Temperature-Dependent Growth and Life Cycle of Nemoura sichuanensis (Plecoptera: Nemouridae) in a Chinese Mountain Stream

Plecoptera constitute a numerically and ecologically significant component in mountain streams all over the world, but little is known of their life cycles in Asia. The life cycle of Nemoura sichuanensis and its relationship to water temperature was investigated during a 4-year study in a headwater stream (known as the Jiuchong torrent) of the Xiangxi River in Central China. Size structure histograms suggest that the life cycle was univoltine, and the relationships between the growth of Nemoura sichuanensis, physiological time, and effective accumulated water temperature were described using logistic regressions. The growth pattern was generally similar within year classes but growth rates did vary between year-classes. Our field data suggest a critical thermal threshold for emergence in Nemoura sichuanensis, that was close to 9 degrees C. The total number of physiological days required for completing larval development was 250 days. The effective accumulated water temperature was 2500 degree-days in the field. Development during the life cycle increased somewhat linearly with the physiological time and the effective accumulated water temperature, but some non-linear relationships were best developed by logistic equations.

Floral survey of the diatom genera Cymbella and Gomphonema (Cymbellales, Bacillariophyta) from the Jolmolungma mountain region of China

We report on taxa from the diatom genera Gomphonema and Cymbella (Cymbellales, Bacillariophyta) found in the Jolmolungma Mountain region of China. This region is unique for its diversity of habitats, which include rivers, springs, moist soil, snowfields, swamps and lakes. We re-examine diatom taxa found in samples first documented in 1973 (Jao et A, 1973) and incorporate recent taxonomic revisions from the literature. In the genera Gomphonema and Cymbella we report 113 species and varieties. Of these 113 taxa, 59 are new record for China; 1 new combination, Encyonema jolmolungmensis, is made. Morphometric data and habitat features are reported for each taxon. Their distribution is strongly correlated to their microhabitats.

A taxonomic study of Oconnorella (Enchytraeidae, Oligochaeta) from Changbaishan Mountain, China

We describe three enchytraeid species, including two new species, from Mt. Changbaishan, Jilin Province, northeastern China. Oconnorella cheni sp. nov. is characterized by a simple spermatheca; absence of the oesophageal appendages and seminal vesicle; and nephridia from 6/7, with a distinct funnel and the efferent duct arising from the anterior part of the postseptale. Oconnorella globula sp. nov. is distinguished by a spermatheca with two diverticula; lack of oesophageal appendages and seminal vesicle; and nephridia from 6/7, with distinct funnel and the efferent duct arising from the mid-ventral or posteroventral part of the postseptale. We redescribe Oconnorella changbaishanensis (Xie et al., 2000) from type and live specimens, and amend some characters that cannot be investigated clearly from mounted specimens. We revise the generic diagnosis of Oconnorella.

A survey of the gomphonemaceae and cymbellaceae (Bacillariophyta) from the Jolmolungma Mountain (Everest) region of China

Gomphonemaceae and Cymbellaceae from Jolmolungma Mountain region of China, comprised 79 taxa belonging to five genera. The dominant species were Gomphonema angustatum var. productum, G. gracile var. gracile, G. parvulum var. parvulum, G. hedini, Cymbella aequalis var. pisciculus, C. delicatula, C. cistula, C. cistula var. hebetata, C. cesatii, C. cymbiformis, C microcephala, C. minuta var. minuta., C. minuta var. silesiaca, C. pusilla, C. affinis. Some arctic and alpine forms also occurred, and the following taxa were unique to this region: Cymbella delicatula, C. naviculiformis, C. gracilis, C. minuta var. minuta, C. affinis, C. cistula, C. cymbiformis, C. cistula var. hebetata, C. arctica, Didymosphenia geminata, Gomphonema hedinii, G. olivaceum. Numbers of taxa in each samples varied greatly, It appears that species diversity of diatoms is related not only to macro-environments (e.g., geographic zonation) but also to microenvironments (e.g., microhabitats and microclimates). Cymbella spp. are not only comparatively widespread in the region but also outnumber Gomphonema spp. A large number of species found in the Jolmolungma Mountain region are also found in Tibet and the headwaters of Yangtze River.