An Island Apart: Notes on Kahoolawe Seed Collections

By Kenneth R. Wood, Research Biologist

Isolated and with no permanent residents, the island of Kahoolawe is veiled in a deep, penetrating stillness that floats out toward the vast blue horizons of day and star-spinning heavens of night.

The waters surrounding Kahoolawe are clear, sparkling, and rich with sea life, while its landscape holds many mysteries hidden in thousands of archeological sites and features. Early Hawaiians dedicated Kahoolawe to Kanaloa, Hawaiian deity of the ocean, and used the island as a place to study celestial navigation. Although Kahoolawe is the smallest and one of the driest of the major Hawaiian Islands, it continues to have great significance to Hawaiians.

Studying the Flora of Kahoolawe

Since I began my studies of the flora of Kahoolawe, I have made over 50 visits, exploring a majority of its arid gulches and coastal sites. My research was focused around the Kamohio Bay region which harbors the inspiring Aleale seastack and the nearshore islet of Puu Koae.

One of my earliest visits to Kahoolawe was around the vernal equinox of 1992 when I found myself in a magical realm. A mother and baby whale were splash-dancing in Kamohio Bay, brown boobies and other seabirds were calling along the seacliffs, and spring echoed in the earth, sea, and air. I explored and rappelled Kahoolawe’s dangerous southern seacliffs down to their crumbling base, and pushed myself further to ultimately climb the adjacent Aleale.

In those forthcoming moments a new endemic Hawaiian genus of plant was found, and was given the most appropriate name, Kanaloa kahoolawensis, by NTBG’s Director of Science and Conservation Dr. David Lorence.

Subsequently over the next few decades, NTBG continued to support our Kahoolawe research, allowing me to partner with staff from the Kahoolawe Island Reserve Commission (KIRC) and others, and we were able to collect seed of Kanaloa and cultivate several individuals. Although this genus has since gone extinct in the wild, several Kanaloa plants still survive on Maui from seed collected during these visits. Today those young — yet evolutionarily ancient — trees give hope to the future of Kanaloa and to those who wish to perpetuate the Hawaiian flora.

Seed Collections

From 1992 to the present, NTBG and the KIRC have collected seed from almost all the wild native plant species we encountered on Kahoolawe. One especially rewarding seed conservation effort took place during the turn of the century when I teamed-up with Maya LeGrande, a Master’s student at the University of Hawaii, Manoa. Her research focused on the charismatic dry forest tree, wiliwili (Erythrina sandwicensis [Fabaceae]) which occurs throughout the main Hawaiian Islands.

As dry forests are the most drastically altered and endangered ecosystems in Hawaii, I keenly supported her research. On Kahoolawe we tagged, mapped, and collected seed and DNA from as many naturally occurring wiliwili as we could find. Maya’s thesis work centered on the supposition that the preservation and conservation of wiliwili populations may be critical for the success of other native dryland forest species.

In the end, we mapped 75 mature wild wiliwili individuals along with 34 juveniles, all mostly around the upper Kaukamoku and Puu Moaulanui region of Kahoolawe and we achieved our goal of preserving a significant percentage of their genetic variability. Sadly, following this research several groupings of those wiliwili trees burned-up in a wild fire, while others were negatively impacted by infestations of Erythrina gall wasps and bruchid beetles. It felt timely and fortunate that we facilitated our conservation collections prior to those events.

Conservation, Restoration and Outplanting

In 2002 I worked closely with the U.S. Fish and Wildlife Service and Dr. Michael Maunder, then NTBG Chair of Conservation, to create the Offshore Islet Restoration Committee (OIRC) whose goal was to inventory, protect, and make conservation collections from all of Hawaii’s offshore islets and I spent many years as the principal islet biologist.

One important focus of the OIRC was Kahoolawe’s islet, Puu Koae, where there is a very rich population of endemic ohai (Sesbania tomentosa [Fabaceae]). I loved this colony of ohai which grew alongside the endangered ihi (Portulaca molokiniensis [Portulacaceae]) and I considered the Puu Koae ohai to be the most attractive ecotype of the species. With around 300± shrubs, depending on seasonal rainfall, we collected and stored seed of this beautiful and rare dryland shrub for many years.

In my most recent attempts to collect ohai seed on Puu Koae, I’ve been finding undeveloped seed which may be the result of flower predation by larval insects, lack of pollinators, or perhaps some fungal pathogens. This recent absence of seed production once again demonstrates the importance of timely collections and the need for life-cycle studies of our endangered flora.

During my overnight stays on Kahoolawe, I would reside along the southwestern shore where there is an old navy base in Hanakanaea. At the end of our long work days, and if there was still some daylight left, I would hike to the adjacent coastal shrublands near Honukanaenae, Lea o Kealaikahiki, and Kaukaukapapa to make seed collections from Hawaii’s native cotton, mao (Gossypium tomentosum [Malvaceae]). This species has my great admiration with its silvery-green leaves, translucent multi-colored bracts, and yellow hibiscus-like flowers.

For me it is a certainty, that the mao, and all of Kahoolawe’s wild native plant populations, great or small, are evolutionarily significant and invaluable for restoration and out-planting efforts. I feel grateful to all who have supported these collections; most notably KIRC who are on the front line of dry shrubland and forest restoration and NTBG whose mission statement prescribes collecting and cultivating tropical floras’, especially those that are threatened with extinction.

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