Module 5: Riparian condition and land-use practices: A survey of riparian health on dairy farms

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Background Intensive grazing reduces environmental quality through the degradation of riparian land, loss of vegetation and biodiversity, and reduced water quality. A variety of rapid-appraisal methods have been developed in Australia to assess riparian condition over a variety of spatial scales. In all cases, several variables are measured in a rapid (1-2 hour) survey of sites (100 m-1 km stream reaches) with the intention of providing indicator measures of riparian ecosystem function.
Aim This research uses previously tested physical variables as indicators of riparian and in-stream condition. The indicators of condition provide information on the ability of the riparian habitat to minimise the impact of high flow events on soil erosion, provide habitat for native biodiversity (in-stream and riparian) and sustain in-stream health.
Our approach A rapid appraisal system developed at Charles Sturt University was used to asses 107 riparian sites of different conditions, ranging from relatively pristine (remnant) to highly degraded streams, across Gippsland. The physical measurements have been compared with farm management variables collected for each site such as stocking rate, stock management, fertiliser application in relation to stream and use of riparian land.

• Riparian sites in paddocks used for grazing of milking herds were generally in ‘very poor’ condition.
• Riparian sites in the best condition were those contained within fenced-off areas of remnant vegetation, without access to stock
• Fenced off and replanted riparian sites generally received a low condition score owing to the short amount time elapsed since replanting. A significant, positive linear relationship was observed between time since rehabilitation work and condition score ie. longer time since fencing / replanting higher condition score.
• Riparian sites that had been replanted / rehabilitated more than 16 years ago attained condition scores within / approaching ‘excellent’.
• Riparian condition index scores for fenced off streams containing remnant vegetation reached a plateau when vegetation was 30 metres wide on each side of the stream.
• Rehabilitation of degraded riparian sites currently subject to direct access by stock is best achieved by fencing the riparian land to exclude stock. Practices such as the provision of off-stream watering points and the resting of riparian paddocks (that are not fenced to exclude stock) are not effective management practices on dairy farms in Gippsland under current stocking rates.

Final Report - Module 5

Contact Dr Sharon Aarons Ph: (03) 5624 2222 Email: Sharon.Aarons@dpi.vic.gov.au