Upland wetlands of the drainage divide of the New England Tableland Bioregion - endangered ecological community listing

NSW Scientific Committee - final determination

The Scientific Committee has found that:

1. Upland Wetlands of the Drainage Divide of the New England Tableland Bioregion is the name given to the ecological community in shallow-temporary to near-permanent wetlands naturally restricted to the higher altitudes (above about 900m) associated with the Great Dividing Range in northern NSW. This ecological community is currently known to occur in the Local Government Areas of Tenterfield, Guyra, Severn, Dumaresq and Uralla but may occur elsewhere in the Bioregion.

2. These wetlands have small local catchments and can also be called watershed wetlands (Haworth 1994). They are in the upper parts of both North Coast (Clarence, Macleay and Hastings Rivers) and Murray Darling catchments generally above 900m above sea level and are not connected to rivers by floodplains. The wetlands are found on a range of geological formations, although they are most common on landscapes associated with Tertiary basalt flows (Pressey and Harris 1988; Bell 2000; Haworth 1994). They are geographically restricted to the drainage divide of northern NSW.

3. Vegetation within the ecological community frequently consists of sedges, rushes and aquatic plants in a closed to mid-dense sedgeland, herbland or grassland community on the shores of open water or extending across shallow or dry wetland beds as described by Benson and Ashby (2000) and Bell (2000). Plant assemblages differ between wetlands and within a wetland over time depending on the water regime (Brock 1998). Upland Wetlands of the Drainage Divide of the New England Tableland Bioregion are characterised by some of the following assemblage of aquatic species when the wetlands contain water. At times when wetlands are dry, species may only be represented in the seed bank.

4. The total plant species list is considerably larger than the list given in 3 (above) with many species present in one or two sites or in small patches. In any particular wetland site only a subset of the species listed may be present. At any one time while a particular wetland is flooded 10-30 species may be found whereas over time the species list for that wetland may be considerably larger. At any one time when the wetland is flooded or dry, many species may only be present as seeds in the soil seed bank only, with no above ground individuals present. The species composition of a site will be influenced by the size of the site and recent flooding and drying patterns. The nature and timing of wetting and drying causes a dynamic vegetation, from open water bodies with submerged vegetation and vegetated margins to wetlands with central vegetation beds, to completely vegetated wetlands, to completely dry wetlands.

5. These wetlands are important habitat for a diverse vertebrate and invertebrate fauna although much of the invertebrate fauna is not as fully assessed. Water birds, frogs, turtles and eels are common inhabitants when the wetlands are flooded. Some of these wetlands are sites of significance for the migratory Latham's Snipe (Gallinago hardwickii) which is listed under the international treaties, the Japan- Australia Migratory Bird Agreement and the China-Australia Migratory Bird Agreement.

6. Most of these wetlands are naturally temporary, some are near-permanent and dry only once in 20 years; others are seasonal and dry and rewet annually; while others are intermittent and wet and dry on unpredictable aseasonal patterns (Boulton and Brock 1999). Together these wetting and drying patterns provide a mosaic of habitats in space and time across the landscape (Brock and Jarman 2000).

7. It is estimated that over 70% of sites formerly occupied by the community have been lost through draining or damming since European settlement (Bell 2000; Benson and Ashby 2000; Brock et al. 1999) and most of the 55 remaining wetlands have been severely modified by change in water regime.

8. Major ongoing threats to Upland Wetlands of the Drainage Divide of the New England Tableland Bioregion of New South Wales are alteration of water regimes to make these wetlands more predictably flooded or dry (Brock et al.1999). Such alterations have been made intentionally by draining or damming or unintentionally through sedimentation from catchment erosion as a result of soil surface crust damage from stock hooves or clearing of catchment vegetation (Gale et al. 1995; Haworth 1994; Haworth et al. 1999). Stock trampling and grazing within a wetland can be a threat if stocking rates are high and invasion by introduced plants and animals (e.g. Gambusia Gambusia holbrooki, Goldfish Carassius auratus and Jointed Rush Juncus articulatus) can also alter the community structure and its biodiversity.

9. Only three Upland Wetlands are fully or partially within conservation reserves namely, Billy Bung and Little Llangothlin in the Little Llangothlin Nature Reserve (which is listed as a Ramsar Wetland of International Importance) and part of Mother of Ducks Lagoon in the Mother of Ducks Lagoon Nature Reserve. Other wetlands are on freehold, or crown land. However presence in a conservation reserve has not protected the ecological community from damage by alteration of water levels as many of the water regime changes and sedimentation from catchment erosion occurred before becoming a reserve.

10. In view of the above, the Scientific Committee is of the opinion that the Upland Wetlands of the Drainage Divide of the New England Tableland Bioregion of New South Wales is likely to become extinct in nature in NSW unless factors threatening its survival or evolutionary development cease to operate and that listing as an endangered ecological community is warranted.

Proposed Gazettal date: 28/06/02
Exhibition period: 28/06/02 - 02/08/02

References

Bell, D.M. 2000. The ecology of coexisting Eleocharis species. PhD Thesis, University of New England, Armidale.

Benson, J.S. and Ashby, E. 2000. The natural vegetation of Guyra 1:100 000 map sheet, New England Bioregion, New South Wales. Cunninghamia 6: 747-872.

Boulton, A.J. and Brock, M A. 1999 Australian Freshwater Ecology: Processes and Management. 250 pp. (Gleneagles Publishing, Adelaide).

Brock, M.A. 1998. Are temporary wetlands resilient? Evidence from seed banks of Australian and South African wetlands In A.J. McComb and J.A. Davis (Eds.) Wetlands for the Future. pp. 193-206, (Gleneagles Publishing, Adelaide).

Brock, M.A. and Jarman, P.J. 2000. Wetland use and conservation in the agricultural environment: management of processes for the components. In J.L. Craig, D.A. Saunders and N. Mitchell (Eds.) Nature Conservation 5; Conservation in Production Environments: Managing the Matrix. pp. 258-268, (Surrey Beatty & Sons, Chipping Norton).

Brock, M. A., Smith, R.G.B. and Jarman, P.J. 1999. Drain it, dam it: alteration of water regime in shallow wetlands on the New England Tableland of NSW. Wetlands Ecology and Management 7: 37-46

Gale, S.J., Haworth R.J. and Pisanu P.C. 1995. The Lead-210 chronology of late Holocene deposition in an east Australian lake basin. Quaternary Science Reviews

(Quaternary Geochronology) 14: 395-408.

Haworth, R.J. 1994. Lake sedimentation in upland eastern Australia: case studies from the New England tablelands of New South Wales. PhD thesis, University of New England, Armidale.

Haworth, R.J., Gale, S.J., Short, S. and Heinjes, H. 1999. Land use and lake sedimentation on the New England Tablelands of NSW, Australia. Australian Geographer 30: 51-73

Pressey, R.L. and Harris, J.H. 1988. Wetlands of New South Wales. In A.J. McComb and P.S. Lake (Eds.) The Conservation of Australian Wetlands. pp. 35-57,(Surrey Beatty and Sons Chipping Norton).