Biogeography and taxonomy of New Zealand Cladocera (Anomopoda, Chydoridae): a review
- Authors: Kattel, Giri , Augustinus, Paul
- Date: 2010
- Type: Text , Journal article
- Relation: Journal of the Royal Society of New Zealand Vol. 40, no. 3-4 (2010), p. 209-224
- Full Text: false
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- Description: Studies of the biogeography of Cladocera in New Zealand lakes are rare and only a few species of littoral chydorid Cladocera have been documented. Consequently, a number of issues relating to their taxonomy and systematics have yet to be resolved. The majority of chydorid Cladocera in the northern hemisphere have been given new names after a detailed investigation of their morphology and genetic variability. However, knowledge of their inter-hemispheric distribution is poor. It is likely that many species of chydorid Cladocera in the southern hemisphere, including in the New Zealand lakes, will show significant genetic variability from their northern hemisphere counterparts, although this has not yet been investigated. Here we review the taxonomy and biogeography of the New Zealand chydorid Cladocera. This is important when we consider the limited knowledge of New Zealand cladocerans and the consequent difficulties encountered by freshwater ecologists and paleolimnologists when using them to identify rapid environmental changes in the southern hemisphere.
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
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- 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 (
Spatial and temporal distribution patterns of zooplankton in a shallow lowland coastal lake, Lake Waihola in New Zealand
- Authors: Kattel, Giri , Closs, Gerard
- Date: 2011
- Type: Text , Book chapter
- Relation: Zooplankton and phytoplankton; Types, characteristics and ecology p. 123-140
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- Description: Communities in shallow coastal lakes are inclined to change with environmental variations quite frequently due to their proximity to marine environments. The pelagic zooplankton community of shallow lowland coastal lake, Lake Waihola in South Island, New Zealand was examined by monthly day and night sampling by hand-operated bilge pump. Over 15 sampling trips, each consisted of diel (D/N) measurement at 50 m apart with five replicate samples at four positions, shallow-inshore (Sh/ln), shallow-offshore (Sh/Of), deep-inshore (Dp/In) and deep-offshore(Dp/Of) corresponded a total of 600 samples being collected. Zooplankton individuals collected in D/N samples in four positions were pooled and averaged for each season. Distribution of zooplankton community over temporal and spatial scales were visualized in ordination using nonmetric multi-dimensional scaling (MDS) followed by permutational multivariate ANOVA in PRIMER. Four-factor interaction (Date*D/N*Sh/Dp*ln*Of) reveals that the effect of sampling dates was significant on distribution of zooplankton, but the distribution across the diel timeframe over spatial scales (D/N*In/Of*Sh*Dp) was insignificant. Some degree of distribution was observed along vertical (Sh/Dp) gradient, but no significant patterns were evident across the horizontal (In/Of) gradient. Amongst zooplankton, cladocerans such as Daphnia, Ceridaphnia and Bosmina showed a poor and patchy distribution pattern where Bosmina being dominant in January 1998. Except the Sh/Of day sample of February 1998, when calanoid copepods were absent, the distribution of calanoid copepods, cyclopoid copepods and amphipods was relatively common throughout the period of study. The overall distribution patterns of zooplankton in Lake Waihola indicate that there may be significant differences amongst zooplankton community (e.g., cladocerans vs non-cladocerans) to respond to local environmental and seasonal changes, consequently our understanding of shallow lentic coastal ecosystems in South Island, New Zealand is becoming increasingly complex.
Late Quaternary paleolimnology of Onepoto maar, Auckland, New Zealand : Implications for the drivers of regional paleoclimate
- Authors: Augustinus, Paul , Cochran, Ursula , Kattel, Giri , D'Costa, Donna , Shane, Phil
- Date: 2012
- Type: Text , Journal article
- Relation: Quaternary International Vol. 253, no. (2012), p. 18-31
- Full Text: false
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- Description: A high-resolution record of lacustrine environments spanning ca. 30-9calkaBP was obtained from Onepoto maar, northern North Island, New Zealand. The multi-proxy record of environmental change is constrained by tephrochronology and AMS 14C ages and provides evidence for episodes of rapid environmental change during the Last Glacial Coldest Period (LGCP: 28.5-18calkaBP) and Late Glacial-Interglacial Transition (LGIT) from northern New Zealand. The Onepoto pollen record indicates that the LGCP was cold, dry and windy in the Auckland region with vegetation dominated by herbs and grasses in a beech forest mosaic. At the same time the diatom record indicates oligotrophic conditions with low lakes levels and turbulence whilst cladocerans indicate low water temperatures. The inference of cold, dry and windy conditions during the LGCP is supported by geochemical evidence for increased sediment influx, charcoal and CO 2 limiting conditions for terrestrial macrophytes. Rapid climate amelioration and forest expansion after ca. 18calkaBP corresponds with reduced sediment influx, diatom and cladoceran-inferred higher lake levels indicating increasing moisture availability and temperature. Diatom flora indicates that an oligotrophic, circumneutral lake was becoming established during the LGIT but conditions were still variable. Between ca. 13.8 and 12.5calkaBP two brief drier and possibly cooler episodes are apparent (ca. 13.8-13.2 and 13-12.5calkaBP) followed by a warm phase combined with generally stable high lake levels between ca. 12.5 and 10.5calkaBP. Subsequently the lake water chemistry became more alkaline and eutrophic, possibly because sea level had risen high enough by this time to influence ground water chemistry. © 2011 Elsevier Ltd and INQUA.
Palaeocladocerans as indicators of environmental, cultural and archaeological developments in Eifel maar lakes region (West Germany) during the Lateglacial and Holocene periods
- Authors: Kattel, Giri , Sirocko, Frank
- Date: 2011
- Type: Text , Journal article
- Relation: Hydrobiologia Vol. 676, no. 1 (2011), p. 203-221
- Full Text: false
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- Description: The use of subfossil cladocerans is rare for understanding environmental, cultural and archaeological developments of lakes in Europe. In 2007, we collected a 12-m long sediment core from Lake Schalkenmehrener Maar (SMM), Germany for the analyses of subfossil cladocerans. Dating of core was based on tephrochronology, radiocarbon and pollen stratigraphy. Pollen-based chronostratigraphy indicated a decline of species richness and abundance of chydorids during the Lateglacial (ca.14500 cal yr bp) with dominant cold preferring taxa Acroperus harpae Baird and Alona affinis Leydig. During the early Bölling, the abundance of cladocerans increased commensurate with growth of birch (Betula L.) and pine (Pinus L.) trees. Except a spike of Bosmina coregoni Baird during the Younger Dryas, cladoceran assemblages remained stable from the Bölling to the mid-Atlantic period. During the Neolithic (ca. 4300 bc), the abundance of B. coregoni increased sharply with reciprocal decrease in Daphnia. However, as soon as Daphnia was dominant (ca. 4250 bc), a reciprocal decline in abundance of B. coregoni occurred. The mid-Holocene change in cladoceran abundance coincided with the use of hardwood forest. This situation ended at ca. 4000 bc and remained unchanged throughout the Neolithic and Bronze Age (ca. 3000-1200 bc). Low Daphnia abundance indicated reduced water quality in the Hunsrück-Eifel culture (ca. 800 bc). A spike of B. coregoni at ca. ad 150 indicates construction of the Roman Villa Rustica and extensive farming. However, reoccurrence of Daphnia at ca. ad 470 indicates the retreat of the Romans from the Eifel region. From the early Frankish rule (ca. ad 500) to the Medieval period (ca. ad 1500), species richness reduced but abundance of B. coregoni increased indicating a switch in lake ecosystem. The loss of species richness and the lack of precise evidence of the human activity in the region in the past have impeded the restoration of the ecosystem of the Lake SMM. © 2011 Springer Science+Business Media B.V.
Developing a complementary framework for urban ecology
- Authors: Kattel, Giri , Elkadi, Hisham , Meikle, Helen
- Date: 2013
- Type: Text , Journal article
- Relation: Urban Forestry & Urban Greening Vol. 12, no. 4 (2013), p. 498-508
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- Description: Cities are characterized by dynamic interactions between socio-economic and biophysical forces. Currently more than half of the global population reside in cities which influence the global biogeochemical cycles and climate change, substantially exacerbating pressures on urban pollution, water quality and food security, as well as operating costs for infrastructure development. Goods and services such as aesthetic values, water purification, nutrient recycling, and biological diversity, that urban ecosystems generate for the society, are critical to sustain. Urban planners are increasingly facing the considerable challenges of management issues for urban ecosystems. Poor understanding of the complementary roles of urban ecology in urban infrastructure, and the functioning of ecosystems and ecological resilience of a complex human-dominated landscape has impeded effective urban planning over time, resulting in social disharmony. Here a complementary framework for urban ecology is proposed, in which ecosystems interact with land use, architecture and urban design - "E-LAUD"-affecting ecosystem and human health, and building on the concept that land uses in urban green areas, road-strips, wetlands, 'habitat islands' and urban architecture could synergistically benefit when clustered together in different combinations of urban landscapes. It is proposed that incorporation of the E-LAUD framework in urban planning forms the context of a new interdisciplinary research programme on ecological resilience for urban ecosystems and helps promote ecosystem services. (C) 2013 Elsevier GmbH. All rights reserved.
Management strategies for large river floodplan lakes undergoing rapid environmental changes
- Authors: Kattel, Giri , Gell, Peter
- Date: 2014
- Type: Text , Book chapter
- Relation: International Perspectives on Global Environmental change p. 329-353
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Can we improve management practice of floodplain lakes using Cladoceran zooplankton?
- Authors: Kattel, Giri
- Date: 2011
- Type: Text , Journal article
- Relation: River Research & Applications Vol. 28, no. 4 (2011), p. 1-9
- Full Text: false
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- Description: Natural resource managers across Australia intend to promote healthy floodplain lake ecosystems with rich diversity and composition of biota because such ecosystems provide economically valuable services to society. However, management practice of these floodplain lake ecosystems is impeded by confounding effects of anthropogenic impacts and natural climate variability in recent decades. Yet, there are a few potential biological markers available that profoundly respond to ecological effects of climate change and human disturbances. Cladoceran zooplankton plays an intermediary role in food web dynamics. They show distinct responses to changes in temperature and environmental perturbations, such as acidification, nutrient loading and salinization. The effects of temperature and land-use changes on food web dynamics and water quality, in particular, are major concerns for shallow lowland large river floodplain lakes management in Australia. Information on zooplankton assemblages and diversity can help increase our understanding of ecological processes in a wide range of environmental exposures. The study of cladoceran fossils and their ephippia preserved in floodplain lake sediment has substantially furthered our understanding of species–environment relationships at different temporal and spatial scales and allowed us to develop powerful inference models for degraded floodplain lake ecosystems. This consequently defines a benchmark of a shift from a naturally intact ecosystem to an ecologically poor regime. In this paper, I have made an attempt to persuade wetland managers through application of contemporary and palaeocladoceran communities to improve management practice of floodplain lake ecosystems in Australia by providing a range of examples. Copyright © 2011 John Wiley & Sons, Ltd
- Description: 2003009403
Zooplankton and phytoplankton : types, characteristics, and ecology
- Authors: Kattel, Giri
- Date: 2011
- Type: Text , Book
- Full Text: false
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Ecological shift and resilience in China's lake systems during the last two centuries
- Authors: Zhang, Ke , Dong, Xuhui , Yang, Xiangdong , Kattel, Giri , Zhao, Yanjie , Wang, Rong
- Date: 2018
- Type: Text , Journal article , Review
- Relation: Global and Planetary Change Vol. 165, no. (2018), p. 147-159
- Full Text: false
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- Description: The worldwide decline of wetland ecosystems calls for an urgent reassessment of their current status from a resilience perspective. Understanding the trajectories of changes that have produced the current situation is fundamental for assessing system resilience. Here, we examine long-term dynamics of wetland ecosystem change by reviewing paleoecological records from 11 representative lakes in China. We identify unprecedented change in alga communities in the context of last two centuries. Striking ecological shifts have occurred in all lakes, yet with spatial and temporal differences. The long-term trajectories of change in diatom species composition and structure indicate gradually eroded system resilience. These ecological shifts were shaped by socio-economic activities as China transformed from a rural agricultural to an industrialized society within the last several decades, during which multiple drivers have accumulated and acted synergistically. The balance between ecosystem and society, which appeared to exist for thousands of years, was broken by increasing population, new technology, and urbanization since the 1980s. The consequences are the emergence of new positive feedbacks with the potential to drive the coupled systems into undesirable states. By linking long-term social and ecological change at a regional scale, our study provides a novel contribution to the understanding of lake ecosystems resilience in present-day China. We argue that sustaining wetland ecosystems requires integrated approaches that incorporate a deeper understanding of social-ecological dynamics over decadal-centennial timescales to address the complex underlying mechanisms leading to the current degradation.
Within-lake spatio-temporal dynamics of cladoceran and diatom communities in a deep subtropical mountain lake (Lugu Lake) in southwest China
- Authors: Wang, Qian , Yang, Xiangdong , Kattel, Giri
- Date: 2018
- Type: Text , Journal article
- Relation: Hydrobiologia Vol. 820, no. 1 (2018), p. 91-113
- Full Text: false
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- Description: Within-lake spatio-temporal variability of remains of cladocerans and diatoms were examined, using trap and surficial sediment sampling approaches in Lugu Lake, one of the deep mountain lakes in the subtropical region of southwest China, to understand the response to recent environmental change. Seasonality played a strong role in the distribution patterns of both cladocerans and diatoms, but their responses to seasonal change varied. The rich resources of food supported a cladoceran population peak during summer, while increased mixing and higher nutrient triggered diatom blooms in spring. The summer also witnessed increased grazing effects of primary consumers on diatoms when the water column was nutrient-enriched. In particular, Ceriodaphnia intensified grazing on small diatoms (Cyclotella ocellata), consequently affecting community patterns during summer, while increased wind activity during spring induced turbulence, remixing, transportation and depositional processes of remains of littoral Alona guttata and benthic diatoms. The distribution pattern of cladocerans in surface sediments was similar to that of diatoms. Seasonal community patterns and trophic interactions between cladocerans and diatoms in trap and surface sediments of differential depth gradients provide evidence that high-resolution sampling of multi-proxy biological remains in deep mountain lakes of southwest China can help reduce biases in paleoenvironmental reconstructions.
Estimating visual quality, a component of culturally-associated ecosystem services in palaeo-lake environments
- Authors: Chhetri, Prem , Kattel, Giri , Dong, Xuhui , Yang, Xiangdong , Min, Xu
- 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. 23-26
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- Description: Evaluation of visual quality is essentially a multi-dimensional and multi-sensory experience of landscape assessment. Visual quality refers to the character, condition and quality of lakes/wetlands. It involves perceiving, preferring and valuing the visual quality by the public. Visual quality is an outcome of the perceptual, cognitive and emotional processes in response to visual stimuli of a lake environment. Visual quality therefore is dependent upon the perceptual and structural aspects of perceived scenes of wetlands. Visual assessment, an evaluating process of gaining non-material or intangible benefits by people from ecosystems, through spiritual enrichment, cognitive development, self-reflection, recreation, and aesthetic experiences, has now become one of significant research areas under cultural components of ecosystem services. Public perception in such studies is composed from both the objective and subjective elements of human–landscape interactions. However, it is still a matter of debate whether subjective–objective realities are dichotomous or supplementary to enhancing the quality of human experiences in natural settings. In fact, much research considers them as inseparable and integral parts of landscape perception, despite the tendency for disintegrating landscapes into their constituent components. There is a fundamental theoretical divergence of opinions over the question whether a landscape has an intrinsic or ‘objective’ beauty, which may be in some ways measurable or comparable, or whether beauty is a value that can be only attributed subjectively to an area or a specific landscape.
Proceedings of the Australia-China Wetland Network Research Partnership Symposium
- Authors: Kattel, Giri
- Date: 2014
- Type: Text , Conference proceedings
- Full Text:
- Description: This publication is a compilation of short papers presented at the Australia-China Wetland Network Research Partnership Symposium, held in China at the Nanjing International Conference Hotel, 24 March 2014. The symposium, jointly organised by the Collaborative Research Network (CRN) of Federation University Australia and the Nanjing Institute of Geography and Limnology Chinese Academy of Sciences (NIGLAS), brought together a range of scientists including the neo-ecologists, palaeoecologists and hydrologists from both Australia and China. More than 100 students and scientists from across China attended the symposium. A majority of papers presented at the symposium have overlapping themes between ecology and hydrology of the large river and wetland systems that are exposed to a range of impacts posed by humans and recent climate change. The research focus of this volume is around the topic highlighting the conservation and management of degraded wetlands in Australia and China and the maintenance of a long term ecological resilience.
A century-scale, human-induced ecohydrological evolution of wetlands of two large river basins in Australia (Murray) and China (Yangtze)
- Authors: Kattel, Giri , Dong, Xuhui , Yang, Xiangdong
- Date: 2016
- Type: Text , Journal article , Review
- Relation: Hydrology and Earth System Sciences Vol. 20, no. 6 (2016), p. 2151-2168
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- Description: Recently, the provision of food and water resources of two of the world's largest river basins, the Murray and the Yangtze, has been significantly altered through widespread landscape modification. Long-term sedimentary archives, dating back for some centuries from wetlands of these river basins, reveal that rapid, basin-wide development has reduced the resilience of biological communities, resulting in considerable decline in ecosystem services, including water quality. Large-scale human disturbance to river systems, due to river regulation during the mid-20th century, has transformed the hydrology of rivers and wetlands, causing widespread modification of aquatic biological communities. Changes to cladoceran zooplankton (water fleas) were used to assess the historical hydrology and ecology of three Murray and Yangtze river wetlands over the past century. Subfossil assemblages of cladocerans retrieved from sediment cores (94, 45, and 65 cm) of three wetlands: Kings Billabong (Murray), Zhangdu, and Liangzi lakes (Yangtze), showed strong responses to hydrological changes in the river after the mid-20th century. In particular, river regulation caused by construction of dams and weirs together with river channel modifications, has led to significant hydrological alterations. These hydrological disturbances were either (1) a prolonged inundation of wetlands or (2) reduced river flow, both of which caused variability in wetland depth. Inevitably, these phenomena have subsequently transformed the natural wetland habitats, leading to a switch in cladoceran assemblages to species preferring poor water quality, and in some cases to eutrophication. The quantitative and qualitative decline of wetland water conditions is indicative of reduced ecosystem services, and requires effective restoration measures for both river basins which have been impacted by recent socioeconomic development and climate change. © 2016 Author(s).
Towards threshold-based management of freshwater ecosystems in the context of climate change
- Authors: Liu, Junguo , Kattel, Giri , Arp, Hans Peter , Yang, Hong
- Date: 2015
- Type: Text , Journal article
- Relation: Ecological Modelling Vol. 318, no. (2015), p. 265-274
- Full Text: false
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- Description: Climate change is an increasing threat to freshwater ecosystem goods and services. We review recent research regarding the direct and indirect impacts of climate change on freshwater ecosystems and the severity of their undesirable effects on ecosystem processes and services. Appropriate management strategies are needed to mitigate the long-term or irreversible losses of ecosystem services caused by climate change. To address this, this review puts forward a threshold-based management framework as a potential platform for scientists, decision makers and stakeholders of freshwater ecosystems to work together in reducing risks from climate change. In this framework, the susceptibility of local freshwater ecosystems to change beyond thresholds is continuously investigated and updated by scientists, used to design policy targets by decision makers, and used to establish mitigation measures by local stakeholders. © 2014 The Authors.
Cladoceran-inferred environmental change during the LGM to Holocene transition from Onepoto maar paleolake, Auckland, New Zealand
- Authors: Kattel, Giri , Augustinus, Paul
- Date: 2010
- Type: Text , Journal article
- Relation: New Zealand Journal of Geology and Geophysics Vol. 53, no. 1 (2010), p. 31-42
- Full Text: false
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- Description: Subfossil cladocerans have rarely been used for paleoenvironmental reconstruction from New Zealand lake sediments, and here we detail the first examination of the response of cladocerans to past environments from an Auckland maar paleolake. Cladoceran remains were examined in the upper 230 cm of the lacustrine sediments spanning c. 9-31 cal. ka BP from Onepoto maar during which time the lake underwent significant changes. Lake level was relatively high during the Last Glacial Coldest Period (c. 28-18 cal. ka BP), with limited forest in the catchment, shoreline vegetation and low water temperature indicated by the presence of a planktonic taxon, Bosmina meridionalis, and a cold tolerant chydorid cladoceran Alona sp. (affinis type). However, the climate during the last glacial termination after c. 17.9 cal. ka BP changed abruptly, perhaps becoming extremely dry and windy, resulting in increased production of cladoceran resting eggs. Between c. 17.6 and 14.1 cal. ka BP, a gradually ameliorating climate with sustained windiness and dryness might have been unfavourable for hatching of chydorid cladoceran eggs and their recolonisation. After c. 14.1 cal. ka BP, continued climatic amelioration was accompanied by reduced lake levels inferred from high cladoceran littoral: planktonic ratios as well as increased cladoceran diversity and abundance of less cold tolerant chydorid taxa: Alona guttata, Alona sp. (intermedia type) and Alonella excisa. At c. 9 cal. ka BP, the maar crater rim was breached by the marine waters commensurate with postglacial sea-level rise, resulting in degraded water quality and production of a large number of cladoceran ephippia in the sediments. © 2010 The Royal Society of New Zealand.
First human impacts and responses of aquatic systems : A review of palaeolimnological records from around the world
- Authors: Dubois, Nathalie , Saulnier-Talbot, Emilie , Mills, Keely , Gell, Peter , Battarbee, Rick , Bennion, Helen , Chawchai, Sakonvan , Dong, Xuhui , Francus, Pierre , Flower, Roger , Gomes, Doriedson , Gregory-Eaves, Irene , Humane, Sumedh , Kattel, Giri , Jenny, JeanPhilippe , Langdon, Peter , Massaferro, Julieta , McGowan, Suzanne , Mikomagi, Annika , Ngoc, Nguyen , Ratnayake, Amila , Reid, Michael , Rose, Neil , Saros, Jasmine , Schillereff, Daniel , Tolotti, Monica , Valero-Garces, Blas
- Date: 2018
- Type: Text , Journal article , Review
- Relation: Anthropocene Review Vol. 5, no. 1 (2018), p. 28-68
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- Description: Lake sediments constitute natural archives of past environmental changes. Historically, research has focused mainly on generating regional climate records, but records of human impacts caused by land use and exploitation of freshwater resources are now attracting scientific and management interests. Long-term environmental records are useful to establish ecosystem reference conditions, enabling comparisons with current environments and potentially allowing future trajectories to be more tightly constrained. Here we review the timing and onset of human disturbance in and around inland water ecosystems as revealed through sedimentary archives from around the world. Palaeolimnology provides access to a wealth of information reflecting early human activities and their corresponding aquatic ecological shifts. First human impacts on aquatic systems and their watersheds are highly variable in time and space. Landscape disturbance often constitutes the first anthropogenic signal in palaeolimnological records. While the effects of humans at the landscape level are relatively easily demonstrated, the earliest signals of humaninduced changes in the structure and functioning of aquatic ecosystems need very careful investigation using multiple proxies. Additional studies will improve our understanding of linkages between human settlements, their exploitation of land and water resources, and the downstream effects on continental waters.
- Description: Lake sediments constitute natural archives of past environmental
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
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- 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.
Palaeoecological evidence for sustained change in a shallow Murray River (Australia) floodplain lake: regime shift or press response?
- Authors: Kattel, Giri , Gell, Peter , Zawadzki, Atun , Barry, Linda
- Date: 2017
- Type: Text , Journal article
- Relation: Hydrobiologia Vol. 787, no. 1 (2017), p. 269-290
- Full Text: false
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- Description: Paleolimnological techniques can reveal long-term perturbations and associated stable state transitions of lake ecosystems. However, such transitions are difficult to predict since changes to lake ecosystems can be abrupt or gradual. This study examined whether there were past transitions in the ecological regime of Kings Billabong, a shallow River Murray wetland in southeast Australia. A 94-cm-long core, covering c. 90 years of age, was analysed at 1 cm resolution for subfossil cladocerans, diatoms and other proxies. Prior to river regulation (c. 1930), the littoral to planktonic ratios of cladocerans and diatoms, and bulk sediment delta C-13 values were high, while the period from c. 1930 to c. 1970 experienced considerable changes to the wetland ecosystem. The abrupt nature of changes of planktonic cladocerans and diatoms, particularly after the onset of river regulation (1930s), was triggered by inundation, high rates of sedimentation and shifts in bulk sediment delta N-15 values. However, the transition of a once littoral-dominated community, to one favouring an increasingly turbid, plankton-dominated trophic condition following river regulation was relatively slow and lasted for decades. The progression to a new regime was likely delayed by the partial recovery of submerged plant communities and related internal dynamics.
The response of Cladocerans to recent environmental forcing in an Alpine Lake on the SE Tibetan Plateau
- Authors: Kong, Lingyang , Yang, Xiangdong , Kattel, Giri , Anderson, N. J. , Hu, Zhujun
- Date: 2017
- Type: Text , Journal article
- Relation: Hydrobiologia Vol. 784, no. 1 (2017), p. 171-185
- Full Text: false
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- Description: Global environmental change has affected aquatic ecosystems of the southeast Tibetan Plateau during the past 200 years, altering the composition and biomass of primary producers (e.g. algae). However, the response of primary consumers (e.g. cladocerans) to this recent environmental forcing is not well documented. Samples of cladoceran remains from sediment traps (1-year deployment), surface sediments covering a range of water depths and a short 22.5-cm sediment core were analysed in a small, remote alpine lake (Moon Lake) in Sichuan Province (SW China). Littoral forms, notably Chydorus sphaericus and Acroperus harpae, together with Daphnia pulex dominated the cladoceran community. Remains of these cladocerans were well represented in the sediment core assemblages as indicated by their relative abundance in the surface sample. There was a marked increase in the abundance of D. pulex and total cladoceran fluxes in the sediment core from ca. 1880 AD, coinciding with the changes in diatom assemblages and pigments. Analysis of the multi-proxy data (cladocerans, diatom, pigment, total organic carbon, C/N ratio, air temperature and atmospheric NO3 (-) records) suggests that both direct and indirect climatic forcing, coupled with enhanced nutrient supply (e.g. NO3 (-) deposition) effects on primary producers have changed cladoceran community dynamics in Moon Lake over the last similar to 200 years.