Description of Chlorogomphus auripennis spec. nov. from Guangdong Province, with new records of Chlorogomphidae from Yunnan Province, China (Odonata: Chlorogomphidae).

A new chlorogomphid, Chlorogomphus (Orogomphus) auripennis spec. nov. (holotype male; Mt Nankunshan, Longmen County, Guangdong Province, China, 20. V. 2008) is described and illustrated. It is the first species belonging to the subgenus Orogomphus recorded from mainland China. The holotype will be deposited in the Collection of Aquatic Animals, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan City, Hubei Province, China. Chlorogomphus auratus Martin, 1910 and Chloropetalia selysi (Fraser, 1929) are recoded from Chinese territory for the first time. The total number of Chlorogomphidae in China reaches 20. Description of the hitherto unknown female of Chlorogomphus yokoii Karube, 1995 is provided.

Aeshna shennong sp. nov., a new species from Hubei Province, China (Odonata: Anisoptera: Aeshnidae).

Aeshna shennnong sp. nov. (holotype male: Dajiuhu national wetland park in Shennongjia National Nature Reserve, Shennongjia City, Hubei Province, China, 28. VIII. 2013) is described, illustrated and compared with its most similar congener, A. petalura Martin, 1908. The holotype will be deposited in the Collection of Aquatic Animals, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan City, Hubei Province, China. New distribution records of A. petalura from mainland China are also provided.

Discovery of four new species of the genus Planaeschna from Southwestern China (Odonata: Anisoptera: Aeshnidae).

Four new species of the genus Planaeschna, P. robusta sp. nov. (holotype male; Mt. Emeishan, Emeishan City, Sichuan Province, China, 16. VIII. 2007), P. maculifrons sp. nov. (holotype male; Mt. Emeishan, Emeishan City, Sichuan Province, China, 20. VIII. 2007), P. caudispina sp. nov. (holotype male; Mt. Qingchengshan, Dujiangyan City, Sichuan Province, China, 30. VIII. 2007) and P. monticola sp. nov. (holotype male; Sanjiacun Stream, Fengyi Town, Dali City, Yunnan Province, China, 19. XI. 2012) are described and illustrated and diagnosed from their congeners. All the holotypes have been deposited in the Collection of Aquatic Animals, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan City, Hubei Province, China. Brief notes on the biology of each species are also provided.

A new species of Siphlonurus Eaton, 1868 (Ephemeroptera, Siphlonuridae) from Yunnan, China.

Siphlonurusdongxi Li & Tong, sp. nov. from Shangri-La City, Yunnan Province, China, is described based on egg, nymph, and winged stages. The new species is closely related to S.davidi (Navás, 1932), and can be distinguished by the colour of the imago, the forking point of MP, the penis, posterolateral spines of tergum IX of imagoes, and first abdominal terga nymph, as well as the structure of the egg. The new species and S.davidi have the same morphological and structural characteristics, such as the long cubital area with many intercalaries, cross veins between C, Sc, RA, and RSa1 surrounded with distinct pigments, the strong curvature of vein CuP in the forewing, the broad expansion of the hindwing, the membranous penis lobes fused without teeth, supporting the proposition of a new species complex, the Siphlonurusdavidi group. The structures of the penis and the egg of the new species could help understand the origin and evolution of the genus Siphlonurus.

A new species of Lamelligomphus Fraser, 1922 (Odonata: Gomphidae) from southern Yunnan, China.

Lamelligomphus annakarlorum sp. nov. is described based on specimens collected from southern Yunnan Province, China (holotype male: Xishuangbanna National Nature Reserve, 21°57'59''N, 101°12'37''E, Xishuangbanna Dai Autonomous Prefecture, Yunnan Province, China). All type specimens of the new species have been deposited in the Collection of Aquatic Animals, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan City, Hubei Province, China. It is compared with Lamelligomphus camelus (Martin, 1904), which shares some similar characters.

[Total nitrogen and total phosphorus thresholds for epilithic diatom assemblages in inflow tributaries of the Three Gorges Reservoir, China.] / åŸºäºŽé™„çŸ³ç¡ è—»çš„ä¸‰å³¡æ°´åº“å ¥åº“æ”¯æµæ°®ã€ç£·é˜ˆå€¼.

To study the relationships between in-stream total nitrogen (TN) and phosphorus (TP) loads and responses of epilithic algal metrics, nonparametric change-point analysis (nCPA) and thresholds indicator taxa analysis (TITAN) were used to detect possible TN and TP thresholds for algal chlorophyll a, diatom richness, Shannon diversity index, and diatom community composition for tributary rivers of the Three Gorges Reservoir (TGR). We found that nCPA simulated similar TP thresholds for all the four algal metrics (-0.03 mg·L-1), with similar TN thresholds (-0.8 mg·L-1) for all metrics but community composition. In contrast, TITAN provided specific nutrient thresholds for both sensitive and tolerant taxa within the whole community, and the threshold ranges covered thresholds for the other metrics. Additionally, nine (one sensitive and eight tolerant taxa) and ten indicator taxa (five sensitive and five tolerant taxa) for TN and TP were detected by TITAN, respectively. Therefore, we used the results of TITAN to define nutrient thresholds for the study rivers. That is, when in-stream TN concentration exceeded 0.382 mg·L-1 or TP concentration exceeded 0.016 mg·L-1(i.e. negative response threshold), sensitive taxa within river epilithic diatom assemblages would respond with decrease in density. When TN exceeded 1.298 mg·L-1 or TP exceeded 0.065 mg·L-1(i.e. positive response threshold), even tolerant taxa would be influenced and the whole assemblage would be changed significantly. Based on such criteria, we found that 87% sites had TN concentrations higher than the negative response threshold, with 22% sites being higher than the TN positive response threshold. As for TP, 94% and 14% sites exceeded the negative and positive response threshold, respectively. Our findings suggest that although most of the inflow tributaries of Three Gorges Reservoir were disturbed by human disturbance, yet the disturbance was not so extensive. Our findings provided significant information for managing river ecosystems of the TGR region.

New species and records of Burmagomphus Williamson, 1907 (Odonata, Gomphidae) from China.

Four new species of Burmagomphus Williamson, 1907 are described from Southwestern China: B. apricus sp. nov. from Xishuangbanna National Nature Reserve, Menglun Town, Xishuangbanna Dai Autonomous Prefecture, Yunnan Province; B. magnus sp. nov. from Huayudong, Nanxi Town, Hekou County, Hani-Yi Autonomous Prefecture of Honghe, Yunnan Province, B. dentatus sp. nov. from Zhangjiang River in Xiaoqikong scenic spot, altitude 400 m, Libo County, Guizhou Province, and B. latescens sp. nov. from Sifangjing, Mengding Town, Gengma County, Lincang City, Yunnan Province. New records of Burmagomphus spp. in China are provided, with B. asahinai and B. williamsoni williamsoni for the first time reported from China. A revised checklist of Burmagomhus spp. of China is provided which includes 14 species. A doubtful record of B. arboreus and relations of the newly described species are discussed. All types are deposited in the Collection of Aquatic Animals, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan City, Hubei Province, China.

Somatochlora shennong sp. nov. from Hubei, China (Odonata: Corduliidae).

A new species, Somatochlora shennong sp. nov. (holotype ♂, Dajiuhu National Wetland Park in Shennongjia National Nature Reserve, Hubei Province, China, 9 August 2012) is described, illustrated, and compared with the related species S. dido Needham and S. taiwana Inoue & Yokota. 

[Spatiotemporal distribution of total nitrogen and total phosphorus in sediments of Xiangxi Bay, Three Gorges Reservoir].

The spatiotemporal distribution of total nitrogen (TN) and total phosphorus (TP) in sediments of Xiangxi Bay, Three Gorges Reservoir was investigated from October 2004 to July 2006, with related affecting factors analyzed. The TN and TP concentrations in the sediments were higher in the middle stretch but lower in the two edges of the Bay. The maximum value of TN concentration (1.08 mg x g(-1)) appeared in the middle part of the Bay, and the minimum (0.89 mg x g(-1)) occurred at the adjacent areas to the river mouth; while the maximum value of TP concentration (1.07 mg x g(-1)) appeared in the middle, and the minimum (0.80 mg x g(-1)) was in the edges of the Bay. The TN concentration decreased in the sequence of autumn-winter-spring, but increased from spring to summer dramatically; while the seasonal variation of TP concentration was not very significant, with the maximum occurred in spring. Significant inter-annual variations were observed in the TN and TP concentrations. The spatial distributions of TN and TP concentrations were mainly affected by the sedimentation of suspended matter. In the regions where sedimentation rate was high, the TN and TP concentrations were also very high. The seasonal fluctuation of TN concentration was mainly affected by river discharge, while that of TP concentration was mainly affected by point source pollution.

[Dynamics of suspended solids in Xiangxi Bay of Three Gorges Reservoir during spring algal bloom period].

The dynamics of total suspended solids (TSS) in Xiangxi Bay of Three Gorges Reservoir (TGR) during the period of spring algal bloom were weekly investigated. The results showed that the TSS in the Bay ranged from 0.66 to 134.92 mg x L(-1), with a median of 6.80 mg x L(-1), and tended to be increased from headwater to down-lake zones. The spatial pattern of non-volatile suspended solids (NVSS) was similar to that of TSS, while volatile suspended solids (VSS) showed obviously different pattern from TSS and followed the spatial pattern of chlorophyll a. Regression analysis indicated that in the mid-zone of the Bay, chlorophyll a was significantly related to TSS and VSS, and explained 66.7%-96.7% and 58.9%-85.5% of the variance in TSS and VSS, respectively. In the headwater and down-lake zones, there were no significant relationships between chlorophyll a and TSS (including NVSS and VSS). The TSS in mid-lake had more close relationship with VSS than with NVSS, while that in headwater and down-lake had more close relationship with NVSS than with VSS, implying that the mid-lake of Xiangxi Bay was a more autochthonous system than the headwater and down-lake where allochthonous influences were the more determinant factors.

[Spatiotemporal dynamics and related affecting factors of summer algal blooms in Xiangxi Bay of Three Gorges Reservoir].

In June - August 2008, the cyanobacterial bloom and chlorophycean bloom broke out one after the other in the Xiangxi Bay of Three Gorges Reservoir. Based on the weekly monitoring in summer in the Bay, and by using cluster analysis and discriminant analysis, the spatiotemporal dynamics and related affecting factors of the two blooms were studied. Each of the blooms could be divided into non-bloom group, transitional group, and bloom group. The two blooms had different uptake levels of dissolved Si (DSi), NO3(-)-N + NO2(-)-N, and PO4(3-)-P. Cyanobacterial bloom had lower DSi concentration and lower TN/TP, DSi/TN and DSi/TP ratios than chlorophycean bloom. The discriminant factors of cyanobacterial bloom were Chl a, TN and PO4(3-)-P, while those of chlorophycean bloom were Chl a and DSi. Better discriminant results were obtained when dividing each bloom into non-bloom group and bloom group. The critical value of Chl a for cyanobacterial bloom and chlorophycean bloom was 40 and 20 microg x L(-1), respectively.

[Impacts of large hydropower station on benthic algal communities].

To investigate the impacts of large hydropower station in Gufu River on benthic algae, monthly samplings were conducted from September 2004 to June 2007 at the site GF04 which was impacted by the hydropower station, with the site GL03 in Gaolan River as reference. During sampling period, no significant differences were observed in the main physicochemical variables between GF04 and GL03, but the hydrodynamics differed significantly. GL03 was basically at a status of slow flow; while GF04, owing to the discharging from the reservoir, was at a riffle status during more than 60% of the sampling period. Such a difference in hydrodynamics induced significant differences in the community similarity of benthic algae and the relative abundance of unattached diatoms, erect diatoms, and stalked diatoms between GF04 and GL03, which could better reflect the impacts of irregular draw-off by large hydropower station on river eco-system.

[Seasonal dynamics of macrozoobenthos community structure in Xiangxi River].

To study the seasonal dynamics of macrozoobenthos community in Xiangxi River, the individuals of macrozoobenthos in the River were quantitatively monitored. A total of 197 taxa belonging to 6 class and 68 families were collected, among which, Baetis spp., Epeorus spp., and Nemoura spp. were the dominant groups, and their compositions varied with seasons. The macrozoobenthos community was most complicated in winter, followed by in spring and autumn, and the simplest in summer. Gather-collector was the main component of functional feeding groups in Xiangxi River system, followed by scraper, predator, and filter-collector, while shredder only accounted for a small part. Canonical correspondence analysis showed that the factors affecting the macrozoobenthos community were dissimilar among seasons. In summer and autumn, nutrients had greater effects; and in all seasons, water depth had definite effects.

[Spatiotemporal variation of epilithic algae in Xiangxi River system].

Xiangxi River system is the greatest branch in the Hubei reservoir area of the Three Gorges reservoir. In this paper, the epilithic algae in the River and its three major tributaries were investigated from July 2005 to June 2006. A total of 218 taxa were identified, including 183 species of Bacillariophyta, 24 species of Chlorophyta, 10 species of Cyanophyta, and one species of Xanthophyta. The diatom Achnanthes linearis was the most predominant species. The richness and Shannon-Wiener diversity indices varied significantly (or almost significantly) over time and space, and the total average values were 32 and 1.54, respectively. The total averages of annual epilithic algal density and chlorophyll a concentration were 8.75 x 10(9) cells x m(-2) and 14.62 mg x m(-2), respectively. There were significant differences in the algal density and chlorophyll a concentration among different sampling sites, and the maximum values were observed in Gufu River tributary, which were one order of magnitude higher than the minimum ones in Jiuchong River tributary. The algal density and chlorophyll a concentration tended to be higher in winter and spring than in summer and autumn, but no significant differences were observed in various seasons. Epilithic algal density and chlorophyll a concentration were significantly negatively correlated with elevation and water current, but positively correlated with the total nitrogen concentration in water.

[Spatial distribution of macroinvertebrates in Xiangxi River].

An investigation was made from July 2005 to June 2006 to understand the spatial distribution of macroinvertebrates in Xiangxi River, the largest tributary in Hubei portion of Three Gorges Reservoir. The results showed that Ephemeroptera baetis spp., Ephemeroptera epeorus spp., and Plecoptera nemoura spp. were the dominant taxa. There existed greater differences in the habitat characters and in the community structure of macroinvertebrates among the major tributaries of Xiangxi River, and the relative abundance of functional feeding groups could reflect the characters of different habitats. A comparison of the diversity of dominant taxa and their tolerance towards pollution among the major tributaries showed that Jiuchong River had the best habitat, followed by the main stream of Xiangxi River, and Gaolan River and Gufu River. Canonical correspondence analysis showed that the NH4+ -N concentration in the main stream of Xiangxi River, the pH, turbidity, water depth, SiO2, conductance, and alkalinity in Jiuchong River, the turbidity in Gaolan River, and the NH4+ -N and NO3- -N concentrations in Gufu River had significant impact on the community structure of macroinvertebrates.

[Macrobenthos in Jinping reach of Yalongjiang River and its main tributaries].

In this paper, an investigation was made on the macrobenthos at 25 sites in the Jinping reach of Yalongjiang River and its main tributaries in May and November 2004, aimed to study the relationships between macrobenthos distribution and environmental factors. The results showed that the dominant species of macrobenthos was Baetis sp. (Baetidae, Ephemeroptera), with a relative abundance being 14.9% and 27.0% in May and November, respectively. Based on the species composition and their relative abundance, and by using two-way indictor species analysis (TWINSPAN) and detrended correspondence analysis (DCA), the macrobenthods was divided into four groups, according to the habitat types of the sites. Canonical correspondence analysis (CCA) on the relationships between macrobenthods community structure and environmental factors indicated that in May, elevation and water hardness and NH4+ -N content were the main environmental factors affecting macrobenthods distribution, while in November, elevation, water hardness, NH4+ -N and SiO2 contents were the main ones.

[Influence of cascaded exploitation of small hydropower on phytoplankton in Xiangxi River].

With the five small hydropowers (SHPs) from up- to downstream of Xiangxi River as test objects, this paper studied the influence of SHPs cascaded exploitation on the phytoplankton in the river. The results showed that phytoplankton assemblages were dominated by diatoms, occupying 95.54% of the total number of species. Achnanthes linearis, A. lanceolata var. elliptica and Cocconeis placentula were the most abundant species, with the relative abundance being 23.96%, 18.62% and 12.48%, respectively. The average algal density at 25 sampling sites was 6.29 x 10(5) ind x L(-1), with the maximum of 1.81 x 10(6) ind x L(-1) and the minimum of 2.35 x 10(5) ind x L(-1). Two-way ANOVA indicated that water flow velocity was the main factor affecting the phytoplankton. The establishment of the cascaded SHPs on the river made the habitat of lower reach has a significant difference with the others, resulting in a dramatic change of many parameters including Margalef diversity index, species richness, generic richness, taxonomic composition, and the percentage of diatoms.