云南横断山区小型兽类物种多样性与地理分布趋势

以云南横断山区的高黎贡山、怒山和云岭等重要山脉的7个山系作为样区,进行小型兽类的垂直分布调查并参考有关资料,采用不同山系样区各垂直带小型兽类物种多样性指数的平均值作为指标,对横断山区小型兽类的地理分布趋势、规律和相关影响因素进行了研究。结果表明：小型兽类物种多样性的地理分布趋势是由南向北,由西向东呈递减的趋势。与此趋势变化密切相关的主要因素是纬度的影响,其次是水湿条件,另外还与小型兽类的密度,物种丰富度、地理环境（坡向）和垂直带的影响等因素有关。此外,对横断山区不同区域小兽物种密度高峰问题作了分析和讨论。     

中国"三江并流"纵谷地蚤类丰富度与区系沿纬度梯度的水平分布格局

为探讨横断山区蚤类物种丰富度与区系沿纬度梯度变化的基本规律以及影响它们分布的主要生态因子,作者就云南西部横断山区21o-28oN的8个纬度梯度带目前所知分布的9科45属153种(亚种)蚤类的水平分布资料进行了综合整理和统计分析。结果表明:(1)这一区域蚤类科、属、种丰富度,特有种丰富度和特有度,以及东洋界和古北界区系成分物种丰富度沿纬度梯度的变化,都呈现了随纬度增加先增高后降低的单峰分布格局,最大峰值出现在25o-27oN之间,研究认为,形成物种密度高峰的主要因素是两大区系分界线和交错区的边缘效应;(2)东洋和古北两大区系成分构成比的水平分布格局截然不同,前者随纬度的增加递减,后者则随纬度的增加呈递增的趋势,两区系成分过渡或交错区的跨度在23o-29oN之间,并在25o-27oN形成交汇和分异的中心;(3)聚类分析结果表明,横断山8个纬度梯度带的蚤类总体上归为3个主要地域区系类型,反映出纬度、地理气候环境等因素对蚤类区系及物种分布的影响,以及蚤类区系和物种组成沿纬度梯度的水平分布格局与地理和气候环境的统一性;(4)蚤类的属、种β多样性沿纬度梯度的水平分布基本呈现双峰格局,峰值反映出蚤类的组成及分布在不同纬度梯度、气候带之间的过渡与转变,说明β多样性的水平分布格局与纬度梯度的气候、环境变化程度的关系密切,以及过渡区的边缘效应对两区系物种丰富度高峰的形成具有重要影响;(5)横断山区蚤类物种丰富度与区系的水平分布与垂直分布的规律和格局基本相同,显示了具有同源性的水平地带性与垂直地带性对蚤类空间分布格局所产生的类似影响,证实了横断山区蚤类物种丰富度与区系的水平分布格局理应出现近似于它们垂直分布的一般规律与格局的推论;(6)横断山25o-27oN的区域形成了两大区系物种交汇和分异的中心,由于边缘效应和复杂的地理景观,这里蚤类科、属、种、特有种都具有较高多样性,据此作者推断,这里可能是我国横断山区多物种保存、分布和分化的核心区。     

云南横断山区蚤类物种丰富度与区系的垂直分布格局

为探讨横断山区蚤类物种丰富度与区系垂直分布格局的基本规律以及影响它们分布的主要生态因子,本文以云南西部横断山区18个山峰为主体,对海拔高度在1000–5000m之间已知分布的9科43属142种(亚种)蚤类的垂直分布资料进行综合整理和统计分析。结果显示:(1)蚤类的属丰富度、物种丰富度、特有种丰富度和特有度以及不同区系成分物种丰富度的垂直分布都呈现随海拔先增高后降低的单峰分布格局,最大峰值出现在中山海拔2500–3800m之间;(2)东洋和古北两区系成分物种构成比的垂直分布格局截然不同,前者随着海拔梯度的升高基本递减,后者则随着海拔的升高递增,垂直分布格局反映了它们沿纬度梯度分布的一般规律;(3)聚类分析将横断山9个不同海拔带的蚤类归为6个生态类型,反映出海拔高度、气候环境和森林植被等重要因素对蚤类分布的影响以及蚤类群落的组成、分布沿海拔梯度变化的一般规律,表达了蚤类分布与环境条件的统一性;(4)β多样性沿海拔梯度呈现为双峰形分布格局,两高峰值都反映出蚤类的组成和分布在不同气候环境和植被带之间的过渡与转变,说明β多样性垂直分布格局与海拔梯度上的气候和生境的变化程度有关。研究认为,中山地段物种丰富度高峰的形成主要是由于两大动、植物区系过渡区的边缘效应和山地水湿条件的影响。影响该区域蚤类垂直分布格局的综合因素有山体海拔高度、动植物区系过渡区的边缘效应、山地雨量分配特征、气候环境条件以及人们的生产活动等。     

云南省吸虱昆虫区系及物种多样性

吸虱是寄生于真兽类哺乳动物体表的专性吸血寄生虫,广布于世界各地。云南省已知吸虱昆虫9科13属44种,分别占中国已知吸虱科、属、种的81.82%,59.09%,45.83%。文章参考大量相关文献,从分类阶元、特有物种、动物地理区划和宿主动物4个方面分析云南省吸虱的物种多样性。云南省吸虱特有种有13种,占云南省已知吸虱种类的29.55%,27种为东洋种,15种为古北和东洋两界兼有种,广布种9种。吸虱在5个地理小区的分布,以横断山中部和横断山南部2个地理小区的吸虱物种多样性较高,其它3个区的物种多样性较低。相对于全国而言,云南省吸虱物种多样性较高,吸虱的宿主动物种类丰富。但蚤、恙螨和革螨等其它体表寄生虫相比较,兽类宿主动物体表吸虱的物种多样性明显低于其它体表寄生虫,1科(属)阶元的吸虱其宿主多为相对一致的1个科(属)动物阶元,反映了吸虱宿主特异性较高的事实,吸虱昆虫与其对应的宿主动物已经形成了比较稳定的"一对一"的寄生关系,这是吸虱昆虫与其宿主动物协同进化的生态学表现。     

准噶尔盆地荒漠景观不同地貌类型鼠、蚤多样性及分布特征

为揭示鼠、蚤空间分布特征与变化规律,本研究以准噶尔盆地鼠疫自然疫源地为靶区,基于鼠类和蚤类的样点采集数据,计算不同地貌的鼠、蚤生态学指标并分析其相关性。基于不同行政区生态学指标计算结果,借助Moran′s I指数、重心模型、标准差椭圆等分析方法探究不同行政区鼠、蚤生态学指标的聚类特征,开展鼠、蚤的空间分布特征及变化规律的相关研究。结果表明：(1)通过对不同地貌鼠、蚤生态指标的研究,可得出鼠、蚤的物种多样性和生态优势度呈负相关,表明在物种多样性较高的群落中,鼠、蚤生态优势度表现不明显。鼠类物种多样性较高的地貌类型与蚤类物种多样性呈正相关,证实鼠类(宿主)物种数量增加,蚤类(寄生)物种的数量也在增加。低海拔地区鼠、蚤群落的相似性总体上大于中海拔地区群落相似性,且相似性系数q值与Cody指数呈相反变化趋势;(2)不同鼠、蚤指标单变量Moran′s I指数表明,鼠类数量、子午沙鼠数量、蚤类均匀度的全局Moran′s I指数大于0,且P值小于0.05,表现出空间集聚现象。单变量局部空间自相关分析结果表明,部分鼠、蚤指标存在多种聚类模式,其中最为典型的聚类模式是高—高聚类模式。不同鼠、蚤指标双变量...     

中国鼠疫宿主鼠类丰富度格局及疫区环境因子分析

鼠疫等媒介疾病地理分布规律的认识对于疫病防控具有重要意义,分析影响疾病地理分布的因素进而预测疾病发生趋势已经成为目前研究的热点。本文在分析鼠间鼠疫及其宿主鼠类地理分布数据以及相关环境数据的基础上,探讨了鼠疫宿主丰富度与环境因子的关系以及影响鼠间鼠疫发生的主要环境因素。我国的鼠疫宿主鼠类在干旱区和季风区过渡带的县级行政单元中物种丰富度最高,物种丰富度与高度差正相关性最高。发生鼠间鼠疫的地区,宿主鼠类丰富度较高,未发生鼠间鼠疫的地区,宿主鼠类丰富度较低。影响鼠间鼠疫发生的主要环境因子包括蚤类物种数、年均气温、年降雨量、年均相对湿度和年日照时数和气候因子,其次是包括高度差、植被类型数、土壤类型数和地貌类型数的景观因子,以及反映海拔和宿主鼠类物种数的地形和宿主鼠类因子。在未来全国气候变干变暖条件下,我国鼠间鼠疫发病区可能随宿主鼠类的迁移而扩展。     

云南地区唇形科(Labiatae)植物多样性的地理分布格局

植物多样性的地理分布格局的研究有利于人们更好地了解研究区域内植物多样性保护的热点区域及其形成机制。云南地区的唇形科植物资源在我国占较大比重, 因此, 研究云南唇形科植物多样性的地理分布格局具有重要意义。以大尺度的唇形科植物物种分布信息为基础, 结合地理信息系统和数理统计分析方法, 探讨云南地区唇形科植物的物种组成、分布宽度、区系地理成分及其多样性的地理格局。研究结果表明, 云南地区拥有唇形科植物67 属430 种。比较重要的属主要包括香茶菜属(Rabdosia)、鼠尾草属(Salvia)和黄芩属(Scutellaria)等。在种水平, 77%的物种分布范围少于20 个县域, 其中181种唇形科植物只分布于滇西北地区。在属水平, 唇形科植物区系地理成分复杂, 具有鲜明的温带性, 热带性区系成分也有一定比例。云南地区从南到北, 唇形科植物的物种丰富度随纬度呈单调递增分布趋势(P < 0.01), 在滇西北地区达到最大值。云南地区唇形科植物多样性从南到北呈递增趋势, 可能与区系地理起源有关, 滇西北地区物种丰富可能与生境异质性有关。     

大理苍山洱海自然保护区山地蚤类区系与生态的研究

１９９２－１９９７年,对大理苍山洱海自然保护区山地蚤类进行了垂直分布的调查研究,共采获蚤类５科２１属３９种（亚种）３２４１头,并对以苍山为主体的山地各主要生态环境蚤类的群落结构,物种丰富度,物种多样性,均匀度和生态优势度进行了测定和比较,分析蚤类及其宿主动物的分布特点和自然环境因素后认为,在苍山所获３９种蚤类中有１６种（占４１．０３％）属东洋界种类,２１种（占５３．８４％）,属古北界种类,２种属广     

云南高黎贡山蚤类的生态区系

本文报道了１９８５年以来对我甸横断山南端高黎贡山东、西坡蚤类生态区系的调查及研究结果。共发现蚤类５科２３属４７种（亚种）。文中对该山脉蚤类在不同森林植物带的群落结构、种的多样性及均匀度,各种蚤的栖境幅度、宿主多样性进行了陈述和比较,并对蚤类的区系特征、特有种的区系划分等问题进行了讨论。     

云岭山脉云南地区两栖爬行类动物多样性

云岭位于云南省西北部、西藏自治区东南部及四川省西南部,是横断山系的重要山脉,同时也是澜沧江和金沙江的分水岭。为了掌握云岭山脉云南地区的生物多样性状况与威胁因素,促进区域的生物多样性保护和监管,本文开展了云岭山脉云南地区的两栖爬行动物多样性调查与评估。2019年和2020年采用以样线法为主、访问为辅的野外调查,共计布设样线239条,共记录两栖类37种,隶属2目10科22属;爬行类44种,隶属2目10科25属。多样性分析结果显示:云岭山脉云南地区的两栖爬行动物种类相较西双版纳等热点地区的更少,且爬行动物较两栖动物更为丰富,造成这种现象可能的原因是海拔限制或调查错过繁殖期。在2,200–2,300 m的海拔段能够记录到更多数量的两栖爬行物种,因此中高海拔具有更为丰富的两栖爬行动物多样性。在云岭山脉云南地区的非保护区区域,栖息地破坏和人为干扰是威胁两栖爬行动物生存和繁殖的主要因素。此外,调查还发现了外来物种,需进一步进行外来种的监测,及时控制种群数量,避免大规模的生态入侵。本研究摸清了云岭山脉云南地区的两栖爬行动物多样性本底,查明了调查区域内生物多样性保护中存在的问题和胁迫因素,为该区域内生物...     

Ectogenesis and the case against the right to the death of the foetus

Ectogenesis, or the use of an artificial womb to allow a foetus to develop, will likely become a reality within a few decades, and could significantly affect the abortion debate. We first examine the implications for Judith Jarvis Thomson’s violinist analogy, which argues for a woman’s right to withdraw life support from the foetus and so terminate her pregnancy, even if the foetus is granted full moral status. We show that on Thomson’s reasoning, there is no right to the death of the foetus, and abortion is not permissible if ectogenesis is available, provided it is safe and inexpensive. This raises the question of whether there are persuasive reasons for the right to the death of the foetus that could be exercised in the context of ectogenesis. Eric Mathison and Jeremy Davis have examined several arguments for this right, doubting that it exists, while Joona Räsänen has recently criticized their reasoning. We respond to Räsänen’s analysis, concluding that his arguments are unsuccessful, and that there is no right to the death of the foetus in these circumstances.     

On the diversity of the Cladocera in the tropics

The mythical concept of an impoverished tropical cladoceran fauna is refuted. On a planetary scale, around half of the cladoceran species presently known occur exclusively in the tropics-subtropics, often with considerable restriction to particular geographical subzones. On a regional (political) scale, the situation is often unclear because of the continued fragmentary nature of studies, and because political units are not a good basis for biogeographical comparisons. At the finest level of resolution (lake-perlake comparisons), there appears to be an upper limit of c. 50 cladoceran species per individual lake. No significant difference between lakes in the temperate zone and in the tropics could be established here. Daphnia is largely absent from the tropics, but is replaced by more Sidids, Moinids, and Bosminids, such that the average cladoceran community in the limnetic zone of a tropical lake is not characterized by less species but rather by lower population densities. This, in turn, is considered a consequence of higher prevalent predation levels in the tropics.     

Tubular networks in the terminal endings of the visual receptor cells in the human,the monkey,the cat and the dog

Summary A tubular network was found in the terminal endings of the visual receptor cells in the human, the monkey (Macaca mulatta), the cat and the dog. These tubules are arranged in close groups in the vicinity of the synaptic lamellae and the invaginated dendrites. According to the form, diameter, density of the tubules and to the consistence of the network formed by them one can distinguish at these places an initial type (type I), a transitory (type II) and a vesicular one (type III). In the the type III branching, bizarre forms are frequent. The diameter of all the tubules reaches 500–600 Å, their density and walls being the same as in the synaptic vesicles.Similar networks also occur in the axons of the visual receptor cells of the monkey.

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Zusammenfassung In den Endigungen der Photorezeptorzellen von Mensch, Affe (Macaca mulatta), Katze und Hund kommen aus Tubuli bestehende Komplexe vor. Organellenartig in geschlossenen Gruppen angeordnet, liegen sie in Nähe der synaptischen Lamellen und der invaginierten Dendriten. An diesen Stellen kann man nach Form, Durchmesser, Dichte und Konsistenz der von den Tubuli gebildeten Komplexe drei Typen unterscheiden: 1. einen initialen (Typus I), 2. einen Übergangstypus (Typus II) und 3. einen vesiculären Typus (Typus III). In letzterem kommen häufig verzweigte, bizarre Formen vor. Der Durchmesser sämtlicher Tubuli erreicht 500–600 Å. Ihre Dichte und ihre Wand gleicht denen der synaptischen Vesikel.Ähnliche Komplexe fanden wir auch in den Axonen der Photorezeptorzellen vom Affen.

     

Assessing the Physiological State of the Fucoids from the Barents Sea Littoral by the End of the Polar Night

Methods of amperometry and potentiometric titration were used to follow dark respiration (DR) and apparent photosynthesis (AP) in the fucoids Ascophyllum nodosum (L.) Le Jol, Fucus vesiculosus L., and F. serratus L. from the Barents Sea littoral by the end of the 40-day-long polar night. The macroalgae were shown to manifest species-specific low rates of photosynthesis and respiration. However, in spite of their low photosynthetic status due to the effects of subzero temperature and prolonged low or zero illumination, the macroalgae have been able to restore DR and AP to the initial level already by the day 9; the ability to restore AP depended on the level of illumination. The study of the changes in the carbonate–bicarbonate system in the light and darkness demonstrated that the macroalgae grown in darkness, in contrast to those grown in twilight, could absorb bicarbonate in darkness; however, they lost this capacity after two-day-long illumination at an irradiance of 7 mol/(m² s). Bicarbonate uptake in darkness and the capacity to restore the systems of photosynthesis and respiration in fucoid cells are discussed in the context of algal energy metabolism under the polar night conditions.     

Arranging the elements of the potassium channel: the T1 domain occludes the cytoplasmic face of the channel

The voltage-gated potassium channel is currently one of the few membrane proteins where functional roles have been mapped onto specific segments of sequence. Although high-resolution structures of the transmembrane portions of three bacterial potassium channels, the tetramerization domain and the cytoplasmic ball are available, their relative spatial arrangement in mammalian channels remains a matter of ongoing debate. Cryo-electron microscopic images of the six transmembrane voltage-gated Kv channel have been reconstructed at up to 18 Å resolution, revealing that the T1 domain tetramerizes and is suspended below the transmembrane segments. However, the resolution of these images is insufficient to reveal the location of the third piece of the puzzle, the inactivating ball domain. We have used the aberrant interactions observed in a series of chimæric channels to establish that an assembled T1 domain restricts access to the cytoplasmic face of the channel, suggesting that the N-terminal ball and chain may be confined in the space between the T1 domain and the transmembrane portion of the channel.     

Feeding the vertebrate retina from the Cambrian to the Tertiary

The retina of the vertebrate eye is metabolically active and requires nutritive support. During the last 540 million years it has evolved into forms as complicated and nutritionally demanding as those found in avian or primate eyes. Diffusion from the choroid is generally able to supply the metabolic needs of thin retinae. However, when the thickness exceeds the limits of diffusion, structures are needed to supplement the vascular supply from the choroid. These supplemental nutritive devices include the choroidal gland, the falciform process and preretinal vascular plexus of fish, the conus papillaris of lizards, the pecten oculi of birds, the intraretinal vessels of mammals and a few novel systems that remain difficult to classify. These vascular systems are among the most variable features of the vertebrate eye. Here, we review classical and recent findings regarding such retinal nutrition systems, propose a three category classification for them based on histologic origins and speculate on the evolutionary forces which drove their development.     

Observations on the permeability of the choriocapillaris of the eye

Summary The choriocapillaris is a fenestrated capillary bed located posterior to the retinal pigment epithelium. It serves as the main source of supply to the photoreceptors, retinal pigment epithelium, and other cells of the outer retina. The permeability of these capillaries to intravenously injected ferritin (MW — approx. 480,000; mol. diam. 11 nm) was examined in the mouse, rabbit, and guinea pig, each of which is characterized by a different type of retinal vascularization. In all three species, the bulk of the ferritin remained in the capillary lumina, where it appeared to be blocked at the level of the diaphragmed fenestrae. Some ferritin was present in endothelial cell vacuoles. The results confirm previous work on the rat choriocapillaris and indicate that the barrier function of the choriocapillary endothelium is present even among species in which the retinal circulation differs significantly.Supported by NIH grant EY03418