Turbidity: Is caused by the washing away of soils along the waters edge.The lack of sedges, reeds and reeds to hold the soil allows for it to easily washed away. High turbidity can effect the temperature of the water, the amount of sunlight able to penetrate and particles can block the gills of some macroinvertebrates.Acidity:Is caused by a number of sources including pollution, fertilisers and iron ore rich soils. A healthy river system has a neutral pH of 7.0. Some macro invertebrates and vegetation can not survive if the water is too acidic or alkaline.
Salinity: In Australia the primary cause of salinity is the remove of deep rooted trees. This allows salt normally held in the ground to work it's way up onto the soil and into the waterways. Like acidity some vegetation and macroinvertebrates are not able to cope with high levels of salt.
Macroinvertebrate Sampling: Measuring the variety and frequency of macroinvertebrates can give a very good indication of the health of a wetland. Some species such as water fleas are very tolerant to adverse conditions. Others such as Caddisfly larvae as very sensitive and are refered to as indicator species.