Identifying Extrinsic versus Intrinsic Drivers of Variation in Cell Behavior in Human iPSC Lines from Healthy Donors

1. Download high-res image (169KB)
2. Download full-size image

     

Realized niche shift associated with Galinsoga quadriradiata (Asteraceae) invasion in China

粗毛牛膝菊在中国的入侵与生态位漂移有关 在外来物种入侵和扩散过程中,生态位的漂移可能起到了重要作用。粗毛牛膝菊(Galinsoga quadriradiata) 在中国已造成了较为严重的入侵,占据了许多与其原产地不同的气候区。为此,本研究力图揭示粗毛牛膝菊入侵过程中的气候生态位漂移,分析其在该物种入 侵中国过程中可能发挥的作用。本研究结合粗毛牛膝菊原 产地和入侵地的分布点与气候数据, 采用Maxent模型预测了其在中国潜在的分布,并采用主成分分析的方法评估 了在入侵中国过程中粗毛牛膝菊气候生态位的漂移。模型结果显示,该物种原产地种群和入侵地种群之间只 有32.7%的生态位重叠,两个种群的生态位相似性较低(Schoener's D = 0.093, P < 0.005),这暗示了在其入侵过程中发生了生态位漂移。相比于其原产地种群,其在中国的入侵种群气候生态位的整体范围和中心都明 显地漂移向了温度更低、降水更少的区域;中国南方大部分区域属于粗毛牛膝菊的稳定适生区,而位于入侵 前沿的北方地区则存在局域适应和潜在拓殖区域。这些研究结果说明,粗毛牛膝菊在中国的入侵种群仍处于准平衡阶段,未来有可能继续向新的适生区扩散入侵,其生态位的变化有力地解释了为什么该物种在中国的入侵性强、危害范围大。     

Niche characteristics of rodents by diverse disturbance in Alashan desert, Inner Mongolia, China

Four diverse disturbance types, namely, farmland, rotationally grazed grassland, overgrazed grassland and forbidden grazing grassland, were identified in the Alashan desert region of Inner Mongolia. Rodents were sampled in April, July and October in 2002 and 2003 using the trap-day method. Their spatial and temporal niches among the four disturbance types were assessed using the Shannon-Wiener niche breadth index and the Pianka niche overlap index. The Shannon-Wiener niche breadth index was the highest for Allactaga sibirica and Meriones meridianus (0.925 and 0.908, respectively), intermediate for Cricetulus eversmanni, Phodopus roborovskii and Citellus dauricus (0.789, 0.782 and 0.711, respectively), and lowest for Cardiocranius paradoxus (0.003). The Pianka niche overlap indices of six-paired species were the highest and varied from 0.900 to 1.000, suggesting their spatial niche overlapped almost completely. Conversely, the spatial niche overlap index for Meriones unguiculatus, Cardiocranius paradoxus, and Salpingotus kozlovi was zero, thus indicating a complete absence of competition among them. In addition, the temporal niche breadth and overlap indices varied greatly in relation to disturbance types and season. The level of temporal niche overlap in spring and autumn was low while in summer it was high. For all disturbance types and for each season, the temporal niche overlap index of Meriones meridianus and Cricetulus barabansis was always highest but for Meriones unguiculatus and Salpingotus kozlovi always lowest. __________ Translated from Acta Ecologica Sinica, 2005, 25(10): 2,637–2,643 [译自: 生态学报]     

林窗尺度对马尾松人工林林下灌草层优势种生态位的早期影响北大核心CSCD

马尾松作为中国广泛栽植的乡土树种,其人工林群落结构简单和生物多样性低下是普遍存在的生态学问题。探究不同林窗尺度对马尾松人工林林下植被群落的影响,可为马尾松人工林近自然经营提供理论依据。该研究在45 a生马尾松人工林中分别设置A(50 m^(2))、B(100 m^(2))、C(200 m^(2))和D(667 m^(2))4种不同尺度的林窗,以不做任何处理的马尾松人工林作为对照(CK),探究采伐开窗后林窗内自然更新1 a后的灌草层植物组成、优势种生态位宽度和生态位重叠度分布特征。结果显示:(1)除100 m^(2)林窗下灌木层物种数与对照无显著差异外,其余林窗灌草层物种数均显著高于对照(P<0.05),且200 m^(2)林窗下灌草层物种数均最多,分别为35种和20种;4种林窗下灌草层物种丰富度指数较对照均显著增加(P<0.05),最大值均出现在200 m^(2)林窗下,其值分别为对照的1.5倍和2.6倍。(2)林窗增加了灌草层喜光植物种类,且在200 m^(2)林窗下种类最多,灌木层喜光植物有13种,草本层喜光植物有5种。(3)4种林窗下灌草层优势种中,喜光植物生态位宽度均较大,200 m^(2)林窗下灌草层生态位宽度平均值最小,其对资源利用程度低,重要值与生态位宽度之间无显著相关性(P>0.05)。(4)4种林窗下灌草层优势种间生态位重叠度指数均较小。667 m^(2)林窗下,灌草层优势种平均生态位重叠度指数最小,分别为0.029和0.024,200 m^(2)林窗下灌草层优势种高生态位重叠度占总数比例最大,分别为20%和23.8%。研究表明,采伐开窗促进了马尾松人工林林下植被发育,丰富了林下植物多样性,有利于马尾松林稳定持续发展,对精准提升马尾松人工林质量具有重要意义。     

互花米草入侵对红树林底栖甲壳动物和鱼类功能群及生态位的影响

为了解互花米草入侵对红树林湿地生态系统底栖甲壳动物和鱼类的影响,本研究利用地笼方式于2020年8月、2021年1月和4月对福建漳江口2个原生红树林样地(白骨壤和秋茄)、2个互花米草入侵样地以及1个光滩样地的底栖甲壳动物和鱼类进行采样调查。采用相对重要性指数、Shannon多样性指数、Pielou均匀度指数和Margalef丰富度指数分析底栖甲壳动物和鱼类的优势种及物种多样性,统计其功能群,并计算其生态位宽度和生态位重叠指数。结果表明: 3个季节共采集到底栖甲壳动物和鱼类种类37种,隶属于2门2纲8目17科,其中大多数为暖水性和广盐性物种,且以肉食性和杂食性功能群为主。双因素方差分析和非度量多维尺度分析结果表明,相比光滩,互花米草入侵后,底栖甲壳动物和鱼类的群落多样性指数变化不显著,但功能群发生了显著变化,浮游生物食性功能群以及肉食性和植食性功能群物种均有一定程度的增加。相比红树林样地,互花米草样地内底栖甲壳动物和鱼类物种丰富度更高。优势物种的时空生态位宽度变化范围在0～1.4186,其中棱鮻最高(1.4186),其次是中华乌塘鳢(1.0168)、刀额新对虾(0.9469)、脊尾白虾(0.8922)。     

四川卧龙国家级自然保护区三种高山同域鸡形目鸟类的时空生态位比较

高海拔山区气候条件恶劣, 资源匮乏, 探究同域分布的近缘物种如何利用有限的资源以实现稳定共存, 对于了解高山生态系统生物多样性格局的形成和维持机制具有重要意义。鸡形目鸟类飞行能力弱, 属于典型的地栖物种, 生态位空间相对狭窄, 可能面临更高的种间竞争压力。本研究旨在比较几种同域分布的鸡形目鸟类的时空生态位, 为了解高山生态系统同域物种的共存机制提供新的研究案例。2020年4-9月, 研究人员在四川卧龙国家级自然保护区海拔3,300-4,200 m的高山区域进行了野外调查, 通过样线法和样方法对鸡形目鸟类群落优势物种绿尾虹雉(Lophophorus lhuysii)、雉鹑(Tetraophasis obscurus)和雪鹑(Lerwa lerwa)繁殖期的微生境进行调查, 使用红外相机对其活动节律进行监测, 并运用核密度估计法从微生境利用和日活动节律两个生态维度进行了种间生态位比较。结果显示, 雪鹑在微生境利用和日活动节律上均与其他两个物种存在显著差异。绿尾虹雉与雉鹑在微生境的利用上具有相似偏好; 但绿尾虹雉的早活动高峰晚于雉鹑, 晚活动高峰早于雉鹑, 表现出显著的种间日活动节律差异; 然而, 整合两个维度后, 绿尾虹雉和雉鹑的整体生态位仍然高度重叠, 没有显著分化。本研究表明高山鸡形目物种间的生态位分化体现于多个不同的生态维度, 并且不同物种之间的分化方式有所差异。在空间和时间生态位上的显著分化使雪鹑与同域物种间的竞争压力相对较小, 有利于其实现稳定共存。而绿尾虹雉与雉鹑的整体生态位高度重叠, 建议进一步对其食性开展研究, 探讨营养生态位上的潜在种间分化。     

Forecasting the potential distribution of Spodoptera exigua and S. littoralis (Lepidoptera,Noctuidae) in Iran

The beet armyworm, Spodoptera exigua (Hübner, 1808) and the Egyptian cotton leafworm, S. littoralis (Boisduval, 1833), are amongst the most notorious agricultural pest species in Iran. Spodoptera exigua is considered a serious pest of different crops, whereas S. littoralis is known as an important pest of cotton.In this paper, the potential distribution areas of these species in Iran and the important climatic factors affecting their distribution were predicted using the MaxEnt model and the ArcGIS. The results indicate that the main environmental variables contributing to S. exigua’s distribution were precipitation of the coldest quarter (bio19), average wind speed in April (wind4), and annual precipitation (bio12). Also, minimum temperature of the coldest month (bio6), mean temperature of coldest quarter (bio11), altitude and average wind speed in May (wind5) were dominant climatic factors that affected the potential distribution of S. littoralis. These species overlapped in most parts of coastal areas in the southern and northern parts of Iran, with an average overlapping range of 33.2%. Considering their preferred host plants in Iran, it is necessary to strengthen biosurveillance programes and management of these two species in their suitable areas to prevent further invasion, which endangers agricultural security.     

Segregation in space and time explains the coexistence of two sympatric sub‐Antarctic petrels

Biological communities are shaped by competition between and within species. Competition is often reduced by inter‐ and intraspecific specialization on resources, such as differencet foraging areas or time, allowing similar species to coexist and potentially contributing to reproductive isolation. Here, we examine the simultaneous role of temporal and spatial foraging segregation within and between two sympatric sister species of seabirds, Northern Macronectes halli and Southern Macronectes giganteus Giant Petrels. These species show marked sexual size dimorphism and allochrony (with earlier breeding by Northern Giant Petrels) but this is the first study to test for differences in foraging behaviours and areas across the entire breeding season both between the two species and between the sexes. We tracked males and females of both species in all breeding stages at Bird Island, South Georgia, to test how foraging distribution, behaviour and habitat use vary between and within species in biological time (incubation, brood‐guard or post‐brood stages) and in absolute time (calendar date). Within each breeding stage, both species took trips of comparable duration to similar areas, but due to breeding allochrony they segregated temporally. Northern Giant Petrels had a somewhat smaller foraging range than Southern Giant Petrels, reflecting their greater exploitation of local carrion and probably contributing to their recent higher population growth. Within species, segregation was spatial, with females generally taking longer, more pelagic trips than males, although both sexes of both species showed unexpectedly plastic foraging behaviour. There was little evidence of interspecific differences in habitat use. Thus, in giant petrels, temporal segregation reduces interspecific competition and sexual segregation reduces intraspecific competition. These results demonstrate how both specialization and dynamic changes in foraging strategies at different scales underpin resource division within a community.     

Non-native species and lake warming negatively affect Arctic char Salvelinus alpinus abundance; deep thermal refugia facilitate co-existence

This study finds that non-native species and warming temperatures have significant negative effects on Arctic char Salvelinus alpinus abundance in Irish lakes. Eutrophication was not important at the range of total phosphorus tested (0.005–0.023 mg l⁻¹). Model results predict that S. alpinus occur across the temperature range sampled (8.2–19.7°C) when non-natives are absent, but S. alpinus catch is predicted to be close to zero irrespective of temperature when non-native catch is high. This result indicates that to persist, S. alpinus may require a habitat where non-natives are at low abundance or absent. Salvelinus alpinus segregated from other species along the thermal axis, inhabiting significantly colder water and actively avoided non-native species, which appeared to limit their distribution. The thermal niche realized by S. alpinus in non-native dominated lakes was thus compressed relative to native dominated lakes and S. alpinus population density was significantly lower. These findings were consistent even when the only non-native present was Perca fluviatilis. Temperature appeared to limit the distribution of non-native species, such that the presence of deep thermal refugia is currently facilitating S. alpinus co-existence with non-natives in associated lakes. Diet analysis identified P. fluviatilis as potential predators and competitors. This study provides strong evidence that non-native species are a key driver of low S. alpinus abundance in Irish lakes. Temperature increases associated with climate change are identified as a secondary concern, as they could erode S. alpinus' thermal niche and lead to their extirpation. The lower thermal buffering capacity of shallow lakes identifies these as higher risk systems. Salvelinus alpinus conservation in Ireland should focus on preventing future illegal non-native species introductions because unlike other stressors (e.g., eutrophication etc.), species introductions are rarely reversible.     

First description of the environmental niche of the epibenthic dinoflagellate species Coolia palmyrensis,C. malayensis,and C. tropicalis (Dinophyceae) from Eastern Australia

Environmental variables such as temperature, salinity, and irradiance are significant drivers of microalgal growth and distribution. Therefore, understanding how these variables influence fitness of potentially toxic microalgal species is particularly important. In this study, strains of the potentially harmful epibenthic dinoflagellate species Coolia palmyrensis, C. malayensis, and C. tropicalis were isolated from coastal shallow water habitats on the east coast of Australia and identified using the D1‐D3 region of the large subunit (LSU) ribosomal DNA (rDNA). To determine the environmental niche of each taxon, growth was measured across a gradient of temperature (15–30°C), salinity (20–38), and irradiance (10–200 μmol photons · m^?2 · s^?1). Specific growth rates of Coolia tropicalis were highest under warm temperatures (27°C), low salinities (ca. 23), and intermediate irradiance levels (150 μmol photons · m^?2 · s^?1), while C. malayensis showed the highest growth at moderate temperatures (24°C) and irradiance levels (150 μmol photons · m^?2 · s^?1) and growth rates were consistent across the range of salinity levels tested (20–38). Coolia palmyrensis had the highest growth rate of all species tested and favored moderate temperatures (24°C), oceanic salinity (35), and high irradiance (>200 μmol photons · m^?2 · s^?1). This is the first study to characterize the environmental niche of species from the benthic harmful algal bloom genus Coolia and provides important information to help define species distributions and inform risk management.