Variations of fish composition and diversity related to environmental variables in shallow lakes in the Yangtze River basin

a b s t r a c tHabitat modifications induced by humans severely impact biotic components of freshwater ecosystems. In China, shallow lakes in the Yangtze River basin are facing severe habitat degradation induced by pollution, habitat losing, macrophytes disappearing and fishery activities. Effectively modeling the fish communities on the basis of biotic and abiotic environmental descriptors would be helpful to understand the relationships between fish and their environment, and to develop suitable conservation strategies to sustain the biodiversity in these ecosystems. From 2007 to 2009, investigations were carried out on fish and their environment in 6 lakes distributed in the mid-reach of the Yangtze River basin. According to the CPUE values of each fish species from each sampling, 117 datasets were ordinated using self-organizing map (SOM). Fish communities were classified into three clusters of species assemblages, spatial and temporal distributions were showing in it. Seasonal changes in fish community were more obvious in vegetated habitats than in unvegetated areas. The total CPUE, fish diversity and species richness were significantly different among the assemblages (p < 0.01). Based on the indicative value of each species in each cluster calculated by Indval method, 16 species were identified as indicators: 13 indicators in cluster G1 are pelagic or benthopelagic fish, the only one indicator species in G2 is a tolerant species (Culter dabry B.), while the other two indicator species in G3 are demersal fish (Rhinogobius giurinus R. and Odontobutis obscurus T. & G.). These results are in agreement with the contributions of different ecological groups of fish in each assemblage in the trained SOM, pelagic and benthopelagic fish were found having more activities in spring and winter, while more activities of demersal fish were found in summer and autumn. Fish community assemblages, the total fish CPUE, diversity and species richness in those lakes were then predicted by 15 abiotic and biotic factors using random forest (RF) and classification and regression tree (CART) predictive models. The predicted assignment of each site unit to the correct assemblage had an average success of 74.4% and 60.7% in RF and CART models, respectively. The dominant variables for discriminating three fish assemblages were water depth, distance to the bank and total phosphorus. While the two important variables in prediction fish CPUE, diversity and species richness were lake surface area and water depth, density of rotifer and water depth, water depth and water temperature, respectively. The overall percentages of successful prediction varied from 56.5% to 67% utilizing leave-one-out for cross-validation tests.

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“…All the lakes are suburban lakes except Tangxunhu Lake. Specific details of these lakes are shown in Cheng et al (2010).…”

Section: Study Areamentioning

confidence: 99%

Predicting fish assemblages and diversity in shallow lakes in the Yangtze River basin

et al. 2012

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“…Daga et al (2009) reported that the temperature yielding the highest abundance of fish larvae in the tropics was around 30 o C which was also found true for Sirindhorn Reservoir, where water temperatures were above 29 o C for the majority of the wet season. There was little difference in DO among areas and months similar to the other relatively shallow lakes (Cheng et al, 2010) and there were no obvious Lowess trends with larval abundance. Besides, DO ranged between 4 and 9 mg l -1 in this study and was beyond 50% of oxygen saturation, which is suitable for zooplankton (Guevara et al, 2009) and should be also suitable for ichthyoplankton, i.e., fish larvae, as well.…”

Section: Patterns Of Larval Fish Assemblagesmentioning

confidence: 74%

Spatio-temporal variations in abundance and assemblage patterns of fish larvae and their relationships to environmental variables in Sirindhron Reservoir of the Lower Mekong Basin, Thailand

et al. 2016

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The spatio-temporal dynamics of fish larvae in Sirindhron Reservoir, north-east Thailand, were investigated from February 2008 to January 2009. The five most abundant species accounted for 53.6% of the total catch and comprised Clupeicthys aesarnensis, Rasbora borapetensis, Barbonymus gonionotus, Esomus metallicus and Oreochromis niloticus. Total larval abundance and species richness varied among sampling months but did not vary with zones in the reservoir. The abundance and species richness of fish larvae showed correlation with flooding, vegetation cover, water level, water temperature and turbidity. A self-organising map (SOM) was used to represent the larval fish assemblage patterns and three assemblage patterns were clearly distinguished primarily according to seasons. In conclusion, the fish larval abundance was greatest during the wet season and the most diverse assemblages were found in the zones adjacent to the connected river upstream during the wet season.

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“…Previous studies found that nutrients such as total phosphorus and total nitrogen also had significant correlation on the fish composition and diversity in shallow lakes of the Yangtze River basin (Cheng et al., ). Therefore, changes in nutrient flux and water pollution would have an influence on the structure of fish assemblages as well as population densities (Cheng, Lek, Loot, Lek‐Ang, & Li, ). Here we found that nitrogen – but not phosphorus – impacted fish assemblages, which may be due to the fact that nitrogen is the main contaminant in Hongze Lake (Li et al., ).…”

Section: Discussionmentioning

confidence: 99%

Predicting impacts of south-to-north water transfer project on fish assemblages in Hongze Lake, China

et al. 2017

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Summary The Chinese government implemented the ambitious south‐north water transfer project (SNWTP), which aims to transport water from the Yangtze to the north of China where water shortages are severe. Although the ecological impacts of this project have been addressed publically, there remains a poor understanding of the effects of such large‐scale water transfers on the populations of aquatic species. The potential ecological impacts of such water transfers on the Hongze Lake fish assemblages are assessed here using Self‐Organizing Map (SOM) and Random Forest (RF) modeling. Using SOM, twenty‐three fish species in 15 sampling sites were classified into two assemblages and four sub‐assemblages corresponding to four distinct habitats (deep water macrophytes, deep water bare silt, shallow water bare silt, and shallow water macrophytes). The RF model further showed that water depth and transparency were the abiotic drivers underpinning fish assemblages in Hongze Lake. As the SNWTP is forecasted to modify the distribution of water depth and water clarity, major knock‐on effects are expected on downstream lake fish assemblages.

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Variations of fish composition and diversity related to environmental variables in shallow lakes in the Yangtze River basin

Cited by 20 publications

References 41 publications

Predicting fish assemblages and diversity in shallow lakes in the Yangtze River basin

Predicting fish assemblages and diversity in shallow lakes in the Yangtze River basin

Spatio-temporal variations in abundance and assemblage patterns of fish larvae and their relationships to environmental variables in Sirindhron Reservoir of the Lower Mekong Basin, Thailand

Predicting impacts of south-to-north water transfer project on fish assemblages in Hongze Lake, China

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