Bowling Green Bay
Agricultural, and urban and industrial developments in the
catchment area external to the site pose the most significant
threats to the integrity of the site, particularly the lowland
areas. The potential impact posed by these is through cumulative
changes to water regimes and the chemistry of both surface and
subsurface waters. As already evident within the coastal region,
such changes initiate rapid changes in biological communities and
degrade the natural functioning of wetlands within the landscape,
and their value as habitat. The low lying topography of the site
would make it extremely susceptible to marine flooding as the
result of relatively small rises in sea level, one of the predicted
outcomes of the greenhouse effect. Some simulation modelling has
been undertaken to show the potential extent of this over the area
of the site to the north of the Haughton River.
Burdekin Coastal Aggregation
The hydrology of the delta has been modified by the operation of
an artificial aquifer recharge pumping program that diverts water
from the main Burdekin River channel down the distributary channels
including Plantation and Sheepstation creeks. Nutrient inputs have
contributed to the eutrophication of freshwater wetlands and have
assisted the domination of exotic pasture grass species
Para grass ( Brachia mutica ) and
Guinea grass ( Panicum maximum ) in the emergent
vegetation zone (J. Tait pers. com. 1995). Stock dams constructed
on the lower reaches of coastal plain drainage depressions have
altered the hydrology and salinity regime by preventing the inflow
of high spring tides, and have promoted the growth of ponded
pasture species to the detriment of native sedge communities. On
levee areas, a high frequency of intense fires associated with cane
burning and pryrophytic exotic grasses, combined with the invasion
of Rubber
vine ( Cryptostegia grandiflora ) has caused major
disturbance to riparian vegetation communities.
Recently introduced ponded pasture species e.g. Hymenachne
( Hymenachne amplexicaule ) and Echinochloa sp .
have become established in the area and may pose a future threat to
wetland vegetation communities. There are proposals to expand the
area of aquaculture development within the site. Further irrigated
agriculture development is planned on areas of marginal suitability
in the southern section of the site. Proposals for new aquifer
recharge projects could result in additional hydrological
changes.