A lack of native seeds is spurring a federal plan to replant invasive, fire-loving grasses

A lack of native seeds is spurring a federal plan to replant invasive, fire-loving grasses

The proposal surprised local elected officials and conservation groups that were already working on local seed issues.

A USDA plan to spray parts of Maui’s fire-ravaged landscape with seeds of invasive weeds underscored how Hawaii has not stored enough native seeds for watershed-scale planting.

Parts of Lahaina and the Upcountry face the risk of significant soil runoff whenever the next heavy rain falls since the Aug. 8 fires consumed much of the vegetation that held the topsoil in place.

The USDA’s Natural Resources Conservation Service proposal surprised local invasive species group leaders, a Maui County Council member and even state land officials when it came to light last week.

Ohia are considered a “backbone species” that lay the foundation for entire local ecosystems. But it takes years to grow and painstakingly protect against invasive species. (Thomas Heaton/Civil Strike/2023)

Council President Alice Lee said it was “very disturbing information” when asked about it at a news conference on Thursday.

Councilwoman Tamara Baltin, who represents West Maui, said she hopes there will be a discussion with conservationists and community members who live in the affected areas.

“This is the first time I’ve heard that stabilization includes replanting the invasive grasses that contributed to those fires,” Baltin said Thursday. “I don’t know that this has been vetted by the community.”

Efforts are already underway to restore parts of the burn area with native, non-invasive plants. Community leaders don’t doubt the need to reduce erosion, but replanting invasive weeds would present a major dilemma.

Non-native weed species have been a long-standing conservation concern, since they choke out native plants and increase Hawaii’s vulnerability to statewide wildfires.

Federal officials said Monday that the plan still needs to be rolled out to all interested landowners, and there are plans to consult with county and state agencies.

Coordination with DLNR, the Hawaii Department of Agriculture and Maui County is the goal moving forward, according to Michael Constantinides, assistant director of technology for USDA’s NRCS.

Planting invasive weeds to control soil is better than doing nothing, says Michael Constantinides, associate director for technology at the USDA's Natural Resources Conservation Service.  (Nathan Eagle/Civil Rhythm/2023)
Michael Constantinides of the USDA NRCS says it’s better to plant invasive weeds to control soils than to do nothing. (Nathan Eagle/Civil Rhythm/2023)

NRCS’ work falls under the Emergency Watershed Protection Program and is conducted at the request of the Central Maui and Olinda Kula Soil and Water Conservation Districts.

“First we will try to find species that are available locally. These quantities will be limited. So this should be something that everyone understands,” Constantinides said in an interview on Monday.

It is likely that the rest of the plant material must come from the mainland.

Regardless of the source, the USDA will ensure inspection and testing are done “to ensure weeds and other unintended species are not included,” Constantinides said.

The USDA did not specify which species it was considering spreading, though it would not recommend species that “do not already exist in significant quantities in the landscape,” he said.

More details are expected to be released in the next few weeks.

Hawaii needs seeds

Many state conservationists acknowledge the harsh reality underlying this plan: Hawaii does not have enough seed banks to restore thousands of acres to its home state.

Ohia seeds take years to grow into trees, making them especially difficult to plant in time-sensitive landscape restoration projects. (Thomas Heaton/Civil Strike/2023)

“It would be great if we had a bunch of pili weed seeds and put them out there, but we don’t,” said Clay Trauernicht, a wildfire researcher at the University of Hawaii.

But over the past few decades, conservation efforts have focused on rare and endangered native species of Hawaiian plants, not “common or matrix species,” according to Matthew Kerr of the Hawaii Department of Forestry and Wildlife.

Kerr says he and his colleagues have faced seed shortages before.

“Not surprising, right? This is exactly what we’re talking about: We don’t have an adequate supply of native plant material to replace (invasive species),” Kerr said.

These workhorse plants — like ohia — lay the foundation for local ecosystems, but conservation groups realize there isn’t enough stock to help their dwindling numbers recover.

“Unfortunately, the fires showed us the work we should have done on Maui.”
Matthew Kerr, a botanist with the Hawaii Department of Forestry and Wildlife

A confluence of pressures on the landscape continue after the August 8 fires, including pivotal deer populations, which have been eating non-native plants again.

NRCS did not evaluate seed banks of species affected by the fires, although it found at Polihu that “nearly 100%” of non-native grasses were eaten by deer after being weakened by fire, Constantinides said.

Fence projects would also likely be part of the regional NRCS proposal, which would require signature from USDA national headquarters.

“They are very stressed, and if they continue to graze the deer, they will probably die and there will be no plant life in that landscape,” Constantinides said.

He added that any work recommended in the proposal “would not be done without the consent of the landowner.”

The proposal to plant plants such as non-native buffalo grass would likely apply to farms mostly affected by fire, not necessarily places like the vacant land surrounding Haina, said Central Maui Soil and Water Conservation District President Mai Nakahata.

“In this case, I wouldn’t call it an invasive species but it is a valuable forage species,” Nakahata said.

Nakahata added that because buffalo grass may be able to establish itself quickly, under drought, it was considered the best seed to spread to stop drought and replant fodder for livestock on fire-affected farms.

“Later, you can develop the landscape but at least you have the quick protection, which is what everyone needs now,” she said.

The USDA could also recommend “short-lived or temporary varieties as part of the seeding mix” that are used nationally and have “little or no potential for naturalization or establishment,” Constantinides said.

The Laukahi Hawaii Plant Conservation Network maintains a list of 78 different native species that would be useful in large-scale restoration work, such as koa, ohia, and aalii, or pili and kawelu.

Ohia seeds are brown and small sickle shaped inside the seed pod.  Individual seeds are about 1 mm long.  Cookie, kawaii.
Harvesting the seeds of the ohia, which are about 1 mm long, is an arduous task undertaken by some conservation groups to help the species survive. But there are not enough stocks to ensure the survival of plants in larger restoration projects. (Corey Lum/Civil Strike/2019)

But the 16 seed banks under the Hawaii Seed Bank Partnership are run by conservation groups that stockpile seeds largely for their own programs, not for the looming problem Maui faces, said Kimberly Shay, coordinator of the Lokahi network.

A survey was sent out earlier this month, seeking to understand conservation communities’ needs for native ecosystem functioning, including post-fire landscape restoration.

Such an effort would likely require teams of seed collectors to continually search for seeds suitable for planting across multiple climates and landscapes and suitable facilities to store them.

This would require an annual operating budget of a few million dollars, with an upfront investment of $10 million to $15 million to bring the seed banks up to scale and create a central repository for large collections, Kerr said.

“We have probably 30 years of research on native seeds here that shows us the way forward,” Kerr said. “We really want to move forward with this. Unfortunately, the fires showed us the work we should have done on Maui.”

Civil Beat’s climate change coverage is supported by the Hawaii Community Foundation’s Environmental Funders Group, the Hawaii Community Foundation’s Marisla Fund, and the Frost Family Foundation.

“Hawaii Grown” is funded in part by grants from the Ulupono Fund at the Hawaii Community Foundation and the Frost Family Foundation.

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