Endangered Species: `Aiakeakua, Popolo

The 'Aiakeakua popolo, also known in Latin as the Solanum Sandwichense, is an endangered plant located in Hawaii.  The plant is "... a member of the nightshade family (Solanaceae), [and] is a large sprawling shrub that can grow up to 4 meters (13 ft) tall" (Hawaii.gov, Popolo‘aiakeakua Solanum sandwicense). The full taxonomic name of this plant is:

Plantae, Tracheobionta, Magnoliophyta, Magnoliapsida, Asteridae, Solanales, Solanaceae, Solanum L., Solanum sandwicense.   (USDA, Solanum sandwicense)

From the taxonomic order, we learn this plant is vascular, a seed plant, a flowering plant, a dicotyledon, part of the potato family, and part of the nightshade genus (USDA, Solanum sandwicense).

The 'Aiakeakua popolo, informally known as 'Hawaiian horse-nettle', has been endangered since 02/25/1994. The main threat to the Aiakeakua are feral pigs, degradation of their natural habitat, and competition with introduced plants in Hawaii (Center for Plant Conservation, Solanum sandwicense). Another factor to consider is this is an island plant; this creates an inability for this plant to easily move to a new setting.

The 'Aiakeakua does not provide any services to the human culture; however, it is noted that it's a member of the Solanum family. From the same family, the Solanum americanum is highly sought after for its medicinal use. Being part of the nightshade genus, 'Aiakeakua is poisonous. (Hawaiian Native Plants, Popolo (sandwicense)).  In Poisonous Weeds in Horse Pastures,one can read about the type and power of the poison within horse-nettle.  It is noted that between one and ten pounds of the plant are fatal to horses; a prime example of why this plant is not a typical part of any consumer's diet (Rutgers, Poisonous Weeds in Horse Pastures).

Similar to many plants, the 'Aiakeakua is "... a hermaphrodite that is insect pollinated"  and "their seeds are bird-dispersed".  With this in mind, the Aiakeakua does have a specific role/relationship with the insects and birds of the ecosystem (Hawaiian Native Plants, Popolo (sandwicense)). Given the size of the plant, one could assume other organisms of the ecosystem could take shelter with this plant; in my research, I was unable to confirm or deny this theory.

The 'Aiakeakua is originally from the mesic forests of O'ahu and Kaua'i. This plant is a native species, but not a keynote species. While this plant is rare and has a narrow niche (making it a specialist species), this plant has no reported issues regarding density dependency.  Because this plant is a hermaphrodite, and is pollinated by insects, there is not a threat from a lack of other 'Aiakeakua needing to be present for the survival of one. An independent density factor that is a noted threat to the 'Aiakeakua is fire, reported by Hawaii.gov within their plant face sheet for the Popolo ‘Aiakeakua.

There wasn't any information available regarding the previous population of the 'Aiakeakua in its natural habitat. Unfortunately, it appears this plant did not receive much attention or recognition until it was noted to be endangered. Per the Recovery Plan for the Kaua'i Plant Cluster (1995), " Little is known about the life history of Solanum sandwicense. Flowering cycles, pollination vectors, seed dispersal agents, longevity, specific environmental requirements, and limiting factors are unknown."

While there may not have been much interest in the 'Aiakeakua prior to its endangered classification, now their are many entities of the Hawaiian islands that are working to get the plant off of the endangered species list.  The most prominent and successful thus far is the Lyon Arboretum, housing 12 plants as of 1995.  The Lyon Arboretum is part of the University of Hawaii at Manoa.  Their mission statement is " To increase the appreciation of the unique flora of Hawai'i and the tropics, by conserving, curating, and studying plants and their habitats; providing inclusive educational opportunities; encouraging use by the broader community; and supporting the educational, scientific, and service activities of the University of Hawai'i" (Lyon Arboretum, Mission and History).

The conservation of the 'Aiakeakua has not been achieved yet. Below is a graph showing the progress made thus far.  While the number of plants have met their desired 50 plants per 3 populations, they had not matured at the time of the 5 year review (from which this data was retrieved), thus marking the plan as progressing, but not complete.

Works Cited

Barbour, Bruce, Laura Gladney, and Carey Williams. "Poisonous Weeds in Horse Pastures." Rutgers NJAES. The State University of New Jersey, 1 May 2013. Web. 6 Nov. 2015.

Garrett. "Hui Ku Maoli Ola." Hui Ku Maoli Ola. GOING GREEN PRO THEME ON GENESIS FRAMEWORK, 11 Nov. 2013. Web. 7 Nov. 2015.

"Mission & History." Harold L Lyon Arboretum. University of Hawai'i at Mānoa, 9 May 2014. Web. 7 Nov. 2015.

"Plants Popolo‘aiakeakua Solanum Sandwicense." Hawaii.gov. Web. 6 Nov. 2015.

"Plants Profile for Solanum Sandwicense (Hawai'i Horsenettle)." Plants Profile for Solanum Sandwicense (Hawai'i Horsenettle). United States Department of Agriculture. Web. 7 Nov. 2015.

"RECOVERY PLAN FOR THE KAUA'I PLANT CLUSTER." U.S. Fish and Wildlife Service, 20 Sept. 1995. Web. 7 Nov. 2015.

"Solanum Sandwicense (Popolo ‘aiakeakua) 5-Year Review Summary and Evaluation." U.S. Fish and Wildlife Service Pacific Islands Fish and Wildlife Office, 21 July 2009. Web. 6 Nov. 2015.