Riparian Vegetation Of The River Murray

Author : Susanne Claudia Watkins
Publisher :
ISBN 13 :
Total Pages : 420 pages
Book Rating : 4.:/5 (815 download)

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Download or read book The Importance of Riparian Vegetation and Inundation Patterns for Billabongs of the Murray River written by Susanne Claudia Watkins and published by . This book was released on 2008 with total page 420 pages. Available in PDF, EPUB and Kindle. Book excerpt: Mesocosm experiments in summer and spring, mimicking seasonal inundation, used sediment collected from natural billabongs cleared of their riparian zones and billabongs with intact riparian zones. River red gum leaf litter was added to or excluded from mesocosms, simulatiang the effects of riparian clearing. Field surveys of natural billabongs on the Murray River floodplain (regulated) and the Kiewa River floodplain (unregulated) provided a context for, and some verification of, the experimental data. River red gum leaf decomposition during the mesocosm experiments was faster in summer than spring, due to rapid leaching, and physicochemical parameters such as dissolved oxygen were significantly affected by the addition of leaf litter. This suggested that prior weathering results in changes to red gum leaf chemistry between summer and spring. The mesocosm experiments indicated that a loss of organic matter from riparian clearing leads to changes to the billabong microinvertebrate and macroinvertebrate community structure in summer. However, leaf litter suppressed microinvertebrate abundances and some macroinvertebrate taxa in summer by altering physicochemical parameters. In spring, leaf litter had little effect, and instead the impact of riparian clearing on sediment characteristics appeared to influence the billabong community. Fewer microcrustaceans were found in the presence of sediment sourced from cleared billabongs, and abundance of Coleoptera and Chironomidae were higher in mesocosms containing cleared and forested sediment respectively. These responses may be linked to land use, perhaps altering the distribution and viability of invertebrate dormant stages. This study demonstrates that the loss of an input of leaf litter through clearing, and changing the timing of inundation, alter billabong ecosystem functioning. In addition, there was some indication from the field surveys to suggest that the absence of a riparian 'buffer zone' exposes billabongs to other land use impacts, such as cattle access. Furthermore, these two disturbances interact, so that the timing of billabong inundation fundamentally alters carbon dynamics within these systems. Riparian clearing and seasonal reversal of inundation also interact antagonistically -- clearing billabong riparian zones results in a reduced response to a change in the timing of inundation, whereas forested billabongs are more acutely affected.