Long-term intervention monitoring in the Gwydir River Selected Area: The influence of hydrology on channel aquatic invertebrates.

Abstract

<p>The Basin-wide Environmental Watering Strategy forms a part of a program of water reform in the Murray-Darling Basin to deliver water to instream channels and wetlands through environmental flows. A key objective of the 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 whole fish and waterbird community. Therefore, key Basin Environmental Watering Strategy targets of successful fish and waterbird recruitment can only be achieved if environmental water delivers sufficient energy that is both available to, and accessible by aquatic biota.</p><p> In this report we assess the responses of three groups of aquatic invertebrates, including epi-benthic and zooplankton microinvertebrates and macroinvertebrates to the environmental water releases and natural flows that occurred in the channels in Gwydir River Selected Area during the Long term Intervention Monitoring (LTIM) program. We found that the responses in either richness or abundances of individual taxa due to various associations with channel hydrology significantly affected in assemblage structure of all three invertebrate groups. The response of invertebrates to channel hydrology was mainly demonstrated for epibenthic and zooplankton microinvertebrates and not macroinvertebrates but those associations were not strong. Due to the presence of invertebrates at all sites and times when water was available environmental water can play a significant role in contributing to the basal food resources in the Gwydir Selected Area.</p>