新疆雪豹调查中的痕迹分析

雪豹(Unciauncia)属于中亚高山高度濒危动物,夜行性,极其罕见。新疆雪豹研究小组2004年9~11月,在新疆的北塔山、阿尔泰山东部、天山东部和托木尔峰地区大约9个地点,对雪豹的痕迹进行了全面调查。共计完成67个样线,总长度47776m,其中发现遗留痕迹的样线有27条,痕迹数118个,平均为2.47个/km。记录到的痕迹有粪团、嗅痕(气味标记)、足迹、刨痕、卧迹、爪印、毛发、尿迹、血迹、剩余食物(动物尸体)和吼声等。同步还完成了200余份问卷调查表,充分了解雪豹与当地居民的冲突。最后,通过痕迹学的分析,初步掌握雪豹的栖息地选择、领域范围、分布规律和相对密度。这对于种群数量估计和物种的保护管理具有重要意义。     

S100在猫小脑中的分布及其表达的年龄相关性变化

用免疫组织化学ABC法标记S100免疫阳性(S100-IR)细胞,观察S100蛋白在青年猫和老年猫小脑中的分布,探讨其表达的年龄相关变化及意义。光镜下计数颗粒层和髓质中S100-IR细胞密度及浦肯野细胞(PC)层阳性细胞线密度。结果显示,颗粒层和髓质中S100-IR细胞密度较小、分布均匀,PC层阳性细胞相对密集,分子层未见阳性反应;阳性细胞胞浆深染。与青年猫相比,老年猫小脑颗粒层、髓质和PC层中S100-IR细胞密度显著增加(P<0.01),胞体较大,阳性较强。表明S100-IR细胞在小脑中的分布具区域性差异,呈明显的年龄相关性增生,推测其增生对衰老神经元的丢失起保护作用。     

真空渗入转化法中农杆菌在植株体内的分布和活力变化

以真空渗入处理后的白菜植株为材料,采用组织化学染色法和细菌平板培养的方法,研究了农杆菌在植株体内的分布特点及其活力变化。结果表明：不同器官中农杆菌的分布量不同,以花器官中分布最多,叶中次之,茎中最少;农杆菌存在于细胞间隙中,维管束及其周围分布较集中,在胚珠中大量分布。处理后植株体内,各器官中农杆菌的生活力及其数量都随时间延长而减少,但是花器官中的农杆菌存活量较大,处理15d后的花蕾中仍然有一定量(约10.3个CFU/g组织)具有活力的农杆菌存在。讨论了这些研究结果在揭示真空渗入转化法的转化过程和提高转化频率中的意义。     

Distribution of <Emphasis Type="Italic">Calanus</Emphasis> populations in a glaciated fjord in the Arctic (Hornsund,Spitsbergen)—the interplay between biological and physical factors

The distribution and diversity of copepods of the genus Calanus were investigated in Hornsund Fjord (on the southwest coast of Spitsbergen) in summer 2001. The Bhattacharya method was used to sort individuals by species based on their prosome length. The established prosome length boundary values for the Calanus copepodid stages coincided with those defined for the Calanus species from Kongsfjorden (on the northwest coast of Spitsbergen). The predominant species in the main and inner fjord basins was Calanus glacialis, whereas Calanus finmarchicus was the prevailing species outside Hornsund. Younger copepodid stages (CI–CIII) of both species concentrated in the surface water layers (0–50∼70 m), while older copepodids (CIV–CVI females) that were ready for wintering stayed in deep layers (50∼70 m to bottom). Calanus hyperboreus was present in low numbers, predominantly as CIV, and in Hornsund deep water layers. The distribution and diversity of Calanus species complied with the notion that the marine fauna in Hornsund is of a more Arctic character than in Kongsfjorden, a fjord 260 km to the north on the west coast of Spitsbergen.     

Global diversity of lizards in freshwater (Reptilia: Lacertilia)

No lizards are strictly aquatic, but at least 73 species in 11 different families can be considered to regularly utilize freshwater habitats. There are no aquatic lizards in the Nearctic or Palearctic regions, whereas the Neotropics, Southeast Asia, and the Indo-Australian Archipelago support the greatest diversity of freshwater forms, particularly in the families Gymnophthalmidae, Scincidae and Varanidae. A number of larger aquatic lizards are harvested for food and for the reptile skin trade and several are CITES listed. Guest editors: E. V. Balian, C. Lévêque, H. Segers & K. Martens Freshwater Animal Diversity Assessment     

Global diversity of dipteran families (Insecta Diptera) in freshwater (excluding Simulidae, Culicidae, Chironomidae, Tipulidae and Tabanidae)

Today’s knowledge of worldwide species diversity of 19 families of aquatic Diptera in Continental Waters is presented. Nevertheless, we have to face for certain in most groups a restricted knowledge about distribution, ecology and systematic, particularly in the tropical environments. At the same time we realize a dramatically decline or even lack of specialists being able, having the time or the opportunity to extend or even secure the present information. The respective families with approximate numbers of aquatic species are: Blephariceridae (308), Deuterophlebiidae (14), Nyphomyiidae (7), Psychodidae (∼2.000), Scatopsidae (∼5), Tanyderidae (41), Ptychopteridae (69), Dixidae (173), Corethrellidae (97), Chaoboridae (∼50), Thaumaleidae (∼170), Ceratopogonidae (∼6.000), Stratiomyidae (∼43), Empididae (∼660), Lonchopteridae (2), Syrphidae (∼1.080), Sciomyzidae (∼190), Ephydridae (∼1.500), Muscidae (∼870). Numbers of aquatic species will surely increase with increased ecological and taxonomical efforts. Guest editors: E. V. Balian, C. Lévêque, H. Segers & K. Martens Freshwater Animal Diversity Assessment     

浙江省中华水韭分布现状与濒危原因

中华水韭(Isoetes sinensis Palmer)为水韭科水韭属多年生沼泽植物,现分布范围急剧缩小,种群数量稀少,处于濒危状态。通过查阅文献、标本,咨询专家学者,深入实地考察,访问产地农民,基本弄清了中华水韭在浙江省的分布情况及现有种群状况,结果如下：据记载,中华水韭在浙江省分布在杭州、诸暨、松阳、庆元、丽水、建德和天台等市、县。但仅查阅到杭州(1号)、诸暨(2号)和松阳(1号)3地共4号标本。实地考察仅发现在松阳有2个野生亚种群;杭州、诸暨和丽水野生种群可能已灭绝;杭州植物园、武汉植物园目前迁地保存有杭州种群;天台是否有中华水韭分布尚存疑问。松阳2个野生亚种群总面积约1000m2,分布在4块废弃的水田中,海拔约1110m,居群集中分布的面积不到300m2。中华水韭生存生境的人为直接破坏及水体污染,是其种群消失的主要原因。中华水韭残存种群在与禾草和灯芯草(Yuncus effuses)等主要优势种的竞争中处于劣势,在群落演替过程中,可能会被这些物种所取代,进而整个群落有可能被其他植被所取代,故现有的2个亚种群正处于濒危状态,亟待加强保护研究。     

Distribution of dimethylsulfide and dimethylsulfoniopropionate and its relation with phytoneuston in the surface microlayer of the western North Atlantic during summer

One of the key steps towards predicting dimethylsulfide (DMS) emission to the atmosphere is to understand the distribution and cycling of biogenic sulfur in the microlayer. In this study, we examined the distribution of DMS and dissolved and particulate fractions of dimethylsulfoniopropionate (DMSPd and DMSPp) in the surface microlayer and bulk water of the western North Atlantic during July 2003. DMS concentrations in the bulk water varied from 0.71 to 7.65 nM. In contrast, DMS concentrations in the surface microlayer were fairly low (0.17–1.33 nM). Average concentrations of DMSPd and DMSPp in the bulk water were 2.09 (1.87–6.25) and 44.1 (8.06–119.8) nM, respectively, and those in the surface microlayer were 15.4 (4.06–54.3) and 29.9 (7.32–97.0) nM. In general, DMS was depleted in the microlayer (mean concentration: 0.60 nM) relative to the bulk water (mean concentration: 2.38 nM) with enrichment factors (the ratio of the microlayer concentration to bulk water concentration) ranging from 0.13 to 0.54. There was no consistent enrichment of DMSPp and chlorophyll a in the microlayer. On the contrary, DMSPd appeared to be highly enriched in the microlayer with an average EF of 4.89. The concentration of phaeopigments was also generally greater in the microlayer than in the bulk water, presumably due to enhanced photo-oxidation of chlorophyll a under high surface light intensities in the microlayer. In the study area, the concentration of DMSPp was significantly correlated with the abundance of dinoflagellates in the microlayer. Moreover, a significant correlation between the distributions of DMS, DMSPp, chlorophyll a and phaeopigment concentrations in the microlayer and the bulk water demonstrated that the biogenic materials in the microlayer come primarily from the bulk water below.     

Host species and habitat affect nodulation by specific Frankia genotypes in two species of Alnus in interior Alaska

Alders (Alnus spp.) are important components of northern ecosystems due to their ability to fix nitrogen (N) in symbiosis with Frankia bacteria. Availability of optimal Frankia may be a contributing factor in limiting the performance and ecological effects of Alnus, but the factors underlying distribution of Alnus-infective Frankia are not well understood. This study examined the genetic structure (nifD–K spacer RFLP haplotypes) of Frankia assemblages symbiotic with two species of Alnus (A. tenuifolia and A. viridis) in four successional habitats in interior Alaska. We used one habitat in which both hosts occurred to observe differences between host species independent of habitat, and we used replicate sites for each habitat and host to assess the consistency of symbiont structure related to both factors. We also measured leaf N content and specific N-fixation rate (SNF) of nodules (¹⁵N uptake) to determine whether either covaried with Frankia structure, and whether Frankia genotypes differed in SNF in situ. Frankia structure differed between sympatric hosts and among habitats, particularly for A. tenuifolia, and was largely consistent among replicate sites representing both factors. Leaf N differed between host species and among habitats for both hosts. SNF did not differ among habitats or host species, and little evidence for differences in SNF among Frankia genotypes was found, due largely to high variation in SNF. Consistency of Frankia structure among replicate sites suggests a consistent relationship between both host species and habitat among these sites. Correlations with specific environmental variables and possible underlying mechanisms are discussed. Nomenclature: Flora of North America ().     

Summer and spring trophic niche of larval and juvenile <Emphasis Type="Italic">Pleuragramma antarcticum</Emphasis> in the Western Ross Sea,Antarctica

The aim of this paper is to contribute to the knowledge on the feeding habits of larvae and juvenile Pleuragramma antarcticum in the western Ross Sea. In summer, the diet of P. antarcticum postlarvae (8–17 mm) was dominated by calanoid eggs (35.5%), Limacina (32.1%) and tintinnids (17.6%), while the principal food of juveniles consisted mainly of copepods (98.2%), with Oncaea curvata being the most abundant (85.1%) and the most frequently consumed prey. The food composition of P. antarcticum postlarvae (24–29 mm), collected in spring, suggest that they fed actively under the sea ice. Stephos longipes, Harpacticus furcifer and Paralabidocera antarctica sea ice copepods represent, in all their different developmental stages, the most abundant biomass food in Terra Nova Bay in this period. Our results therefore suggest that the diet of younger Pleuragramma specimens shifted in prey composition from the first summer to the following spring. This study draws attention to the key role of the copepod, P. antarctica, in the food web of Terra Nova Bay. This article belongs to a special topic: Five articles coordinated by L. Guglielmo and V. Saggiomo appear in this issue of Polar Biology and are a result of a workshop on Sea-ice communities in Terra Nova Bay (Ross Sea) held in August 2007 in Capo Calavà, Messina, Italy.