A large number of species have been introduced, many intentionally. A
number of species have become widespread and troublesome and include
animal (e.g. rats, mice, wasps, fruit flies) and plant (e.g. Lantana
camara, Sorghum sudanense) species (Binggeli 1997, Binggeli & Starmer 1997). The number of
introductions has increased steadily, and the problems associated with
these species have only become acute over the past five decades. The
pace of introductions does not appear to have decreased in recent years
despite a growing awareness of the problems caused by introduced
species.
As far as introduced plant species are concerned the
threats to native biodiversity is mainly posed by the widespread
species (e.g. Lantana
camara, Canna indica, etc.) or as yet
poorly dispersed species (e.g. Crinum sp., Carpobrotus
edulis, Leucaena leucocephala, etc.). Most of these
species are not considered by Pitcairners to be a problem in
agricultural areas. The islanders are more concerned with typical
agricultural weeds and the spread of Syzygium
jambos.
An attempt to eradicate rats and cats was made in 1997
but failed. This has resulted in a greater rat population and the
islanders are struggling more than ever before to grow crops (see report).
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Soil erosion formerly caused by goats (Pandanus
tectorius in centre, Shiplandings Point in background)
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