The Experts below are selected from a list of 30873 Experts worldwide ranked by ideXlab platform
Simon Creer - One of the best experts on this subject based on the ideXlab platform.
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annual time series analysis of aqueous edna reveals ecologically relevant dynamics of Lake Ecosystem biodiversity
Nature Communications, 2017Co-Authors: Iliana Bista, Gary R Carvalho, Kerry Walsh, Mathew Seymour, Mehrdad Hajibabaei, Delphine Lallias, Martin Christmas, Simon CreerAbstract:The use of environmental DNA (eDNA) in biodiversity assessments offers a step-change in sensitivity, throughput and simultaneous measures of Ecosystem diversity and function. There remains, however, a need to examine eDNA persistence in the wild through simultaneous temporal measures of eDNA and biota. Here, we use metabarcoding of two markers of different lengths, derived from an annual time series of aqueous Lake eDNA to examine temporal shifts in Ecosystem biodiversity and in an ecologically important group of macroinvertebrates (Diptera: Chironomidae). The analyses allow different levels of detection and validation of taxon richness and community composition (β-diversity) through time, with shorter eDNA fragments dominating the eDNA community. Comparisons between eDNA, community DNA, taxonomy and UK species abundance data further show significant relationships between diversity estimates derived across the disparate methodologies. Our results reveal the temporal dynamics of eDNA and validate the utility of eDNA metabarcoding for tracking seasonal diversity at the Ecosystem scale.
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annual time series analysis of aqueous edna reveals ecologically relevant dynamics of Lake Ecosystem biodiversity
Nature Communications, 2017Co-Authors: Iliana Bista, Gary R Carvalho, Kerry Walsh, Mathew Seymour, Mehrdad Hajibabaei, Delphine Lallias, Martin Christmas, Simon CreerAbstract:The use of environmental DNA (eDNA) in biodiversity assessments offers a step-change in sensitivity, throughput and simultaneous measures of Ecosystem diversity and function. There remains, however, a need to examine eDNA persistence in the wild through simultaneous temporal measures of eDNA and biota. Here, we use metabarcoding of two markers of different lengths, derived from an annual time series of aqueous Lake eDNA to examine temporal shifts in Ecosystem biodiversity and in an ecologically important group of macroinvertebrates (Diptera: Chironomidae). The analyses allow different levels of detection and validation of taxon richness and community composition (β-diversity) through time, with shorter eDNA fragments dominating the eDNA community. Comparisons between eDNA, community DNA, taxonomy and UK species abundance data further show significant relationships between diversity estimates derived across the disparate methodologies. Our results reveal the temporal dynamics of eDNA and validate the utility of eDNA metabarcoding for tracking seasonal diversity at the Ecosystem scale. DNA from macrobial taxa can be extracted from environmental samples, including water, and be used to assess biodiversity in the region. Here, Bista and colleagues show that temporal shifts in the biodiversity of a Lake invertebrate community can be detected by analysis of environmental DNA (eDNA).
Xiangdong Yang - One of the best experts on this subject based on the ideXlab platform.
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cladocera responses to climate changes and treeline shifts in an alpine Lake catchment since the last glacial maximum
Palaeogeography Palaeoclimatology Palaeoecology, 2021Co-Authors: Qian Wang, John N Anderson, Xiangdong YangAbstract:Abstract The study of alpine Lake Ecosystem ontogeny provides an understanding of how climate dynamics and the associated catchment changes impact on Lake functioning. Here, a high-resolution subfossil Cladocera sedimentary record, together with geochemistry proxies, from an alpine, treeline Lake (Cuoqia Lake) in SW China were analyzed to understand the Lake Ecosystem response to changes in the regional Indian summer monsoon (ISM) climate and the local mountain environment since the Last Glacial Maximum (LGM, ca. 19.5 cal kyr BP to present). The results show that the cladoceran record from Cuoqia Lake clearly responds to long-term climate change and significant climate events. The Lake was depauperate in cladoceran species throughout the late glacial period (ca. 16–11 cal kyr BP) but Daphnia longispina-group and Chydorus sphaericus were the pioneer taxa when the Lake was formed. The rapid proliferation of open-water and littoral cladoceran taxa began with increasing water temperature. The Younger Dryas (YD) cold event was recorded by high abundance of the cold-tolerant taxon C. sphaericus during ca. 12–11 cal kyr BP. At the onset of the Holocene (ca. 11 cal kyr BP), Alona spp. and macrophyte-associated taxa became dominant while numbers of C. sphaericus decreased dramatically. In the mid- to late-Holocene, the productivity of Cuoqia Lake seemed to have increased as reflected by higher Cladocera concentration and the appearance of Ceriodaphnia spp. and raptorial P. pediculus which are common in high nutrient waters. Partial Redundancy Analysis (partial-RDA) results highlight the strong effect of indirect climate change (mediated via catchment processes) on cladoceran assemblages during the Holocene. Abrupt shifts in sediment geochemical proxies and regional catchment vegetation at ca. 11 cal kyr BP indicate that substantial nutrient inputs, treeline advancement, and soil development in catchment resulted from the intensified ISM. Therefore, the cladoceran community changes suggest a long-term direct response of the alpine Lake Ecosystem to climate change since the LGM, but one that was strongly mediated by catchment-vegetation processes, such as the treeline shifts.
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interactions between climate change and early agriculture in sw china and their effect on Lake Ecosystem functioning at centennial timescales over the last 2000 years
Quaternary Science Reviews, 2020Co-Authors: Qian Wang, John N Anderson, Xiangdong YangAbstract:Abstract The responses of alpine Lake Ecosystems to combined climate and human impacts are ecologically important to understand. It is necessary to differentiate natural, climate-forced Ecosystem changes from those driven by human disturbance with a long-term (i.e. 102–103-yr) perspective. Here a14C, 210Pb and 137Cs-dated sediment core covering approximately 2500 years was analyzed for diatoms, pigments, cladocerans and geochemistry in Lugu Lake-catchment in southwest China to examine the response of the Lake to climate change and human impacts. Between 1000 and 1300 AD, a warming climate coupled with declining summer monsoon precipitation resulted in the increase of oligotrophic taxa and low catchment runoff. Prior to 1300 AD the Lake Ecosystem was primarily responding to natural, regional climate-related processes. After 1300 AD, the clear ecological shifts and reorganizations in community structure across multiple trophic levels suggest that major transitions took place in the Lugu Ecosystem. An increase in Poaceae (grass) pollen from 1300 AD indicates human settlement in the area, and is followed by rapid decline in Tsuga, most likely a consequence of logging. Use of change point analyses of the multi-proxy data demonstrate that the Lake Ecosystem has been highly variable since 1300 AD and exhibiting enhanced vulnerability to both natural and anthropogenic disturbance. Our results suggest that agriculture-climate interactions played a major role in the ecological transitions over the last ∼700 years. This conclusion provides insight into how the anthropogenic land-use intensity, vegetation cover and surface erosion fluctuated with natural temperature and precipitation change over the past 2000 years.
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freshwater Lake Ecosystem shift caused by social economic transitions in yangtze river basin over the past century
Scientific Reports, 2018Co-Authors: Ke Zhang, Giri Kattel, Xiangdong Yang, Ji ShenAbstract:Global Lake systems have undergone rapid degradation over the past century. Scientists and managers are struggling to manage the highly degraded Lake systems to cope with escalating anthropogenic pressures. Improved knowledge of how Lakes and social systems co-evolved up to the present is vital for understanding, modeling, and anticipating the current and future ecological status of Lakes. Here, by integrating paleoenvironmental, instrumental and historical documentary resources at multi-decadal scales, we demonstrate how a typical shallow Lake system evolved over the last century in the Yangtze River Basin, an urbanized region containing thousands of shallow Lakes. We find abrupt ecological shift happened in the Lake Ecosystem around the 1970s, with the significant reorganization of macrophyte, diatom and cladocera communities. The Lake social-ecological system went through three stages as the local society transformed from a traditional agricultural before 1950s to an urbanized and industrialized society during the recent thirty years. The timing and interaction between social, economic and ecological feedbacks govern the transient and long-term dynamics of the freshwater Ecosystem. Our results highlight the importance of accounting for the long-term dynamics and feedbacks between ecological, social and economic changes when defining safe operating spaces for sustainable freshwater Ecosystem management.
Ji Shen - One of the best experts on this subject based on the ideXlab platform.
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late holocene lacustrine environmental and ecological changes caused by anthropogenic activities in the chinese loess plateau
Quaternary Science Reviews, 2019Co-Authors: Can Zhang, Ke Zhang, Aifeng Zhou, Cheng Zhao, Rong Wang, Ji ShenAbstract:Abstract Numerous studies have focused on environmental changes and lacustrine ecological transitions in the modern industrial era. However, little is known about the processes of ecological transitions during early human disturbances. The current Lake Ecosystem state is the result of long-term integrated human influences on Lakes. In this study, we present multi-proxy evidence of changes in the lacustrine environment, Ecosystem, and human activities inferred from a sediment core collected from Beilianchi Lake in the southwestern Chinese Loess Plateau, to document the lacustrine ecological transitions with increasing human disturbances during the past 5000 years. Our data reveal the lacustrine Ecosystem was quite stable with unchanging terrestrial versus aquatic sourced organic matter before major human disturbances (4400-1400 BP), although there was a decline in precipitation and a transition from tree-to herb-dominated vegetation. From 1400 to 300 BP, when early humans began to occupy and disturb the catchment, the Lake experienced high-magnitude, centennial-to decadal-scale oscillations between aquatic and terrestrial sourced organic contributions. Thereafter, as human activities further increased, the lacustrine Ecosystem finally stabilized at a state with terrestrial dominated organic matter. Our results suggest that the Lake experienced large-magnitude ecological oscillations during the period of 1400–300 BP, probably indicating the Lake Ecosystem retained the capability of recovery from the modest early human disturbances on the catchment. The recovery of the Ecosystem to these external disturbances lasted hundreds of years with centennial to decadal scales oscillations. With further increased human influences since 300 BP, the lacustrine Ecosystem probably finally shifted to another state largely deviating from its natural (climate-driven) background.
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freshwater Lake Ecosystem shift caused by social economic transitions in yangtze river basin over the past century
Scientific Reports, 2018Co-Authors: Ke Zhang, Giri Kattel, Xiangdong Yang, Ji ShenAbstract:Global Lake systems have undergone rapid degradation over the past century. Scientists and managers are struggling to manage the highly degraded Lake systems to cope with escalating anthropogenic pressures. Improved knowledge of how Lakes and social systems co-evolved up to the present is vital for understanding, modeling, and anticipating the current and future ecological status of Lakes. Here, by integrating paleoenvironmental, instrumental and historical documentary resources at multi-decadal scales, we demonstrate how a typical shallow Lake system evolved over the last century in the Yangtze River Basin, an urbanized region containing thousands of shallow Lakes. We find abrupt ecological shift happened in the Lake Ecosystem around the 1970s, with the significant reorganization of macrophyte, diatom and cladocera communities. The Lake social-ecological system went through three stages as the local society transformed from a traditional agricultural before 1950s to an urbanized and industrialized society during the recent thirty years. The timing and interaction between social, economic and ecological feedbacks govern the transient and long-term dynamics of the freshwater Ecosystem. Our results highlight the importance of accounting for the long-term dynamics and feedbacks between ecological, social and economic changes when defining safe operating spaces for sustainable freshwater Ecosystem management.
Iliana Bista - One of the best experts on this subject based on the ideXlab platform.
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annual time series analysis of aqueous edna reveals ecologically relevant dynamics of Lake Ecosystem biodiversity
Nature Communications, 2017Co-Authors: Iliana Bista, Gary R Carvalho, Kerry Walsh, Mathew Seymour, Mehrdad Hajibabaei, Delphine Lallias, Martin Christmas, Simon CreerAbstract:The use of environmental DNA (eDNA) in biodiversity assessments offers a step-change in sensitivity, throughput and simultaneous measures of Ecosystem diversity and function. There remains, however, a need to examine eDNA persistence in the wild through simultaneous temporal measures of eDNA and biota. Here, we use metabarcoding of two markers of different lengths, derived from an annual time series of aqueous Lake eDNA to examine temporal shifts in Ecosystem biodiversity and in an ecologically important group of macroinvertebrates (Diptera: Chironomidae). The analyses allow different levels of detection and validation of taxon richness and community composition (β-diversity) through time, with shorter eDNA fragments dominating the eDNA community. Comparisons between eDNA, community DNA, taxonomy and UK species abundance data further show significant relationships between diversity estimates derived across the disparate methodologies. Our results reveal the temporal dynamics of eDNA and validate the utility of eDNA metabarcoding for tracking seasonal diversity at the Ecosystem scale.
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annual time series analysis of aqueous edna reveals ecologically relevant dynamics of Lake Ecosystem biodiversity
Nature Communications, 2017Co-Authors: Iliana Bista, Gary R Carvalho, Kerry Walsh, Mathew Seymour, Mehrdad Hajibabaei, Delphine Lallias, Martin Christmas, Simon CreerAbstract:The use of environmental DNA (eDNA) in biodiversity assessments offers a step-change in sensitivity, throughput and simultaneous measures of Ecosystem diversity and function. There remains, however, a need to examine eDNA persistence in the wild through simultaneous temporal measures of eDNA and biota. Here, we use metabarcoding of two markers of different lengths, derived from an annual time series of aqueous Lake eDNA to examine temporal shifts in Ecosystem biodiversity and in an ecologically important group of macroinvertebrates (Diptera: Chironomidae). The analyses allow different levels of detection and validation of taxon richness and community composition (β-diversity) through time, with shorter eDNA fragments dominating the eDNA community. Comparisons between eDNA, community DNA, taxonomy and UK species abundance data further show significant relationships between diversity estimates derived across the disparate methodologies. Our results reveal the temporal dynamics of eDNA and validate the utility of eDNA metabarcoding for tracking seasonal diversity at the Ecosystem scale. DNA from macrobial taxa can be extracted from environmental samples, including water, and be used to assess biodiversity in the region. Here, Bista and colleagues show that temporal shifts in the biodiversity of a Lake invertebrate community can be detected by analysis of environmental DNA (eDNA).
Chuanbo Guo - One of the best experts on this subject based on the ideXlab platform.
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the need for improved fishery management in a shallow macrophytic Lake in the yangtze river basin evidence from the food web structure and Ecosystem analysis
Ecological Modelling, 2013Co-Authors: Chuanbo Guo, Sovan Lek, Jiashou Liu, Tanglin Zhang, Jin YuanAbstract:There are numerous shallow macrophytic Lakes distributed in the middle reaches of the Yangtze River basin, which are an important fishery resource for this part of China. However, there is limited knowledge about the food web structure and energy flows of these highly disturbed Ecosystems, mainly due to lack of suitable Ecosystem approaches applied to the abundant but isolated ecological data from these Lakes. To better manage the important Ecosystems, Ecopath with Ecosim was applied to establish a mass-balance model for a typical shallow macrophytic Lake (Bao'an Lake) as a case study, with the aim of describing the food web structure and the properties of the Ecosystem to evaluate the ecological implications for fishery resource management and the protection of the aquatic Ecosystem of these Lakes. Given that there were extensive first-hand data available for the target Lake, a credible trophic model including 23 functional groups was constructed. The results showed that all the commercial fish groups suffered from high fishing pressure for their higher ecotrophic efficiency (EE) values, normally more than 0.5. On the contrary, forage resources such as attached algae, submerged plants and molluscs were not fully utilized by the Lake fishery, with EE values even as low as 0.089, 0.120 and 0.126 respectively. The discrete trophic level of large culters was highest (3.143) in the Lake Ecosystem, followed by mandarin fish (3.138) and snakehead fish (3.131). For the transfer efficiencies in the food web structure, a mean value of 8.68% was calculated for the Lake Ecosystem. Ecosystem maturity indices such as TPP/TR (1.640), TPP/TB (6.993), as well as ascendency (0.387) which were derived from the network analysis together with the revealed detritus-based trophic flow, illustrated that the Bao'an Like Ecosystem was a mature system according to Odum's theory. However when compared with some other Lake Ecosystems, the Bao'an Lake Ecosystem, as well as some China Lake Ecosystems, showed extremely low values of CI (Connectance index), FCI (Finn's cycling index) and SOI (system omnivory index), indicating that the food web structures of these Chinese Lake Ecosystems tended to be simpler and more linear than Lake Ecosystems in other countries. Consequently, this study established the first food web model for a shallow macrophytic Lake and provided overall insights and Ecosystem knowledge for this kind of shallow macrophytic Lake, and indicated an urgent need for fishery resources management to shift from traditional population-based to Ecosystem-based models. (C) 2013 Elsevier B.V. All rights reserved.
