By Stephen Balcombe and Samantha Capon, Griffith University (supported by CRDC). Pictured: Peter Norrie & Dr Stephen Balcombe.
For cotton farms with streams and riverine areas, healthy functioning riparian zones represent significant areas of high biodiversity and play a large role in the provision of ecosystem services. Such services include natural pest control (beneficials), prevention of soil erosion, water filtration, shade provision, shelter and barrier effects, pollination and aesthetic human benefits.
Griffith University has been undertaking research into the ecosystem services provided by natural areas on cotton farms.
Part of this research involved interviews with growers seeking on-ground input into understanding the values and ecosystem services provided by natural ecosystems on Australian cotton farms. The survey aimed to understand the drivers and benefits of retaining natural vegetation on cotton farms, the characteristics of these and how, and why, they are managed.
From the 22 grower interviews undertaken, most farms were largely dryland and irrigated mixed cropping with half of these also supporting grazing animals. The natural areas on these farms ranged between 10 and 40 per cent of property area, dominated by riparian lands. The most common motivators of managing riparian areas was to either increase profit margins or provide long-term farm sustainability.
To maintain and improve riparian areas the common management actions were: fencing and restricting grazing (to reduce erosion losses and increase regeneration of plants), pest and feral animal suppression (increased ecological health) and management of weeds to (improve regeneration of natives and encourage more beneficials).
These interviews provide a basis for good management in general especially active actions such as either completely removing stock or running lower stocking rates, or use fencing options to periodically graze such as strip grazing or seasonal grazing, particularly in the most sensitive areas of banks and gullies. Such management will have significant effects including reduced erosion and increased groundcover, and general plant diversity. Further there will be better water filtration (of nutrients and contaminants), meaning cleaner and healthier water returned to the river and an overall healthier ecosystem.
A great example of good riparian management was observed at a recent Gwydir Catchment field day at 'Norwood' Moree, hosted by Peter Glennie. Around one third of Peter’s property is dedicated to riparian conservation areas which he has maintained for the last 40 years.
He notes that his riparian areas provide many benefits for his land, including great shade for his stock when present, high vegetation diversity and social amenity both for fishing and aesthetics. In the river Peter also has the famous “raft” which is a mass of in-stream wood that moves around depending on the flow through the years, but it provides a huge geomorphological feature that influences riverine processes and provides habitat for both aquatic life and animals that feed in these areas.
Peters’ view on the raft is to leave all the wood in the river as it should be, and to not take any actions that disturb the river channels or sensitive areas, especially given the Gwydir sediments are so sensitive to movement (eg erosion). Peter has managed a great balance between running a successful farming enterprise by using low intensity grazing, fencing as needed and leaving his riparian areas to thrive and provide multiple benefits to the rest of the farm.
This blog is part of a year long program from CottonInfo, with the themes aligned with the 2019 CottonInfo cotton calendar. For more information, view the calendar, or contact the CottonInfo Technical Lead for Natural Resources, Stacey Vogel.
The April blog is continued in Part 2 - Domestic stock management in riparian areas.