2012 and June 2013. Overall, the expected outcomes of Commonwealth environmental watering actions were largely achieved. With respect to native fish reproduction and larval and juvenile recruitment, the following outcomes were achieved: Overall, the total abundance and biomass of native fish increased significantly after the delivery of Commonwealth environmental water, due to recruitment by some small-bodied native species (carp gudgeon and Australian smelt) and immigration of large bodied fish, in particular Golden perch. Wetland fish communities were dominated by small-bodied native fish species, which outnumbered exotic fish species such as carp, goldfish and gambusia by more than 100 to one. There was no evidence of significant carp recruitment in the Murrumbidgee River main channel following the delivery of Commonwealth environmental water. Twenty-seven Murray cod (Maccullochella peelii), six trout cod (Macchullochella macquariensis), five golden perch (Macquaria ambigua) and two silver perch (Bidyanus bidyanus) were implanted with acoustic tags to examine spawning related movement before, during and after delivery of the 2012-13 Commonwealth environmental fresh in the Murrumbidgee River. Movement behaviours of tagged Murray cod were consistent with spawning related movements during Commonwealth environmental water delivery (which also coincided with the known spawning season of this species). Improved longitudinal connectivity provided by Commonwealth environmental water coincided with reach scale movements by tagged silver perch, throughout the mid-Murrumbidgee River. Larval fish communities were surveyed weekly in the Murrumbidgee River and Old Man Creek to assess fish spawning responses to Commonwealth environmental watering from September to December 2012. 519 cod larvae (Maccullochella spp.) were captured, with a peak in abundance coinciding with the Commonwealth environmental water delivery period. River blackfish (Gadopsis marmoratus), Australian smelt (Retropinna semoni) and carp gudgeon (Hypseleotris spp.) larvae were also collected during the sampling period in small numbers, as well as juvenile carp gudgeon and juvenile Australian smelt. Very few exotic fish larvae were collected. With respect to the Commonwealth environmental watering objective “support habitat requirements of native fish in the Murrumbidgee River” peaks in nutrients,
Figure 38 Example of the change in vegetation functional groups over time at key lagoon wetlands in the Mid-Murrumbidgee. Sites are ordered in relation to the number of years dry before rewetting from most frequently flooded (Turkey Flat C2) to least frequently flooded (Euroley (C1) Control site 1). Discussion The key objective of the Commonwealth environmental watering action with respect to vegetation was to “maintain health of existing extent of riparian, floodplain and wetland native vegetation communities”. However, capacity constraints within the Murrumbidgee River meant that it was not possible to achieve enough height in the River to reconnect with the mid-Murrumbidgee wetlands, and, as a result, all sites were drying down during 2012-13. Environmental watering in the previous year (2011-12) had benefited vegetation communities in many of the wetlands. However, in 2012-13 there was an increase in terrestrial species while the percent cover of aquatic vegetation species remained stable or declined. The recovery of vegetation communities in the mid-Murrumbidgee wetlands to their condition () will require a long-term commitment to Commonwealth environmental watering. McKennas summer 1999 (Photo James Maguire) McKennas from the same - summer 2013
Microcrustacea models Full model: Model-averaged coefficients (Intercept) 3.44 0.06 62.16 <0.001 Veg.comp1 <0.001 0.03 -9.69 <0.001 0.15 0.03 4.33 <0.001 WQ.comp1 0.02 <0.001 Lowbidgee 2.06 0.09 22.11 <0.001 mid-Murrumbidgee 1.09 0.10 11.29 <0.001 SmallfykeGambusia 0.00 0.00 12.89 <0.001 highFlowDays30d 0.01 0.00 3.00 <0.001 totalFlowSinceJuly 0.00 0.00 -4.46 <0.001 fillyearsin10 0.11 <0.001 Null deviance: 6221.9 on 53 degrees of freedom Residual deviance: 3513.4 on 43 degrees of freedom Run through 512 model combinations leaves us with the full model (above). (Intercept) fillyearsin10 highFlowDays30d location SmallfykeGambusia totalFlowSinceJul1 Veg.comp1 Veg.comp2 Veg.comp3 WQ.comp1 df logLik AICc delta weight 3.44 0.01 + 0.00 0.00 0.15 11.00 3792.92 0.00 1.00 Estimate Std. Error z value Pr(>|z|) mid-Murrumbidgee - Lowbidgee 2.28808 0.03645 62.77 <0.001 *** Western Lakes - Lowbidgee 5.21397 0.05056 103.12 <0.001 *** Western Lakes - 0.04742 61.71 <0.001 ***