Oral Presentation Australian Freshwater Sciences Society Conference 2018

Application of floodplain Eucalypt condition score systems to support environmental watering management decisions (#59)

Todd Wallace 1
  1. The University of Adelaide, Adelaide, SA, Australia

Throughout the Murray-Darling Basin, river red gums and black box are increasingly vulnerable to water stress through climate change and water abstraction for consumptive use. A marked decline in tree condition over recent decades has triggered a number of management programs that specifically target maintaining the extent and improving the condition of communities of river red gum and black box via the delivery of environmental water. A standardised approach to visually assessing the condition of these floodplain eucalypts has previously been developed that provides extensive guidance on how to collect field data on tree crown extent and crown density, but little guidance on how to convert that data into a readily interpretable index of crown condition. This makes it difficult for environmental water holders to make informed and repeatable decisions on the relative priority of competing sites for water allocations. In this project, six existing approaches for converting field data into crown condition scores were reviewed in order to identify a standardised approach to calculating tree condition scores. Existing multi-year data sets from managed watering sites were assessed to increase understanding of likely responses of black box and river red gum to wetting and drying phases. A standardised approach to analysing and reporting data that does not require complex statistical analysis, and meets the needs of floodplain managers as a reporting, communication and decision support tool is presented, along with a revised conceptual model of tree decline and recovery. The findings provide improved lines of evidence to support floodplain managers and environmental water holders to make informed and repeatable decisions on the relative priority of managed sites for water allocations.