Biomedical subjects

Qinghua Cai

Publications and source records attributed to Qinghua Cai.

11 recordsLinked to original sources

PubMed2006

Using epilithic diatom communities to assess ecological condition of Xiangxi river system.

Assessment method for ecological condition of Xiangxi River system was studied by using 13 candidate metrics of epilithic diatom which can reflect conditions in pH, salinity, nitrogen uptake metabolism, oxygen requirements, saprobity, trophic state, morphological character and pollution tolerant capability etc. By one-way ANOVA, the metrics of relative abundance of acido-bionotic algae (ACID), freshwater algae (FRESH), high oxygen requirement (HIGH-O), eutraphentic state (EUTRA) and mobile taxa (MOBILE) were suitable for distinguishing sites in different conditions. Then, the river diatom index (RDI) composed of these five metrics was used to evaluate ecological condition of the river. The results showed that the healthiest sites were in the Guanmenshan Natural Reserve (with the mean RDI of 79.73). The sites located in tributary of Jiuchong River also owned excellent state (mean RDI of 78.25). Mean RDI of another tributary - Gufu River and the main river were 70.85 and 68.45 respectively, and the unhealthiest tributary was Gaolan River (with mean RDI of 65.64). The mean RDI for all the 51 sites was 71.40. The competence of RDI was discussed with comparison of evaluation results of DAIpo and TDI, it can be concluded that multimetrics is more competent in assessment task.

Analysis of Variance↗

PubMed2004

[River continuum characteristics of Xiangxi River].

The density of epilithic algae and concentration of chlorophyll a, Shannon-Wiener index and primary productivity were chosen to study the river continuum characteristics of Xiangxi River. The results showed that in general, the algal density, chlorophyll a concentration and Shannon-Wiener index tended to be increased with increasing stream order, but this trend was not very evident in the first three orders and even reversed. The primary productivity was also higher in the higher than that in the lower stream orders, and reached the maximum in the fourth order, then decreased slightly. The ratio of gross primary productivity to community respiration was the highest in the first stream orders, which means autochthonous productivity was dominant in the river. The results did not absolutely tally with the RCC forecast, therefore, we can conclude that Xiangxi River had been undergone anthropogenic influence.

Chlorophyll↗

PubMed2003

[Discussion on freshwater ecosystem service and its evaluation index system].

The importance of freshwater ecosystem and the connotation of ecosystem service were expounded in this paper, and the insufficiency in studies on freshwater ecosystem service was pointed out. Freshwater ecosystem service cannot be fulfilled without ecosystem health, yet there is a scarcity of synthetic studies integrating freshwater ecosystem service with ecosystem health, while these studies are necessary and important. Water resources should include water capacity, water quality, water energy, and aquatic organism. Based on the new meaning of water resources, the freshwater ecosystem service and its evaluation index system were discussed, and the evaluating methods were introduced briefly. The consideration and technical course of developing studies on freshwater ecosystem service in China were also discussed.

Conservation of Natural Resources↗

PubMed2003

[Several research hotspots in river ecology].

River ecology is a vital field in limnological research, and several new theories and methods have been developed and used in the study of lotic systems. In this article, a summary of these new theories was introduced, which includes river continuum concept, ecological water consumption of river ecosystem, services and health of river ecosystem, ecosystem management, and watershed ecology. The authors suggested that the research of river ecology should be carried out on the scale of watershed, and that the combination of ecosystem health and ecosystem services could be the key point in the sustainable development management of river ecosystem. Seeing that there are few studies in this area in China, relevant research should be conducted as soon as possible.

Conservation of Natural Resources↗

PubMed2003

[Application of geostatistical analysis in study of macrophytes community's pattern].

In this paper, the Log-log semivariogram and theoretical models of Geostatistics and fractal theory were applied to study the mosaic spatial pattern of macrophytes community and its different characters on different scales in littoral zone of the Baoan Lake, Hubei Province. The macrophytes in the littoral zone with a square area of 25,600 m2, which was divided in to 1,024 grids, were investigated, and the macrophytes species in every grid were recorded. If the species was discovered in the grid, the variable of the grid had a value of 1, otherwise, it was 0. The community had a value of the total species discovered in the grid. By the method, the sampling results of Vallisneria spiralis, Ceratophyllum oryzetorum, Myriophyllum spicatum and the community were made into four worksheets. With help of the software GS+ for Windows to treat these worksheets, we got their log-log semivariogram, isotropic model, anisotropic model, isotropic fractal dimension and anisotropic fractal dimension. According to the results of isotropic models, the exponential models of Vallisneria spiralis and Myriophyllum spicatum indicated their contagious distribution with a high proportion of spatial structure, which indicated that their distribution changed lesser at microscale. In their range of 48.6 m and 34.2 m respectively, they had a spatial autocorrelation. Isotropic models of Ceratophyllum oryzetorum and the community were linear, and their proportions of spatial structure were low, indicating their great change at microscale and their moderate contagious distribution. The isotropic fractal dimension and anisotropic fractal dimension results indicated the dominant pattern of Vallisneria spiralis in the direction of NE-SW, the dominant patterns of Myriophyllum spicatum and Ceratophyllum oryzetorum in the direction of N-S, and the community's dominant pattern in the direction of NW-SE. Compared with other analysis tools, the method had advantages in deciding whether the community components had a spatial autocorrelation and in quantitatively classifying the aggregation density. It provides us a new way to quantitatively describe the pattern of the macrophytes community.

Fresh Water↗

PubMed2003

[Spatial distribution of water quality in Xiangxi River, China].

Cluster analysis and principal component analysis were used to analyze the physical and chemical characteristics of water samples collected from 19 sampling sites along Xiangxi River. The result of cluster analysis showed that Xiangxi River could be divided into three reaches, which belonged to different sub-basins. The principle component analysis on each reach showed that the main information of water quality was different from each other. In the upper reach, the main information of river water quality was hardness and total alkalinity; in the middle reach, the main information was dissolved phosphorus, total phosphorus and Cl-, in the lower reach, the main information was pH, NO2(-)-N, total nitrogen and COD. Furthermore, considering the geographical and environmental backgrounds of the Xiangxi River basin, the reason that caused the different distribution pattern of water quality in Xiangxi River was discussed. Hence, a simple approach to analyze the spatial distribution of water quality was provided.

Cluster Analysis↗

PubMed2002

[Comparison of leaf decomposing rate in a headwater stream in Xiangxi River catchment].

With the litterbag method, the decomposition of leaf of 4 tree species growing in riparian forest in a headwater stream was investigated in 90 d consecutively in Xangxi River catchment. The results showed that the loss rate of dry weight of leaf differed among 4 species. The loss rate of dry weight of Pterocarya insignis and Cercidiphyllum japonicum was 77% and 71%, and shat of Fagus engleriana and Cyclobalanopsis multinervis was 43% and 42%. Using exponential equation, the loss process of dry weight of leaf was modeled. According to the value of constant k, 4 species could be divide into to fast group and medium group. The invertebrate was also collected, and there were 22 species, belong to 3 classes, 6 orders, and 21 families. The quantity of invertebrate differed in each tree species litterbag and different periods. The invertebrate was rich in number and small in body during early time of leaf decomposing, and it was less in number and big in body during middle and late time of decomposing.

Animals↗

PubMed2002

[Lake ecosystem services and their ecological valuation--a case study of Baoan Lake in Hubei province].

Along with the maturation of estimation methods for biological resources, the studies on the services value of ecosystem become a hotspot in ecology. The studies on the services value of lake ecosystem were not been reported before this issue, and this issue firstly attempted to estimate the Baoan Lake ecosystem services and its indirect economic values on the basis of ecological function analysis and some economic methods. The results showed that the indirect economic value (in RMB) of organic matter production, CO2 fixation, O2 release, nutrient recycling, water conservancy and water supply and SO2 degradation were 1.51 x 10(7), 4.77 x 10(7), 3.63 x 10(7), 4.45 x 10(5), 1.10 x 10(8), 5.15 x 10(5) yuan.yr-1, respectively. The sum was about 2.24 x 10(8) yuan.yr-1. From the above incomplete estimation, it was known that the Baoan Lake ecosystem has great ecological and economic values.

Animals↗

PubMed2002

[River ecosystem health and its assessment].

Ecosystem health is a hot topic in ecological research. In this paper, the concept of river ecosystem health was generalized, and the main methods used to assess the health condition of river ecosystem was introduced, which are based on bioindictors such as epilithic algae (diatom specially), benthic invertebrate and fish, and were classified into two types in terms of their assessment principles. Based on research actuality, the development tendency in this area is put forward. The authors suggest that the relevant study should be carried out as soon as possible in China.

Ecosystem↗

PubMed2002

[Distribution pattern of rare plants along riparian zone and its implication for conservation in Shennongjia area].

Due to the importance of riparian zone in maintaining and protecting regional biodiversity, more and more ecologists paid their attentions to riparian zone, and had been aware of the important effects of riparian zone in basic study and practical management. In this study, forty sampling belts (10 m x 100 m) parallel to the bank of Xiangxi River at different elevations in Shennongjia area were selected to investigate the riparian vegetation and rare plants. Fourteen species of rare plants were found in riparian zone, accounting for 42.4% of total rare plant species in Shennongjia area. The main distribution range of the fourteen rare plant species was the mixed evergreen and deciduous broadleaved forest at elevation of 1200-1800 m, where species diversity of plant community was the maximum at the moderate elevation. Fourteen rare plant species could be divided into three groups against the elevation, namely low elevation species group, moderate elevation species group, and high elevation group. In the paper, the authors discussed the reasons forming the distribution pattern of rare plant species, and pointed out the important function of riparian zone on rare plant species protection.

China↗

PubMed2002

A comprehensive model for assessing lake eutrophication.

The evaluation of eutrophication or trophic state of a lake is in fact a multivariate comprehensive decision-making process quantifying the qualitative problem. Therefore, we should use a comprehensive method to assess lake eutrophication. On the basis of summarizing some comprehensive methods for assessing lake eutrophication reported in China and abroad, it is pointed out that the trophic state index (TSI) should be a major method for evaluating lake eutrophication, since it could provide a continuous numerical class of lake trophic state and a rigorous foundation of quantitative studies of eutrophication mechanism. Using analytic hierarchy process (AHP) to determine the weight attributions in the selected comprehensive indices, the authors, constructed a comprehensive assessment model as: TSI = W(Chla) x TSI(Chla) + W(Sd) x TSI(Sd) + W(TP) x TSI (TP) or TSIM = W (Chla) x TSIM(Chla) + W(Sd) x TSIM(Sd) + W(TP) x SIM(TP) where W(X) were the weights for the above three parameters with value in percentage as 54.0, 29.7 and 16.3, respectively. Additionally, the relations between comprehensive evaluation and other statistical methods such as cluster analysis were briefly discussed.

Animals↗