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HomeMy WebLinkAboutCOM 0261.001 2000-2002 ~~~~"'~s United States Animal and Wildlife Services Hawaii Field Station ~ Department of Plant Health National Wildlife P.O. Box 10880 Agriculture Inspection Research Center Hilo, Hawaii 96721 Service TEL (808) 961- 4482 FAX (808) 961 - 4776 Rory Flynn, Researcher Hawaii County Council 25 Aupuni Street Rm. 209 Hilo, HI 96720 ~ ~n c.a n 3'~\~ 19 July 2001 ~j rv v -=r=' ;-iii ~s C~ Dear Mr. Flynn: ~ Thank you for your inquiries about recently introduced Caribbean tree frogs on the Island of Hawaii. Below is a general summary of the information I would present to the County Council on the issue. Two species of tree frogs [the coqui (Eleutherodactylus co ui) and the greenhouse frog (_E. planirostris)] native to the Caribbean have recently become established in the Hawaiian Islands. Since their introduction via the import horticultural trade, the frogs have rapidly expanded their range on the islands of Hawaii, Maui, Oahu, and Kauai. 'There are two ways that new tree frog populations are being spread in the state. The first is the accidental transport via horticultural products or material from infected nurseries or gardens to uninfected areas. The second is the intentional introduction of frogs by citizens into sites that aren't infested. Surveys of the islands of Hawaii and Maui (see attached maps) indicate that frog populations have become firmly established in nurseries, parks, residential gardens, resort areas, and lowland forest habitats. "The number of reported locations has significantly increased on these islands in the last 2 - 3 years. Frog populations have been documented on the islands of Oahu (19 reported and 15 verified frog sites) and Kauai (4 reported frog sites and 1 verified frog site) and there is concern these populations will continue to spread. In one horticultural site on the island of Hawaii, one species of tree frog (E. coqui) has been documented to obtain densities comparable to the native range 2.1 frogs/m' or ~ 21,000 frogs/ha). Localized loud vocalization of male frogs (80 - 90 dB) throughout the night-time hours has also been a source of numerous angry complaints from sleepless residents and tourists alike. There is a concern on the part of federal, state, and private agencies/entities managing natural and agricultural resources in Hawaii that introduced Eleutherodactylus frogs pose a threat to these resources. Eleutherodactylus coqui can reach densities of greater than 24,000/ha (capable of consuming approximately l 14,000 arthropod prey items per hectare in a single night) in its native range in Puerto Rico. There is relevant concern that tree frogs, once established in native habitats, could prey on endemic arthropods as well as compete indirectly and directly with native birds for limited food resources (data has current been collected from the Big Island verifying the statement • R,N+e 11T~m Ref. To• ~ Q Ref. Date v~ri°ie~ ~r~c r~~~r~e a~~~~r~ roc ~~~r~~~er~aG~~~s ~~.'~oca~~or~s ~I ~ 4 M.U. _ ~ rig ~~ca~i~ns ~ ~ l/1~j~~ ~'©ads ~C~ ~ 'rf Kiiorret~rs _