I joined the Hawaii Audubon Society for a service project to weed and care for several patches of ‘ihi‘ihilauakea — a rare endangered endemic fern — at Hanauma Bay.

It was a beautiful morning when about 25 of us met at the picnic tables under the ki‘awe trees at Hanauma Bay Nature Preserve.  After checking in with Meagan Rathjen who organized the event for the Audubon Society we met Marian Chau, who did her Ph.D. dissertation on ‘ihi‘ihilauakea (Marsilea villosa) and led the service project for the day.  Marian shared fascinating aspects about ‘ihi‘ihi — its nickname — which is found in only 6 naturally occurring populations on O‘ahu and Molokai.

The first place Marian took us to was a depression/ditch/culvert that drains the park where the ferns have been outplanted.  Under “normal” conditions ‘ihi‘ihi grows as ground cover rarely growing a few inches high.  But the fern has a unique adaptation — it can survive alternating periods of flood and drought.

The ferns can live submerged in water with long stems that can be several feet long and permit its leaves — which resemble four leaf clovers — to float on the surface like lily pads.  Hence its English name — villous waterclover.

The fern goes through its life cycle putting out spores before the pool of water dries out.

When the water is gone, the green part of the plant dies and its roots go dormant.  The roots remain dormant until the next rain whereupon the fern springs back to life.  The ferns have a second strategy for surviving even longer prolonged periods of droughts.  Their spores have a super hard coating that protects them for decades and germinates only when submerged in water which softens the coating and permits the spore to burst through and germinate.

After Marian shared the fascinating life cycle of the fern, she lead us to ‘Ihi‘ihilauakea Crater which is named after the fern and is located on the far side of Koko Head.

While making our way up Koko Head, long time volunteer Larry Abbot pointed out endemic kawelu grass (Eragrostis variabilis) to the group.

When we reached the top of Koko Head we were thrilled to see a rain squall with a rainbow blowing in from Maunalua Bay.

We then descended the crater rim and dropped down to hike along the very edge of the coast.

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What a gorgeous day to admire Hanauma Bay and the Ka Iwi Coast!

Recent rain caused many native plants to flower such as this endemic ma‘oli‘oli — the native carnation (Scheidea globosa) — which produces cute little flowers in ball like clusters.

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We were thrilled to see so many ma‘oli‘oli flowers along the edge of the bay.

We also enjoyed seeing the bright yellow flowers of endemic nehe (Melanthera integrifolia).

And the beautiful yellow-orange color of indigenous ‘ilima flowers (Sida fallax).

We even saw an ‘iwa — frigate bird (Fregata minor) flying high above circling the bay.

After regrouping at the front of ‘Ihi‘ihilauakea Crater we entered the ancestral home of the fern.  The plan was to remove weeds and grasses that choke the ferns and create conditions more favorable to ‘ihi‘ihi.

The largest patch of ferns were under a ki‘awe tree knocked over on its side.

We split up into smaller groups and weeded several different patches of ferns.

Because of the good turnout in volunteers, the work was completed quickly — no more than 90 minutes of actual work.

We cleared ferns of weeds and placed branches around and over them to provide protection and shade.

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Time flew by quickly and soon it was time to leave.  As we climbed back up to Koko Head and made our way back to our cars along the rim of Hanauma Bay, I felt good helping to keep this rare and unique fern alive its ancestral home.  What a great place to visit!

SOURCES

‘Ihi‘ihilauakea, HawaiianForest.Com

Kawelu Grass (Eragrostis variabilis), USDA

Maolioli, Schiedea globosa, Native Plants Hawaii

Recovery Plan for Marsilea villosa, USFW