Terry J. Hillman

Multidisciplinary Approaches to Natural Resource Management

Counter-acting forces to increase rural production and/or its efficiency, and to sustain an ecosystem now recognised to be under increasing and destructive pressures have created exigencies in achieving balanced natural resource management (NRM). Nowhere is this more apparent than in the management of the Murray Darling System in south-eastern Australia. All actions affecting natural resources impinge on the ecosystems that support those resources, the economy based on them, and the human society and culture connected to them. Change is best managed with the cooperation of those most affected. If NRM is to be achieved through informed community decisions, there is a need for a multidisciplinary process, drawing on specialist (intra-disciplinary) expertise, and a requirement to pull the resultant knowledge into an integrated form which supports decision-making at the management and community level. We propose a framework that identifies tasks necessary to support community decision-making and inject specialist technical knowledge into the process. For complex NRM issues, it is likely that there is insufficient information in one or more disciplines to support a strong decision. Where possible, this should lead to the interposition of targeted pilot trials, based on principles of adaptive management, prior to the final assessment and (presumedly) management plans. These ‘management experiments’ follow a similar path to specialist hypotheses and measurements (based on the same management intervention) followed by an integrated assessment. It appears that identification of, and engagement with, components of the community, and analytical techniques to support integrated assessment are two major areas in which new knowledge is urgently needed.

Scale-dependent lateral exchanges of organic carbon in a dryland river during a high-flow experiment

We estimated the magnitude and direction of exchanges of particulate organic carbon (POC) and dissolved organic carbon (DOC) between the river and four floodplain wetlands (billabongs) and a 140-km reach of riverbank and floodplain of the Murrumbidgee River during a managed high-flow experiment. There was a net transport of organic carbon from the river to billabongs during connection, ranging from 87 to 525kg POC per billabong or from 1.4 to 5.7g POC m–2 of billabong sediment surface area and from 36 to 4357kg DOC, or from 0.4 to 29.8g DOC m–2. At the whole-reach scale, there was a net loss of 754Mg POC from the river channel to riverbank and floodplain and a net input of 821Mg DOC to the river channel. This DOC input, which was small relative to the total organic carbon in transit, was likely to have contributed significantly to oxidative processes in the river. The DOC entering the river was derived from litter and soils in riverbank habitats or from abraded biofilms in the river channel. The results support an extended flood-pulse concept that includes in-channel flow pulses as important elements in the biogeochemistry of dryland rivers. Piggybacking dam releases on tributary flows to deliver in-channel flows delivers significant benefit for riverine organic-matter cycles.

Advances in the study of River Murray ecology and the legacy of Keith Forbes Walker (1946−2016)

The rivers of the Murray-Darling Basin are central to the lives of many in south-eastern Australia, through provision of water for human consumption and agriculture, through ecosystem services and by providing enormous recreational and cultural capital. The development of the River Murray as a water resource has fundamentally altered the integrity of the river’s aquatic and floodplain ecosystems. Many researchers, conservationists, managers, and policymakers have devoted their careers to a better understanding of the ecology of this river system, with the ultimate aim of rehabilitating it. A central character in River Murray ecological research was Keith Forbes Walker. Keith was born in Aberdeen, Scotland, on 20 June 1946. In 1951, his family emigrated to Australia and lived in Melbourne. Keith completed a Bachelor of Science (Honours) at Monash University and then continued on to a PhD at Monash where his supervisor (and mentor) was WD (Bill) Williams, a pioneer in Australian limnology. After completing his PhD, he undertook Post-Doctoral studies at the University of Washington with the famous limnologist Tommy Edmundson who developed our understanding of lake eutrophication, and more importantly how to manage it. Keith returned to Australia to take up a postdoctoral position with Professor Ralph Slatyer at the Australian National University (ANU). While at ANU, Keith took part in the first ecological review of the River Murray at Albury-Wodonga with a small TRANSACTIONS OF THE ROYAL SOCIETY OF SOUTH AUSTRALIA, 2017 VOL. 141, NO. 2, 87–91 https://doi.org/10.1080/03721426.2017.1373456