How do vegetation responses to CEW vary between sites with different channel features and different bank conditions? Yes but see comments above and in Appendix E The cover of vegetation in regions of the bank inundated by spring freshes increased following spring freshes at Loch Garry but not at McCoys Bridge where vegetation cover did not change. Although spring freshes are likely to have contributed to the increase in vegetation cover, it was not possible to distinguish flow effects from natural variation in cover. Further monitoring is needed to determine if patterns persist. It is unclear why responses of vegetation to the spring fresh differed among sites, but one possibility is that these sites are at different points along their recovery trajectories after drought and floods. The cover of vegetation tended to be lower on outside bends of the river compared with straight sections or inside bends. This pattern is consistent with typical distributions of bank stability in rivers with inner bends generally being most stable and thereby providing suitable conditions for vegetation establishment. Based on patterns of changes in percent cover of vegetation along the elevation gradient pre and post fresh at each site. Mean cover of vegetation at transects located on outside, inside and straight sections of the stream Short-term evaluation questions Does the CEW contribution to spring freshes and high flows trigger germination and new growth of native riparian vegetation communities on the banks of the lower Goulburn River? Yes but see comments in row 1 of this table and in Appendix E The elevation reached by spring freshes represents a boundary in the distribution of some species along the bank. Several species with an affinity for wet habitats were limited to regions inundated by the fresh, whereas the native perennial grass Poa labillardierei preferred elevations at or above the inundation level. Vegetation cover within the region of the bank inundated by spring freshes was higher following the spring fresh at Loch Garry but not at McCoys Bridge. Woody recruits represented by Acacia dealbata and Eucalyptus camaldulensis were rare and limited to higher elevation that experience shorter and more shallow inundation. Based on patterns of change in vegetation cover and inundation along the elevation gradient resulting from spring freshes Presence of woody recruits along the elevation gradient along with the upper elevation inundated by spring freshes at both sites. How does CEW delivered as low flows and freshes contribute to maintaining new growth and recruitment of native vegetation on the banks of the lower Goulburn River? Unknown as yet, requires 2015 survey data
Fish In spring 2014, environmental water was delivered to the lower Goulburn River over 3 weeks from to early December in accordance with seasonal watering plans. The primary aim of this flow event was to trigger spawning and movement of golden perch. A maximum discharge of about 6300 ML/d was released. Immediately prior to this event there was also an environmental water release from mid-October to early November over 3 weeks for vegetation objectives. A maximum discharge of about 7600 ML/d was released. Observed effects on fish are summarized below, with detail provided in Appendix F. Evaluation Basin-scale evaluation questions Question Were appropriate flows provided? Effect of environmental flows What information was the evaluation based on? Long-term evaluation questions What did CEW contribute to native fish populations? Possibly Spawning and spawning associated movement of golden perch observed during environmental flow events Qualitative and statistical analysis of larval survey and fish tracking data. What did CEW contribute to fish species diversity? Unknown at this stage Unknown at this stage There is only a single data point from the first annual survey Short-term evaluation questions What did CEW contribute to fish community resilience? Unknown at this stage Unknown at this stage There is only a single data point from the first annual survey What did CEW contribute to native fish survival? Unknown at this stage Unknown at this stage There is only a single data point from the first annual survey. Size frequency data from target species may answer this question in future What did CEW contribute to native fish reproduction? Yes (for golden perch and silver perch) Golden perch exhibited a strong spawning response to increased flows. Silver perch also spawned in association with increased flows. Quantitative observations based on drift netting data. Peak egg abundances were collected coinciding with an environmental flow release What did CEW contribute to native fish dispersal? Yes (for golden perch) Long-distance movements coincided with increases in flow associated with environmental flow releases Qualitative observations based on telemetry data Area specific evaluation questions Question Were appropriate flows provided? Effect of environmental flows What information was the evaluation based on? Long-term evaluation questions What did CEW contribute to the recruitment of golden perch in the adult population in the lower Goulburn River? Unknown Population surveys revealed no strong relationships between golden perch spawning and recruitment of juvenile fish, suggesting that spawning may not necessarily translate into recruitment of juveniles into the local population Qualitative observations based on comparisons between electrofishing and drift netting data
The re-establishment of vegetation on the banks of the Goulburn River is limited, with many locations having no vegetation. The limited recovery of vegetation at some location may be due to a number of factors and warrant investigation through field based experimental manipulations. Field based experimental manipulations should aim to assess if vegetation recovery is limited by: The availability of propagules. Poor retention of propagules on the banks due to the lack of wood/litter, soil surface roughness or erosion. The depth and duration of inundation experienced during early plant establishment. The availability of microclimates required for establishment.