Ecological impacts of dams, water diversions and river management on floodplain wetlands in Australia

Kingsford, Richard T.

doi:10.1111/j.1442-9993.2000.tb00012.x

Cited by 289 publications

(432 citation statements)

References 86 publications

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“…The Murray-Darling basin represents a series of interconnected reservoirs, facilitated by construction of dams, and small-to-medium-sized ephemeral water bodies that occur within numerous floodplains (Kingsford, 2000). Yanga Lake represents a shallow ephemeral eutrophic freshwater lake largely representative of many of the water bodies present throughout the floodplains of the Murray-Darling Basin that are utilised for recreation, agriculture and rural drinking water Thomas, 2004, Kobayashi et al, 2013).…”

Section: Introductionmentioning

confidence: 99%

Microbial communities reflect temporal changes in cyanobacterial composition in a shallow ephemeral freshwater lake

et al. 2015

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The frequency of freshwater cyanobacterial blooms is at risk of increasing as a consequence of climate change and eutrophication of waterways. It is increasingly apparent that abiotic data are insufficient to explain variability within the cyanobacterial community, with biotic factors such as heterotrophic bacterioplankton, viruses and protists emerging as critical drivers. During the Australian summer of 2012-2013, a bloom that occurred in a shallow ephemeral lake over a 6-month period was comprised of 22 distinct cyanobacteria, including Microcystis, Dolichospermum, Oscillatoria and Sphaerospermopsis. Cyanobacterial cell densities, bacterial community composition and abiotic parameters were assessed over this period. Alpha-diversity indices and multivariate analysis were successful at differentiating three distinct bloom phases and the contribution of abiotic parameters to each. Network analysis, assessing correlations between biotic and abiotic variables, reproduced these phases and assessed the relative importance of both abiotic and biotic factors. Variables possessing elevated betweeness centrality included temperature, sodium and operational taxonomic units belonging to the phyla Verrucomicrobia, Planctomyces, Bacteroidetes and Actinobacteria. Species-specific associations between cyanobacteria and bacterioplankton, including the free-living Actinobacteria acI, Bacteroidetes, Betaproteobacteria and Verrucomicrobia, were also identified. We concluded that changes in the abundance and nature of freshwater cyanobacteria are associated with changes in the diversity and composition of lake bacterioplankton. Given this, an increase in the frequency of cyanobacteria blooms has the potential to alter nutrient cycling and contribute to long-term functional perturbation of freshwater systems.

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Section: Introductionmentioning

confidence: 99%

Microbial communities reflect temporal changes in cyanobacterial composition in a shallow ephemeral freshwater lake

et al. 2015

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“…It is the largest floodplain forest on the lower Murray River (KINGSFORD, 2000) and is part of 'Riverland Wetlands' listed under the UNESCO Ramsar Convention (Section 14.5) as wetlands of international importance because of unique bird-life and woodlands of E. camaldulensis and E. largiflorens (NEC, 1988). The area is located away from the moderating influence of the ocean and experiences generally clear skies allowing free heat exchange.…”

Section: Locationmentioning

confidence: 99%

“…Instead salt has built up to detrimental concentrations. Rainfall is less than 350 mm annually therefore plants rely on flooding for replenishment and leaching of salt from the root zone (KINGSFORD, 2000). Along the length of the Murray River in Australia, it is estimated that approximately 18 000 ha of floodplain vegetation is severely degraded with saline ground water (MARGULES AND PARTNERS et al, 1990).…”

Section: Introductionmentioning

confidence: 99%

Statistical associations between morphology, physiology and AFLP DNA markers enable selection of a putative eucalypt hybrid able to tolerate salt affected floodplains

Hancock

2012

Silvae Genetica

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A naturally occurring putative hybrid between Eucalyptus largiflorens F. Muell and Eucalyptus gracilis F. Muell called Green Box tolerates saline conditions of the River Murray floodplains better than E. largiflorens. Revegetation strategies utilizing seedlings of Green Box have had limited success because only a few are Green Box and the majority are throw backs to E. gracilis and E. largiflorens. Therefore, the purpose of this study was to identify traits characteristic of Green Box and AFLP markers associated with the traits enabling selection at the seedling stage. This was done by non-linear canonical correlation analysis (OVERALS) to test for statistically significant associations between morphological and physiological traits with 232 AFLP markers from 9 primer combinations. OVERALS with all markers produced 1st and 2nd dimensions accounting for 80 and 74% of variation respectively. Green Box plants were placed intermediate between E. gracillis and E. largiflorens according to leaf colour, gloss and nitrogen with component loadings (lc) of 0.340, 0.615 and 0.294 respectively. A second approach of simple linear regression of morphological and physiological traits against all 232 AFLP markers singled out 17 with significance P<0.05. Thirteen of these were also identified by OVERALS. Four occurred with high frequency in Green Box and E. largiflorens distinguishing them from E. gracilis. In order to separate Green Box and E. largiflorens, the segregation of a further three markers can be used to align Green Box with E. gracilis. Therefore, the segregation of 7 markers can be utilized to select Green Box.

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“…The Murray system is now controlled by many dams and weirs, and water from the Snowy River has been diverted westward across the Great Dividing Range to augment the Murray flow. However, the economic and social benefits of this control and use of the Murray's waters have had major environmental costs through declining river health, including hydrological, geomorphological, salinity and water quality impacts, as well as impacts on fish, aquatic invertebrates, floodplain vegetation and wetland biota (Walker and Thoms 1993, Thoms et al 2000, Kingsford 2000, Gippel and Blackham 2002, Gehrke et al 2003, Davies et al 2008, Jensen and Walker 2012.…”

Section: Introductionmentioning

confidence: 99%

Floodplain vegetation of the River Murray in 1987–1988: an important pre-drought benchmark for subsequent studies.

Smith¹,

Smith²

2014

Cunninghamia

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Abstract:As part of a wider study of floodplain vegetation along the River Murray, we carried out a field survey in 1987-1988 involving collection of floristic and vegetation condition data from 335 sample plots (each 400 m 2 in area), between Hume Dam and Lake Alexandrina (including the Edward-Wakool anabranch system). The floodplain vegetation is dominated by just two tree species, River Red Gum (Eucalyptus camaldulensis) and Black Box (Eucalyptus largiflorens), but the composition of the understorey shows much greater variation, both along the river and across the floodplain. A total of 499 plant species, subspecies and varieties were recorded from the survey plots, of which 316 (63%) were native and 183 (37%) were exotic. From analysis of the floristic data we identified 37 vegetation communities, not including the vegetation of permanent wetlands and cleared areas; 21 communities were distinguished in the River Red Gum zone, 12 communities in the Black Box zone, and 4 communities on rises within the floodplain. The main floristic division among the River Red Gum communities was between Riverine Plain/ Headwaters Zone communities of the upper Murray, and Mallee Zone communities of the lower Murray. Among the Black Box communities, the main floristic division was between inner floodplain communities and outer floodplain communities, with a further division between South Australian communities and New South Wales/Victorian communities. Major factors influencing the floristic patterns included flooding frequency/duration and soil salinity.Eucalypt health declined steadily downstream and was poorest in the lower reaches of the river below the Darling Junction, where 60% of the trees were healthy, 18% unhealthy (at least 40% of the canopy dead) and 22% dead. By comparison, at the upper end of the river, above Tocumwal, 84% of the trees were healthy, 14% unhealthy and only 2% dead. Overall, the condition of Black Box trees (44% unhealthy or dead) was worse than the condition of River Red Gum trees (29% unhealthy or dead). Eucaypt regeneration was also poorest below the Darling Junction, with regenerants present in 77% of plots upstream of the Darling but only 35% of plots downstream. The findings of poor tree health and sparse regeneration below the Darling coincide with the most heavily regulated part of the Murray, where the reduction in flooding due to upstream storages and water extraction, mainly for irrigation, has been greatest. Black Box regeneration was much sparser overall than River Red Gum regeneration (regenerants present in 69% of River Red Gum plots but only 29% of Black Box plots). The poor condition of the Black Box trees, coupled with their poor regeneration, suggests that the long-term future of this species along the Murray, particularly below the Darling Junction, is tenuous, even though it is a dominant component of the vegetation.The integrity of floodplain vegetation along the Murray has been severely compromised by weed invasion. Weeds were common throughout the survey area, but were most ...

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Ecological impacts of dams, water diversions and river management on floodplain wetlands in Australia

Cited by 289 publications

References 86 publications

Microbial communities reflect temporal changes in cyanobacterial composition in a shallow ephemeral freshwater lake

Microbial communities reflect temporal changes in cyanobacterial composition in a shallow ephemeral freshwater lake

Statistical associations between morphology, physiology and AFLP DNA markers enable selection of a putative eucalypt hybrid able to tolerate salt affected floodplains

Floodplain vegetation of the River Murray in 1987–1988: an important pre-drought benchmark for subsequent studies.

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