PREDICTION OF BENTHIC MACROINVERTEBRATE COMPOSITION USING MICROHABITAT CHARACTERISTICS DERIVED FROM STEREO PHOTOGRAPHY

1. Benthic macroinvertebrate community and habitat features varying at the microscale (less than or equal to 0.09 m(2)) were measured on one sampling occasion in the Thredbo River, Kosciusko National Park, NSW, Australia. 2. Most of the substratum habitat variables were measured in three dimensions using stereo photography. This is the first time t hat this method has been used so extensively for this purpose in fresh water ecology. 3. Microhabitat variables most related to benthic macro invertebrate distribution and abundance were selected with multivariat e analyses included rock length, height, area and water velocity. Indi vidual variables alone could not account for macroinvertebrate variati on, indicating the importance of interactions among variables. 4. Nine selected habitat variables were used to predict macroinvertebrate tax onomic content of additional sites. Predictions were 87% accurate for taxa with a >50% chance of occurrence and 93% accuracy for taxa with a >70% chance of occurrence. Variability observed in macroinvertebrate assemblages at the time of sampling was largely physically controlled and highly deterministic.