Are the fish of the upper and lower Mekong interconnected?

The Mekong supports one of the richest inland fisheries in the world, with many of the fish migrating long distance to spawn. Little is known about the fisheries and migration strategies of the Upper Mekong whilst it is supposed that many fish species move between the Lower and Upper Mekong. Most likely, natural fish migration in the river has been altered by dam construction across the mainstream of the Upper Mekong. In this paper, the interconnectivity of fish species between different sections of the Mekong and negative impacts of dams on migratory fish are studied. Of the 162 fish species in the Upper Mekong and the 869 species in the Lower Mekong, 61 species are common. Results show that there is no significant difference at order level between the UM and LM. Similarity coefficients are used to evaluate interconnectivity at species, genus and family levels among four different sections of the Upper Mekong with each other and with the Lower Mekong as a whole. The highest similarity is found between the middle and lower reach of the Upper Mekong at species and genus levels and the middle and upper reach at family level. Of the eight cascade dams, Mengsong Dam in planning is considered as the biggest threat to migratory fish from the Lower Mekong and should be particularly concerned.

Efflux Estimate of Greenhouse Effect Gases in Three Different Forest Formations and the Influence of Soil

In carbon global cycle, the relationship between the terrestrial ecosystem and the atmosphere where there are, among others, gases that contribute to the greenhouse effect, has become object of relevant scientific interest. The content of organic matter in soil, expressed by its supplies as well as the organic matter degree of stability, are factors that can prevent the soil from acting as a drain and at the same time contribute for it to become a source of those gases. The variations in the way land is used in Brazil are factors responsible for the increase in emission of greenhouse effect gases. Based on these facts, this study was aimed to evaluate the CO2 and CH4 efflux using a gas retention chamber, and to associate these emissions to the organic carbon content in the soil. Two different areas were selected for the study, one in Tijuca Forest National Park, in a forest area, and the other at the Rio de Janeiro Federal Rural University campus. In the latter, the area was stratified in three sub areas according to the vegetation, use and water saturation degree. Samplings were performed during 8 months between 2013 and 2014.

崧泽地名考略

崧泽,旧名崧宅,是上海地区比较古老的地名,最迟至宋代作为里名出现。历史上相传东晋袁崧居此而得名,本文赞同明文裕公陆深关于崧泽非袁崧宅的观点,并对崧泽及其相近的地名进行了进一步梳理和考述。

Stuck in a rut： Potential costs of sand roads to gopher tortoises Gopherus polyphemus

Roads affect wildlife significantly through direct mortality but also through behavioral change. We explored the ef- fects of unsurfaced sand roads with a low traffic volume on the travelling behavior of gopher tortoises Gopherus polyphemus in scrub habitat in central Florida, as evidenced by the tracks left by tortoises on sand roads. Tortoises （and most other taxa leaving tracks on the roads） did not appear to make use of roads for travel but attempted to cross them, the success of which was influ- enced by the size of the individual. Smaller animals （presumably younger tortoises） were more challenged than larger animals by both sand road widths and depths of vehicle ruts in sand roads. Sand roads may present both physical and physiological challenges to gopher tortoises, particularly to small ones. This research provides further evidence that the negative influence of roads in fragmenting the environment is not limited to vehicle mortality [Current Zoology 61 （4）： 578-585, 2015].

The relationship between extension of lower crust and displacement of the shelf break

With deep sea petroleum explorations become more and more popular,some geological phenomena have emerged:extension of lower crust and upper crust is inhomogeneous;shelf break has been moved rapidly after crustal stretching.These geological phenomena are important to the continental margin evolution.To investigate the thinning of the whole crust and the contribution of the upper crust versus the lower crust to the crustal stretching since the Cenozoic,we calculated the stretching factors of the upper and the lower crust based on the 13 seismic lines in the Baiyun Sag from CNOOC.The results indicated that the whole crustal thickness decreases seaward while the whole crustal stretching factor increases from shelf to slope.Our calculations showed that the lower crustal stretching factor is higher than that of the upper crust in the Baiyun Sag.In the Cenozoic,deformation of the Baiyun Sag is controlled mainly by ductile shearing rather than brittle shearing.Based on the numerical modeling,we can conclude the initial crust in the Baiyun Sag is thermally attenuated.The stretching factor(β)of the lower crust increases from the north to the south of the continental margin,indicating two stretching centers:the Baiyun Sag and the Liwan Sag.The geometry of the shelf break and theβisoline trap have the similar trend in 23.8 and 13.8 Ma,both located in the intense deforming zone of the lower crust,and therefore we conclude the stretching and flowing of the lower crust cause the displacement of the shelf break before and after 23.8 Ma.