An Assessment of 1000Km of the Billabong, Yanco and Colombo Creeks, NSW, in Vietz, G; Rutherfurd, I.D, and Hughes, R

7th Australian Stream Management Conference – Short Communication

Do native fish need healthy riparian vegetation? An assessment of 1,000km of the Billabong, Yanco and Colombo Creeks, NSW.

James Kaye 1 Monica Hersburgh 1 Clayton Sharpe 2 Trish Bowen 3 Anthony Conallin 3

1. Water Technology, Wangaratta, VIC, Australia; [email protected] 2. CPS Environmental Research, Irymple, VIC, Australia 3. Murray Local Land Services, Albury, NSW, Australia

Key Points • A range of key vegetation and habitat attributes were measured over 1000km of NSW tributaries to the Murray River. • There is a correlation between healthy riparian vegetation and Murray Cod abundance. • Other instream conditions (e.g. habitat, flow velocity and depth) are also importance if ideal habitat conditions are to be met.

Keywords Riparian condition monitoring, native vegetation, native fish habitat, natural resource management, Murray Catchment, Billabong Creek, Yanco Creek, Colombo Creek.

Introduction The Murray Local Land Services (Murray LLS, NSW) initiated this project to assess key attributes of riparian vegetation throughout nearly 1,000km of creek network. Native fish communities and riparian vegetation are key natural assets of the Billabong-Yanco Creek system. A new project is about to commence to enhance these assets through on-ground rehabilitation works and improved management skills and practices, and a baseline of riparian vegetation condition and fish community status was desired to inform management actions, provide a comparison for future monitoring and evaluation and enhance understanding of links between these key system components.

The Billabong Creek originates in the foothills of the Great Dividing Range east of Holbrook and flows in a westerly direction for more than 700km before flowing into the Edward River at Moulamein (Figure 1). The Yanco Creek is an effluent of the Murrumbidgee River, originating west of Narrandera and flowing in a south-westerly direction for approximately 250km before flowing into the Billabong Creek near Conargo. The Colombo Creek in turn is an effluent of the Yanco Creek that flows south from Morundah to the Billabong Creek upstream of Jerilderie. The Yanco Weir on the Murrumbidgee River allows water to be delivered down the Yanco Creek and in turn, down the Colombo Creek and into the downstream half of the Billabong Creek.

This vegetation mapping project assessed the majority of the length of Billabong Creek (Walbundrie to Moulamein, 561km), the entire Yanco Creek (249km) and entire Colombo Creek (126km). A key challenge of this project was to design and roll out a field assessment method that was relatively rapid, yet provided a representative snapshot of condition across such a large project area with a limited budget.

The Project area waterways were divided into reaches primarily based on hydrologic boundaries. The Billabong Creek was divided into reaches, commencing at Walbundrie and being defined by confluences with the Colombo Creek, the Yanco Creek and the Edward River. The Yanco Creek was divided where the Colombo Creek leaves the creek and heads generally south to the Billabong Creek. The project area creek system and reaches are shown schematically in Figure 1.

Kaye, J., Hersburgh, M., Sharpe, C., Bowen, T. & Conallin, A. (2014). Do native fish need healthy riparian vegetation? An assessment of 1000km of the Billabong, Yanco and Colombo Creeks, NSW, in Vietz, G; Rutherfurd, I.D, and Hughes, R. (editors), Proceedings of the 7th Australian Stream Management Conference. Townsville, Queensland, Pages 352-356. 352 7ASM Short Communication

James Kaye et.al. – 1,000km Riparian Vegetation Assessment – Billabong, Yanco and Colombo Creeks

N Murrumbidgee River Narrandera Yanco Ck Reach 5

Moulamein Billabong Creek Yanco Ck Reach 6 Reach 4 Colombo Creek Reach 7 Jerilderie Edward River Billabong Creek Reach 3 Deniliquin Billabong Creek Reach 2 Walbundrie Figure 1. Schematic map of the project area creek system and reaches.

This technical communication presents the results from the Riparian Vegetation Condition Mapping and makes some comparisons with findings from the fish survey. Figure 2 and Figure 3 provide indicative photos towards each end of the Yanco and Billabong Creeks.

Figure 2. Yanco Creek - upstream Reach 5, and downstream Reach 6

James Kaye et.al. – 1,000km Riparian Vegetation Assessment – Billabong, Yanco and Colombo Creeks

Figure 3. Billabong Creek, upstream Reach 2 near Walbundrie, and downstream Reach 4 near Moulamein

Method The methods adopted for this vegetation mapping project needed to be rapid and repeatable. There needed to be a balance between scientific rigour and practicability so that a reasonable number of sites could be assessed within the budgetary constraints. The method also needed to be well documented and relatively easy to apply so that future monitoring could be undertaken by suitably skilled consultants or Murray LLS staff.

It was agreed that the key deliverables would include: • Riparian canopy width. • Longitudinal continuity of native woody vegetation. • Condition of riparian trees. • Intactness of native understorey layers. • Extent of regeneration of all native vegetation layers. • Continuity of macrophytes. • Condition of riparian and instream habitat. • Land-use type, any major threats to riparian vegetation condition and the predicted condition trajectory assuming the current observable management practices continue. The following methods were adopted to gather this information: • “Land manager self-assessment method” (DSE 2004) (tree density, cover of over and understorey, weediness, recruitment, logs and litter, patch size and connectivity). • Sub-set of the “Index of Stream Condition” (DNRE 1999) physical habitat variables (stream-side zone width, presence of significant discontinuities, macrophyte cover and Large Woody Debris (LWD) abundance). • Tree health - proportion of healthy canopy cover expected. • Threats /land-use pressures and condition trajectory. • Species lists of native and exotic plants at each site to determine diversity and intactness. • General site details and photo-point information. Over 20 fieldwork days, 123 sites were assessed across the project area at an average of one site every 7.6km of creek length.

Result and Discussion

Riparian Vegetation Condition trends across the entire Billabong, Yanco and Colombo Creek systems, analysed by theme, are as follows:

James Kaye et.al. – 1,000km Riparian Vegetation Assessment – Billabong, Yanco and Colombo Creeks

• Habitat Quality – This measures riparian vegetation and habitat condition. The results indicate that the condition of frontages is quite variable and that there are no strong condition trends across the project area. However, site scores out of 20 for the six reaches indicates that the middle Billabong Creek Reach 3 (13.8/20) has the highest average score while the Colombo Creek has the poorest average (10.4/20). • Riparian and Instream Health - The data shows a general trend of condition decline in score in a downstream direction along the Billabong Creek from Reach 2 (12.0/20) to Reach 4 (10.4/20), and downstream along the Yanco Creek from Reach 5 (12.8/20) to Reach 6 (12.5/20). Although the Colombo Creek (10.6/20) scores an average slightly above Reach 4 (10.4/20), it scored very poorly for the instream habitat component. • Canopy Health – The Billabong Creek shows a distinct decline in tree health within its downstream Reach 4. This correlates with the drier climate and the higher levels of water extraction. Conversely, the Yanco Creek Canopy Health improves in the downstream reach and the Colombo Creek has the healthiest canopy of all reaches. • Weed Cover - Weed cover shows a general trend of reducing as one moves further downstream into the drier western plains, however, overall cover also tends to decrease. • Condition Trajectory - The results are variable across reaches but the following is evident:

o Although the upstream Reach 2 has the highest percentage of sites considered to have an improving condition trajectory, this reach also has the highest percentage of sites likely to decline in condition. o Reach 3 has no sites considered likely to decline under current management arrangements. o Reach 4 has more sites likely to decline than improve. o Most of Reach 5 sites are considered to be in a stable condition, however, no sites were considered to have an improving condition trajectory under current management.

Fish In total, 18,293 fish representing 14 species (10 native and 4 exotic) were sampled (boat electrofishing and small and large fyke nets) across 40 survey sites and reported by Sharpe and Stuart (2013). However, for the purposes of comparison with riparian vegetation and instream habitat condition results, only Murray Cod relative abundance within reaches was considered. The upper Billabong Creek Reach 3 was not surveyed. The relative abundance of Murray Cod within the three creeks indicated the following:

• Billabong Creek – There was a decline in fish abundance in the middle of these reaches with relatively high abundance at either end. It might be assumed that the downstream end of the Yanco Creek is being supported by fish entering the backwater and lower sections of Reach 4 from the Edward River. • Yanco Creek – There is clear decrease in Murray Cod abundance from upstream to downstream. The upper Yanco (Reach 5) is supported by relatively regular irrigation flows from the Murrumbidgee River. The irrigation flow is split between the Colombo Creek (Reach 7) and the lower Yanco Creek (Reach 6) at the Tarabah Weir.

Conclusions The condition of vegetation across the project area shows a general decline down the catchment. Since the trees appear to be increasingly flow stressed in the downstream Reach 4, it is believed that the lack of natural flooding, water extraction and natural losses contribute to this decline in condition. It is interesting that the Murray Cod population tends to decline downstream before increasing again nearer the Edward River. Although there is a general correlation between continuous, broad, healthy native riparian vegetation and Murray Cod distribution, there is no question that the flow, channel form (i.e. suitable depth) and instream habitat play a significant role in providing desirable habitat for Murray Cod. That said, continuous woody vegetation provides stability, food, shade and wood to the stream that may also be considered vital for creating suitable habitat. It might therefore be argued that fish do need healthy self- sustaining riparian vegetation to provide current and future habitat.

Acknowledgments The Riparian Vegetation Mapping projects have been supported by the Murray LLS and Caring for our Country Funding. Thanks go to the Murray LLS project managers, Anthony Conallin and Rowan Winsemius, and to Jim Parrett for providing access and contact details that helped us efficiently navigate around the Yanco and Colombo Creeks. We also thank the landholders for allowing us access to their properties and for their overall friendliness. This is both a credit to the landholders of the region and to the waterway managers who have obviously forged good relationships in the past.

James Kaye et.al. – 1,000km Riparian Vegetation Assessment – Billabong, Yanco and Colombo Creeks

References DNRE (1999), An index of stream condition: Field manual. Department of Natural Resources and Environment, East Melbourne. DSE (2004), Assessing habitat quality using the ‘Land manager self-assessment method’, Work Sheet No 4. Victorian Government Department of Sustainability and Environment, Melbourne. Sharpe, C. & Stuart, I. (2013) Billabong, Yanco and Colombo Creek Fish Baselining Project 2012-13. Consultants draft report for the Murray Catchment Management Authority, Albury. Water Technology (2013), Yanco & Colombo Creek Riparian Vegetation Mapping Baseline Condition Survey 2013. Report for the Murray Catchment Management Authority, Albury. Water Technology (2012), Billabong Creek Riparian Vegetation Mapping 2011-12. Report for the Murray Catchment Management Authority, Albury.