干旱区生态环境知识资源中心

River management continues to challenge riparian systems worldwide, with climate change impacts and anthropogenic extractions escalating. The Murray-Darling basin (MDB) in Australia is critical to agricultural production and habitat provision to maintain biodiversity. Concern for the condition of native trees and biota in the MDB has led to substantial research investment to increase ecosystem function understanding and improve floodplain and wetland management. This field study offers new insights into tree nutrition and physiology as interpreted against the plant-soil-environment dynamics of recent flooding. Black Box (Eucalyptus largiflorens (Myrtaceae) is the only key native riverine MDB tree restricted to that region; and appears stressed at the far reaches of certain significant floodplain ecosystems. Here, nutritional and ecophysiological comparisons were made between Black Box trees that had just been inundated, and those nearby that had not. Leaf stomatal conductance, transpiration, total soil aluminium (Al) concentration, soil pH, and soil conductivity were different between inundated and dry sites. Soil moisture increased due to inundation, thus reducing tree water stress across the three study locations. Changes in leaf chemistry were not detected at the very early stages of flooding examined in this study. An increase in soil acidity due to inundation may also enhance bioavailability of nutrients to trees. New insight into immediate plant benefits gained from this study suggests further investigation is warranted to elucidate the influence of flood and drought on nutrient balance and how future wetland management can benefit from a more holistic understanding of plant-soil-environment dynamics.