As described above, water type has 1. Salinity: Vegetation mapping layers are one a major impact on both habitat source of remote sensing • Fresh (<3000 mg/L) conditions and biota found at a information that may be used to • Brackish* (3000–5000 mg/L) location. It also impacts on many derive this attribute, as well as other • Saline (>5000 mg/L) other facets. documented ground-based information. OR Within the ANAE, ‘water type’ relates to chemistry and is Radke (2003, pers. comm.) proposes 2. pH** influenced by the surrounding that more appropriate salinity • Acidic (<6) landscape (geological setting, water thresholds are: • Neutral (6–8) balance, quality, type of soils, fresh <1000 mg/L; • Alkaline (>8) vegetation and land use) which in brackish 1000–3000 mg/L; turn dictates habitat of the aquatic saline 3000–10000 mg/L; *Brackish may not be important for all systems. If environment. Water type hypersaline > 10,000 mg/L. so, change saline metric to 3000 mg/L. information can be used to The calcium carbonate branchpoint **pH may change with the changing hydrograph; if determine the ‘normal’ water so, the ‘normal’ pH should be used. occurs at chemistry of a waterbody. ~1000–1200 mg/L in Australian Metrics and thresholds have been waters (lac/pal/riverine). This is chosen that provide a suitable basis when calcium carbonate starts to for differentiating and precipitate, and causes a very major characterising different systems. change in the ionic composition of water. New aquatic genera emerge Whilst these salinity thresholds have at this time been proposed, it is acknowledged (see also Buckney & Tyler 1976). that they may not be appropriate for some parts of the Australian Significant ion pair formation occurs landscape. They should be critically at ~10,000 mg/L, causing another evaluated before using, and major change in the substituted with more appropriate ionic structure of the water local levels if necessary. The AETG and ecological transition should be notified of the changes (e.g. emergence of halobionts). made and their justification, to ensure that future versions of the ANAE reflect the scientific advances in this area. Water regime
As described above, water type has a major impact on both habitat conditions and biota found at a location. It also impacts on many other facets. Within the ANAE, ‘water type’ relates to chemistry and is influenced by the surrounding landscape (geological setting, water balance, quality, type of soils, vegetation and land use) which in turn dictates habitat of the aquatic environment. Water type information can be used to determine the ‘normal’ water chemistry of a waterbody. Metrics and thresholds have been chosen that provide a suitable basis for differentiating and characterising different systems. Whilst these salinity thresholds have been proposed, it is acknowledged that they may not be appropriate for some parts of the Australian landscape. They should be critically evaluated before using, and substituted with more appropriate local levels if necessary. The AETG should be notified of the changes made and their justification, to ensure that future versions of the ANAE reflect the scientific advances in this area. 1. Salinity: • Fresh (<3000 mg/L) • Brackish* (3000–5000 mg/L) • Saline (>5000 mg/L) OR 2. pH** • Acidic (<6) • Neutral (6–8) • Alkaline (>8) *Brackish may not be important for all systems. If so, change saline metric to 3000 mg/L. **pH may change with the changing hydrograph; if so, the ‘normal’ pH should be used. Vegetation mapping layers are one source of remote sensing information that may be used to derive this attribute, as well as other documented ground-based information. Radke (2003, pers. comm.) proposes that more appropriate salinity thresholds are: fresh <1000 mg/L; brackish 1000–3000 mg/L; saline 3000–10000 mg/L; hypersaline > 10,000 mg/L. The calcium carbonate branchpoint occurs at ~1000–1200 mg/L in Australian waters (lac/pal/riverine). This is when calcium carbonate starts to precipitate, and causes a very major change in the ionic composition of water. New aquatic genera emerge at this time (see also Buckney & Tyler 1976). Significant ion pair formation occurs at ~10,000 mg/L, causing another major change in the ionic structure of the water and ecological transition (e.g. emergence of halobionts). Water regime
ae-toolkit-module-2-anae-classification.docx