Supported by the Special Fund for Agro-Scientific Research in the Public Interest (No. 20130356), the National Key Technology Research and Development ...
Chinese Journal of Oceanology and Limnology Vol. 32 No. 5, P. 1083-1091, 2014 http://dx.doi.org/10.1007/s00343-014-3354-5
Response of rotifer community to environmental changes in five shallow lakes in the middle reach of Changjiang River, China* DU Xue (都雪)1, 2, FENG Weisong (冯伟松)1, LI Wei (李为)1, YE Shaowen (叶少文)1, LIU Jiashou (刘家寿)1, ZHANG Tanglin (张堂林)1, LI Zhongjie (李钟杰)1, ** 1
State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China
2
University of Chinese Academy of Sciences, Beijing 100049, China
Received Dec. 26, 2013; accepted in principle Feb. 20, 2014; accepted for publication Mar. 4, 2014 © Chinese Society for Oceanology and Limnology, Science Press, and Springer-Verlag Berlin Heidelberg 2014
Abstract We evaluated the response of a rotifer community to environmental changes in five shallow lakes in the middle reach of the Changjiang (Yangtze) River in summer and autumn 2010. These five lakes differed in trophic status and rotifer community structure. Twenty-nine rotifer species were collected, of which Keratella cochlearis, Polyarthra dolichoptera, and Trichocerca elongate were dominant. The mean density, Shannon-Wiener diversity, and equitability among the five lakes differed significantly (P20 indicate strong collinearity and indicate the variable should be eliminated from further analysis (er Braak
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a
WHL TXH
BDT
NSH LZH
WD 4
c
b
Chl a COD
3
NH4-N TN
Macrophyte 2
Conductivity
DO
1
SD
0
pH
TP
WT
Fig.2 Results of PCA performed on environmental variables a. ellipsoid represents samples for each lake ordinated in the PCA plane; b. barplot of eigenvalues of each PCA axis (the eigenvalues of the first two PCA axes are color-code differently); c. the correlation circle of environmental variables (Abbreviations for environmental variables see Table 1) in the first two axes.
and Smilauer, 2002). Forward selection of environmental variables was used to explain the composition of the rotifer community to obtain a small set of environmental variables maximally related to the rotifer species composition. RDA was performed using the “vegan” package in R.
3 RESULT 3.1 Difference of environmental variables in five lakes The results of PCA analysis described 36.66% and 19.63% of the variance in the environmental variables in the first two axes, respectively. The ordination of environmental variables on the first PCA axes is illustrated in Fig.2. TN (0.743), NH4-N (0.837), conductivity (0.724), chlorophyll a (0.666), and COD (0.559) had the highest positive correlation with the first PCA axis, whereas macrophytes (-0.787), Secchi
depth (-0.605), and dissolved oxygen (-0.542) exhibited a negative correlation with this axis. Clearly, the first component axis was related to the eutrophic status of the lakes. Water depth (0.455) was positive correlated with the second PCA axis, while water temperature (-0.909) was negative correlated with this axis. The location of Tangxun Hu (TXH) in the ordination diagraph was separated from the other lakes (Fig.2). This lake was strongly associated with the concentrations of nutrients, such as TN, TP, NH4-N, and chlorophyll a. Niushan Hu (NSH) and Liangzi Hu (LZH), which were close to each other and distant from TXH, had the highest values for macrophyte coverage, dissolved oxygen, and Secchi depth. The remaining two lakes, Wuhu Lake (WHL) and Biandan Tang (BDT), were located in the middle position between TXH Lake and NSH and LZH Lakes.
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Table 2 List of rotifer species found in the five lakes* Species
Family
Abbr.
BDT
NSH
LZH
TXH
WH
Keratella cochlearis
Brachionidae
K. coch
+
+
+
+
+
Polyarthra dolichoptera
Synchaetidae
P. doli
+
+
+
+
+
Trichocerca elongata
Trichocercidae
T. elon
+
+
+
+
+
Trichocerca pusilla
Trichocercidae
T. pusi
+
+
+
+
+
Trichocerca rousseleti
Trichocercidae
T. rous
+
+
+
-
-
Trichocerca similis
Trichocercidae
T. simi
-
+
+
-
+
Brachionus angularis
Brachionidae
B. angu
+
+
+
+
+
Keratella valga
Brachionidae
K. valg
+
+
+
-
-
Trichocerca cylindrica
Trichocercidae
T. cyli
-
+
+
-
-
Filinia longiseta
Testudinellidae
F. long
+
-
+
+
+
Polyarthra vulgaris
Synchaetidae
P. vulg
+
-
+
+
-
Harringia eupoda
Asplanchnidae
H. eupo
-
-
+
+
-
Trichocerca longiseta
Trichocercidae
T. long
-
+
+
+
-
Brachionus diversicornis
Brachionidae
B. dive
-
-
+
+
+
Brachionus forficula
Brachionidae
B. forf
-
-
+
+
+
Asplanchna priodonta
Asplanchnidae
A. prio
-
-
+
+
+
Hexarthra mira
Testudinellidae
H. mira
+
+
+
+
-
Brachionus calyciflorus
Brachionidae
B. caly
-
+
+
+
+
Monostyla unguitata
Lecanidae
M. ungu
-
-
-
-
+
Trichocerca bicristata
Trichocercidae
T. bicr
-
-
-
+
-
Polyarthra minor
Synchaetidae
P. mino
-
-
-
+
-
Monostyla lunaris
Lecanidae
M. luna
-
-
+
+
-
Trichocerca gracilis
Trichocercidae
T. grac
-
-
+
-
-
Keratella quadrata
Brachionidae
K. quad
-
-
-
+
-
Trichocerca capucina
Trichocercidae
T. capu
-
-
+
-
-
Monostyla closterocerca
Lecanidae
M. clos
-
-
+
-
-
Trichocerca rattus
Trichocercidae
T. ratt
-
-
+
-
-
Filinia minuta
Testudinellidae
F. minu
-
-
+
-
-
Lecane luna
Lecanidae
L. luna
-
-
+
-
-
Note: + and - indicate the presence and absence of rotifer species in each lake. BDT: Biandan Tang; NSH: Niushan Hu; LZH: Liangzi Hu; TXH: Tangxun Hu; WHL: Wuhu Lake. Column Abbr. shows the abbreviations for the species names of rotifers.
3.2 Composition, dominance, and biological index of the rotifer community A total of 29 rotifer species were identified in the five lakes with in the highest and lowest number of species in LZH and BDT, respectively (Table 2). The rank-abundance curve for rotifer species in the five lakes is illustrated in Fig.3. Keratella cochlearis was the most dominant species in the five lakes followed by Polyarthra dolichoptera and Trichocerca elongata. The genera Keratella, Polyarthra, and Trichocerca were the only dominant species, and their distribution was similar in all five lakes. Some rare species ranked lowly in the rank-abundance curve, including
Monostyla closterocerca, Trichocerca rattus, and Lecane luna, which were only found in LZH. The rotifer densities differed significantly among the lakes (P
