy of Forest and Kim Starr

One of these invaders is pineapple chamomile–about as authentically Hawaiian as a coconut bikini. But here it is, growing just outside the parking lot of the summit viewing area at 10,032 feet, comfortable in the extreme, high-elevation climate of a Pacific volcano. It’s no wonder; this aromatic herb’s home range includes a wide sampling of climates and terrains: Western North America from Baja through British Columbia to Alaska, the Russian Far East, and Hokkaido, Japan.

The weed likely hitched a ride up to Haleakalā on a tourist, as seed on a shoe or jacket, brushed off as the unwitting carrier geared up for the crisp mountain climate. This is not unusual. Without realizing it, people carry little hitchhiking seeds throughout the world in their socks and gear.

Pineapple chamomile is a relative of the chamomile in your tea bag and can also be brewed up. This small shrub thrives in disturbed areas with gravelly soil and full sun, just like Haleakalā. The fern-like leaves are somewhat sticky and the leaves and flowers smell like pineapple when crushed. It has a weedy reputation in many places, springing up across the United States.

Forest and Kim Starr do regular botanical surveys on Halakalā summit. Not a bad “office.” Photo courtesy of Forest and Kim Starr.

Isolated ecosystems are populated by a relatively small number of plants and animal species, generally highly specialized to survive. But introduced plants or animals often come from diverse environments, populated by many different species, and have developed strategies to compete and survive in their native range. When a plant or animal is introduced to an isolated ecosystem, like an island, it arrives with a competitive advantage the native species may not have.

In Antarctica, researchers spent 2007-2008 collecting seeds from tourists’ bags and clothing. They found that on average a visitor to Antarctica carried 9.5 seeds along with them. An estimated 33,054 tourists visited the frozen continent during the study period, demonstrating how many seeds could be introduced. Though not all seeds would germinate or survive in their new home, the researchers estimated that as many as 61% of the seeds carried to the Antarctic came from a part of the world with a climate similar enough that they could pose an invasion risk. Researchers working in Antarctica carried even more seeds on their clothing and gear though they visited Antarctica in much lower numbers.

The Starrs also found Henbit, a non-native mint, during surveys. Photo courtesy of Forest and Kim Starr

On Haleakalā, botanists Forest and Kim Starr found pineapple chamomile, henbit (a weedy member of the mint family common in North America), and a handful of other non-native plants during their surveys of the high-traffic areas of Haleakalā National Park, a project done in conjunction with the University of Hawaiʻi and National Park Service.

When the Starrs find a single weed or very few in a small area, they can remove the unwanted plants easily. Eradicating an invasive species at this stage of invasion is highly effective, second only to preventing its arrival in the first place.

If the plant has gone to seed, eliminating the resulting seedlings may take multiple visits. Pineapple chamomile has proven a little more persistent than some of the other plants. It produced seeds before the Starrs first found it, so they keep finding a few scattered plants.

Boots are a notoriously common vector for seeds of invasive species.

The Starrs are careful not to carry hitchhikers when they survey sensitive ecosystems. Follow their lead. Take a minute to brush off your boots, clothing, and gear before traveling or visiting pristine areas. You can help prevent new species from invading in the areas you frequent, whether your expeditions take you to Antarctica, Haleakalā, or the beach.

Written by Lissa Strohecker. Originally published in the Maui News on September 13th, 2015 as part of the Kia‘i Moku Column from the Maui Invasive Species Committee.

Clearing the weeds for albatross

Posted on October 15, 2015 by Lissa Strohecker

Space is at a premium for nesting Laysan albatross on Midway atoll. Removal of the invasive golden crownbeard may have helped provide more nesting area. Photo by Forest and Kim Starr

Midway Atoll has gone to the birds. Every year 3 million seabirds flock to 1,500 acres of land 1200 miles northwest of Honolulu. The former Naval Air Station is also the most remote seabird colony in the world, home to 1.5 million Laysan albatross (65% of the global population) as well as 19 other species of seabirds – shearwaters, terns, boobies, noddies, curlews, and most recently, the translocated Laysan duck. But albatross and their feathered kin were not nearly as plentiful some years ago.

Hungry rats that devoured seabird eggs were the most obvious cause, but after rats were eradicated in the 1990s and seabird populations began to rebound, biologists were concerned that the birds’ continued recovery was blocked – literally – by an invasive plant.

Drought tolerant and fast-growing golden crownbeard, Verbesina encelioides, thrives in the harsh tropical sun on Midway Atoll. This yellow-flowered daisy-like plant grows head-high, creating a dense barricade that seabirds can’t walk through, much less nest in. Photo by Forest and Kim Starr.

Golden crownbeard, or Verbesina encelioides, is an aggressive annual herb from the desert southwest. This yellow-flowered daisy-like plant grows head-high, creating a dense barricade that seabirds can’t walk through, much less nest in. For the birds who do find a place to lay their eggs, the tangle of flowering stems limit airflow to nests, leaving chicks vulnerable to dehydration and death.

Like all invasive species in Hawaiʻi, golden crownbeard made the long journey to the Islands with the help of people. In 1903, the Commercial Pacific Cable Company was building a trans-Pacific cable and Midway was one of three intermediate stations, along with Honolulu and Guam. To transform a seabird colony into the semi-permanent home of a handful of cable operators, the Company constructed four two-story concrete buildings and shipped over 9,000 tons of soil from Hawaiʻi and Guam so the new human residents could plant shade trees and grow food. It’s possible that seeds of golden crownbeard were mixed in the soil or on equipment, but it’s equally plausible that the new islanders or later residents stationed there with the military planted this North American native as a reminder of home.

Regardless of how it arrived, golden crownbeard flourished in the harsh tropical sun. This weed is the most invasive of the more than 225 non-native plants on the low-elevation islands of Midway. It’s very drought tolerant and needs only a monthly sprinkling once the roots are established. This yellow scourge goes from seedling to flowering plant within months of germination and a single plant can produce 350 seeds.

Native Cyperus grass is replanted on Midway after invasive species are removed. The native grasses allow for more airflow to the nest as well as more space to build nests. In 2012-2013 Laysan and black-footed albatross nested at near-record levels. Photo by Forest and Kim Starr

Only a few years ago, golden crownbeard covered 80 percent of the three islands that make up Midway. In the late 1990s, the US Fish and Wildlife Service began removing the head high plants. With more funding the work pace quickened; crews head out almost daily to spray this pest. Tractors or heavy equipment can’t be used with so many seabirds above and below ground, so hand spraying is the way to go. All this work is starting to pay off.

Golden crownbeard will hopefully be eradicated from the smaller Eastern Island and Spit Islands by early 2017. The last batch of seedlings will be removed from the bigger Sand Island by 2018. As the invader is knocked back, the native grasses and coastal plants are being replanted to stabilize dunes and protect the reef.

The seabirds seem pleased with the efforts to restore their habitat. In 2012-2013, Laysan and black-footed albatross nested at near-record levels, though biologists won’t know if this increase is a result of the golden crownbeard removal efforts for several more years.

To learn more about golden crownbeard and the amazing birds on Midway visit the Friends of Midway Atoll website: www.friendsofmidway.org or the Papahānaumokuākea website: www.papahanaumokuakea.gov

Originally published in the Maui News, August 9th, 2015 as part of the Kia‘i Moku Column from the Maui Invasive Species Committee.

From the Forest to the Faucet – Every Drop Counts

Posted on October 6, 2015 by Lissa Strohecker

Big Bog, high above Hāna on the windward slopes of East Maui, and Puʻu Kukui, on West Maui are some of the wettest places on the earth with 360-400 inches of rainfall a year, so it’s hard to imagine water could ever run short. When overrun with water, it’s easy not to think about times of scarcity, much like the flow of money. Knowing now how much, when, where the dollars are coming from helps, as does prioritizing needs versus luxuries. If needs exceed income, we can earn more, spend less, or combine the two approaches.

ear the summit of Puʻu Kukui on West Maui clouds are the norm. The rain that falls here and on the slopes of Haleakalā supplies Maui residents year-round.

Near the summit of Puʻu Kukui on West Maui clouds are the norm. The rain that falls here and on the slopes of Haleakalā supplies Maui residents and visitors throughout the year.

The same is true for managing our limited water resources. Studies in Hawaiʻi are looking to see how what happens in our forests affects what comes out of our faucets.

Stream runoff is captured from East Maui to meet the needs of upcountry residents and agriculture.

Hydrologists develop water “budgets” to quantify how water moves through our environment and how much is captured for our use. They look at all the drops that go into and out of the watershed, whether in by rainfall and fog drip or out by runoff and evaporation. Sometimes water goes into the savings account – absorbed by the soil, then into the water table or aquifer through infiltration and recharge. On Maui, the water we use is either captured from surface runoff or pumped from the aquifer.

The Maui County Department of Water Supply tracks overall water use while striving to meet the needs of the community. Understanding hydrological cycles and water budgets, helps the Department plan for the future by looking at how to capture more water from the sky or spend less through runoff and evaporation to meet the needs of tomorrow. But how? Many factors influence water budgets. Research done on the mainland might not be relevant for Hawaiʻi, a comparatively tiny sprinkling of islands in the middle of a massive ocean. So the Department is working with the U.S. Geological Survey to study water systems on Maui to help prepare for the future.

The plants in a native Hawaiian forest effectively capture more water than many of the invasive plants that make up the lower elevation forests.

Differences in land cover and use affect hydrological processes, including whether native or non-native plants rule our forests. The drip-drip of water, condensing and falling from plants, is a critical source of moisture; it can easily make up 20% of the total water collected. On Lānaʻihale (the forested top of Lānaʻi), fog drip accounts for a whopping 60-80% of water input. Cook pines were planted on the island because of their impressive ability to capture fog drip, but native plants may do better. One study in forests on Hawaiʻi Island showed that 27% of the total precipitation was collected as fog drip in an ʻōhiʻa-dominated forest, but that number decreased to 16% where a forest had been invaded by strawberry guava.

Not all water that falls from the heavens makes it into the aquifer. Soil in a forest absorbs more water, and does so more quickly, than soil in nearby fields, pastures, or grassland. Forests transformed into monotypic stands of miconia plants typically have bare soil which likely captures less moisture. Water also evaporates into the atmosphere from the ground and off leaf surfaces, but the rate varies for different species. Research has shown that non-native plants release more water into the atmosphere than our native ʻōhiʻa.

One study on Hawaiʻi Island found that restoring a forest dominated by invasive trees to a native forest increased aquifer recharge. But results aren’t always consistent. A restoration project on Molokaʻi actually yielded a slight decrease in recharge. Given the complexities of our forest systems and the number of changes humans have caused over the years, it’s clear there are many mysteries yet to unravel about water systems in Hawaiʻi.

We do know that overall demand for water will only increase. Over time, so too will our understanding of how to preserve or restore healthy forests to help ensure we will have the amount of water we need, now and for future generations.

Find more information about how water cycles through forests in Hawaiʻi and on Maui including a water-budget model. You can also find tips on stretching your water budget at home on the County of Maui – Department of Water Supply’s website.

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, July 14th, 2015 as part of the Kia‘i Moku Column from the Maui Invasive Species Committee.

A Haʻiku gulch full of suprises

Posted on July 24, 2015 by Lissa Strohecker

The prickly seed ponds on this climbing vine led to a concernd Ha'iku resident reporting it to MISC as a potential invader. Turns out it is a native plant, Mucuna sloanei. Photo by Hank Oppenheimer

The prickly seed pods on this climbing vine led to a concerned Ha’iku resident reporting it to MISC as a potential invader. Turns out it is a native plant, Mucuna sloanei. Photo by Hank Oppenheimer

“Anything that bristly has got to be invasive,” said the Haʻiku resident who reported a vine that she found in the gulch on her family property. She called the Maui Invasive Species Committee (MISC) when neither she nor her relatives could identify the strange climber with seedpods covered in fiberglass-like hairs. No one in the family had noticed it before and they had worked or played in the gulch since small-kid times. She collected a specimen, prickly seedpods and all, and brought it into the MISC office.

Though bristly, it turned out not to be an invasive species after all. The unusual creeper was a native plant once widespread in low elevations on Maui and other Hawaiian Islands. Commonly known as seabean, botanists call it Mucuna sloanei.

Mucuna comes in two varieties: sloanei, indigenous to Hawaiʻi; and persericea, endemic to windward East Maui and found nowhere else in the world. There are only a few of the persericea plants left. Because of the rarity of the persericea variety, and the damage caused by pigs and cattle to its habitat, the vine was recently listed as endangered by the U.S Fish & Wildlife Service. The possibility that it could be thriving in a Haʻiku gulch, only a stone’s throw from the Haʻiku Marketplace, was therefore pretty exciting. But it takes an expert to know the difference between the two varieties and Hank Oppenheimer fits the bill.

Oppenheimer is the Maui Nui Coordinator for the Plant Extinction Prevention Program (PEPP), a Pacific Cooperative Studies Unit project that works to protect the most rare and threatened plants in Hawaiʻi. Throughout the state, a handful of people like Oppenheimer and technician Keahi Bustamente hike deep into remote forests, scaling cliffs and doing whatever they can to prevent the rarest species’ extinction. This includes collecting seeds from rare Hawaiian plants, propagating them in greenhouses, and then outplanting the precious plants in protected habitat.

For plants, garnering listing as a PEPP species of interest is a mixed blessing; it means there are less than 50 individuals left in the wild. Oppenheimer is investigating the distribution of persericea to determine if it should be included with the other 236 PEPP targets.

Finding the native Mucuna sloanei was a pleasant surprise. Photo by Hank Oppenheimer

Oppenheimer and Bustamente headed to the Ha’iku gulch. The vine turned out to be the more common sloanei, but Oppenheimer was still excited. “It was really interesting to see Mucuna in a place like that,” he said. Most of the habitat for Mucuna has been turned into pasture, farmland, or long ago taken over by invasive plants.

But as the team was leaving the gulch, they made a troubling discovery. Bustamente noticed an unusual plant with massive 2-3 foot long leaves, purple on the underside. He knew it instantly as miconia. This notorious pest and MISC target was certainly out of place; miconia is primarily between Keʻanae and Hāna. The discovery marks the westernmost naturally occurring plant in recent history.

So when the Haʻiku resident reported what she thought was an invasive vine, she actually helped uncover a relatively rare native species as well as one of the most invasive plants in Hawaiʻi. A great example of the more you look, the more you find.

Can you spot the miconia plant? The characteristic large leaves with purple undersides cued botanists into this plant’s presence in a Ha’iku Gulch. MISC file photo

To learn more about the Plant Extinction Prevention Program, visit the website www.pepphi.org. And if you think you may have Mucuna on your property, contact Hank Oppenheimer at henryo@hawaii.edu. If you would like help identifying an unusual plant, native or not, you can find a number of resources available online, including the Flikr site “Hawaii Plant ID,” curated by some of the state’s best botanists, or you can call MISC at 573-6472, particularly if you think you’ve found miconia.

Originally published in the Maui News, April 12th, 2015 as part of the Kia‘i Moku Column from the Maui Invasive Species Committee.

Mapping the Kamehameha butterfly with your help

Posted on July 22, 2015 by Lissa Strohecker

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A Kamehameha butterfly on Waiheʻe ridge on Maui. Photo by Forest and Kim Starr

Brilliant orange and fluttering through the forest, the Kamehameha butterfly, or pulelehua, is our state insect. It’s one of only two butterfly species native to Hawaiʻi, and its ancestors flew to these Islands long before the first humans stepped ashore.

Knowing māmaki is in your area can cue you in to looking for Kamehameha butterflies. Photo by Forest and Kim Starr

“A lot of butterflies could have arrived here,” says University of Hawaiʻi researcher Will Haines. “But unless they could find a host plant they died.” The Kamehameha butterfly’s ancestors had suitable hosts: Hawaiian māmaki and other close relatives in the nettle family. The pulelehua caterpillars feed only on these native plants, once common throughout the Islands. But as humans transformed forests into fields and pastures, and invasive species spread from backyards, the māmaki, olonā, and ōpuhe plants became scarce. As this caterpillar food became less common at lower elevations, so did the Kamehameha butterfly. Today, any low-elevation populations of the butterfly depend on the scattered māmaki plants found in gulches, and this endemic butterfly is mostly found in the native forests higher in the mountains where food is more plentiful.

The ancestors of the Kamehameha butterfly found a food source in māmaki and related plants in the nettle family. Photo by Nathan Yuen

But thanks to an exciting citizen science activity, the Pulelehua Project, researchers are discovering that the Kamehameha butterfly is fluttering around in surprising places. Like a community on the North Shore of Oʻahu and a backyard in Kēōkea on Maui. “This butterfly is a strong flyer – it seems to be cruising through,” says Haines.

The Pulelehua Project emerged out of Haines’ research. With funding from the State of Hawaiʻi Department of Land and Natural Resources, Division of Forestry and Wildlife, Haines has been investigating various threats to the species’ survival in the field and mapping the Kamehameha butterfly’s distribution throughout the state. Mapping butterflies across the archipelago is a big job; Haines thought others may be interested in helping.

The tiny egg case of the Kamehameha butterfly. Photo by Will Haines

The tiny egg case of the Kamehameha butterfly resembles a sea-urchin shell. Photo by Will Haines.

Kamehameha butterflies are charismatic and relatively easy to recognize, so Haines started contacting other conservation groups for help for help. He created a website, www.kamehamehabutterfly.com, filled with resources to help amateur entomologists identify the species in its different and fascinating life stages, from tiny urchin-shell like eggs to colorful adults. The website has excellent photographs of the eggs, caterpillars, adults, and their favored host plants. Butterfly lovers across the state volunteered– reports came in from conservationists and the public alike.

The Kamehameha butterfly can be recogized by the pattern of white patches on the upper surface of the forewings. Pulelehua has only three main white patches in this area (though some are divided by dark wing veins). Look-alike butterflies have more white spots. Photo by Nathan Yuen

The Kamehameha butterfly can be recognized by the pattern of white or light patches on the upper surface of the forewings. Pulelehua has only three main white patches in this area (though some are divided by dark wing veins). Look-alike butterflies have more white spots. Photo by Nathan Yuen

To date, the reports have turned up 52 confirmed sightings of the iconic state insect. Anyone can participate and reports can be recent sightings or several years old, so long as there is a photo to accompany the information about when and where the butterfly, caterpillar, egg, or even feeding damage was observed. The data collected from the mapping project will help Haines and his colleagues better estimate the distribution of the pulelehua and could shape efforts to restore habitat for the Kamehameha butterfly.

The project is ongoing and you can help. Checking a māmaki patch is a good place to start. If you have māmaki in your area, or find māmaki while out hiking, inspect the leaves for eggs, caterpillars, and even feeding damage, and submit a report.

Caterpillars of the Kamehameha butterfly can be several different colors, from green to brown, but always covered in spines and bumps. Photo by Will Haines.

Use the photos on the website to make sure you’ve got the right butterfly. At one time, the Kamehameha butterfly was the only pair of orange wings around, but now, painted ladies, red admirals, monarchs, and gulf fritillary all flit through Hawaiʻi yards and forests. These exotic species, which can easily be confused with adult pulelehua, do not seem to pose a threat to the native butterfly. Other insects do. Ants, and potentially the little fire ant to a greater degree, can prey on caterpillars and the pupa in the chrysalis. Introduced katydids have an appetite for butterfly eggs. And, as the caterpillars of Kamehameha butterfly don’t dine on introduced nettles, it’s critical to protect their native food source.

The caterpillars create a distinctive pattern as the munch māmaki leaves. This distinct pattern can bu used to document the presence of the Kamehameha butterfly. Photo by Will Haines

These are all reasons to take your butterfly-hunting habit to the next level. To attract the Kamehameha butterfly to your yard, plant māmaki and encourage your neighbors to do the same. A single plant can support ten caterpillars, but according to Haines, it’s more about establishing a critical mass of māmaki across the landscape. Physical barriers, like tanglefoot, a tacky substance designed to keep crawling critters from climbing up plants, can protect eggs and caterpillars from ants and other predatory insects. Learn more about the Pulelehua Project and submit sightings at www.kamehamehabutterfly.com.

Originally published in the Maui News, June 14th, 2015 as part of the Kia‘i Moku Column from the Maui Invasive Species Committee.

Rapid ʻŌhiʻa Death – a new threat to our watersheds

Posted on May 19, 2015 by Lissa Strohecker

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

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

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

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

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

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

Invasive species can sting aloha

Posted on April 15, 2015 by Lissa Strohecker

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.

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.

“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.”

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?

Posted on March 25, 2015 by Lissa Strohecker

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 18^th 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.

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/).

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

Look closely—the endemic insects of Haleakalā

Posted on March 13, 2015 by Lissa Strohecker

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.

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/

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

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