Conclusion - The Great Barrier Reef: An Environmental History - page 225

numbers were substantially reduced by commercial whaling (between 1952 and
1962), leading to the near-collapse of that population, despite the existence of
government regulation and scientific monitoring of the industry (Chapter 8).
Corals and shells have also been over-harvested at many locations in the Great
Barrier Reef due to the activities of both commercial and recreational collectors,
with the result that some reefs have been gradually, yet relentlessly, depleted
(Chapter 9) .
Exploitation of non-living parts of the Great Barrier Reef has also led to some
profound transformations of the reefs, islands and cays of the ecosystem. Some
islands - including Raine, Lady Elliot, Lady Musgrave, Fairfax and North West
Islands - are probably among the most dramatically modified environments of
the Great Barrier Reef, not least because of the activities of guano miners who
had removed all of the commercially-viable guano from most of those cays by
1900. Other substantial changes occurred at Raine Island (with quarrying and the
construction of a navigation beacon, prior to the guano mining); at Holbourne
Island (due to rock phosphate mining); and at Upolu and Oyster Cays (as a result
of guano mining which persisted until at least 1940) (Chapter 10). Therefore,
the extraction of mineral resources from the Great Barrier Reef spanned almost a
century and affected at least ten islands; those impacts ranged from the removal
of thousands of tons of guano (at their most benign) to the complete alteration of
the geomorphology of the cays (at their most extreme). In the cases of Raine and
Lady Elliot Islands, the impacts of guano mining remain in the landscape today
and may be irreversible. At Lady Musgrave Island, those landscape modifications
became visible when as a result of another impact - overgrazing by introduced
goats - the surface of that cay was exposed. Coral itself - both living and dead -
was also exploited by the coral mining industry in at least twelve reef locations
between 1900 and 1940 in order to produce agricultural and industrial lime;
that industry removed thousands of tons of coral from some reefs, particularly at
Snapper Island, the North Barnard Islands and Kings Reef (Chapter 11).
Further dramatic changes occurred to reefs and islands as a result of blast
fishing using dynamite; the construction of access tracks and channels across
and through reefs; the use of reefs and islands for military target practice (as
at Lady Musgrave and Fairfax Islands); the practice of reef-walking; and the
construction of infrastructure, including tourist resorts (Chapter 12) . Although
they are difficult to reconstruct, some significant changes in island biota
have also occurred as a result of various human activities. The establishment
of coconut palm plantations on at least 46 islands, between 1892 and 1900,
involved the planting of around 500,000 coconut palms, particularly in the
Mackay, Townsville, Cairns and Cooktown areas. Further significant changes in
island vegetation occurred with the introduction of goats to many islands - some
of which held over 1,000 animals - that, in some cases, destroyed all of the grass
and shrub vegetation and also affected Pisonia trees. Particular impacts due to
overgrazing by goats were sustained at Lady Musgrave and Fairfax Islands, both
of which were reportedly denuded of vegetation so that bare coral rubble was