Last weekend, students from introductory biology and botany classes met at Piliokahe Beach on the Waianae Coast to restore native dune ecosystems! We have been working our way down the dune for several years now, and my favorite part of this site is how visible our progress is across the dune. The dune slopes that we’ve planted in past semesters are overrun with native vegetation, and each semester we work our way a bit further down the dune.
Last semester, we discovered that a number of our plantings from the previous fall had been killed by squatters setting tents on our plantings. Bruce and I had discussed posting signs indicating that restoration was in progress and to take care where you step and set up camp. Since then, Bruce created and posted these signs, and fortunately, there was no evidence this semester of our previous plantings being trampled.
Hopefully these signs protect our baby plants as they establish on the dune
Erosion of last semester’s plantings
Unfortunately, the summer and fall have been extremely dry on this part of the island, and a number of our plants from the Spring 2016 semester are struggling. The dune also faced extensive erosion since our last outing, washing away some of the plants we planted on the front of the dune. Consequently, we spent our third semester filling in the same small area of the dune we worked on for Spring 2016 and Fall 2015.
Which leads me to a realization I had while we were working out there this weekend. The two sites we take the students to each semester (Kalaeloa Heritage Park and Piliokahe Beach) are different in many ways. KHP is a wahi pana (sacred place) and archeological site, which will eventually be open to the public as an educational park. Piliokahe is a public recreation beach. It is also called Tracks Beach because of the railroad tracks nearby which carried sugarcane from the rural fields to the processing plants in the city (the tracks are no longer used, but have not been removed). While both sites are in the Ewa Plain, KHP is more inland, reflecting more of a lowland scrub ecosystem, while Piliokahe is shoreline dune. None of this was the realization I had, as that is all fairly obvious if you’ve ever been to these sites. My realization was in how I view these sites and the importance and meaning of our restoration work there. In my mind, our work at Kalaeloa honors Hawaii’s past, while our work at Piliokahe represents the struggles facing the future of conservation. Our goal at Kalaeloa is to restore the site to what it might have looked like when it was inhabited, to contribute to the physical preservation of Hawaii’s past in the form of the archeological structures, and the intellectual preservation of Hawaii’s past in the educational role the park will serve when it is open. Our goal at Piliokahe is to counter the impacts of public recreation and help the native plants take back the dune from the humans and buffel grass that have slowly overrun it. Our plants at Kalaeloa are protected by a fence, and by Shad Kane and his crew who are developing the park. Our plants at Piliokahe are vulnerable. Vulnerable to the elements and to human ignorance and apathy.
Bruce instructs the students against the backdrop of recreational use at Piliokahe
The good news is that the older plantings that have established a bit more are still doing extremely well. In particular, the ‘akulikuli plants (which can take up water from ocean spray) were not surprisingly, much less affected by recent dry conditions. Across the older sections of the dune, ‘akulikuli, pohuehue, and naio were still thriving, which shows that if we can just get our little plants past the critical early stage, they will be more successful.
Successful naio (background shrubs) and ‘akulikuli (foreground vine)
As with past semesters, the students first removed invasive buffel grass from a portion of the dune before planting our plants. Buffel grass is particularly problematic because it is fire adapted. All it takes is one cigarette butt out the window of Farrington Highway right next to the beach, and even a small fire promotes the spread of buffel grass, which recolonizes burned areas much faster than the native Hawaiian plants.
After that, we planted the following plants (the first three species were propagated by my students. The rest were propagated by Olivia George’s class, or by Bruce directly):
Pōhinahina, poh-hee-nah-hee-nah (Vitex rotundifolia) This native shrub gets its name from its tendency to fall over (pohina) as it grows taller and from the silvery-gray (hinahina) hairs that protect it from the sun. It is native to Hawai’i, but also found in Japan, India and many other Pacific islands.
Pōhuehue poh-hoo-ay-hoo-ay (Ipomoea pes-caprae subs brasiliensis) This vine also assists with erosion control, and is already well-represented throughout the dune from previous plantings, so we know it will do well at Piliokahe.
‘Akulikuli, ah-coo-lee-coo-lee (Sesuvium portulacastrum) This native shrub is common in coastal areas, marshes, lagoons, and rocky shorelines and can grow directly out of exposed coral beds. It is so well-adapted to shore life that it can take up moisture directly from sea-spray off the ocean, despite the salt content of this water source. ‘Akulikuli bears a strong physical resemblance to the invasive pickleweed, and the two are sometimes confused.This plant is also edible – the small, succulent leaves can be eaten raw or cooked.
Aki’aki ah-kee-ah-kee (Sporobois virginicus) This indigenous grass is common along many Hawaiian coastlines. Like many grasses, ‘aki’aki forms extensive underground root and stem systems, making it also an excellent choice for erosion control and soil retention. Bruce identified this plant as the most important of our Piliokahe plantings because of its impressive erosion control abilities.
Pā’ū o Hi’iaka pah-ooh-oh-hee-eee-ah-ka (Jacquemontia ovalifolia subsp sandwicensis) The Hawaiian name of this endemic vine translates as ‘the skirt of Hi’iaka’ – the vine is said to have protected Hi’iaka, the infant sister of the volcano goddess Pele, from the harsh Hawaiian sun as she lay on the beach while Pele was fishing. The vine produces rather pretty thick green leaves and small bluish purple flowers, which resemble a skirt. Pā’ū o Hi’iaka readily spreads throughout the dunes, and mature plants can be seen in many of the restored areas in the photos below.
Hinahina kū kahakai hee-nah-hee-nah koo kah-hah-kye (Heliotropium anomalum) This endemic shrub also takes its name from silvery-gray (hinahina) hairs that protect the leaves from the sun, and its location near the ocean (kahakai). It is the official flower of Kaho’olawe and is frequently used in lei.
My students’ plants, all ready for their new home!
My previous comments about Piliokahe representing the future of conservation in Hawai’i are perhaps why I always find the tray of baby plants so hopeful. We have this little army of plants, that we’ve cared for and trained, and we’re going to strategically place them on the dune to fight back against the buffel grass, the dry soil, the eroding waves, the human obliviousness, and they’ll do it one leaf, one flower, one microscopic root hair at a time, with no help from us. And Bruce and I will come back next semester with a new crop of students and a new batch of plants to congratulate the winners and try again in the space left by the losers.
Laci M. Gerhart 