Implications of river regulation on in-stream ecosystems in Goulburn River, Australia

Abstract:

The streamflow pattern is one of the most important abiotic drivers of the riverine biodiversity and ecosystems. However, a little is known about links between altered streamflow patterns as result of river operations and richness, abundance and diversity of riverine species. This study aimed to analyze how riverine species respond to altered flow patterns. We used taxa richness, EPT density index (EPT), and Shannon-Wiener diversity as indictors of macroinvertebrate community, and frequency and magnitude as the flow pattern metrics. We divided the Goulburn River into three reaches with spatially distinct regulation and diversion conditions (without regulation or diversion, with regulation, and with both regulation and diversion). Five hydrological gauging stations and macroinvertebrate data from 35 sampling points, for the period of 2005 to 2011 were used. The preliminary results revealed that the taxa abundance was significantly influenced as demonstrated that Reach 1 had 53 % higher EPT than that Reach 2, which had 63% higher EPT than Reach 3. We also found a strong correlation between variability of flow pattern and taxa diversity in Reach 1. These findings have important implications on river operations for ecological restoration.