ALIEN SPECIES
Miconia
(Miconia calvescens)Miconia is a fast-growing, weedy tree from South and Central America that is invading Hawai`i. It is easily distinguished by its large leaves, which reach up to three feet long, have three bold veins, and are dark green above and purple beneath. This tree reaches 20-50 feet in height and can grow in either direct sunlight or full shade. Each mature plant can produce up to 3 million or more seeds each year, which are dispersed by birds feeding on the fruits. The seeds can remain dormant in the soil and subsequently sprout after periods of up to at least three years.
In 1937, miconia was introduced to a botanical garden in Tahiti.
By the late 1980's, over 60% of the island was heavily invaded with
dark groves of the trees, shading out the native forest plants and
the wildlife dependent upon them. 
Scientists
estimate that 1/4 of indigenous Tahitian species of plants and
wildlife are now directly threatened with extinction because of
miconia. Because the root system of miconia is very shallow it does
not hold the soil in place as well as the native vegetation did and
leads to increased erosion. Consequently, entire hillsides in Tahiti
now often slide away after heavy rains (see photo at right),
resulting in further losses of wildlife and native vegetation and
silting of streams. Because Hawai`i's environment is so similar to
that in Tahiti, miconia poses an equally severe threat to our native
forests and wildlife.
As in Tahiti, miconia was brought to Hawai`i to serve as an ornamental plant and has escaped from cultivation. Large populations have become established on Maui and Big Island, with much smaller ones on O`ahu and Kaua`i. Several government agencies and private organizations have been working on eradicating this pest from the state. All known individuals on O`ahu and Kaua`i have been killed and periodic searches are made in neighboring areas to ensure that any new seedlings that sprout are rapidly removed. A full-time crew and many volunteers have been working on controlling miconia populations on Maui, where several satellite populations have spread from the main infestation near Hana. On Big Island, where the infestation is largest, work crews have been mapping infestations, removing plants, conducting herbicide trials, and educating the public about the problem. Work on both islands will need to continue for several years to ensure that plants germinating from dormant seeds are all removed.
To stop miconia from destroying Hawai`i's forests it is important that all plants be removed. Overlooked plants could start new populations, continuing the threat to Hawai`i indefinitely. If you think you have seen miconia, report it to the hotline on your island:
|
Island |
Phone (area code 808) |
|
Hawai`i |
961-3299 |
|
Kaua`i |
274-3069 |
|
Lana`i |
565-7430 |
|
Maui |
984-8100 |
|
Moloka`i |
553-5236 |
|
O`ahu |
973-9541 |
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