Introduction - The Great Barrier Reef: An Environmental History - page 6

significant cause for concern. The impacts of coastal runoff are most significant
for nearshore reefs and seagrass beds within 20 kilometres of the coast, with the
most severely impacted areas lying between Port Douglas and Hinchinbrook
Island, and between Bowen and Mackay (Williams et al., 2002, p1).
The Commonwealth of Australia Productivity Commission (2003, pp xxviii,
37, 42) has acknowledged evidence of an increase in sediment and nutrients
entering the Great Barrier Reef lagoon since European settlement, due to the
runoff of sediments, nutrients and chemicals from agricultural and pastoral
land, especially as a result of cattle grazing and crop production. This has led
to the decline of corals, seagrass communities and fish populations. The Great
Barrier Reef Protection Interdepartmental Committee Science Panel (2003, pp2,
9, 12-13) also found evidence of accelerated erosion and a large increase in
the delivery of nutrients to the Great Barrier Reef over pre-1850 levels, with
consequent disturbance of the ecological function of inshore coral reefs. The
report stated that some areas of the Great Barrier Reef - those most affected by
terrestrial runoff - now appear to be degraded and/or slow to recover from natural
disturbances such as tropical cyclones. In addition to the effects of deteriorating
water quality, the degradation of the Great Barrier Reef has also occurred due to
the over-exploitation of reef organisms, leading to the depletion of resources at
Langford, Heron, North West, Tryon and Lady Musgrave reefs, and near Dingo,
Four Mile and Kurrimine Beaches (QEPA, 1999, p5.13). Particular damage has
been caused by commercial and recreational shell collecting, commercial coral
collecting, aquarium fish collecting and bêche-de-mer ( trepang or sea cucumber)
collecting (QEPA, 1999, p5.27).
Besides these scientific and official reports, many anecdotal reports of a decline
in the Great Barrier Reef have been made, attributing the degradation of coral
reefs and other parts of the ecosystem to a multitude of human impacts: shipping,
dredging, coastal and marine pollution, sediment and nutrient runoff, habitat
destruction, coastal development, fishing, tourism and the collection of marine
specimens (Lucas et al., 1997, pp65-6). The degradation of the Great Barrier
Reef is considered by some observers to have occurred - or to have accelerated
- in living memory. The most severe degradation is thought to have affected the
nearshore habitats in the most accessible parts of the ecosystem: in the Cairns,
Townsville and Whitsunday regions, which have experienced intensive human
use and substantial terrestrial runoff. Given the immense ecological, economic
and social importance of the Great Barrier Reef, there has been considerable
scientific and public interest in either confirming or refuting those anecdotal
reports of decline in the ecosystem. Furthermore, establishing the extent to
which the Great Barrier Reef has changed since European settlement is important
to inform the effective management of the ecosystem. However, extensive,
systematic, scientific monitoring of the Great Barrier Reef commenced only
around 1970, and scarce scientific data exist for the earlier period. Consequently,
anecdotal claims that the ecosystem has deteriorated - especially prior to 1970 -
are difficult to assess using existing scientific baselines.