Tributary of Pedler Creek, NE from McLaren Flat
2013 Aquatic Ecosystem Condition Report
- Dry in autumn and spring 2013
- Likely to be enriched with nutrients when wet due to the surrounding land uses
- Riparian vegetation mostly consisted of ash and gum trees over woody weeds and introduced grasses
- Minor bank erosion of soft banks recorded in spring
About the location
Tributary of Pedler Creek is a small third order stream that rises at an elevation of about 350m off the Sellicks Hill Range, and flows west for several kilometres before merging with other tributaries to form Pedler Creek to the north of McLaren Vale. Pedler Creek continues flowing in a westerly direction through Landcross Farm, Seaford Rise and Moana, and eventually flows into Gulf St Vincent near Moana Sands Conservation Park. The major land use in the 814 hectare catchment was stock grazing (78%), with minor areas used for other minimal uses, residential living, irrigated horticulture, roads, plantation forestry, nature conservation and dams. The site was located off a track at the end of Douglas Gully Road, about 9 km north-east from McLaren Flat.
The creek was given a Poor rating because the site sampled showed evidence of major changes in ecosystem structure and function. There were obvious signs of human disturbance of the creek due to the limited riparian zone and its dominance by weeds and introduced grasses, lack of any buffering vegetation, and the extent of land use modification of the entire upstream catchment.
The1.2-3 m wide channel was dry in both autumn and spring 2013. No macroinvertebrate or water quality data was consequently available for this site.
The sediments were dominated by detritus, sand and clay, with smaller amounts of silt, gravel and pebble also present; samples taken from below the surface were grey silts and sands that showed no clear evidence to indicate if the sediments were anaerobic or lacking in oxygen when the creek last dried. There were some minor bank erosion extending over nearly 10% of the site observed during the spring survey, which was attributed to winter flood damage of the soft, erodible banks. No animal droppings or sign of any animal damage was seen in the vicinity of the site.
About 10% of the margins of the channel was covered by an aquatic plant called a sedge (Cyperus); there was no evidence of any dried filamentous algal mats on the dry sediments of the creek to indicate if an algal bloom was present when the creek last held water at the site. The riparian zone was limited in extent and generally less than 5m wide. It was dominated by introduced ash trees, gums and wattles over woody weeds (olives and wild rose), dock and introduced grasses. The surrounding vegetation near the creek mostly comprised vineyards with some scattered gums and introduced grasses in the local landscape.
Special environmental features
Pressures and management responses
|Widespread introduced weeds in the riparian zone at the site and upstream (reducing habitat quality).||The Adelaide and Mount Lofty Ranges NRM Board has several pest plant (weed) mitigation and control programs. They work closely with landholders to control weeds on their property and to help stop the spread to other properties and waterways.|
This aquatic ecosystem condition report is based on monitoring data collected by the EPA. It was prepared with and co-funded by the Adelaide and Mount Lofty Ranges NRM Board.