Warrego and Darling rivers Selected Area 2021-22 -Appendix C Food Webs

A key objective of the Basin-wide Environmental Watering Strategy is ‘Improved Ecological Processes’ based on more productive and diverse food webs and ecological communities supported by the increased movement of carbon and nutrients. In turn, achieving these productivity and water quality objectives supports the Basin Plan Objectives of improving the life cycle completion of key plants and animals, and meeting the needs of the fish and waterbird community. Water quality and stream metabolism are both responsive to flow management and interact to regulate rates of energy production that underpin many ecological processes to form the basis of riverine food webs. Therefore, key Basin Environmental Watering Strategy targets of successful fish and waterbird recruitment can only be achieved if environmental water delivers sufficient energy resources that are both available to, and accessible by aquatic biota.

The production and transfer of energy within an ecosystem (ecosystem energetics) is a key functional process, fundamental to determining population and community structure and productivity. The production and transfer of energy in an ecosystem begins with nutrient and light availability driving primary production, in-turn creating basal resources that are transferred along a myriad of pathways to higher order consumers. Water for the environment influences water quality (nutrients, temperature, light, and salinity), which in turn can regulate rates of metabolism and productivity (carbon and energy availability) and this energy fuels the trophic carrying capacity of food webs (microinvertebrates and macroinvertebrates) that support fish and waterbird recruitment. This chapter integrates these fundamental ecosystem processes, linking environmental watering actions to water quality, energy production and understanding the potential food web responses within key habitats of the Warrego-Darling/Baaka (Selected Area).