The natural context of changes in the Great Barrier Reef - The Great Barrier Reef: An Environmental History - page 41

Another informant, a coral reef scientist, witnessed tropical cyclone damage
at Heron Island, when the disturbance came from an unusual direction and
affected corals that had not adapted to cyclone conditions (see also Bennett,
1971, p25) . 11 Many other oral history accounts describe the impacts of tropical
cyclones, although much of that evidence refers to the period after 1970, which
is relatively well-documented by other sources . 12 Nonetheless, there is abundant
evidence that many coral reefs have been damaged periodically by tropical
cyclones, although offshore reefs have generally recovered more rapidly from
storm damage; in contrast, fringing and nearshore reefs have experienced slower
recovery rates or - as at Stone Island - no recovery has apparently occurred.
Summary
This chapter has presented a brief overview of some of the major natural factors
that have influenced the condition of the Great Barrier Reef: the geomorphological
evolution of the continental shelf during the Holocene epoch, and the effect of the
tropical cyclones that are a recurrent feature of the region. Those natural processes
and events have been described here in order to provide a context for the accounts
of historical human impacts on the ecosystem that follow. Due to the Holocene
evolution of the continental shelf, changing patterns of sea level and sedimentation
mean that some of the coral reefs of the Great Barrier Reef - especially those in
the nearshore zone - are now found in a geomorphologically senile condition and
are therefore highly vulnerable to other impacts. Superimposed upon that natural
context of deterioration are the impacts of tropical cyclones on individual coral
reefs, which may be severe, although (in the absence of other significant pressures)
many reefs nevertheless display a remarkable capacity to recover from the effects
of those storms. This natural context - one of variable and patchy deterioration
and recovery - means that the accounts of human activities that follow must be
interpreted with care. Yet it also suggests that some already-vulnerable reefs - ones
that naturally exist close to critical ecological thresholds - may have been the
same ones that have been intensively exploited by humans, sometimes over long
periods of time. Those superimposed patterns of both natural and human impacts
have led to the creation of complex patterns of vulnerability, degradation and
decline of some parts of the Great Barrier Reef, and they indicate that some parts
of the ecosystem were probably far from pristine at the time of the formation of
the GBRMP in 1975.
Notes
1 Oral History Cassette (OHC) 35, 20 October 2003, Changes in the Great Barrier Reef
since European Settlement , Oral History Collection, School of Tropical Environment
Studies and Geography, JCU, October 2002-December 2003, pp10-11.
2 GBRMPA, 'Green Island economic study: summary report, October 1979', Economic
Associates Australia, Economic and Management Consultants, 1979, Appendix A:
history of Green Island and its reef, SRS5416/1 Item 434, QSA.