Issue: Species, habitats and ecological communities - Condition of freshwater biodiversity
This is an issue under the Biodiversity theme of the Data Reporting System.
The health of freshwater biodiversity is crucial to the condition of inland waters, riparian vegetation and the land itself. Freshwater biota are important to both water quality and to the capacity of freshwater to regulate local climate. Conversely, physical conditions such as water quality, salinity, acidity and temperature are essential to the well-being of freshwater life.
- IW-11 Number of licences dams, weirs, regulators and levees
As barriers to movement both upstream and downstream, dams and weirs can have a significant impact on the condition of freshwater flora and fauna. Individuals may migrate for several reasons, including seasonal changes, for dispersing populations and to food, shelter and mates. Number of weirs and dam is a crude but direct measure of this pressure.
- IW-27 Extent of significant wetlands (incl. Ramsar)
Although extent of wetlands is to some extent seasonal, long term trends in extent of wetlands is a surrogate indicator for condition of wetlands, and both extent and condition of wetlands are in turn indicative of the condition of wetland biodiversity, including aquatic biodiversity.
- IW-28 Number of effective fishways
The construction of dams and weirs change the connectivity of aquatic systems. Fishways go someway in improving connectivity for fish. Number of effective fishways could be indicative of improved management of this aspect of freshwater biodiversity.
- IW-29 Blue Green Algae
Number and distribution of algal blooms is a direct indicator of this pressure on freshwater biota.
- IW-30 Macroinvertebrate condition
Aquatic macroinvertebrates are a diverse group of animals that include a range of insect, crustacean and molluscan groups such as snails, water boatmen, dragonflies, stoneflies, mayflies and aquatic worms. Their composition reflects the historical impact of environmental changes on the stream ecosystem for up to several months before sampling. They therefore provide an ‘integrated’ indicator of human impact on the stream ecosystem.
- IW-31 Fish - Abundance and distribution
The health of populations and communities of native fish species is an indicator of the overall condition of the aquatic ecosystem. A decline in fish communities provides a warning that the natural ecological functioning of the aquatic system is at risk.
- IW-32 Frogs - Abundance and distribution
Frogs are very sensitive indicators of declining water condition as they are very sensitive to changes in their environment. Many species have suffered dramatic population declines since the 1980s, including disappearances from pristine habitats. Declines in abundance and distribution of frogs may be indicative broader declines in freshwater biodiversity.
- IW-33 Abundance and distribution of waterbirds
The health of populations of waterbird species is an indicator of the overall condition of the aquatic system. A decline in bird numbers provides a warning that the natural ecological functioning of the aquatic system is at risk.
- IW-34 Examples of deterioration of condition of wetland vegetation
Condition of wetland species of vegetation may be indicative of condition of freshwater biodiversity more generally.
- Inland Waters - Habitat scale influences - In-stream habitat - woody debris and sand slugs
- Inland Waters - Habitat scale influences - Riparian vegetation
- Inland Waters - Habitat scale influences - Wetlands
- Inland Waters - Habitat scale influences - Fish passage
- Inland Waters - Response of biota - Bacteria and algae
- Inland Waters - Response of biota - Macroinvertebrates
- Inland Waters - Response of biota - Fish
- Inland Waters - Response of biota - Frogs
- Inland Waters - Response of biota - Wetland and floodplain communities
- Biodiversity - Pressures on biodiversity - Changed hydrology
- Biodiversity - Species, habitats and ecological communities - Species diversity
- Biodiversity - Species, habitats and ecological communities - Condition of wetlands and riparian vegetation