Systematics

1. Wang, H. Z., 2002. Studies on taxonomy, distribution and ecology of microdrile Oligochaetes of China, with description of two new species from the vicinity of the Great Wall Station of China, Antarctica. Higher Education, Press Beijing. (In Chinese with English summary)

Summary:

The present paper embodies the results of a comprehensive investigation of Microdrile oligochaetes (Annelida, Oligochaeta) of China carried out in 1990-1994. Qualitative and quantitative samples were taken from localities in Shaanxi, Henan, Hubei, Hunan Provinces and Guangxi Autonomous Region. As a part of the author's work, findings from the Great Wall Station of China in Antarctica are provisionally involved.

At the beginning of the paper, a systematic account of 82 microdrile species belonging to 5 families and 38 genera is presented (see the list). 6 species of 5 genera among them are described as new to science. 14 species of 12 genera are regarded as new recorded species in China. A new combination of the Naididae is also re-described. The diagnoses of the new species including 2 antarctic ones will be given in the hindmost section of the present summary. In addition to the new forms, it should be pointed out that species of the Enchytraeidae constitute a major part of the findings. It demonstrates that the widely accepted opinion referring to the rarity of Enchytraeidae in our country should be modified.

The characteristics of freshwater microdrile fauna of China is analyzed mainly by means of fuzzy clustering. In worldwide scale, it reveals that the microdrile fauna of China is close to that of England, former Czechoslovakia, former Soviet Union, North America and Japan, less similar to India and Africa, and even lesser to South America and Oceania. Dealing with China itself, there are some Holartic taxa in Heilongjiang Basin and Xinjiang Autonomous Region, while those in Changjiang and Zhujiang Basins are more or less Oriental. A transition zone between south and north seems to lie in Huanghe Basin. Of the entire microdrile fauna, there are 13 freshwater species reported only from China, including 9 species being regarded as endemic to Changjiang Basin.

Key words: China, Microdrile oligochaetes, Enchytraeidae, Tubificidae, new species, new records, faunal analyses, standing crops, Antarctica

2. Wang, H. Z. & C. Erséus, 2001. Marine Phallodrilinae (Oligochaeta, Tubificidae) of Hainan Island in southern China. Hydrobiologia, 462: 199-204. [Wang01aHydrobiologia.pdf]

Abstract:

Six species of Phallodrilinae are reported from Hainan Island in southern China. The mesopsammic Aktedrilus yiboi sp. nov. is new to science. It is characterized by a combination of (1) small, straight, conical, strongly cuticularized penis sheaths, (2) posterior prostate glands being associated with the most ectal parts of the atria, and (3) small spermathecal ampulla. Bathydrilus ampliductus Erséus, 1997 is recorded for the first time since it was originally described from Australia’s Northern Territory.

Key words: Phallodrilinae, marine oligochaetes, taxonomy, new species, Hainan.

3. Wang, H. Z. & Y. L. Liang, 2001. A preliminary study of oligochaetes in Poyang Lake, the largest freshwater lake of China, and its vicinity, with description of a new species of Limnodrilus. Hydrobiologia, 463: 29-38. (SCI) [Wang01bHydrobiologia.pdf]

Abstract:

The oligochaete fauna of the largest freshwater lake of China, Poyang Lake, has never been investigated before. On the basis of a preliminary survey in the lake and its vicinity in 1997-1999, 25 species belonging to 20 genera and 5 families are recorded. Among them, one genus, Cernosvitoviella (Enchytraeidae), and two species, Bratislavia unidentata (Naididae), Potamothrix bedoti (Tubificidae), are recorded from China for the first time. Another tubificid, Limnodrilus paramblysetus sp. nov., is new to science. It is similar to L. amblysetus Brinkhurst et al., 1990 in chaetal shape but differs in having short hooded penis sheaths.

Key words: Tubificidae, Naididae, freshwater oligochaetes, taxonomy, new species, Poyang Lake

4. Gibson, R. & H. Z. Wang, 2002. A new genus and species of freshwater Monostiliferous hoplonemertean (Nemertea, Enopla) from the People’s Republic of China. Hydrobiologia 489:185-196.〔GibsonWang02Hydrobiologia.pdf〕

Abstract:

A new genus and species of freshwater monostiliferous hoplonmertean, Limnemertes poyangensis gen. et sp. nov., from Poyang Lake, People's Repulic of China, is described and illustrated. the taxon is compared and contrasted with previously described freshwater hoplonemerteans. This is the fourth species of freshwater nemertean to be described from China and the first record from Poyang Lake.

Key words: freshwater nemertean, hoplonemertea, People's Repulic of China, Poyang Lake, Limnemertes poyangensis gen. et sp. nov.

5. Wang, H. Z. & C. Erséus, 2003. Marine species of Ainudrilus and Heterodrilus (Oligochaeta: Tubificidae: Rhyacodrilinae) from Hainan Island in southern China. New Zealand Journal of Marine and Freshwater Research, 37: 205-217.[Wang03 NewZealJMarFresh.pdf]

Abstract:

Six species of Rhyacodrilinae (Oligochaeta: Tubificidae) are reported from intertidal and shallow-water subtidal habitats around Hainan Island in southern China. Four species are new to science: Ainudrilus pauciseta n. sp., Heterodrilus chenianus n. sp., Heterodrilus nudus n. sp., and Heterodrilus uniformis n. sp. Japanese material of Ainudrilus lutulentus (Erséus, 1984) is also briefly described. Hitherto, 27 species belonging to Tubificidae have been recorded from Hainan.

Key words: Ainudrilus; Heterodrilus; Tubificidae; marine oligochaetes; taxonomy; new species; faunal diversity; southern China; Japan

6. Wang, H. Z. & C. Erséus, 2004. New species of Doliodrilus and other Limnodriloidinae (Oligochaeta, Tubificidae) from Hainan and other parts of the north-west Pacific Ocean. Journal of Natural History, 38: 269-299.[Wang04JNatHist.pdf]

Abstract:

Thirteen species of Limnodriloidinae (Tubificidae) are recorded from marine and brackish-water habitats of Hainan Island, southern China, including eleven species of Doliodrilus and two species belonging to Limnodriloides. Eight species are new to science: D. bisaccus sp. n. (types from Japan), D. longidentatus sp. n. (types from Hong Kong), D. ciliatus sp. n., D. adiacens sp. n., D. fibrisaccus sp. n. (also from Fiji), D. brachyductus sp. n., D. bidolium sp. n., and D. chinensis sp. n. In addition, material of D. puertoricensis Erséus and Milligan, 1988, from New Caledonia, is briefly described. This study shows that Doliodrilus is unexpectedly species-rich in Asian seas, in particular, around Hainan. Including an unnamed species from this island, the known members of this genus increase from three to twelve.

Key words: Doliodrilus, Limnodriloidinae, Oligochaeta, taxonomy, new species, southern China, Japan, Fiji, New Caledonia.

7. Cui, Y. D. & H. Z. Wang. 2005. Potamothrix scleropenis sp. nov. (Oligochaeta: Tubificidae) from the Fuxian Lake, the deepest lake in southwest China. Zoological Science, 22: 1353-1357. 〔CuiWang05ZoolSci.pdf〕

Abstract:

Potamothrix scleropenis sp. nov. (Tubificidae: Tubificinae) is described from the profundal zone (74 m) of Fuxian Lake, the deepest lake (up to 155 m) on the Yunnan-Guizhou Plateau in China. The new species is assigned to Potamothrix because of its short vasa deferentia and its tubular atria without ejaculatory ducts and prostate glands. It differs from congeners by its cuticularized penis sheaths; bifurcated, strongly curved spermathecal chaetae; bifurcated lower prongs of bifids; and feathered hairs. P. scleropenis appears closely related to P. cekanovskajae Finogenova, 1972 and P. tudoranceai Šporka, 1994, since all the three species have homogeneous atria without prostate glands.

Key words: Potamothrix, profundal Tubificinae, new species, Fuxian Lake, Yunnan Province

8.Cui, Y. D. & H. Z. Wang. 2009. Three new species of Tubificidae, Oligochaeta, from two plateau lakes in Southwest China. Zootaxa, 2143: 45-54.[CuiWang09Zootaxa]

Abstract:

Three new species of Tubificinae (Naididae, Oligochaeta), Varichaetadrilus vestibulatus n. sp., Aulodrilus apeniatus n. sp., and Ilyodrilus mesoprostatus n. sp., are reported from Fuxian Lake and Xingyun Lake of Yunnan Province, Southwest China. V. vestibulatus differs from its allies by possessing modified spermathecal chaetae and thinner cylindrical penial sheaths. A. apeniatus is unique in the genus by having no penis. I. mesoprostatus is distinguishable from congeners by its prostate glands joining middle portion of atria and having concave, cone-shaped cuticular penial sheaths. Twenty-eight species of freshwater oligochaetes have hitherto been recorded from Yunnan Province, including five endemic species from three plateau lakes.

Key words: Varichaetadrilus, Aulodrilus, Ilyodrilus, Tubificinae, taxonomy, new species, Fuxian Lake, Xingyun Lake,
Yunnan Province

Ecology

1. Xu, Q. Q., H. Z. Wang & S. P. Zhang, 2003. The impact of overstocking of mitten crab, Eriocheir sinensis, on lacustrine zoobenthos community. Acata Hydrobiologica Sinica, 27 (1)：41-46. (In Chinese with English abstract)[XuWang03ActaHydrobiolSin.pdf]

Abstract:

To examine the impact of mitten crabs (Eriocheir sinensis) on zoobenthic community, a comparative study was conducted along Changjiang River in 1998-1999 between crab-overstocking-lake, Huanghu Lake, and the reference waters, viz. unstocked vicinity of Huanghu Lake, natural-fishing-lake, Longganhu Lake, and fish-stocking-lake, Niushanhu Lake. The parameters include species composition, body size, standing crop, functional feeding group and production. The results showed that the species diversity of Huanghu was substantially lower than that of the references. Due to the extinction of submerged macrophytes, small scrappers on the plants were greatly decreased in Huanghu, and subsequently, big gastropods, Bellamya, feeding on the bottom, became dominant. Under the stocking density of about 1 kg×hm^-2 of crab larvae or juveniles, zoobenthic density and production were reduced by more than 60 %. Inferentially, zoobenthos are affected by mitten crabs in two ways, i.e. direct feeding on benthos, and indirect effect through damage of submerged macrophytes. Considering that the method of capacity estimation of mitten crabs has not yet been established, the authors are of the opinion that mitten crabs and planktonivorous fishes should be in rotation of stocking for the purpose of sustainable utilization of natural resources.

Key words: Mitten-crab-stocking; zoobenthos; standing crop; functional feeding group; production; fisheries model

2. Wang, H. Z., H. J. Wang, X. M. Liang, L. Y. Ni, X. Q. Liu & Y. D. Cui. 2005. Empirical modelling of submersed macrophytes in Yangtze lakes. Ecological Modelling, 188: 483-491. [Wang05EcolModel.pdf]

Abstract:

Submersed macrophytes in Yangtze lakes have experienced large-scale declines due to the increasing human activities during past decades. To seek the key factor that affects their growth, monthly investigations of submersed macrophytes were conducted in 20 regions of 4 Yangtze lakes during December, 2001-March, 2003. Analyses based on annual values show that the ratio of Secchi depth to mean depth is the key factor (50% of macrophyte biomass variability among these lakes is statistically explained). Further analyses also demonstrate that the months from March to June are not only the actively growing season for most macrophytes, but the key time the factor acts. Five key-time models yielding higher predictive power (r2 reaches 0.75, 0.76, 0.77, 0.69 and 0.81) are generated. A comparison between key-time models and traditional synchronic ones indicates that key-time models have higher predictive power. Analyses of transparency thresholds during macrophyte growing season and the limitations of the models are presented. The models and other results may benefit the work concerning submersed macrophyte recovery in Yangtze lakes.

Key words: Key-time models; Submersed macrophytes; Yangtze shallow lakes; Biomass; Transparency thresholds

3. Wang, H. Z., H. J. Wang, X. M. Liang & Y. D. Cui. 2006. Stocking models of Chinese mitten crab (Eriocheir japonica sinensis) in Yangtze lakes. Aquaculture, 255: 456-465.[Wang06Aquaculture.pdf]

Abstract:

The farming of Chinese mitten crab, a quality aquatic product in China and neighbouring Asian countries, has been developing rapidly in China since last decade. It reached a total yield of 3.4×105 tonnes in 2002. Due to the successive over-stocking year after year, many lakes in the mid-lower Yangtze Basin, the main farming area, are under deterioration, leading to a reduction of crab yield and quality, and subsequently, a loss of farming profits. Aiming at a normal development of crab culture and the sustainable use of lakes, an annual investigation dealing with lake environmental factors in relation to stocked crab populations was carried out at 20 farms in 4 lakes. The results show that the submersed macrophyte biomass (BMac) is the key factor affecting annual crab yield (CY). Using the ratio of Secchi depth to mean depth (ZSD/ZM), an easily measured parameter closely correlated to BMac, as driving variable, 10 regression models of maximal crab yields were generated (r2 ranging 0.49-0.81). Based on the theory of MSY (Maximum Sustainable Yield), in combination with body-weight (BW) and recapture rate (RR) of adult crabs, a general optimal stocking model was eventually formulated. All models are simple and easy to operate. Comments on their applications and prospects are given in brief.

Key words: Yangtze lakes; Chinese mitten crab culture; Maximal yield models; Optimal-stocking model

4. Liu, X. Q., H. Z. Wang & X. M. Liang, 2006. Food web of macroinvertebrate community in a Yangtze shallow lake: trophic basis and pathway. Hydrobiologia, 571: 283-295.[LiuWang06Hydrobiologia.pdf]

Abstract:

No detailed food web research on macroinvertebrate community of lacustrine ecosystem was reported in China. The present study is the first attempt on the subject in Lake Biandantang, a macrophytic lake in Hubei Province. Food webs of the macroinvertebrate community were compiled bimonthly from March, 2002 to March, 2003. Dietary information was obtained from gut analysis. Linkage strength was quantified by combining estimates of energy flow (secondary production) with data of gut analysis. The macroinvertebrate community of Lake Biandantang was based heavily on detritus. Quantitative food webs showed the total ingestion ranged from 6930 to 36340 mg dry mass m-2 bimonthly. The ingestion of macroinvertebrate community was higher in the months with optimum temperature than that in other periods with higher or lower temperature. Through comparison, many patterns in benthic food web of Lake Biandantang are consistent with other detritus-based webs, such as stream webs, but different greatly from those based on autochthonous primary production (e.g. pelagic systems). It suggests that the trophic basis of the web is essential in shaping food web structure.

Key words: Yangtze shallow lake, macroinvertebrates, trophic basis, food web quantification

5. Wang, H. J., B. Z. Pan, X. M. Liang & H. Z. Wang. 2006. Gastropods on submerged macrophytes in Yangtze Lakes: community characteristics and empirical modelling. International Review Hydrobiology, 91(6): 521-538.[WangWang06InternatRevHydrobiol.pdf]

Abstract:

Epiphytic gastropods in Yangtze lakes have suffered from large-scale declines of submersed macrophytes during past decades. To better understand what controls gastropod community, monthly investigations were carried out in four Yangtze lakes during December, 2001-March, 2003. Composed of 23 species belonging to Pulmonata and Prosobranchia, the community is characterized by the constitution of small individuals. The average density and biomass were 417±160 ind/m² and 18.05±7.43 g/m², with maxima around August. Submersed macrophyte biomass is shown to be the key factor affecting species number, density, and biomass of gastropods. Accordingly, a series of annual and seasonal models yielding high predictive powers were generated. Preference analyses demonstrated that pulmonates and prosobranchs with different respiratory organs prefer different macrophyte functional groups.

Key words: epiphytic gastropods, Yangtze shallow lakes, community structure, empirical models, preference analyses.

6.Jiang, P. H., X. M. Liang, F. Chen, Y. Y. Zhou & H. Z. Wang, 2006. Indication of macrophytes-restorable area by spatial pattern of macrobenthos in a eutrophic Yangtze Lake. Resource and Environment in the Yangtze Basin, 4: 439-445. [JiangWang06ResEnvYangtzeBasin.pdf]

Abstract：

Substrate suitability is critical to the restoration of submersed macrophytes in shallow eutrophic lakes. Since benthic animals are good indicators of sediment eutrophication, the authors conducted a pioneer study during 2002-2003 in Yuehu Lake, a hypertrophic urban lake of Wuhan City, with the purpose to explore the indicative value of macrobenthos distribution in determining macrophyte-restorable area．First, by correlating density and biomass of different benthos with trophic variab1es of sediment，density of Tubificidae (Oligochaeta) was selected as the best indicator. Secondly, on the basis of the data from 16 Yangtze lakes, a significant negative relationship between tubificids and macrophytes was detected, and it is demonstrated that the sediment with tubificids less than 100 ind/m² could be suitable for macrophyte growth．Finally, the horizontal isograms of tubificid density in Yuehu Lake were drawn, showing two proper places for macrophyte restoration. As the first attempt, the authors have established a principal framework for indicating macrophyte-restorable area by macrobenthos distribution, and will focus on the threshold analysis in the future．

Key words: macrobenthos；tubificid isograms; threshold for macrophyte restoration; eutrophic shallow lake; Yuehu Lake in Wuhan City

7. Liu, X. Q. and Wang, H. Z. 2007. Food composition and dietary overlap of macroinvertebrates in a shallow eutrophic lake in China: spatial and temporal variations. Fundamental and Applied Limnology, 168: 71-82. 〔LiuWang07FundApplLimno.pdf〕

Abstract:

The present study was conducted in Lake Donghu, a suburban eutrophic lake arising from the middle reaches of the Yangtze River, China. Food composition of 32 taxa of zoobenthos was analyzed from 1251 gut samples. Macroinvertebrate primary consumers ingested mainly detritus, sand grains and diatoms. The predators primarily preyed on rotifers, crustaceans, oligochaetes and chironomid larvae. The dietary overlap was relatively high among collector taxa but low among other macroinvertebrates. Food composition and dietary overlap of macroinvertebrates changed considerably, both spatially and temporally. Food web structure differed between inshore and offshore regions of Lake Donghu. The inshore web was relatively complex and dynamic whereas the offshore web was simple and stable. Taxon-specific changes of diet seem to have little effect on the benthic food web structure in offshore waters of a eutrophic lake.

Key words: food composition, dietary overlap, macroinvertebrates, eutrophic lake

8. Wang, H. Z., Xu, Q. Q., Cui, Y. D. and Liang, Y. L. 2007. Macrozoobenthic community of Poyang Lake, the largest freshwater lake of China, in the Yangtze floodplain. Limnology, 8: 65-71.[Wang07Limnology.pdf]

Abstract:

Poyang Lake (Poyang Hu) is located at the junction of middle and lower reaches of the Yangtze (Changjiang) River, covering an area of 3283 km2. As one of the few lakes that are still freely connected with the river, it plays an important role in the maintenance of the unique biota of the Yangtze floodplain ecosystem. To promote the conservation of Poyang Lake, an investigation of macrobenthos in the lake itself and adjoining Yangtze mainstream was conducted in 1997-1999. Altogether 58 benthic taxa, including 22 annelids, 8 molluscs, 26 arthropods, and 2 miscellaneous animals, were identified from quantitative samples. The benthic fauna shows a high diversity and a marine affinity. The standing crops of benthos in the lake were much higher than those in the river, being 659 individuals/m2 and 187.3 g/m2 (wet mass) in the main lake, 549 individuals/m2 and 116.6 g/m2 in the lake outlet, but only 129 individuals/m2 and 0.4 g/m2 in the latter. The dominant group in the lake was Mollusca, comprising 63.4% of the total in density and 99.5% in biomass. An analysis of functional feeding structure indicated that collector-filterers and scrapers were predominant in the lake, up to 42.2 %, 24.7% in density and 70.2%, 29.2% in biomass, while shredders and collector-gatherers were relatively common in the river. The present study was restricted to the northern outlet and the northeast part of Poyang Lake. A scrutiny is required for the remaining area.

Key words: Macrozoobenthos, River-connected lake, Community structure, Yangtze floodplain

9. Cui, Y. D., Liu, X. Q. and Wang, H. Z. 2008. Macrozoobenthic community of Fuxian Lake, the deepest lake of southwest China. Limnologica, 38: 116-125. 〔CuiWang08Limno.pdf〕

Abstract：

Located in the Yunnan-Guizhou Plateau in southwest China, Fuxian Lake covers an area of 211 km2, with maximum depth of 155 m. It is known to have a unique fauna, from which 14 endemic species have been described. Purposing to apprehend the situation of zoobenthic community in the lake, the present study was conducted from August 2002 to August 2003. Altogether 62 benthic taxa including 22 oligochaetes, 21 molluscs and 18 insects were identified, with predominant taxa belonging to Potamothrix, Procladius and Paraprososthenia. The standing crops of benthos were much higher in littoral (824 ind/m² in density, 3.72 g/m² in biomass) than those in profundal (23 ind/m² in density, 0.10 g/m² in biomass). Seasonal fluctuation occurred, showing richer species in summer and higher standing crops in spring and summer. Analyses of functional feeding groups indicated that collector-gatherers and scrapers were predominant in entire lake. Stepwise multiple regression analysis demonstrated that the water depth is the key factor affecting macrozoobenthos.

Key words: Macrozoobenthos, Taxonomic composition, Standing crop, Functional feeding group, Fuxian Lake

10. Wang, H. J., Liang, X. M., Jiang, P. H., Wang, J., Wu, S. K. and Wang, H. Z. 2008. TN:TP ratio and planktivorous fish do not affect nutrient-chlorophyll relationships in shallow lakes. Freshwater Biology, 53: 935-944.[WangWang08FreshwatBiol.pdf]

Summary

1. In previous work, phytoplankton regulation in freshwater lakes has been associated with many factors. Among these, the ratio of total nitrogen to total phosphorus (TN: TP) has been widely proposed as an index to identify whether phytoplankton are nitrogen-limited or phosphorus-limited. From another point of view, it has been suggested that planktivorous fish can be used to control phytoplankton.

2. Large-scale investigations of phytoplankton biomass (measured as chlorophyll a, Chl a) were carried out in 45 mid-lower Yangtze shallow lakes to test hypotheses concerning nutrient limitation (assessed with TN: TP ratios) and phytoplankton control by planktivorous fish.

3. Regression analyses indicated that TP was the primary regulating factor and TN the second regulating factor for both annual and summer phytoplankton Chl a. In separate nutrient-Chl a regression analyses for lakes of different TN: TP ratios, TP was also superior to TN in predicting Chl a at all particular TN: TP ranges and over the entire TN: TP spectrum. Further analyses found that Chl a: TP was not influenced by TN: TP, while Chl a: TN was positively and highly correlated to TN: TP.

4. Based on these results, and others in the literature, we argue that the TN: TP ratio is inappropriate as an index to identify limiting nutrients. It is almost impossible to specify a “cut-off” TN: TP ratio to identify a limiting nutrient for a multi-species community because optimal N: P ratios vary greatly among phytoplankton species.

5. Lakes with yields of planktivorous fish (silver and bighead carp, the species native to China) greater than 100 kg ha-1 had significantly higher Chl a and lower Secchi depth than those with yields less than 100 kg ha-1. TP-Chl a and TP-Secchi depth relationships are not significantly different between lakes with yields greater than or less than 100 kg ha-1. These results indicate that the fish failed to decrease Chl a yield or enhance ZSD. Therefore, silver carp and bighead carp are not recommended as a biotic agent for phytoplankton control in lake management if the goal is to control the entire phytoplankton and to enhance water quality.

Keyword: phytoplankton, chlorophyll a, total phosphorus, TN: TP ratio, planktivorous fish

11. Ru, H. J., X. Q. Liu, X. R. Huang, Y. Z. Ning and H. Z. Wang, 2008. Diversity of fish species and its spatio-temporal variations in Lake Dongting, a large Yangtze-connected lake. Journal of Lake Sciences, 20(1): 93-99.[RuWang08JLakeSci.pdf]

Abstract:

To evaluate the fish diversity of Yangtze River-connected lakes, a monthly survey of fish assemblage was carried out in the Lake Dongting in the middle basin of the Yangtze River in March-December, 2004 and May, 2005. Three sampling areas along a transect from the Yangtze River mainstream to the lake center, i.e. from lake mouth (Chenglinji) to East Lake Dongting (Yueyang) and South Lake Dongting (Yuanjiang) were selected. Totally 69 fish species belonging to 6 orders, 14 families and 44 genera were recorded. Cyprinids were the richest, accounting for 59.4% of total fish species. Species numbers and diversity indices showed that fish diversity of the lake was high, with great spatial and temporal variations. Generally, higher diversities occurred in spring and summer than in autumn and winter, and in South Lake Dongting than in the other areas. With regard to species numbers, the smaller the distance between sampling area and Yangtze River mainstream was, the earlier the diversity peak was reached. Dominant species were determined as species with the value of dominance over 5000. There were 17 dominant species in the lake among which 80.0% were limnicolous species. With regard to ecological groups, limnicolous species dominated the lake, accounting for 74.0% of the total species, while river-lake migratory species was the least, being 13.0% of the total. In comparison with that of 1970s, fish diversity of Lake Dongting had been dramatically decreased, especially for migratory species, and it was mainly due to the loss of habitats, decreased fry resource and over-fishing. Analysis also showed that fish diversities in Yangtze River-connected lakes were much higher than those of disconnected lakes, indicating that river-lake isolation results in species decreasing. Thus, increasing river-lake connectivities is important to the conservation of fish diversity in the Yangtze River floodplain.

Key words: Lake Dongting; fish; species composition; species diversity; Yangtze River-connected lake

12. Liu, X. Q. & H. Z. Wang. 2008. Food web of benthic macroinvertebrates in a large Yangtze River-connected lake: the role of flood disturbance. Fundamental and Applied Limnology. 171/4: 297-309.[Liuwang08FundApplLimno.pdf]

Abstract:
This study was conducted in Lake Dongtinghu, a large river-connected lake on the Yangtze River floodplain, China. Our goal was to determine trophic relationships among benthic macroinvertebrates, as well as the effects of flood disturbance on the benthic food web of a river-connected lake. Macroinvertebrates in the lake fed mainly on detritus and plankton (both zooplankton and phytoplankton). Food web structure in Lake Dongtinghu was characterized by molluscs as the dominant group, low connectance, high level of omnivory, based on detritus and primary production, and most ingestion concentrating on a few links. Our analyses showed that flood disturbance is an important factor affecting the benthic food web in Lake Dongtinghu. The numbers of species and functional feeding groups (FFGs), and the density and biomass of macroinvertebrates decreased significantly during flooding. Connectance was higher during the flood season than in other seasons, indicating that floods have a strong effect on connectance in this Yangtze River-connected lake. Flood effects on the benthic web were also evident in the decrease of niche overlaps within and among FFGs. Our results provide useful information regarding biodiversity conservation on the Yangtze floodplain. Reconstructing and maintaining natural and regular flow regimes between Yangtze lakes and the river is essential for restoration of macroinvertebrates on the floodplain.

Keywords: macroinvertebrates, food web, flood disturbance, floodplain, Lake Dongtinghu

13. Pan, B.Z., H.J. Wang, X.M. Liang & H.Z. Wang. 2009. Phytoplankton chlorophyll a in the Yangtze-connected lakes: present state, influencing factors and empirical relationships. Fresenius Environmental Bulletin, 18 (10): 1894-1900.[PanWang09FreEnvironBull]

Abstract:

To determine the environmental factors influencing phytoplankton chlorophyll a (Chl a), field investigations were conducted in three river-connected lakes (Dongting Lake, Poyang Lake and Shijiu Lake) of the Yangtze flood-plain in 2004. Results showed that the average Chl a concentration in these lakes ranged from 2.98 to 3.65 mg m-3. The major factors influencing Chl a in lentic and lotic regions were total phosphorus (TP) and water velocity (U), respectively. Multiple relationships including total nitrogen (log10TN) and water depth (log10Z) were established. Further analyses found that the absolute Chl a and slope of log10Chl a＝f (log10TP) in the river-connected lakes were obviously lower than those in the river-isolated lakes. This suggests the river-lake connectivity can significantly modify relationship between TP and chlorophyll a concentration.

Keywords: chlorophyll a, water velocity, total phosphorus, river-connected lakes.

14. Wang, H. J., H. Z. Wang. 2009. Mitigation of lake eutrophication: loosen nitrogen control and focus on phosphorus abatement. Progress in Natural Science, 19 (11): 19 (11): 1145-1451.[WangWang09ProNatSciE]

Abstract:

Traditionally, nitrogen control is generally considered an important component of reducing lake eutrophication and cyanobacteria blooms. However, this viewpoint is refuted recently by researchers in China and North America. In the present paper, the traditional viewpoint of nitrogen control is pointed out to lack a scientiﬁc basis: the N/P hypothesis is just a subjective assumption; bottle bioassay experiments fail to simulate the natural process of nitrogen ﬁxation. Our multi-year comparative research in more than 40 Yangtze lakes indicates that phosphorus is the key factor determining phytoplankton growth regardless of nitrogen concentrations and that total phytoplankton biomass is determined by total phosphorus and not by total nitrogen concentrations. These results imply that, in the ﬁeld, nitrogen control will not decrease phytoplankton biomass. This ﬁnding is supported by a long-term whole-lake experiment from North America. These outcomes can be generalized in terms that a reduction in nitrogen loading may not decrease the biomass of total phytoplankton as it can stimulate blooms of nitrogen-ﬁxing cyanobacteria. To mitigate eutrophication, it is not nitrogen but phosphorus that should be reduced, unless nitrogen concentrations are too high to induce direct toxic impacts on human beings or other organisms. Finally, details are provided on how to reduce controls on nitrogen and how to mitigate eutrophication.

Key words: Lake eutrophication; Cyanobacteria blooms; Lake restoration

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