Dubautia herbstobatae
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Dubautia herbstobate (Na’ena’e)
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[edit] General Information
The Dubautia herbstobatae which is commonly known as the Na`ena`e is a perennial, spreading shrub that produces yellowish-orange flowers. This shrub grows mainly in moist areas and is known to grow well on ridges and steep slopes. Leaf size and arrangement vary from plant to plant (Wagner, W. L., D. R. Herbst, and D. H. Lorence).
On the Hawaiian Islands, there are 21 endemic species of Dubautia. The Dubautia herbstobatae is currently one of the 2,362 species protected by the Endangered Species List (U.S. Fish and Wildlife Service Threatened and Endangered Species System). While the Dubautia herbstobatae is endangered, other members of the species range from being common plants to also being endangered (College of Tropical Agriculture and Human Resources).
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[edit] Habitat
The Dubautia herbstobatae is a native plant to Hawaii. The plant only grows in two locations within Hawaii. The Dubautia herbstobatae is restricted to Ohikilolo Ridge and Keaau Valley in the Waianae Mountains on Oahu, Hawaii (Hawaii Biodiversity and Mapping Program).
The Hawaiian Islands are the most isolated islands in the world in terms of distance from other land masses. The Hawaiian Islands also have an extremely high diversity of habitat types (Bruegmann, Caraway, and Maunder 2002). This isolation is part of the reasoning behind the Dubautia herbstobatae being on the Endangered Species List. Because of the isolation caused by an island habitat, the spreading of the Dubautia herbstobatae and the amount of habitat for the Dubautia herbstobatae to grow on is limited. The Dubautia herbstobatae usually makes its habitat in dry-mesic to mesic areas. The Dubautia herbstobatae can often be found on open, north facing rocky slopes and cliff faces. The vegetation of habitats in these locations is usually sparse shrub land and scrubby forest grounds (U.S. Fish and Wildlife Service Pacific Islands Fish and Wildlife Office).
[edit] Current Status
The Dubautia herbstobatae was placed on the Endangered Species List in 1975 (U.S. Fish and Wildlife Service Pacific Islands Fish and Wildlife Office). Since the Dubautia herbstobatae was placed on the Endangered Species List, the population has had variation.
When the Dubautia herbstobatae was originally placed on the Endangered Species List, fewer than 100 of the plants were still in existence. With the implementation of a management plan, that number rose to roughly 500. However, the population number then fell back down to approximately 100 plants. The number has again grown, and today approximately 1,200 of the plants are in existence (U.S. Fish and Wildlife Service Pacific Islands Fish and Wildlife Office). However, it is crucial to continue to protect and monitor the Dubautia herbstobatae, because history has shown that it is not safe yet even though numbers have dramatically risen.
[edit] Threats
Of the four forces that make up the “Evil Quartet” (habitat destruction, introduced species, overexploitation and secondary extinctions), only two of those forces play major roles in driving the Dubautia herbstobatae to extinction. However, there are also local forces that threaten the future and the existence of the Dubautia herbstobatae. The Dubautia herbstobatae has not faced overexploitation. It has also not had to deal with circumstances that lead to secondary extinctions. However, the forces that the Dubautia herbstobatae has faced and have caused problems for the plant are habitat destruction and introduced species. In terms of habitat destruction, fire is a major threat that this plant is facing.
Also, the Dubautia herbstobatae is being driven to extinction by introduced species (Hawaii Biodiversity and Mapping Program). In terms of other species threatening the Dubautia herbstobatae, the plant is mainly threatened by feral hogs and goats (Natural History Information for Special Status Species). Goats are considered to be the greatest threat the Dubautia herbstobatae is facing. Goats are causing a major problem, because they are trampling the Dubautia herbstobatae in areas that are inaccessible to humans (U.S. Fish and Wildlife Service Pacific Islands Fish and Wildlife Office). This means that hunting and population control of the goats is hardly an option.
Sometimes an introduced species can be around so long that it can be considered native. There is a gray line between when a species crosses the line from being introduced to native. This is a case where wild pigs and goats that are threatening the Dubautia herbstobatae could be considered either introduced species or a local/native threat. The pigs and goats threatening the Dubautia herbstobatae were not originally from Hawaii, but they were brought to Hawaii so long ago that they can probably be considered native. Alien vegetation is causing problems for the plant (Hawaii Biodiversity and Mapping Program). Other plants are competing for the same habitat. Those plants typically have larger populations and can be more competitive for resources than the Dubautia herbstobatae can be. However, currently alien vegetation is not the greatest threat facing the plant. Because the Dubautia herbstobatae makes its habitat on steep, exposed areas, not nearly as many plants compete for the same area. In less extreme habitats, there is much more competition for the Dubautia herbstobatae (U.S. Fish and Wildlife Service Pacific Islands Fish and Wildlife Office).
Stochastic Threats
Stochastic threats are random events in small populations that may have a large impact on the population’s dynamics and the population’s persistence. The two types of stochastic threats the Dubautia herbstobatae is facing are environmental threats and catastrophes.
Environmental threats cause variation in birth and death rates from season to season in response to factors such as weather, disease, competition, predation and other factors that are external to the population. Human visitation because of local residents and tourists can pose a threat to this plant (U.S. Fish and Wildlife Service Pacific Islands Fish and Wildlife Office).
Catastrophes are an extreme form of environmental stochasticity. If a landslide were to occur, the plant would likely become extinct because the population is so small and concentrated. Also, fires are an issue facing this plant. Again, the threat of fire is intensified more so than in other species because of the small population being located in a concentrated area.
[edit] Projections for the Future
There is little evidence of reproduction among the Dubautia herbstobatae. This is another issue that factors into this plant’s road to extinction (Hawaii Biodiversity and Mapping Program). The limited reproduction of the Dubautia herbstobatae makes the protection of the plant all the more crucial. Currently, 1,206 mature and 11 immature individuals are known to exist in the northern Waianae Mountains of Oahu (U.S. Fish and Wildlife Service Pacific Islands Fish and Wildlife Office). The mature individuals are currently far outweighing the immature individuals due to the lack of reproduction among the Dubautia herbstobatae. However, the number of plants is currently on the rise in this area because of efforts to eradicate the goats (U.S. Fish and Wildlife Service Pacific Islands Fish and Wildlife Office).
Today, because of the Endangered Species Act, the Dubautia herbstobatae is being protected. However, the status of the species still does not have a positive outlook. Due to the small population, a catastrophe such as a landslide or large fire outbreak could bring the end for the Dubautia herbstobatae.
[edit] What Lies Ahead
What Can Be Done
The key to saving the Dubautia herbstobatae is continuing to have a strong management plan implemented. There are several factors and details that need to be taken into consideration when working specifically to protect the Dubautia herbstobatae.
Research needs to be a key component to the plan. Some of the main informational points that need to be collected as the process occurs are: 1) the number of plants alive; 2) the number of plants that have been killed in the process; 3) the number of lab plants vs. plants in the wild; 4) the success rate of plants reintroduced into the wild; and 5) the changing role of the plant’s threats. This information would primarily come from researchers and would need to be relayed to all of the plant’s researchers. The research would then need to be used to educate various audiences.
Researchers would not be the only people who would need to be informed about the plant’s status. Other stakeholders to keep informed would be: 1) interest groups; 2) Hawaiian residents; 3) Hawaiian tourists 4) members of educational institutes; and 5) researchers of similar rare plants. The education of Hawaiian residents and tourists would not have to be in depth, but it would need to require enough information to make the target audiences aware of what the Dubautia herbstobatae is, that it is endangered, that a plan has been put into place to protect it and that they need to do what they can to protect the plant and limit its threats.
[edit] Organizations Making A Difference
The Hawaii Rare Plant Restoration Group, which is a group of federal, state and private organizations and individuals, has developed a generalized management plan that can be adapted to almost all rare plants in Hawaii.
The Hawaii Rare Plant Restoration Group’s plan has five objectives including: 1) to obtain genetic samples from plant populations; 2) to store samples collected; 3) to propagate adequate numbers to maintain genetic diversity and provide stock for reintroduction into native habitat; 4) to integrate off site and on site conservation projects; and 5) to produce an information management system and disperse data promptly to involved stakeholders (The Hawaii Rare Plant Restoration Group). While this is a broad plan generalized for Hawaiian plants, this is a good starting point for protecting the Dubautia herbstobatae.
The U.S. Fish and Wildlife Service - Pacific Islands Fish and Wildlife Office has developed and implemented a plan to monitor this endangered species. This plan has been successful in the past raising the population of the Dubautia herbstobatae from fewer than 100 plants to more than 1,200 plants (U.S. Fish and Wildlife Service Pacific Islands Fish and Wildlife Office).
U.S. Fish and Wildlife Service set aside designated critical habitat for the Dubautia herbstobatae in two units totaling 198 acres on Oahu, Hawaii. The land is consists of habitat on both state and private land (U.S. Fish and Wildlife Service Pacific Islands Fish and Wildlife Office). This land can be more easily monitored for threats to the Dubautia herbstobatae. Also, the plants can be more easily monitored in terms of research.
The Pacific Islands Fish and Wildlife Office has laid out recovery objectives. In order for the Dubautia herbstobatae to be considered stable by the Pacific Islands Fish and Wildlife Office, its threats must be controlled. Since the Dubautia herbstobatae is a short-lived perennial, it is important that these threats are controlled and that off-site collections are managed. Part of the plan to monitor the Dubautia herbstobatae is to have at least three naturally reproducing populations. The hope is that these three populations will have at least 50 individuals and will be able to increase in number. When this objective is met, the Dubautia herbstobatae will be classified as stable (U.S. Fish and Wildlife Service Pacific Islands Fish and Wildlife Office).
A second recovery objective of the Pacific Island Fish and Wildlife Office that must be met before the Dubautia herbstobatae is downlisted is to document five to seven populations on Oahu. The populations must be stable or increasing, they must be secure from threats and they must have a minimum of 300 individuals. These populations must improve or stay at this level for at least five years before downlisting occurs. This objective has yet to be met number (U.S. Fish and Wildlife Service Pacific Islands Fish and Wildlife Office).
The recovery objective of the Pacific Island Fish and Wildlife Office that must be met before delisting occurs is having eight to ten populations of Dubautia herbstobatae documented on Oahu. Again, these populations must be naturally reproducing, they must be stable or increasing in number, they must be secure from threats and they must have at least 300 mature individuals per population. In order to delist, the populations must increase or stay at that level for a minimum of five years. This objective has not been met (U.S. Fish and Wildlife Service Pacific Islands Fish and Wildlife Office).
This U.S. Fish and Wildlife Service’s plan has proposed the following future actions for its plan: Continue seed collection for genetic storage; fence select patches of plants within populations for short-term protection; survey for populations in historical sites and suitable habitat; study Dubautia herbstobatae populations with regard to population size and structure, geographical distribution, flowering cycles, pollination vectors, seed dispersal agents, longevity, specific environmental requirements, limiting factors and threats; and reintroduce individuals into suitable habitat (U.S. Fish and Wildlife Service Pacific Islands Fish and Wildlife Office).
The U.S. Army has become part of the effort to protect the Dubautia herbstobatae population. The U.S. Army is scheduled to manage the Makua Valley and the Makaha side of Kamaileunu Ridge in Hawaii. Currently, the U.S. Army is focusing on two largest populations at Ohikilolo (Implementation Plan for Makua Military Reservation) The goal of the U.S. Army monitoring these areas is to completely eradicate the goats in these areas (U.S. Fish and Wildlife Service Pacific Islands Fish and Wildlife Office).Eliminating the goats in these areas will prevent the Dubautia herbstobatae from being trampled and hopefully allow the plant to continue to repopulate. The U.S. Army has also put up a fence that runs along the southern perimeter of the Makua Valley. This fence has been put into place to prevent goats from entering the valley from the adjacent valleys of Makaha and Keaau (U.S. Fish and Wildlife Service Pacific Islands Fish and Wildlife Office).
[edit] Conclusion
The Dubautia herbstobatae, as with any species, has a role in biodiversity. While the importance of this plant may not be completely understood, it is crucial to protect it. Once a species has gone extinct, there is no way to bring it back. Species may be crucial to the survival of other species, they may be a cure to a disease or they may bring solutions to the world in the future that have not even thought of or considered today. In any case, protecting the world and the species and habitats that exist in the world is a very important cause.
[edit] Works Cited
Bruegmann, M., V. Caraway, and M. Maunder. 2002. A safety net for Hawaii’s rarest plants. Endangered Species Bulletin. Available from http://findarticles.com/p/articles/mi_m0ASV/is_3_27/ai_93608049 (accessed March 2008).
College of Tropical Agriculture and Human Resources, University of Hawaii at Manoa, Manoa Hawaii. Available from http://www2.hawaii.edu/~eherring/hawnprop/dub-spp.htm. (accessed April 2008).
Hawaii Biodiversity and Mapping Program, Honolulu Hawaii. Available from http://hbmp.hawaii.edu/printpage.asp?spp=PDAST330S0 (accessed February 2008).
Hawaiian Ecosystems at Risk Project. Puunene Hawaii. Available from http://www.hear.org/index.html (accessed April 2008).
The Hawaii Rare Plant Restoration Group, Puunene Hawaii. Available from http://www.hear.org/hrprg/ (accessed March 2008).
Implementation Plan for Makua Military Reservation. Available from http://www.botany.hawaii.edu/faculty/duffy/DPW/2003_MIP/Add/Dubher.pdf (accessed April 2008).
Natural History Information for Special Status Species. Available from http://www.25idl.army.mil/sbcteis/feis/Appendices/Appendix%20I1.pdf (accessed April 2008).
U.S. Fish and Wildlife Service Pacific Islands Fish and Wildlife Office, Honolulu, Hawaii. Available from http://www.fws.gov/Pacific/ecoservices/endangered/recovery/Documents/Dubautia%20herbstobatae.pdf (accessed April 2008).
U.S. Fish and Wildlife Service Threatened and Endangered Species System, Portland Oregon. Available from http://ecos.fws.gov/tess_public/SpeciesCountReport.do (accessed February 2008).
Wagner, W. L., D. R. Herbst, and D. H. Lorence. 2005. Flora of the Hawaiian Islands Available from http://ravenel.si.edu/botany/pacificislandbiodiversity/hawaiianflora/index.htm (accessed April 2008)
[edit] External Links
Dubautia herbstobatae 5-Year Review Summary and Evaluation http://www.fws.gov/Pacific/ecoservices/endangered/recovery/Documents/Dubautia%20herbstobatae.pdf
Hawaii Biodiversity and Mapping Program hbmp.hawaii.edu/
The Hawaii Rare Plant Restoration Group www.hear.org/hrprg/index.html
