SPECIES DIVERSITY DYNAMICS OF FRAGMENTED TROPICAL RAINFORESTS IN THE LOWER-LANCANG/ UPPER-MEKONG RIVER BASIN

　在澜沧江下游/ 湄公河上游的滇南西双版纳地区,通过样方法比较了热带雨林的连片与3 个小片断的物 种多样性变化趋势。与连续森林比较,片断热带雨林的植物物种丰富度和物种多样性指数都比较低,而且有相当低 比例的大高位芽、中高位芽和附生等生活型植物,而藤本、小高位芽和矮高位芽等生活型植物的比例则较高;泛热 带、热带亚洲至热带非洲的区系成分比例较高,而当地成分则减少;群落的上层树木比下层树木更加稳定。同样,动 物的物种多样性指数和均衡度在片断热带雨林中都较低,与其密切相关的是片断热带雨林的环境质量,而不是片 断的大小。此外,也探讨了片断热带雨林物种变化与森林小气候的关系,阐明了由凉湿向干暖转化的“林内效应"是 其物种变化的重要原因之一。

Garra rotundinasus, a new species of cyprinid fish (Pisces : Teleostei) from the upper Irrawaddy River basin, China

Garra rotundinasus, a new cyprinid species from the upper Irrawaddy River basin in Yunnan, China, is herein described. It shares with G. gravelyi the presence of a snout having a poorly developed proboscis represented by a truncate area in front of the nostrils, a character distinguishing both from all other Southeast Asian and Chinese congeners. The two species are distinct in coloration, morphometric and meristic characters. The sympatrically occurring G. tengchongensis is very similar to G. rotundinasus in possessing 36-37 perforated lateral line scales, 5 or 6 scales between the anus and anal-fin origin, and an anterior position of the anus (anus to anal distance 32.1-51.8% of pelvic to anal distance). Garra rotundinasus can be differentiated from G. tengehongensis in having a more slender caudal peduncle, a larger disc and no dark central band on the dorsal fin.

Fixation of the type species of the genus Sinilabeo and description of a new species from the upper Yangtze river basin, China (Pisces : Cyprinidae)

The type species of the cyprinid genus Sinilabeo was misidentified as Varicorhinus tungting, and the species under the generic name belong to Bangana and Linichthys. In order to make Sinilabeo available, its type species is fixed under Article 70.3.2 of the 1999 edition of the International Code of Zoological Nomenclature as S. hummeli, a new species herein described from the upper Yangtze River basin in Chongqing City and Sichuan Province, South China. A re-definition is provided for Sinilabeo. It resembles Qianlabeo in having an upper lip only present in the side of the upper jaw and uncovered by the rostral fold, but missing in the median part of the upper jaw that, instead, bears a thin, flexible, and cornified sheath, covered by the rostral fold, a character that can separate both from all other existing genera of Asian labeonins. However, Sinilabeo is distinguished from Qianlabeo in the presence of a rostral fold disconnected from the lower lip; a broadly interrupted postlabial groove only restricted to the side of the lower jaw; an upper lip, which is only present in the side of the upper separated from it by a groove; 9-10 branched dorsal-fin rays; two pairs of tiny maxillary barbels.

Sinibrama longianalis, a new cyprinid species (Pisces : Teleostei) from the upper Yangtze River basin in Guizhou, China

Sinibrama longianalis, a new cyprinid species from the Wu Jiang (upper Yangtze River basin) in Guizhou, China is distinguished from other congeners in having the following combination of characters: last simple dorsal-fin ray well-ossified; a snout shorter than eye diameter; eye diameter 27.1-31.6% HL; lateral line scales 56-64 (mean 59.5); circumpeduncular scales 18-21; anal fin with 24-28 (mean 25.2) branched rays, originating opposite to or slightly in advance of posterior end of dorsal-fin base, basal length 27.0-31.1% SL; pectoral fin reaching to or slightly beyond pelvic-fin insertion.

Garra tengchongensis, a new cyprinid species from the Upper Irrawaddy River basin in Yunnan, China (Pisces : Teleostei)

Garra tengchongensis, a new cyprinid species from the upper Irrawaddy River basin in Tengchong county, Yunnan province, China, is differentiated from all other Chinese and Southeast Asian Garra species except G. kempi by having a combination of the following characters: two pairs of barbels, no proboscis on snout, 12 circumpeduncular scales and 37-42 lateral line scales. Garra tengchongensis is distinguished from G. kempi in having a cylindrical anterior body, a deeper body, a smaller mental adhesive disc, a scaled breast and belly, and a blunt snout.

Effects of temperature change on water discharge, and sediment and nutrient loading in the lower Pearl River basin based on SWAT modelling

National Natural Science Foundation of China [U0633002, 30670385]

Pseudobagrus fui Miao, a valid bagrid species from the Yangtze River drainage, South China (Teleostei: Bagridae)

Pseudobagrus fui Miao is a valid bagrid species that can be separated from all its congeners in having 27-33 anal-fin rays. Among the species of Pseudobagrus, it forms part of a group of approximately 20 species putatively characterized by having a smooth anterior margin of the pectoral-fin spine and short maxillary barbels not extending to the base of the pectoral-fin spine. Pseudobagrus fui, together with P. nitidus and P. vachelli, can be differentiated from all other fork-tailed species of this group by having no fewer than 20 branched anal-fin rays, the posterior end of the anal-fin base posterior to the vertical through the posterior end of the adipose-fin base, and anal-fin base longer than the adipose-fin base. It further differs from P. nitidus in having a gas bladder without beaded lateral and posterior margins, and from P. vachelli in having short maxillary barbels not extending to the base of the pectoral-fin spine. Pseudobagrus fui is currently known from the main stream of the upper Yangtze River and its tributaries, the Min River, Jialing River, Tuo River, Wu River and Chishui River in Sichuan Province, Guizhou Province, and the Chongqing City. The identity and nomenclature of Pseudobagrus nitidus is also discussed.

Silver carp, Hypophthalmichthys molitrix, in the Poyang Lake belong to the Ganjiang River population rather than the Changjiang River population

The Poyang Lake is the largest lake and the main nursery area in the middle basin of the Changjiang (Yangtze) River. We compared molecular genetic markers of silver carp among populations of the Changjiang River, the Ganjiang River and the Poyang Lake using the ND5/6 region of mtDNA. Analysis of restriction fragment length polymorphisms (RFLPs) of this region revealed distinct variation between the Ganjiang River and the Changjiang River populations. The Poyang Lake is linked with the Ganjiang River and the Changjiang River. Shared RFLP fragments between the Ganjiang River population and the Poyang Lake population are as high as 61.4%. The value is 47.74% between the populations of the Changjiang River and that of the Poyang Lake. Frequencies of bands peculiar to the Ganjiang River population are the same as in the Poyang Lake population. We conclude that the Poyang Lake silver carp population consists mainly of the Ganjiang River population. The water level of the Poyang Lake outlet, which is higher than that of the Changjiang River in the silver carp spawning season, supports this conclusion.

Study on Water Resources Regulation and Reservoir Operating Prediction for Suppression of Salt Water Intrusion in the Pearl River Estuary

Salt water intrusion occurred frequently during dry season in Modaomen waterway of the Pearl River Estuary. With the development of region's economy and urbanization, the salt tides affect the region's water supply more and more seriously in recent years. Regulation and allocation of freshwater resources of the upper rivers of the estuary to suppress the salt tides is becoming important measures for ensuring the water supply security of the region in dry season. The observation data analysis showed that the flow value at the Wuzhou hydrometric station on the upper Xijiang river had a good correlation with the salinity in Modaomen estuary. Thus the flow rate of Wuzhou has been used as a control variable for suppression of salt tides in Modaomen estuary. However, the runoff at Wuzhou mainly comes from the discharge of Longtan reservoir on the upper reaches of Xijiang river and the runoff in the interval open valley between Longtan and Wuzhou sections. As the long distance and many tributaries as well as the large non-controlled watershed between this two sections, the reservoir water scheduling has a need for reasonable considering of interaction between the reservoir regulating discharge and the runoff process of the interval open watershed while the deployment of suppression flow at Wuzhou requires longer lasting time and high precision for the salt tide cycles. For this purpose, this study established a runoff model for Longtan - Wuzhou interval drainage area and by model calculations and observation data analysis, helped to understand the response patterns of the flow rate at Wuzhou to the water discharge of Longtan under the interval water basin runoff participating conditions. On this basis, further discussions were taken on prediction methods of Longtan reservoir discharge scheduling scheme for saline intrusion suppression and provided scientific and typical implementation programs for effective suppression flow process at the Wuzhou section.

Drivers of soil net nitrogen mineralization in the temperate grasslands in Inner Mongolia, China

Soil net nitrogen mineralization (NNM) of four grasslands across the elevation and precipitation gradients was studied in situ in the upper 0-10 cm soil layer using the resin-core technique in Xilin River basin, Inner Mongolia, China during the growing season of 2006. The primary objectives were to examine variations of NNM among grassland types and the main influencing factors. These grasslands included Stipa baicalensis (SB), Aneulolepidum Chinense (AC), Stipa grandis (SG), and Stipa krylovii (SK) grassland. The results showed that the seasonal variation patterns of NNM were similar among the four grasslands, the rates of NNM and nitrification were highest from June to August, and lowest in September and October during the growing season. The rates of NNM and nitrification were affected significantly by the incubation time, and they were positively correlated with soil organic carbon content, total soil nitrogen (TN) content, soil temperature, and soil water content, but the rates of NNM and nitrification were negatively correlated with available N, and weakly correlated with soil pH and C:N ratio. The sequences of the daily mean rates of NNM and nitrification in the four grasslands during the growing season were AC > SG > SB > SK, and TN content maybe the main affecting factors which can be attributed to the land use type.

Influences of the Fish-Mouth Project and the Groins on the Flow and Sediment Ratio of the Yangtze River Waterway

A depth-integrated two-dimensional numerical model of current, salinity and sediment transport was proposed and calibrated by the observation data in the Yangtze River Estuary. It was then applied to investigate the flow and sediment ratio of the navigati