River red gums are iconic in all cotton catchments and provide a number of valuable ecosystem services to growers, such as carbon sequestration, erosion mitigation and biodiversity conservation. There has been a decline in the health of these trees in recent decades, and it is likely that this decline is affecting the provision of ecosystem services. In addition, dead and dying trees contradict the environmentally conscious image the cotton industry aspires to. Cotton growers in the Namoi, Gwydir and Border Rivers catchments voiced their concern about the health of red gum trees and low recruitment rates and sought direction on how these factors could be addressed.

A literature review by Reid et al. (2007) provided some insight into the potential causes of river red gum dieback in the Namoi and Gwydir Valleys. The literature indicated water stress (declining groundwater levels, altered flood regimes and reduced groundwater recharge) was the most likely cause of river red gum dieback, but there were also links between grazing intensity and ecosystem health. Growers have pointed out a potential link between the abundance of lippia and ecosystem health in the Namoi Catchment. Climate change may also be implicated in river red gum dieback. With so many interacting variables operating simultaneously, there is still some ambiguity surrounding the causes of red gum dieback and low seedling recruitment, and it is unclear how growers can reverse the current trend of ecosystem decline.

Riverine ecosystems are the lifeblood of the cotton industry. They are also pivotal to the maintenance of much biodiversity in semi-arid catchments, being especially species rich and having high complementarity values (i.e. species that are not found in other parts of the landscape) compared to other vegetation types. Given the concentration of cotton production on major inland river systems, the industry has a duty of care to maintain the health of these ecosystems and protect them for future generations. By demonstrating concern for iconic national symbols in its backyard and restoring healthy riparian ecosystems, the cotton industry can build on its reputation for proactive environmental stewardship and responsible environmental management. This will have flow-on benefits for growers and marketers hoping to supply cotton to environmentally conscious manufacturers and consumers.

The average Australian cotton farm occupies approximately nine kilometres of river frontage and riparian lands. While the area of cotton production in any catchment is small, cotton farmers collectively are responsible for the management of many thousands of kilometres of riparian lands that have disproportionate importance for biodiversity conservation and ecosystem function in the semi-arid and subhumid landscapes where cotton is grown. Management of riparian zones on cotton farms forms part of a growers’ social license as the downstream impacts of a grower’s actions

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has implications for the health and vitality of downstream sites and the river itself, and therefore determines the value of the system for the wider community.

River red gums are a national icon and fringe most river systems across the cotton-growing extent in eastern Australia. They attain grand proportions during their life-span of up to 1000 years, and capture the hearts and minds of growers who proudly point out their favourite big old tree on their farm. In addition to their aesthetic and cultural heritage values, well-connected riparian ecosystems dominated by river red gums enhance biodiversity conservation by facilitating the movement of wildlife and plant propagules through agricultural landscapes, and provide a range of ecosystem services to cotton growers and the community. However, tree health has deteriorated in many cases to the point that trees and riparian ecosystems are no longer able to provide ecosystem services, and may in fact be providing a range of disservices. For example, dead and dying trees are net C sources to the atmosphere as they respire more than they sequester, and weedy riparian zones are a source of insect pests in cotton.

Riparian areas present a complex range of management dilemmas for growers. Weeds (e.g. lippia), livestock grazing and water management influence the health of river red gum trees and the ecosystems they form. Healthy river systems are the lifeblood of the industry, and cotton growers need good information and accurate knowledge to manage riparian ecosystems responsibly. While there are areas of concern, there are also many examples of healthy riparian areas on cotton farms, and these act as exemplars for other growers to aspire to.