Cell Descriptions - South East Natural Resources Management Board

SE6 – Lake Bonney SE
the area only mention small sections of bare sand, i.e. accounts by Goyder and the Henty
brothers in 1864 and 1830. However Goyder records the dunes here and in SE7 were grazed by
sheep, cattle and horses. The management of Lake Bonney and surrounds was discussed in Lands
SA, 1991, s.2.
Cullen & Bird, 1980, p.B1, report here (and further north in the park) that many dunes were destabilised
by 19C grazing and burning, and re-vegetation seen as contingent on rabbit and ORV
control.
Opportunities
This project may provide the opportunity to review the management of the impact of ORVs
within the park.
Lake Bonney is described as the largest freshwater lake in South Australia (Lands SA, 1991). It
receives one of the highest ratings for biological value and wetland attributes by Slater and
Farrington (2010). Historically the lake would have been brackish (Haynes et al. 2007) however
water supply is now supplemented by several drains. Along with an overall freshening of the
system, these inputs have also attributed to an overall decline in the water quality of the lake.
The main contributing factor is wastewater from pulp and paper mills. The lake had its natural
outlet to the sea at the southern end however artificial cuttings were made through the dunes in
1958 and 1972 (SEWC, 1984). The lake level is now controlled by a regulator on an artificial
outlet. The main recommendations regarding Lake Bonney involve activities which will bring
about an improvement in the water quality of the lake. Scientific monitoring has become a focus
in the management of Lake Bonney. The EPA has collected information that suggests the quality
of the lake is improving, however the EPA also recognises that following 60 years of pollution, it
will take a long time to revert back to a healthy system (EPA, 2006). The use of wetland
vegetation to filter inflows is currently being investigated by DENR (Slater and Farrington 2010).
Conservation Analysis (GIS)
The sum of conservation means gives this cell a low priority value (103.9), a result of extensive
areas of low values in the de-vegetated dunes and the Lake Bonney water body reducing the total
means for the cell. (The only high value layer for Lake Bonney was SE Wetlands, based on the
SAWID assessment). However, parts of the Admella Dunes and the dunes bordering the
northern end of Lake Bonney show very high total priority values due to endemic vegetation
values and numbers of threatened plant species, numbers of plant species, habitat for reptiles and
butterflies. This latter area includes small wetlands, which have high values as habitat for reptiles,
including focal species Swamp Skink and Southern Bell Frog. The entire foreshore,