Geranium kauaiense 

Scope: Global
Language: English

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Taxonomy [top]

Kingdom Phylum Class Order Family
Plantae Tracheophyta Magnoliopsida Geraniales Geraniaceae

Scientific Name: Geranium kauaiense (Rock) H.St.John
Geranium humile Hillebr. ssp. kauaiense (Rock) Carlquist & Bissing
Geranium humile Hillebr. var. kauaiense Rock
Neurophyllodes kauaiense (Rock) O.Deg. & Greenwell
Taxonomic Source(s): Wagner, W.L., Herbst, D.R. and Lorence, D.H. 2005 onwards. Flora of the Hawaiian Islands website. Available at:

Assessment Information [top]

Red List Category & Criteria: Critically Endangered B1ab(i,ii,iii,v)+2ab(i,ii,iii,v) ver 3.1
Year Published: 2015
Date Assessed: 2015-08-12
Assessor(s): Tangalin, N.
Reviewer(s): Clark, M.
Contributor(s): Nyberg, B.
Facilitator/Compiler(s): Schatz, G.E.
Geranium kauaiense is assessed as Critically Endangered. The taxon is endemic to the island of Kauai and has an extent of occurrence and area of occupancy of <10 km2. It has experienced severe and ongoing decline in habitat and numbers due to the impacts of invasive plants and animals. Its distribution is severely fragmented, occurring in only four localities. Geranium kauaiense has approximately 120 mature individuals. It is considered to be in two locations to account for differing degrees of fencing.

One subpopulation of G. kauaiense is threatened by pigs, goats, and deer.  All subpopulations are impacted by invasive weeds.

Geographic Range [top]

Range Description:

This species is endemic to the Hawaiian Islands, found in montane bogs on the island of Kauai from the Alakai Plateau to the Waialeale Summit between 1,220 and 1,250 m elevation. 

Countries occurrence:
United States (Hawaiian Is.)
Additional data:
Estimated area of occupancy (AOO) - km2:1.2Continuing decline in area of occupancy (AOO):Yes
Estimated extent of occurrence (EOO) - km2:10
Continuing decline in extent of occurrence (EOO):Yes
Number of Locations:2
Lower elevation limit (metres):1220
Upper elevation limit (metres):1250
Range Map:Click here to open the map viewer and explore range.

Population [top]


The taxon is Critically Endangered, with a total known population of about 120 individuals in four subpopulations.

Current Population Trend:Decreasing
Additional data:
Number of mature individuals:120Continuing decline of mature individuals:Yes
Extreme fluctuations:NoPopulation severely fragmented:Yes
All individuals in one subpopulation:No

Habitat and Ecology [top]

Habitat and Ecology:

The taxon is a decumbent sub-shrub found in Hawaiian montane bogs on the island of Kauai that dominated by Oreobolus and Carex. Furthermore, its habitat is restricted to montane wet mixed communities.

Continuing decline in area, extent and/or quality of habitat:Yes

Use and Trade [top]

Use and Trade: There are no known uses for this species.

Threats [top]

Major Threat(s): The degradation of its habitat by feral pigs and grazing by goats has been a major threat. Fences have been erected around patches of bog habitat to protect it from ungulates and larger landscape level fence is being constructed by the Kauai Watershed Alliance.  The Nature Conservancy is eradicating feral ungulates within the watershed fences. Non-native invasive species of plants have severely degraded habitat.  Direct competition by invasive non-native plant species, especially Juncus planifolius, Psidium cattleianum, Cyathea cooperi, and Axonopus fissifoliusand depredation by non-native animals pigs, goats, and deer (Sus scrofa, Capra hircus, Odocoileus hemionus) have all been observed.  In addition, the taxon is threatened by drought and climate change. Fortini et al. (2013) characterized this taxon as extremely vulnerable to climate change (Vulnerability index 0.926).  

Conservation Actions [top]

Conservation Actions:

The taxon is on the US Endangered Species List, and also on the State of Hawaii Endangered Species List. Three of four subpopulations occur in fenced areas, which provide some conservation management, such as ungulate exclusion, invasive species control, and opportunistic annual to biannual monitoring by the State of Hawaii's Plant Extinction Prevention Program. Ex situ cultivation has been unsuccessful and some seed storage has occurred.

Citation: Tangalin, N. 2015. Geranium kauaiense. The IUCN Red List of Threatened Species 2015: e.T80231538A80231679. . Downloaded on 21 July 2018.
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