Chen J.,Central China Normal University |
Li R.,Wuhan Imagination Science and Technology Development Co. |
Tang Y.,Wuhan Imagination Science and Technology Development Co. |
Li H.-T.,Wuhan Imagination Science and Technology Development Co. |
And 3 more authors.
Wetland Science | Year: 2014
Combining with the field survey results, the comparison of land use patterns in Xiliang Lake in 1990 and 2010 had been explored by the maximum-likelihood method, using remote sensing images from Landsat TM in 1990 and 2010. There were 6 types of land use: waters, forest land, marsh, paddy field, dry land and construction land. The matrix for land use change was obtained by ArcGIS software. The results showed compared with those in 1990, the area of waters was decreased by 2 822.71 hm2 in 2010, the one of dry land was decreased by 378.51 hm2, the ones of paddy field and forest land were decreased by 28.46 hm2 and 25.74 hm2, the one of marshes increased by 3 240.4 hm2, the one of construction land increased by 15.02 hm2 in 2010. Quite a lot of waters turned into marshes, which reflected the marshy tendency of Xiliang Lake. The disturbance of human activities included illegal embankment around the lake, the over-development of fence culture, harvesting water grass, dragging for mussels and discharging pollutants. The natural succession of the plants could be the main natural factor, which led to the degeneration of Xiliang Lake.
Wu S.,Hubei University |
Ge J.,Hubei University |
Miao W.,Hubei University |
Miao W.,Wuhan Imagination Science and Technology Development Co. |
And 3 more authors.
Shengtai Xuebao/ Acta Ecologica Sinica | Year: 2013
Originating from the Shennongjia Forest District, Gufu River is a tributary of Xiangxi River which is the largest tributary of Three Gorges Reservoir Area in Hubei Province, central China. With the development of mining, urbanization and intensification of water source exploitation, the impacts of anthropogenic activities have gradually increased in the Gufu River Basin. Gufu River is diverse with regard to the hydrological and biological characteristics which influence the biomass of epilithic algae. However, there are no previous studies investigating the spatio-temporal variation of epilithic algal biomass and the interactions between epilithic algae and the environmental factors from the headstream of the Gufu River Basin to the Xiangxi Bay. To obtain basic biotic data of the biomass of epilithic aglae and explore the relationship between algal biomass and the environmental conditions in the stream ecosystems with substantially different human impacts, we measured the chlorophyll a of epilithic algae and the main environmental factors at 21 sites in the Gufu River and its major tributaries (Zhuyuan River) once a month from September 2010 to August 2011. From the monitored data, we analyzed the spatial and temporal distribution of chlorophyll a and the main environmental factors influencing the distribution pattern with methods of one-way ANOVA, cluster analysis, partial correlation analysis and stepwise regression analysis. The chlorophyll a concentration ranged between 0.07 mg/m2 and 145.96 mg/m2 with a mean of 11.63 mg/m2. According to the similarity of chlorophyll a concentration in different sampling sites, all samples were divided into five groups by cluster analysis: Group 1, Group 2, Group 3, Group 4 and Group 5. The mean chlorophyll a of epilithic algae in the five groups were 5.90 mg/m2, 24.51 mg/m2, 23.83 mg/m2, 45.59 mg/m2, 50.03 mg/m2 respectively. This result showed that the concentration of epilithic algal chlorophyll a had obvious spatial heterogeneity: the biomass in the upstream was lower than the downstream in Gufu River while it is contrary in Zhuyuan River tributary. This indicated that higher biomass might caused by the increased anthropogenic interference. There were significant differences in chlorophyll a concentration among various seasons: the concentration tended to be higher in winter and spring than in summer and autumn. The analysis of the relationship between the physico-chemical characteristics and the chlorophyll a concentration of the benthic algae demonstrated that chlorophyll a concentration were significantly positively correlated with total phosphorous and hardness of the water and significantly negatively correlated with water velocity. This indicated that total phosphorus in the water could be the first restriction factor of the algal growth, and water velocity has significant inhibitory effect on the algal growth. The results of the stepwise regression between chlorophyll a concentration and the environmental factors showed that water velocity, total nitrogen and dissolved oxygen were related to chlorophyll a concentration in winter and spring, while total phosphorus, water velocity, hardness, dissolved silicate and ammonia were related to chlorophyll a concentration in summer and autumn. We concluded that the spatial pattern of the algal biomass in Gufu River were determined by its habitat scale (nutrients) and watershed-scale characteristics (hardness and conductivity), while the temporal pattern of the algal biomass was mainly affected by its hydrodynamic characteristics (water velocity).
Ran G.H.,Hubei University |
Ge J.W.,Hubei University |
Miao W.J.,Hubei University |
Miao W.J.,Wuhan Imagination Science and Technology Development Co. |
And 4 more authors.
Shengtai Xuebao/ Acta Ecologica Sinica | Year: 2013
In order to provide scientific supports for rivers ecological management of the Three Gorges Reservoir, we conducted a study to determine the spatial and temporal differentiation of water quality in the Gufu River. Gufu River, a tributary of Xiangxi River flowing into Three Gorges Reservoir, passes Shennongjia Forest District and Xingshan County, Hubei Province, Central China. We arranged 20 sampling sites along the Gufu River and measured 9 water quality parameters once a month from August 2010 to July 2011 at these sites. According to landscape difference, the sampling sites were divided into 4 groups: forest area (Group A), cultivated land area (Group B), reservoir area (Group C), village/ small town area (Group D). According to hydrological rhythm, May to August were classed as wet season, and the other months were classed as dry season. The 9 water quality parameters were: total nitrogen (TN), dissolved oxygen (DO), total organic carbon (TOC), total phosphorus (TP), silicon dioxide (SiO2), electrical conductivity (EC), chemical oxygen demand (COD), total hardness(T-Hard)and total alkalinity (T-Alk). Using the Discriminant Analysis (DA) and Analysis of Variance (ANOVA), we found the water quality showed spatial and temporal differentiation pattern: TP, SiO2, EC, COD, T-Hard and T-Alk are significantly different among the different spatial group; TN, COD, DO, SiO2 and TOC are different among the seasons; all water quality parameters presented significant seasonal changes at different spatial types. Using the Principal Component Analysis (PCA), we found the factor determining the water quality at different part of the river in different seasons. At the forest area (Group A), SiO2 and TOC were the main factors which affect the water quality in the wet seasons, but in the dry seasons TP, SiO2, TOC and COD were the mainly factors, which indicated that in forest area water quality was influenced by the natural factor such as surface runoff, vegetation and weathering. At the cultivated land area (Group B), in the wet season, T-Hard and TOC were the main factors affecting water quality while in the dry season TP, COD, T-Hard and T-Alk were the main factors affecting water quality. In cultivated land area, the variation of water quality was not only caused by the influence of natural factors, but also by factors of human activities such as agricultural runoff and domestic sewage without treatment. At reservoir area(Group C), SiO2, TN and TP were the main factors affecting water quality in the wet season, while TN, TOC and SiO2 were the main factors in the dry seasons. The water quality of the stream beside the villages/ small towns was influenced by nitrogen and phosphorus particle entering into reservoir with farmland runoff, surface runoff and untreated domestic sewage. At village/ small town area (Group D), SiO2, TN and TP were the main factors affecting water quality in the wet season, while T-Alk, T-Hard, TN and TOC were the main factors in the dry seasons. The water quality at the village/ small town area was influenced by municipal sewage, agricultural runoff. Our study indicated that the water quality of Gufu River is affected by natural and anthropogenic factors and the later one are greater. Therefore, the strengthening of the management and protection of water resources and good long-term water quality monitoring is particularly important for the improvement of water quality.