Changes in island biota - The Great Barrier Reef: An Environmental History - page 218

'any track work on Brampton Island has been deferred because of the number of
horses, sheep and goats on this island '. 62
In contrast to those reports of the deliberate stocking of islands with grazing
animals, other documentary and oral sources indicate that the introduction of
pest species also occurred. In 1932, when Cristian Poulsen established the first
tourist resort at Heron Island, the cay was 'so infested with rats that it was almost
impossible for anything or anybody to live there'. 63 S ubsequently, domestic cats
were introduced in an attempt to control the rats; however, the cats were allowed
to breed and were subsequently reported to be feeding on the juvenile mutton
birds on that island. By 1966, rats had also infested other islands, including
Fairfax and Wreck Islands, where they were reportedly responsible for significant
destruction of the seabird population, as one oral history informant - a zoologist
and environmental manager - acknowledged. By 1969, Booth reported that
the Fairfax Islands were infested with two species of rats, and by cockroaches . 64
Other exotic fauna included rabbits, which were found by fishermen in 1951
at Humpy Island, near Keppel Island; taipans, which were introduced to South
Molle Island in 1957 by Mr Sacks; a fox that also inhabited South Molle Island;
an agile wallaby at Heron Island; and African guinea fowl that were released at
Lady Musgrave Island in 1974 (Gunn, 1966) . 65
After the formation of the GBRMP, an evaluation of changes in animal
populations at Green Island was made in 1978 by Limpus, who concluded
that the fauna had 'almost certainly changed from its original state' as a result
of the introduction of house sparrows, rats, cats and a small range of reptiles . 66
Other, more recent faunal changes include the presence of cane toads at Lizard
Island by 1980; the introduction of feral pigs at Hinchinbrook Island, reported
in 1999; and the establishment of feral pigs and cane toads at Dunk Island by
2000 (QNPWS, 1999b, 2000) . 67 Those introductions represent the most recent
of a series of changes in island fauna that commenced in the earliest period of
European settlement in the Great Barrier Reef. As a result of the introduction
of a variety of animal species, over an extended period of time, the landscapes of
several islands have been substantially modified.
Summary
Various changes in island biota have been described in this chapter: the
establishment of coconut palm plantations; overgrazing by introduced goats;
the clearance of native vegetation; the destruction of island animal populations
(particularly birds); and the introduction of exotic species of plants and animals.
Although it is difficult to reconstruct the ecological impacts of those changes, the
evidence presented in this chapter suggests that substantial changes must have
occurred in many island ecosystems. The biota of some islands - such as Lady
Musgrave Island - was significantly altered as a result of multiple impacts (such
as guano mining, overgrazing by goats and the construction of tourist facilities),
some of which were both prolonged and intensive. Some changes in island biota