From the muck, healthy anchialine pool habitats emerge
Catherine Spina sank waist deep into the doughnut-shaped anchialine pool in coastal Waiohinu, carefully guiding the “Muck Sucker” along the bottom. This underwater vacuum, uses a trash pump to suck up excessive sediment, leaf litter and other organic matter — all of which are fouling the unique brackish water ecosystem.
Meanwhile, Megan Lamson, Stacey Breining and Lauren Kurpita hand-pulled and removed nonnative plant species, such as seashore paspalum, by the bucket load. Such invasive species are supplanting native vegetation, taking over the habitat. Floating in a borrowed yellow kayak, Nohea Kaawa and her sister, Kaila Olson, steadily gathered the accumulating limu (algae) into a slimy pile.
It’s dirty work, but these six Hawaii Wildlife Fund team members and volunteers laughed off the conditions Tuesday as part of the rewarding experience of repairing damage and improving the environment.
Over the past five years, Hawaii Wildlife Fund has removed nonnative vegetation in and around the Hoonoua anchialine pool complex, which includes two large pools and one small pool within 1,400 acres of shoreline in southeast Hawaii Island. For decades, this debris has accumulated to create a thick layer of anoxic muck that severely degrades the habitat for native wildlife, said Lamson, Hawaii Wildlife Fund project coordinator.
But now the pools’ fortunes are rebounding and a new, healthier habitat is emerging from the muck, thanks to continuing restoration efforts. Today, tiny shrimp (opae) have been observed and recorded in traps placed in all of the pools. Prior to the restoration process, such opae were not present or so easily found in the two large pools. They were possibly hidden under the rapidly expanding mats of invasive grass and extensive amounts of limu, Lamson said.
Other encouraging signs of progress include the growth of native terrestrial plants after the clearing of nonnative plants and pumping of pool sediment into adjacent aa lava sites. The sites are at least 100 feet away, so they don’t threaten the pools should any large waves or rainstorms occur. Ilima papa (Sida fallax), makaloa (Cyperus laevigatus) and ahuawa (Cyperus javanicus) have taken root and are thriving in spots where volunteers removed Christmasberry, sourbush and lantana. Akulikuli (Lycium sandwicense) has sprouted from dried sediment beds created from pumping out pools. The coverage of native seagrass has also increased, Lamson said.
A crew from the state Division of Forestry and Wildlife Hilo office has taken on an uneasy feat: killing about 15 acres of highly invasive fountain grass northwest of the pools and maintaining it. Because of the crew’s continued persistence, most of the fountain grass in the area is dead or dying, Lamson said.
Visiting birds, including the akekeke (ruddy turnstone), kolea (Pacific golden plover) and aukuu (black-crowned night heron), have been spotted at the pools.
The Hoonoua anchialine pool complex offers a wealth of coastal, terrestrial and aquatic natural resources, including more than 52 native plants and animal species. Sometimes, when tinkering with a system, even when attempting to restore it, unintentional damage can occur. However, for this pool complex, there’s an overall benefit, Lamson said. The work has so far proven effective in increasing the native flora and fauna population, as well as in slowing down the unnatural, rapid senescence of the pools, she added.
The restoration work, which occurs up to three times a month, could not be accomplished without tremendous support. The area is remote, access requires maneuvering down a dusty, bumpy four-wheel drive road and there’s typically a two-day volunteer commitment that requires camping, Lamson said. Hawaii Wildlife Fund is a nonprofit organization dedicated to the protection of Hawaii’s native wildlife through research, education and conservation. It relies on grants, donors, partnerships and “die-hard, passionate volunteers.”
It took about 26 days to remove the invasive plants and sediment from the largest pool. However, that pool is not fully restored because of the presence of tilapia. Hawaii Wildlife Fund could not remove the fish as planned because of restrictions on Rotenone, a piscicide. The nonprofit tried various hand-removal methods, but found they were too labor intensive and only reduced the population slightly. It is still examining possible solutions to this challenge, Lamson said.
Besides removing problematic debris and plants, water-quality surveys are conducted, recording the water balance, salinity, temperature, tides and and observed shrimp. Polyvinyl chloride crustacean traps, filled with pieces of Friskies’ seafood-flavor cat food, are also placed in the pools to trap opae. The trapped species are counted and identified according to size characteristics and body morphology.
This restoration project began with a Hawaii Fish Habitat Partnership grant of $22,300 from the U.S. Fish and Wildlife Service. Last year, Hawaii Wildlife Fund received a $10,000 donation from Dolphin Quest Hawaii for continuing the sediment removal in the doughnut-shaped pool. It also received a $25,000 grant from the Hawaii Community Foundation to continue invasive plant removal from the pools outward.
Hawaii Wildlife Fund receives assistance in manpower, borrowed supplies and guidance from DOFAW, as well as David Chai, director of natural resources at Four Seasons Resort Hualalai. Hundreds of volunteers have removed invasive plants, hauled away debris and surveyed opae over the years, but help is needed. Key groups include Imi Pono No Ka Aina, Three Mountain Alliance, Big Island Substance Abuse Council and the Ka‘u Interact Club, Lamson said. “We are indebted and grateful for the support and help in these stewardship efforts,” she added.
Kaawa, DOFAW educational outreach specialist, believes restoration projects are important because they connect people with important habitats, fostering involvement and instilling stewardship. For the youth involved, they discover how they can connect and help the environment, as well as learn self-discipline and kuleana. She also thinks these opportunities are valuable because they engage Hawaiians, allowing them to be rooted in a close connection to the aina.
This project illuminates the interconnectedness of the forest and the ocean, Kaawa said. Anchialine pools typically have mauka freshwater inputs and also maintain subterraneous connection with the ocean, meaning that water levels fluctuate with the tides.
Breining said this place is special because some of the native plants only exist here and the mana is strong. She spoke about the importance of learning about and taking care of the environment. Restoration projects like this one are opportunities for people of all walks of life to feel the importance of a place with their feet and hands, she said, as well as really sink in with their hearts. Breining added that passion and participation help make places better for future generations.
Olson, an 18-year-old Imi Pono No Ka Aina graduate, has volunteered with Hawaii Wildlife Fund four times, usually with Kaawa, the sibling she looks up to the most. She possesses great love for the outdoors and is moved by the landscapes and wildlife. She said it’s important youth are engaged in projects that connect them to natural resources.
“We are the next generation and it’s up to us to help make sure we still have these beautiful things,” she said.
To get involved or for more information, email meg.HWF@gmail.com or visit wildhawaii.org.