The irony and the exclusivity of Atlantic bluefin tuna management

The eastern stock of Atlantic bluefin tuna (thunnus thynnus) was recently nominated for protection under the Convention on International Trade in Endangered Species of Flora and Fauna (CITES). That nomination failed, which leaves management of the heavily overfished stock in the hands of the International Commission for the Conservation of Atlantic Tunas (ICCAT). This paper reviews the history of ICCAT management of Atlantic bluefin tuna to show that (1) early elimination of competitive forces prevented agreement on management in keeping with scientific advice, resulting in the steep decline of the stock, (2) even just the threat of a CITES listing can provide temporary impetus for marked improvement in ICCAT management, and (3) long-term sustainable management by ICCAT will require continued economic and political pressure.     

Changes in soil nutrients, vegetation structure and herbaceous biomass in response to grazing in a semi-arid savanna of Ethiopia

The effect of grazing was studied on vegetation structure, herbaceous biomass, basal and bare ground covers, together with soil nutrient concentrations in two locations in an Ethiopian semi-arid savanna. The lightly grazed sites had significantly higher herbaceous diversity, total abundance, basal cover and aboveground biomass, and a lower percentage of bare ground compared with the heavy grazed sites. Grazing pressure had no effect on the density and number of woody species as well as on the proportion of encroaching woody species. The light grazing sites had higher organic carbon, phosphorus and exchangeable bases, and therefore a higher pH and higher electrical conductance, indicating an improved soil nutrient status compared with heavy grazing sites, mainly attributed to the higher basal cover and standing biomass at light grazed sites, and the export of nutrients through grazing and dung collection from the heavily grazed sites. There were significantly higher soil nutrients, species diversity, aboveground biomass and basal cover in the light grazing sites compared with heavy grazing sites. We concluded that changes in herbaceous vegetation, standing biomass and soil compositions are caused by interactions between grazing, soil and vegetation, and these interactions determine the transitions of semi-arid savannas.     

More than biofuel? Jatropha curcas root system symmetry and potential for soil erosion control

One of the reasons why Jatropha curcas has recently been hailed as one of the world’s most sustainable biofuel crops, is its suitability to grow on arid land where it offers the additional benefit of erosion control. As arid lands are often very vulnerable to land use changes, it is nevertheless important to fully understand (belowground) plant functional and structural development before they are planted at large scale. Here we introduce possible measurement methods for the root system structure of J. curcas seedlings and adult plants, formulate a set of hypotheses on root system structure, and demonstrate these in the light of root structure stability. Initially developing one taproot and four perpendicularly oriented laterals, the root structure of Jatropha appears to be quite promising to control soil erosion by water and wind on arid land. The lateral roots could decrease soil erodibility through additional soil cohesion, while the taproot and sinkers may enable exploitation of subsurface soil moisture and thus enhance vegetative cover, even in very dry environments.     

Spatial and temporal variability of soil properties under Caragana microphylla shrubs in the northwestern Shanxi Loess Plateau, China

Shrub-induced spatial and temporal heterogeneity of soil properties is common in arid and semiarid ecosystems, and it facilitates the development of plant species diversity. We selected 5-, 10-, 20-, 30-, and 40-year-old Caragana microphylla shrubs in the Shanxi Loess Plateau to evaluate the spatial and temporal heterogeneity of soil properties under and outside the shrub canopy. In addition, the presence of adventitious plant species was investigated to assess the development of herbaceous species diversity. Soil samples were collected from two depths (0-5 cm and 5-10 cm). The establishment and development of shrubs promoted temporal variation, improved soil texture, enhanced soil organic matter (SOM), total nitrogen (TN), and cation exchange capacity (CEC), and decreased pH, bulk density (BD), and soil water content (SWC). The results further confirmed that SOM, TN, and CEC were significantly higher at the center than at the outside of the shrub canopies (P < 0.05) and were higher at the 0-5 cm depth than at the 5-10 cm depth. Moreover, the differences in SOM, TN, and CEC from the center to the outside of shrub canopies were greater under 30- and 40-year-old shrubs than under 10- and 5-year-old shrubs. Furthermore, the spatiotemporal heterogeneity of the soil properties facilitated the development of herbaceous species diversity.     

未来气候变化对7种荒漠植物分布的潜在影响

利用CART(classification and regression tree,分类和回归树)模型,采用A2和B2气候情景,分析了气候变化对百花蒿、红砂、灌木亚菊、灌木小甘菊、戈壁藜、瓣鳞花和白梭梭分布范围及空间格局的影响.结果显示:气候变化下,就目前适宜分布范围,这些植物都呈现缩小趋势;就新适宜及总适宜分布范围,...     

基于POM模型的后石电厂附近海域热环境容量计算

阐述了热环境容量的含义,并在POM模型的基础上建立了热传输模型,考虑了热能在垂直方向上的扩散。采用模型试算法计算了后石电厂附近海域的热环境容量和剩余热环境容量,结果表明,后石电厂附近海域的热环境容量为1 496(℃·m3)/s,一、二期工程的剩余热环境容量为350.2(℃·m3)/s,在允许的排放范围;三期扩建后的剩余热环境容量为–413.6(℃·m3)/s,超过该海域的热环境容量。研究结果可为电厂扩建及其附近海域生态环境保护提供参考依据。     

Screening Indian Mustard Genotypes for Phytoremediating Arsenic‐Contaminated Soils

Ten Indian mustard (Brassica juncea L.) genotypes were screened for their phytoremediation potential for arsenic (As) contaminated water under laboratory‐controlled conditions. The genotypes were grown in a hydroponic chamber for 20 days in 250‐mL beakers containing As‐contaminated water. During plant development, changes in plant growth, biomass, and total As were evaluated. Of the 10 genotypes (Pusa Agrani, BTO, Pusa Kranti, Pusa Bahar, Pusa Bold, Pusa Basant, Pusa Jai Kisan, Arka Vardhan, Varuna, and Vaibhav) Pusa Jai Kisan was the most effective in phytoremediating As‐contaminated water under hydroponic conditions. This will provide new information for Indian mustard genotypes for phytoremediating As‐contaminated soils.     

Grime的植物对策思想和生态学研究理念

以Grime教授编写的《植物对策、植被过程和生态系统特性》（PlantStrategies,Ve getat ion ProcessesandEcosystemPropert ies;第二版）一书的主要内容为主,介绍了Grime植物对策思想的核心及其价值,阐述了Grime植物生态学研究理念。     

Holocene environmental history and climate of Råtåsjøen,a low-alpine lake in south-central Norway

The Holocene environmental history and climate are reconstructed for Råtåsjøen, a low-alpine lake in south-central Norway. The reconstructions are based on chironomids, diatoms, pollen, plant macrofossils, and sediment characteristics. From plant macrofossil evidence, birch trees (Betula pubescens) immigrated ca. 10,000 cal BP. The chironomid-inferred mean July air temperature was high, but may be unreliable during the early stages of the lakes history due to the high abundance of Chironomus anthracinus type, a taxon that may include several species. From ca. 9000 cal BP the inferred mean July temperature was lower (ca. 9 °C). Temperatures increased towards 8000 cal BP and pine (Pinus sylvestris) reached its upper limit near the lake. July temperature may have become a significant factor controlling long-term pH in the lake, starting shortly after 8000 cal BP. High pH values were associated with periods of warm summers and lower pH values occurred during periods of colder summers. Alkalinity processes within the lake and/or the catchment are possible factors controlling this relationship. A temperature decline at ca. 5400 cal BP separated two 10.6 °C temperature maxima around 6400 and 4500 cal BP. The 1.5 °C decline in July air temperatures from ca. 4400 cal BP was paralleled by a decrease of pH from 7.2 to 6.8. Following the temperature drop, first pine and then birch trees declined and disappeared from the catchment and organic accumulation in the lake increased. The increased organic accumulation rate had a positive effect on diatom production. At ca. 2700 cal BP the temperature reached a minimum (ca. 9.2 °C) and correspondingly a second pH minimum was reached. Temperature decreased again slightly at ca. 400 cal BP during the Little Ice Age, before increasing by about 0.5 °C towards the present. Percentage organic carbon as estimated by loss-on-ignition appears to be better correlated with chironomid-inferred July temperatures than organic accumulation rates, at least for the last 9000 years. Accumulation rates of organic sediments are more coupled with catchment-related processes, such as erosion and major changes in vegetation, than is percentage organic carbon.     

火焰原子吸收法测定植物样品中微量铜

植物样品在500℃灰化,用硝酸、氢氟酸和高氯酸分解,然后在2％的盐酸介质中,用火焰原子吸收分光光度法测定植物样品中的微量铜。该方法简单、快速、准确。方法的检出限为0.55×10~(-6),回收率97％—102％。对含量为5.14×10~(-6),9.43×10~(-6)和17.63×10~(-6)的三个植物样品进行分析,其相对标准偏差分别是4.62％、4.22％和2.00％。