Tracking a century of change in trophic structure and dynamics in a floodplain wetland: Integrating palaeoecological and palaeoisotopic evidence
- Authors: Kattel, Giri , Gell, Peter , Perga, Marie-Elodie , Jeppesen, Erik , Grundell, Rosie , Weller, Sandra , Zawadzki, Atun , Barry, Linda
- Date: 2015
- Type: Text , Journal article
- Relation: Freshwater Biology Vol. 60, no. 4 (2015), p. 711-723
- Full Text:
- Reviewed:
- Description: The palaeoecological assessment, and the use of stable isotopes of carbon in subfossils of herbivores and omnivores, represents a novel approach to understand transitions in past food-web structure and the dynamics of lake ecosystems in response to natural perturbations and human impacts. Combined with records of subfossil assemblages of cladocerans and chironomids, it may be possible to decipher whether changes are attributable to external forces or internally derived system shifts. A sediment record taken from the shallow (2.3 m depth) Kings Billabong in the River Murray floodplain (Australia) was analysed to explore changes in trophic dynamics over the past century. The palaeoecological assessment revealed that littoral assemblages of cladocerans and benthic diatoms were gradually replaced by planktonic (planktonic and facultative planktonic) assemblages after river regulation in the 1920s. The stable isotopic composition of carbon (
Cladoceran-inferred ecological and hydrological changes of two floodplain wetlands in two large river systems, the Murray (Australia) and Yangtze Rivers (China)
- Authors: Kattel, Giri , Dong, Xuhui , Yang, Xiangdong
- Date: 2014
- Type: Text , Conference paper
- Relation: Symposium on Australia-China Wetland Network Research Partnership; Nanjing Institute of Geography and Limnology Chinese Academy of Sciences (NIGLAS) Nanjing, China; 23rd-28th December 2014 p. 42-49
- Full Text:
- Reviewed:
- Description: The landscapes of two of the world’s large river basins, the Murray and Yangtze Rivers of Australia and China, have been intensively developed for the provision of food and water resources. Long term archives of change, reveal that man-made infrastructures in the river and catchment modifications for agricultural and industrial developments have reduced the resilience of wetlands ecosystem structure and functions in recent decades. The river regulations imposed during the 20th centuries in the Murray and Yangtze Rivers have transformed hydrology and ecology of the river and associated wetlands. High resolution, subfossil cladoceran assemblages retrieved from Kings Billabong and Zhangdu Lake of the Murray and Yangtze Rivers, have strongly responded to human disturbances in the past. Ratios of littoral to planktonic (L:P) assemblages of subfossil cladocerans and the number of ephippial remains in Kings Billabong indicated the shift in hydrology and ecology of Kings Billabong, and ecological stress as a result of changes in naturally occurring dry-wet cycles following river regulation (1927 AD). Similarly, the subfossil cladoceran assemblages and their ephippia in Zhangdu Lake also reflected the impacts of the construction of the Three Gorges Dam (1954) in the Yangtze River on hydrology and ecology of the wetland.