黄河三角洲潮间带不同类型湿地景观格局变化与趋势预测

以1979—2013年7期卫星遥感影像(Landsat TM)为数据源,结合野外实地调查,通过建立黄河三角洲潮间带湿地数据库,探讨不同类型湿地的景观格局以及自然与人为因素对景观格局变化的影响,并基于Markov模型对未来20年三角洲潮间带不同类型湿地的景观格局进行了趋势预测。结果表明,三角洲的潮间带湿地面积在1979—2013年间整体呈先降低后增加变化。其中,1979—2010年的湿地面积持续减少,由1050.28 km~2减少为575.39 km~2,减少率为45.22%;2010—2013年的湿地面积略有增加,由575.39 km~2增加为596.17 km~2,增长率为0.36%。1979—2013年,潮间带主要湿地景观类型随距海远近均呈明显带状分布,但芦苇湿地面积呈明显降低趋势(减少273.53 km~2,减少率为79.68%),盐田养殖池面积呈显著增加趋势(增长12.04km~2,增长率为1584.21%),而光滩、碱蓬湿地、碱蓬-柽柳湿地和柽柳-芦苇湿地等其它类型湿地面积整体均呈波动减少趋势。未来20年,潮间带湿地面积整体将呈降低趋势,其值将由2010年的575.39 km~2减少为2030年的546.98 km~2,减少率为6.60%。芦苇湿地面积将继续减少(减少30.16 km~2,减少率为24.12%),盐田养殖池面积将持续增长(增加3.71 km~2,增长率为38.61%),而光滩、碱蓬湿地、碱蓬-柽柳湿地和柽柳-芦苇湿地等其它类型湿地面积均将呈小幅波动变化。研究发现,尽管自然与人为驱动力的双重作用决定了1979—2013年间潮间带的湿地景观格局及其动态变化,但黄河年输沙量(x_1)、区域GDP(x_2)和水产品产量(x_3)对潮间带湿地面积变化(y)的影响更为重要(y=733.192+35.317 x_1-0.005 x_2-4.085 x_3,P=0.00010.05),其对过去30多年间潮间带湿地面积变化的解释贡献高达76.7%。随着黄河三角洲高效生态经济区国家战略的实施,为实现潮间带区域的可持续发展,潮间带湿地的保护与生态保育应给予特别重视。     

黄河河口盐沼植被分布、多样性与土壤化学因子的相关关系

以黄河河口盐沼实地调查的67个样地19个植物种的重要值,运用双向指示种分析将黄河河口盐沼植被分为柽柳-翅碱蓬+补血草+碱蓬群落、翅碱蓬群落、柽柳-芦苇+翅碱蓬群落、芦苇群落、穗状狐尾藻+芦苇群落和旱柳-芦苇+荻群落.利用典范对应分析(CCA)分析了土壤盐分、pH、Na+、K+、Ca2+、Mg2+、Cl-、全氮、全磷、全碳、有机质等11个土壤化学因子与黄河河口盐沼植被分布的相关关系.CCA排序结果表明,土壤盐分和土壤pH是影响黄河河口盐沼植被分布的主要土壤化学因子.CCA排序第一轴与土壤盐分呈显著正相关关系(P<0.001),第二轴主要和土壤pH呈显著负相关关系(P<0.001).柽柳-翅碱蓬+补血草+碱蓬群落排列于排序图的右上部,与生境土壤中高含盐量及中等pH相对应,穗状狐尾藻+芦苇群落和芦苇群落分布于第一排序轴的最左端,主要与土壤低含盐量相关,翅碱蓬群落位于第二排序轴的下侧, 与较高的土壤pH相关,柽柳-芦苇+翅碱蓬群落和旱柳-芦苇+荻群落,土壤pH和盐分均较低.通过物种丰富度R、香农维纳多样性H′、物种均匀度E等指数与土壤化学因子的相关分析,发现黄河河口盐沼植物物种多样性与土壤盐分没有呈现出与土壤盐分很好的负相关关系,物种丰富度R、香农维纳多样性H′、物种均匀度E均与土壤盐分呈现显著正相关关系;R、H′与土壤pH呈现出十分显著的负相关关系; R、H′与土壤Ca2+、Mg2+含量呈现极为显著正相关关系.     

江苏滨海滩涂湿地盐沼植被动态及机制

江苏省滨海滩涂湿地资源丰富，但由于围垦等人类活动以及外来物种生态入侵等影响，盐沼植被的面积持续下降。本文基于Landsat遥感影像，利用DSAS系统定量分析，对1985—2020年江苏滨海滩涂湿地潮滩植被带的围堰区、盐沼植被区的规模动态及相关关系、围堰规模的植被效应等进行了研究。结果表明：(1)1985—2020年，潮滩植被带向海显著推进岸段与围堰区规模显著增加岸段在空间上具对应性，变化热点区逐渐南移，期初为射阳河口至北凌河口岸段，2015年后，已南移至梁垛河口至遥望港岸段。(2)盐沼植被与围堰区面积在不同岸段间差异较大，但各岸段间围堰区与盐沼植被面积之比均快速上升，比值由1985年的0.017∶1变为2020年的5.59∶1,围堰区面积与盐沼植被面积呈极显著负相关。(3)随盐沼植被带规模逐渐下降，其与潮滩植被带向海延展速率的相关关系也由显著正相关变为不显著相关，显示盐沼植被带规模对潮滩植被带延展的促进作用具一定的规模效应。     

黄河三角洲典型植被与地下水埋深和土壤盐分的关系

土壤盐分和地下水埋深是影响黄河三角洲植被发育和分布的重要因素.本文通过野外调查与统计分析,研究了黄河三角洲区域典型植被(翅碱蓬 柽柳、刺槐、芦苇和棉花)、地下水埋深、土壤盐分之间的关系.结果表明: 研究区地下水埋深显著影响土壤盐分,平均影响系数为0.327,地下水埋深在0.5～1.5 m的土壤盐渍化最严重;整个研究区内植被发育较差,其中,研究区78%面积的归一化植被指数(NDVI)<0.4,地下水埋深、土壤盐分对天然植被分布有显著影响;土壤盐分对研究区翅碱蓬-柽柳、刺槐、芦苇及棉花NDVI的影响显著,地下水埋深对翅碱蓬-柽柳NDVI的影响显著,对芦苇、棉花、刺槐NDVI的影响不显著.     

地形因子对盐城滨海湿地景观分布与演变的影响

地形作为景观结构和空间格局的重要影响因子,不仅为景观格局的形成提供基础,其空间特征也影响着景观的演变过程.基于2002、2011年地形高程信息和遥感影像,运用GIS技术,并结合分布指数,分析了盐城滨海湿地景观分布与演变对地形因子的响应特征.结果表明:①盐城淤泥质滨海湿地总体地形变化平缓,海拔0-2.5m的区域占整个研究区面积的97％以上.其中,米草带主要分布于0.9-1.5m,碱蓬带主要分布于1.5-2.lm,而芦苇带则主要分布于2.1-2.7m.②2002-2011年9年间湿地景观时间变化明显,其中,芦苇面积增加了3倍,碱蓬面积由26.80％骤降至11.51％,同期,米草面积则增加了50％之多.③湿地景观空间分布特征与地形关系比较明显.其中,米草空间分布向0.6-1.2m区间演变,显示出强烈的向低海拔区间扩张的趋势;碱蓬分布范围随地形的升高总体上呈下降趋势;芦苇在地形较高区间上的分布指数增长迅速,其优势分布区间向2.1-3.0m扩展.     

黄河三角洲湿地水盐影响下灌草群落的物种多样性研究

采用样地调查方法, 研究了黄河三角洲滨海湿地灌草群落的物种多样性及其与地下水埋深、土壤盐分之间的关系, 结果表明: 湿地灌草可划分为5 种群丛类型, 分别为(A)碱蓬+芦苇群丛, (B)柽柳-碱蓬群丛, (C)芦苇+碱蓬群丛,(D)芦苇群丛, (E)蒙古鸦葱群丛; 其中, 芦苇+碱蓬群丛具有较高的物种多样性与丰富度, 而柽柳-碱蓬群丛物种丰富度与多样性相对较低; 回归分析表明物种多样性与地下水埋深、土壤全盐量存在明显的线性关系, 随着地下水埋深的增加物种多样性为增长趋势, 反之随着土壤全盐量的增加物种多样性逐渐减少, 可用多元线性回归表明三者的关系为y=0.122+0.005X1-0.001X2。     

盐城保护区生境变化与丹顶鹤数量的耦合关系分析

以江苏盐城国家级珍禽自然保护区的核心区为研究区, 采用灰色关联度模型, 分析了不同生境敏感因子与丹顶鹤数量的耦合关系, 再根据斜率关联度对生态敏感因子进行了综合排序。结果表明: 丹顶鹤数量与研究区的生境敏感因子密切相关, 各因子之间相互作用, 相互影响, 形成了复杂条件下的耦合关系。关联程度的排序为: 碱蓬破碎度指数>芦苇破碎度指数>净初级生产力年总量>景观破碎度指数>芦苇面积>香农生物多样性指数>碱蓬面积。其中碱蓬破碎度指数、芦苇破碎度指数、景观破碎度指数与丹顶鹤数量呈负相关关系。碱蓬破碎度指数与丹顶鹤的数量关联度最强, 对该地区的生境状况具有良好的指示作用。     

基于边界特征的黄河三角洲景观变化及空间异质性

在遥感解译和景观类型制图的基础上,运用滑箱扫描的方法,基于组分边界特征计算景观整体结构指数,同时综合考虑景观要素的空间分布,采用信息熵法和孔隙度指数法对黄河三角洲农田和柽柳-芦苇2种景观组分进行异质性特征分析.结果表明:黄河三角洲景观组分之间的边界趋于复杂化,城镇扩展、石油开采及黄河断流等使耕地大量退化为柽柳-芦苇,潮滩植被侵满滩涂;与基于面积的景观指数相比,基于边界特征的景观指数更能反映景观结构的细节变化;农田和柽柳-芦苇均表现为宏观异质性特征,部分样线中小尺度上表现为微观异质性特征,但柽柳-芦苇的异质性表现尺度较农田小50个像元左右,且这种差异随时间有加大的趋势;2种异质性分析方法从不同的侧面揭示了组分类型的异质性特征,形成有益的补充.     

盐城海滨湿地碱蓬沼泽时空演变人为影响研究

盐城海滨湿地景观演变受人为影响极其显著。研究依据2000、2006 年、2011 年3 个时期ETM+影像为基础数据源, 从对比的角度, 揭示人为影响下碱蓬沼泽景观演变特征。研究结果显示: (1) 2000-2011 年, 北部人工管理区,碱蓬沼泽面积变化明显, 减少了87.158%, 比南部自然区域多减少了22%; 景观破碎度加剧, 景观聚合度指数从95.780下降到65.455, 比南部区域多下降了16%; 斑块平均面积由389.333 hm2 下降到21.429 hm2, 比南部区域多下降了11%;由于不同时期围堰强度的差异, 人工管理区打破了自然条件下碱蓬沼泽相对稳定的变化速率, 呈现先快后慢的特征,2000-2006 年间年减少面积为118.167 hm2·a–1, 2006-2011 年只有51.500 hm2·a–1。景观空间变化上, 人工管理区碱蓬沼泽质心向东南方向偏移666.350 m, 而南部区域向东北方偏移了1042.710 m; 2006-2011 年, 人工管理区碱蓬沼泽质心以向东偏移为主, 而南部区域以向北偏移为主。(2) 人工围堰致使人工管理区生态系统向淡水生态系统转变, 而有利于淡水芦苇沼泽的发育: 2006-2006 年, 在人工管理区, 通过人工围堰539 hm2 的碱蓬沼泽转变为芦苇沼泽和养殖池, 转移率比南部区域高出了近4%。2006-2011 年, 北部人工管理区有178 hm2 的碱蓬沼泽转移为芦苇沼泽, 转移率比南部区域高出了近20%。(3) 由于互花米草超强的扩张能力和种间竞争能力, 致使海滨湿地形成了碱蓬沼泽-互花米草沼泽的演变格局: 2000-2006 年, 北部人工管理区15.24%的碱蓬沼泽转移为互花米草沼泽, 转移率比南部区域高出了13%; 2006-2011 年, 人工管理区30.07%的碱蓬沼泽转移为互花米草沼泽, 比南部区域高出了近10%。     

盐城滨海湿地植物群落种间格局与竞争的关系研究

盐城滨海湿地植物群落种间格局与竞争关系发生变化，导致湿地景观结构与格局发生变化。以江苏盐城国家级珍禽自然保护区核心区为典型研究区，利用1992、1997、2000、2011、2017年TM影像作为数据源，结合GIS技术，运用景观生态学方法分析了滨海湿地植物群落种间格局与竞争关系的时空变化特征。结果表明：①1992-2017年，植物群落结构变化呈现出芦苇群落和互花米草群落持续扩张的特征，其面积百分比到2017年分别达到37.06%和34.50%；碱蓬群落整体上呈现持续萎缩的特征，到2017年仅占5.09%。②1992-2017年，香农多样性指数（SHDI）和边缘密度（ED）值分别先上升至1.482和14.391，再逐渐下降至1.283和11.967，最大斑块指数（LPI）和聚集度指数（AI）先增大再减小，均反映了植物群落竞争关系从单一化走向多元化再到单一化的趋势。③1992-2017年，芦苇-碱蓬群落之间竞争的空间位置先向海方向推进，后向陆方面后退；碱蓬-互花米草群落竞争的位置先向海、再向陆方向、再向海方面演进；芦苇-碱蓬-互花米草群落种间竞争的位置由区域的南部向中部演进。研究可为进一步认识滨海湿地植物群落的基本结构和种间格局的动态变化，为生物多样性保护和修复提供科学参考。     

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.     

Separation of the pineal vesicle from the wall of the third ventricle during the post-hatching development of the chicken

Summary According to light- and electron-microscopic observations the pineal organ of the 3-day-old chicken consists of a prominent end vesicle and a tapering parenchymal stalk. During this stage the pineal lumen is in open communication with the third ventricle. However, in the 40-day-old chicken, which still possesses a well-developed end vesicle, the proximal portion of the pineal stalk displays regressive changes leading to local fragmentation. At this stage the pineal stalk is reduced, and the pineal lumen is missing. In 1-year-old chickens the parenchyma of the proximal portion of the stalk is further diminished, and in 3-year-old domestic fowl is completely displaced by bundles of collagenous fibers, only some nerve fibers being present. This post-hatching pineal development may reflect the sequence of changes leading from pineal sense organs to pineal glands.This work was supported by a grant-in-aid for Scientific Research from the Ministry of Education, Science and Culture of Japan     

On the Dependence of the Quadratic Risk of the Classical Predictor and the Prediction-Horizon

When constructing predictors on the basis of the linear model of time series of various indicators often the question arises on the dependence of forecasting accuracy and the changing prediction horizon. The dependency of the quadratic risk of the classical predictor and the time horizon is considered.     

中国植物区系与其它地区区系的联系及其在世界区系中的地位和作用

基于吴征镒将中国全部种子植物３２３８个属的分布区划分为１５个大类型和３４个变型的基础上,简要地讨论了中国植物区系与其它地区区系的联系,以及它在被子植物起源方面的作用。主要论点如下：（１）与热带亚洲区系的联系。这种联系主要通过第７类型（热带亚洲分布）及其５个变型来体现的。本文列举了１０个科,龙脑香料、狭义隐翼科、交让木科、五隔草科、五列木科、肉实树科、心翼果科、八宝树科、兰花蕉科和四数木科,来说明这