River Red Gum (Eucalyptus camaldulensis Dehnh.) organic matter as a carbon source in the lower Darling River,Australia

The Darling River, in New South Wales, Australia, is a large semi-arid system with a highly variable flow regime, characterised by unpredictable events of flooding and drought. In large lowland rivers like the Darling, lateral (river-floodplain) interactions can greatly influence both physical and biological components of the system. The floodplain and riparian zone of the Darling River is dominated by River Red Gum (RRG), Eucalyptus camaldulensis. The large amount of organic matter they produce accumulates on the floodplain and on benches within the channel, and is subject to alternate periods of flooding and drying as a result of highly variable flows. This paper examines the effect of alternate periods of flooding and drying on the processing of E. camaldulensis organic matter. Results of the 6-month in situ field study, together with results from laboratory experiments comparing dissolved organic carbon (DOC) release from various RRG litter types, suggest that RRG leaves provide the most bio-available source of carbon to the system, while bark may be more important as a habitat for invertebrates and other fauna. Laboratory experiments exploring the effect of drying and re-flooding on litter breakdown and release of DOC suggested that the majority of DOC was released from RRG leaves in the first 24 h of inundation. Also, upon drying and re-flooding of the leaves, a smaller but significant release of DOC occurred. However, an alternative wet/dry cycle did not affect weight loss of the leaf litter. Results of the field and lab experiments suggest that RRG leaves represent an important source of carbon to the Darling River, with inputs being influenced by the highly variable flow regime.     

Likely future extirpation of another Asian river dolphin: The critically endangered population of the Irrawaddy dolphin in the Mekong River is small and declining

The population of Irrawaddy dolphins that occupies the Mekong River in southern Lao People's Democratic Republic and Cambodia is classified as Critically Endangered by the IUCN. Based on capture‐recapture of photo‐identified individuals, we estimated that the total population numbered 93 ±  SE 3.90 individuals (95% CI 86–101), as of April 2007. The combined photo‐identification and carcass recovery program undertaken from 2001 to 2007 established that the Irrawaddy dolphin population inhabiting the Mekong River has reached a critical point with regards to its continued survival, where immediate research and management actions are required to greatly reduce adult mortality, and establish the cause of newborn mortality. In addition, community consultation is required to initiate, and evaluate, urgently required conservation measures. An ongoing well‐designed combined program of abundance estimation (i.e., photo‐identification) and carcass recovery is required to monitor total population size and mortality rates, to inform and evaluate management initiatives. The conclusions of this paper are likely generic to river dolphin populations, particularly where photo‐identification is possible.     

伊洛河流域外来草本植物分布格局

外来生物入侵及其防治已经成为生态学关注的重点和热点问题.目前的研究主要集中在外来入侵种上,然而入侵种仅占外来种中很少一部分,因此,研究外来种现有分布格局对研究生物入侵及其防治有重要意义.以伊洛河流域草本植物群落中的外来种为对象,沿河从河源地到入黄河口选取典型样地,在调查流域内草本植物群落中物种组成的基础上选取外来种,并对外来种种类组成及其分布格局进行研究.结果表明:流域内有外来草本植物27种,分属于15科,种类较多的科为菊科、苋科和豆科;引入方式以有意引种为主.流域横向不同生境间,河滩地在水流的养分富集、季节性洪水物理干扰及人为活动扰动作用下,呈现出受外来种分布较多,而受人类活动扰动最强且营养丰富的农田分布较小的分布格局;纵向环境梯度下,上游河源山地属于自然植被区,人为干扰较轻,且受外来种影响较小;中游丘陵区从自然生态系统向农业生态系统的过渡区域,人类活动的扰动有所加强;下游平原农业区,人类活动强烈,区域内以人工生态系统为主,群落物种组成简单但受外来种影响最大,受自然环境和人类活动的双重影响.不同物种在不同生境间差异明显,其中,小蓬草、钻叶紫菀和反枝苋广泛分布于3种生境中.总体上,伊洛河外来草本植物分布格局在自然因素的基础上强烈受人为因素的影响,呈现出从上游到下游逐渐增多的趋势.     

水肥耦合对玉米籽粒全氮含量的影响

采用四因素五水平(1/2实施)二次通用旋转组合设计,选取灌水、施氮肥、施磷肥和秸秆覆盖四因素作为试验因素,在辽西半干旱区褐土农田进行了水肥耦合效应长期定位试验。按照二次通用旋转组合设计统计分析方法建立回归模型,分析了水肥耦合对玉米籽粒全氮含量的影响。结果表明:水肥单因子对籽粒全氮的含量有较明显的影响,影响顺序为施氮秸秆覆盖施磷灌水;当灌水量为700m3.hm-2、施氮量为180kg.hm-2、施磷量为120kg.hm-2和秸秆覆盖量为7500kg.hm-2时,它们每个因素对玉米籽粒全氮含量的影响都集中11.7g·kg-1,此时籽粒蛋白质含量为73g·kg-1,产量为12000kg.hm-2,表明该处理组合下,玉米的经济效益和生态效益达到最佳,推荐生产上以此进行施肥。     

基于传统生态智慧的江南水网空间韧性机制及实践启示

传统江南水网空间是一种典型的社会—生态系统,人文社会系统和自然生态系统之间的良性互动对于其韧性构建有着重要的积极作用。基于柯林斯等人提出的压力—冲击动态（PPD）模型,以平江府为典型代表,研究传统江南水网空间如何通过生态系统服务的桥梁搭建水网物质空间与人类社区发展之间的联系,从而厘清社会—生态系统在此过程中如何培育、优化和提升江南水网空间韧性。在此基础上,创新性地从生态系统服务供需关系的角度提出社会—生态韧性构建的生态智慧,并倡导以恢复力、适应力与变革力韧性机制培育为导向的、江南地区构建现代社区实践的若干启示,旨在引导江南水网空间实现具有韧性的社会—生态系统转型发展。     

The Marine Component of Ichthyofauna in the Mouth Area and Lower Course of the Tumen River

The species composition of typically marine fishes in the lower course and mouth area of the Tumen River (Sea of Japan) is examined based on original faunistic collections and literature data. Thirty-three species belonging to 19 families were recorded. The ratio of species of boreal and subtropical origins was found; temporary and seasonal migrants were identified. Some species (Platichthys stellatus, Myoxocephalus stelleri, Strongylura anastomella, and Mugil cephalus) can be considered indicators of the state of the environment. It is noted that yearly surveys of the marine fish composition in the river zone are needed for monitoring climatic and anthropogenic influences.     

长江口崇明东滩湿地沉积物对磷的吸附特征

研究了崇明东滩湿地低(S1)、中(S2)、高(S3)潮滩沉积物对磷的吸附特征。结果表明,沉积物吸磷过程主要发生在前24 h内,随后近于达到平衡状态。沉积物对PO43--P的平均吸附速率在0~0.5 h内最大,均超过了140 mg.kg-1.h-1;快速吸附过程主要发生在前11 h,前11 h的平均快速吸附速率表现为S1>S3>S2,且沉积物中细颗粒成分越多,沉积物对PO43--P的平均快速吸附速率越大。沉积物对磷的吸附等温线符合Langmuir吸附等温方程,根据Langmuir方程计算,沉积物对磷的吸附容量均>200 mg.kg-1,同时沉积物对PO43--P的吸附容量也表现为S1>S3>S2。原因可能同S1中细颗粒成分、有机碳和常量金属元素(Al、Ca、Fe、Mg)的百分含量较多而S2中细颗粒成分、有机碳和常量金属元素的百分含量较少有关。温度和pH值也影响沉积物对PO43--P的吸附作用。     

珠江三角洲高畦深沟农田生态系统的结构及功能研究

前言自然和社会经济条件不同,农田生态系统的类型也不同。研究农田生态系统的结构与功能,可了解特定系统对当地环境条件的适应性。近年来,国内外很多学者,都从能流物流和经济效益方面对各类型结构农田生态系统结构与功能作了研究。高畦深沟结构农田生态系统,是珠江三角洲平原区人民为在当地地下水位较高的条件下,进行旱作而发展的一种农田生态系统类型。它的特点是,以一定的比例挖深沟,利用挖沟的泥土起高畦,沟中长期保持有水层,畦面进行旱作,沟里进行种植、养殖或其它利用,结构多年不变,是一种相对稳定的农田生态系统。     

L’étude des bifaces de la Hanshui River Valley,Chine

Hanshui River valley is a frequently human active region. Early human left rich stone artefacts in this region. A number of Palaeolithic sites are distributed in the upper reaches of Hanshui River valley. As yet, there are about 40 handaxes sites. The material of handaxes in. Hanshui River valley is mainly the siliceous lime stone, quartzite, sandstone, tuff, etc. Handaxes made on pebble are in a higher proportion than those made on flake. The shape of handaxes is mainly triangular and ovate. The retouch technique is direct hammer retouch, lacking soft hammer retouch. These handaxes are retouched according to function and the blank's shape. Most of the handaxes don’t retouch on the handle. This is the character of handaxes in China. The discovery of handaxe industry in China poses a question: the origin of this industry is from Africa or Asia? In our opinion, the handaxes discovered in China are very similar to the Acheulian handaxes in European and South Korea, but its different from that in Africa. The main reasons contributed to the difference are the environment, the stone material and technical method etc. So I think the handaxe industry in China was born locally. It is very important for us to study Palaeolithic culture in Asia and Europe.     

九龙江北溪流域干旱植被的初步研究

对福建九龙江北溪流域的乌冈栎林及建楠、小叶蚊母树灌丛进行了初步研究。它们与典型的干旱植被有一定的联系,属于干旱植被的范畴。在我国东部湿润亚热带地区发生的这种植被是由于局部环境条件的恶劣所致。