|Scientific Name:||Alectryon macrococcus Radlk.|
|Infra-specific Taxa Assessed:|
|Red List Category & Criteria:||Critically Endangered C1 ver 3.1|
|Assessor(s):||Bruegmann, M.M. & Caraway, V.|
|Reviewer(s):||Maunder, M. (Plant Conservation Committee) & Hilton-Taylor, C. (Red List Programme Office)|
The population of Alectryon macrococcus var. macrococcus which numbered about 500 plants in 1997, has declined to less than 300 plants (less than 250 mature individuals) and there is continuing decline due to the impacts of invasive species, habitat destruction and fire. Reproduction in the wild is limited. The other variety auwahiensis has an area of occupancy of less than 10 km² (on a site of only 29 ha); has less than 50 mature individuals (only 12 individuals in total) and all are in a single subpopulation.
|Range Description:||Alectryon macrococcus is a tree consisting of two varieties, macrococcus and auwahiensis. There may be a third undescribed variety, which will probably also be listed as Critically Endangered in due course, once the taxonomic status is confirmed. Alectryon macrococcus var. macrococcus occurs on Kauai, O'ahu, Moloka'i and West Maui, while the var. auwahiensis occurs in the Auwahi and Kanaio districts. See the varietal treatments for further details on population sizes, etc.|
Native:United States (Hawaiian Is.)
|Range Map:||Click here to open the map viewer and explore range.|
|Current Population Trend:||Decreasing|
|Habitat and Ecology:||This slow growing, relatively long-lived tree occurs in various lowland dry to mesic forest types (360–1,070 m).|
This taxon was once widespread on leeward sides off all the Hawaiian Islands, but is now almost completely eliminated. The main threats in the past included the impacts of feral cattle, goats and pigs; the impacts of invasive alien plant species; damage from the Black Twig Borer (Xylosandrus compactus); and seed predation by rodents.
Current threats include ongoing competition with invasive alien plant species, Schinus terebinthifolia (Christmas Berry) in particular is now replacing all native vegetation on the southern Waianae Mountains and threatens to occupy the range of all the O'ahu subpopulations. The Black Twig Borer is still a major problem, with most subpopulations sustaining some damage from this. Seed predation by invasive alien rodents (Rattus rattus and Mus musculus) is an ongoing problem inhibiting regeneration. Feral goats and pigs are impacting the habitat of most subpopulations through grazing, trampling and resultant soil erosion. Grazing and trampling by cattle was a major problem in the past for var. auwahiensis, but now all individuals are protected from ungulates by small woven-wire enclosures. Accidental fires as a result of military activities are a potential problem for subpopulations in military training areas on O'ahu, Kaua'i and Maui.
Given the limited numbers and restricted range, a single natural or human-caused disturbance could be catastrophic. Also gene pool limitations may depress reproductive vigor and adaptability.
|Conservation Actions:||The whole species is listed on the US Endangered Species Act. Two subpopulations occur on Federal property, nine are on State land, three in areas leased to the Federal government as part of the Makua Military Reservation and five are in a State Conservation District. A Recovery Plan for the species has been published (U.S. Fish and Wildlife Service 1997).|
|Citation:||Bruegmann, M.M. & Caraway, V. 2003. Alectryon macrococcus. The IUCN Red List of Threatened Species 2003: e.T44144A10863892.Downloaded on 11 December 2017.|