Vol 3 Land Resource Inventory Report - Department of Environment ...

3.13 INTRODUCED SPECIES
An introduced, alien, exotic, non-indigenous or non-native species refers to those species
living outside its native distributional range, which has arrived there by human activity
either deliberate or accidental (Wikipedia Foundation Incorporation, 2010). According
to Convention on Biological Diversity 1997 National Report, the total number of vascular
plants known from Fiji is approximately 2,600 (Department of Environment, 1997:5).
Out of these 1,600 are native and 1,000 are introduced. Furthermore, a study conducted
by Smith from 1979 to 1991 recorded 934 introduced species (Department of
Environment, 1997:5). However, this was an underestimate based solely on herbarium
specimens. The correct figure is estimated to be over 1000 introduced species
(Department of Environment, 1997:5).
There are 11 introduced bird species to Fiji, of which three species, the two mynahs
(Acridotheres tristis and Acridotheres fuscus) and the Red Vented Bulbul (Pycnonotus
cafer) are considered pest species. Since the islands were first inhabited a number of
introduced mammals were brought along either deliberately for food or accidentally (as
stowaways). Most of these mammals have had devastating impacts on the land, including
extirpating some of the native ground-nesting birds. Some of the introductions include
the three species of rats: the Polynesian rat (Rattus exulans) brought by early inhabitants;
the Brown rat (Rattus norgegicus); and the Black rat (Rattus rattus). The Brown and the
Black rats were brought probably by European sea-voyagers, as was the House mouse
(Mus musculus). Pigs (Sus scrofa) were brought by the first inhabitants, most probably
for food; however, many became feral causing serious damage to native forests. Another
unfortunate introduction to Fiji was the Indian mongoose (Herpestes auropunctatus) that
was introduced in 1883 from the West Indies to control rats in sugar cane fields.
Fortunately, the devastation caused by this pest has not yet made it to many of the outer
islands (e.g. Taveuni), and efforts should be made to keep these islands mongoose-free.
Deer (Dama dama) were introduced to Wakaya island, as were goats (Capra hircus) and
cats (Felis catus) to some islands. Horses were introduced probably by the missionaries
in the 1860s, and illustrated in a wooden engraving in Reverend James Calvert‘s book
‗Fiji and Fijians: v. 2 Mission history‘, it was said to have caused such a fright to the
natives.
Eight of the 29 families are solely associated with introduced fauna (Valloniidae,
Ariophantidae, Subulinidae, Streptaxidae, Bradybaenidae, Agriolimacidae, Zonitidae)
while the shell-less family Vaginulidae, commonly known as ―leatherleaf‖ slugs, includes
two introduced and one native species, Semperula wallacei (Issel, 1874). As mentioned
by Barker (2005) this native species is likely to have been confused with the introduced
members of the family. Unfortunately to date no identification guides exist to aid
separation. Besides the identification obstacles, several of the sixteen known introduced
species are considered to have potential implications for agricultural productivity,
biodiversity loss or human and livestock health, however very little information is
currently available to allow risk assessments to be undertaken.
There is an immediate and critical need for collation of existing information into a form
that can be utilised by resource managers. Introduced palms include Metroxylon
warburgii, Pinanga coronata (introduced in the 1970s in Colo-i-Suva but now invasive).
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