Food web modelling to improve understanding of how river ecosystems respond to flow regimes

Start year: 2024

Summary: Anthropogenic modification of hydrological regimes has impacted ecosystem functions in aquatic ecosystems. In the Murray Darling Basin, water reform directed at river and wetland ecosystem restoration has provided water that can be used for environmental flows. Understanding how to maximise environmental flow actions to support productive and healthy food webs, particularly at whole-of-river scale, is limited. Our objective is to explore the influence of different flow scenarios on the food web of the River Murray and to build on previous work conducted in the Lachlan River under Flow MER 1. To do this we will construct dynamic bioenergetic food web models using Ecopath with Ecosim. This application takes a quantitative approach to examining food webs, moving beyond qualitative descriptions of foodweb responses. The models will be parameterised with data obtained through the River Murray Monitoring Program, an allied monitoring program to Flow MER, also funded by the CEWO and focussed on ‘whole of system’ assessment of a large-volume annual spring pulse in the River Murray. Using the fitted models, we will simulate scenarios in the presence and absence of environmental water allocations to see how changes in flow influence the structure and productivity of food webs.