Does seasonality influence freshwater macroinvertebrate communities in the temperate paradise of Sydney?

This paper challenges the validity of current Australian guidelines that recommend seasonal sampling for freshwater macroinvertebrates. Macroinvertebrates are a commonly used indicator to assess the ecological condition of streams and various sampling methods provide a consistent and repeatable approach. Most methods recommend seasonal surveys, which traditionally occur in spring and autumn. The basis for a seasonal approach is to capture specimens at an ideal life-stage when identification can be easily achieved. This is particularly relevant for many invertebrate taxa with lifecycles that are influenced by and dependent on extreme seasonal climatic change. However in more temperate environments, where daytime temperatures seldom drop below 10 degrees Celsius the biological response of macroinvertebrate communities and in-turn, seasonal differences may not be as pronounced. This study reviewed family level macroinvertebrate data sets across the Sydney basin to investigate if seasonality is a factor that influences community composition between spring and autumn sampling periods. The results suggest the time of year that sampling is undertaken is not an important consideration within the study region and that this should inform future sampling protocols.