By Ruby Pap
This month, the world’s largest environmental and nature conservation event is being held in Honolulu. The selection of Hawai‘i as host for the International Union for the Conservation of Nature’s World Conservation Congress brings attention to islands as small scale representations of environmental issues facing the planet.
Kauai’s conservation efforts provide important conservation backdrop to the WCC. The National Tropical Botanical Garden recently spearheaded a statewide group to target over half of Hawai‘i’s native plants for the IUCN’s Red List of Threatened Species. The koki‘o ke‘oke‘o (Hibiscus waimea subsp. Hannarae) story is a wonderful illustration of an iconic Kaua‘i plant on the list. You are probably well familiar with the beautiful ornamental hibiscus flower, landscaping countless home and commercial gardens. What you may not know is these versions are nonnative, and that Kaua‘i has its own endemic hibiscus that is critically endangered due to invasive species, feral pigs and a possible loss of pollinators.
Koki‘o ke‘oke‘o is found exclusively in wet forests of three valleys on Kaua‘i’s North Shore and Nāpali Coast. There are possibly only 100 individuals remaining in the wild. It has a beautiful white, pink and deep red palate combined with a rich fragrance. Like other endemic plants, it plays a key role in the ecosystem, and co-evolved with mutually beneficial native birds and insects. As plant and animal are dependent on each other for food and pollination; if one goes extinct, it often means extinction for the other.
In the world of plant conservation, it is important to not only preserve what is in the wild, but to pursue ex situ strategies with eventual in situ reintroduction. According to the Hawai‘i Strategy for Plant Conservation, ex situ conservation is an insurance policy for rare plants. It involves harvesting seeds, fruits and other clonal materials, storing them in places like seed banks, growing plants in nurseries, and then outplanting them in protected habitat.
Today, NTBG has material represented ex situ from all wild populations of koki‘o ke‘oke‘o, thanks to a collaborative effort between NTBG and the Hawai‘i Department of Land and Natural Resources, Division of Forestry and Wildlife.
This is where the research of Susan Deans, Horticultural Intern from NTBG comes in. Working with conservation biologist Seana Walsh, Deans had a research goal to determine whether the koki‘o ke‘oke‘o require a pollinator (i.e. an insect or bird) to set viable seed; and if outplanted populations are being effectively pollinated.
After determining through several controlled pollination treatments that koki‘o ke‘oke‘o does indeed need a pollinator, the “fun” part of Deans’ research was to observe several of the outplanted flowers at Limahuli Garden’s upper preserve to “catch pollinators, and nefarious visitors, in the act.” According to Deans, “all of the visitors were nonnative and most were not pollinators, but nectar thieves.” These included ants, Japanese white eyes, and honeybees that would feed on the nectar but not come into contact with the plant’s reproductive organs to pollinate them.
Interestingly, the most numerous potential pollinators observed on the koki‘o ke‘oke‘o were three nonnative species of hawkmoths. While she didn’t observe any visiting the plants, Deans’ concludes the native Hawaiian hawkmoths were probably the original pollinators to which the species is adapted. Throughout this year, researchers will continue to observe the “floral visitors” to gain a better understanding of this beautiful flower’s pollination ecology and help save the species from extinction.
If you are interested in participating in the IUCN WCC activities but can’t make it to Honolulu, check out the Kaua‘i Conservation Expo at http://ntbg.org/tours/kcee/
- Ruby Pap is a Coastal Land Use Extension Agent at University of Hawai‘i Sea Grant College Program. She can be reached at firstname.lastname@example.org.