气候变化下青藏高原两种云杉植物的潜在适生区预测

为了预测未来气候变化下云杉属植物的适宜生境,选择青藏高原暗针叶林的两种重要建群植物丽江云杉（Picea likiangensis）和紫果云杉（Picea purpurea）作为研究对象,采用MaxEnt模型预测21世纪50年代（2050s）和70年代（2070s）两物种在未来气候情景下的潜在分布,并结合ArcGIS计算物种分布面积和空间格局变化。结果表明：（1）丽江云杉的潜在适宜分布区主要集中在四川西南部和西藏东部。紫果云杉潜在适宜分布区主要集中在四川西北部、甘肃南部、青海东南部,以及西藏东部地区。（2）在未来两个时期丽江云杉的分布面积总体呈增加趋势,紫果云杉呈先增加后减少的趋势,但与其现代分布面积相比,两种云杉的总适生区面积都有不同程度的增加。（3）丽江云杉适宜生境未来可能会向北迁移,而紫果云杉可能会向西迁移。（4）影响丽江云杉和紫果云杉潜在地理分布的主要气候因子为最暖季降水量和最暖季均温。研究结果可为丽江云杉和紫果云杉在未来气候变化情景下的可持续管理提供一定的理论依据和参考价值。     

中国梭梭属植物历史分布格局及其驱动机制

梭梭属(Haloxylon)植物是藜科的古老孑遗物种, 探究末次间冰期(last interglacial period, LIG)和末次盛冰期(last glacial maximum period, LGM)以来中国梭梭属植物的历史地理分布格局及其驱动机制, 对了解气候变化背景下旱生植物区系的发展与演化具有重要意义。本研究利用梭梭属85个自然分布点数据(60条梭梭(Haloxylon ammodendron)分布记录、25条白梭梭(H. persicum)分布记录)和2套环境因子数据, 整合GIS空间分析和9种物种分布模型, 分析了梭梭属末次间冰期以来的地理分布格局变化及其驱动机制。基于62个梭梭属种群的叶绿体基因测序数据, 利用最小成本路径方法, 模拟了末次间冰期以来梭梭属可能的扩散路径。利用R软件prcomp函数对影响梭梭属分布的环境变量进行主成分分析(principal component analysis, PCA), 评价了环境变量对梭梭属适宜分布的贡献, 并分析了关键变量与分布适宜性的相关性。结果表明: (1)集成模型的模拟精度较单一模型显著提升, 且对白梭梭的模拟精度高于梭梭; (2)末次间冰期以来, 梭梭属植物的分布均经历了显著收缩和冰后期扩张, 末次间冰期至末次盛冰期时期, 在准噶尔盆地、塔里木盆地西部广泛分布的梭梭大面积向西退缩至避难所(准噶尔盆地西北缘和塔里木盆地西北缘); 白梭梭从准噶尔盆地、塔里木盆地西端向南退缩至避难所(准噶尔盆地南缘); 末次盛冰期至今, 梭梭向东沿甘肃北部扩张直至内蒙古西部阿拉善荒漠, 白梭梭向东北方向小范围扩张, 占据了准噶尔盆地西部和南缘; (3)末次间冰期以来的气候波动对梭梭属植物的分布存在较大限制, 降水因子主导了梭梭属适宜分布面积的变化, 温度因子影响了梭梭属分布适宜性的高低。     

采用生态位模拟预测濒危植物白豆杉5个时期的适宜分布区

采用生态位模拟研究不同时期植物分布区变迁模式,有利于了解植物对气候变化的响应,从而更好地在全球气候背景下保护生物多样性。本研究以中国特有濒危裸子植物白豆杉(Pseudotaxus chienii)为对象,根据野外调查及标本记录确定34个野生分布点,结合5个时期(末次间冰期、末次盛冰期、中全新世、现在和未来) 19个生物气候因子,运用生态位模型对5个时期白豆杉的潜在分布区进行重建。结果表明:白豆杉在5个时期的地理分布均与降水有密切关系,其中最干月份雨量是影响该物种分布最重要的气候因子,说明白豆杉适应潮湿气候和较短的旱季;在末次间冰期,白豆杉在中国东南呈大面积分布;在末次盛冰期,白豆杉分布区往浙江、福建和贵州东部扩张,江西、湖南等中部地区最适分布区面积减小;中全新世其适宜分布区面积比末次盛冰期有所减少,相比于末次间冰期其生境片段化更为严重;在未来气候变暖条件下,白豆杉适宜分布区减少,该物种往高海拔山地收缩,低海拔(约600 m以下)的适宜区基本消失。本文通过生态位模拟对白豆杉5个时期分布区进行重建,探究气候变化对其分布区变迁的影响,可以为保护濒危植物白豆杉提供有效依据。     

基于MaxEnt模型和GIS的青藏高原紫花针茅分布格局模拟

气候变化对物种分布的影响是生物地理学研究的热点问题.本研究以广泛分布在青藏高原高寒草甸区域的建群种紫花针茅为研究对象,通过植物标本库查询和实地调查了解紫花针茅在青藏高原的分布情况,利用Max Ent模型模拟紫花针茅在青藏高原历史、当前及未来的分布趋势,分析紫花针茅各历史时期的分布格局,探讨了物种分布变化的产生原因.结果表明:青藏高寒草地的针茅属物种具有较高的物种多样性,代表性植物紫花针茅的主要分布区域为青藏高原腹地及沿喜马拉雅地区;紫花针茅的分布强烈地受最暖季降水量、最湿季降水量和年均降水量的控制.依据紫花针茅在末次冰期的分布格局以及青藏高原的地理地质特点,研究认为:冰期来临时,羌塘以南藏北核心区和喜马拉雅西部阿里地区是紫花针茅潜在分布的核心区,此处提供了比其他地区更适合紫花针茅生存的栖息地,这些区域成为紫花针茅的避难所,当前的紫花针茅都是从这些避难所迁移并扩展开来.生物避难所的存在有助于理解青藏高原高寒植被起源和分化的相关问题.     

中国东北温带针阔混交林植物物种的谱系地理研究进展

中国东北温带针阔混交林是暖温带植被与寒温带植被的交错区,是研究第四纪气候变化对遗传格局影响的关键区域。古植被重建研究显示,在末次冰盛期时,针阔混交林向南退缩至25°–30°N之间。然而,谱系地理研究则表明针阔混交林植物在末次冰盛期时可在35°N以北的一个或多个避难所中原地存活。长白山和朝鲜半岛是针阔混交林植物最重要的两个避难所,在其他区域还可能存在多个避难所,最北可达小兴安岭和俄罗斯远东地区。在避难所种群间冰期或冰期后发生扩张的过程中,形成了复杂的遗传多样性分布模式。单个避难所向北扩张的种群历史并不一定导致种群内遗传多样性随纬度升高而显著降低。在多个避难所模式下,种群内遗传多样性一般呈均匀分布。以往研究揭示了第四纪,尤其是末次冰盛期对针阔混交林植物进化历史的影响,但仍主要是乔木成分,且集中于单一物种。因此,东北和南方地区近缘种或姊妹种的适应性进化比较及针阔混交林的群落构建机制检验是未来研究的两个发展趋势。     

中国亚热带地区阔叶林植物的谱系地理历史

中国亚热带地区因丰富的植物物种多样性备受生物地理学研究关注,丰富的多样性与中新世以来的地质气候变化密切相关。谱系地理学已成为探讨植物分布模式和遗传格局受地质气候变化影响的主要手段。总结了该地区阔叶林植物对中新世以来地质气候变化的响应模式和种群分化的历史成因。在中新世和上新世时,由于全球变冷、青藏高原抬升和亚洲内陆干旱,阔叶林植物被迫向南退缩,形成不同的谱系。同时,亚洲季风的增强为遗传多样性的增加提供了良好的环境。在更新世冰期和间冰期时,大部分落叶阔叶林和常绿阔叶林植物在多个避难所间存在长期隔离,不同的避难所种群各自经历局部地区的收缩和扩张。长期的隔离使不同谱系间进一步分化,形成高水平的遗传多样性和遗传分化。少部分植物在冰期时向南退缩,并在间冰期时明显向北扩张。最后,就分化时间的准确估计和探究遗传格局背后的机制两方面展望了未来的研究趋势。     

基于Maxent模型的檵木分布格局模拟

应用最大熵模型（Maxent）模拟檵木（Loropetalum chinense）在末次间冰期（last inter glacial,LIG）、末次盛冰期（last glacial maximum,LGM）和当代（Present）等不同时期的中国潜在分布格局,分析影响其分布的主导生物气候因子。结果显示：（1）历史气候的变迁,檵木由末次间冰期经末次盛冰期进入当代,适生区面积呈现增加趋势。当代适生区面积占比最大,适生程度也较高;（2）训练数据和测试数据的AUC值分别为0.947和0.954,均达到了极高的精度;（3）刀切法检测表明,影响檵木分布的主导环境因子依次为bio14（最干月份平均降雨量）、bio17（极干季降雨量）、为bio19（极冷季平均降雨量）和bio15（湿度变化方差）,其适生值范围分别是23-93 mm,98-300 mm,110-350 mm和42%-65%;（4）较纬度而言,经度是影响我国檵木分布格局的主要因子;（5）我国檵木当代的潜在地理分布主要在北回归线以北的区域,总面积为162.55万km²,占国土总面积的16.93%,高适生区集中于广西北部、江西东部、以及湖南南部、福建东部等地区。本研究较为准确地模拟了檵木在3个不同时期的适生分布,为深入分析檵木现代分布格局的形成提供科学依据。     

四照花物种分布格局模拟及冰期避难所推测

气候是影响物种多样性的重要自然因素,同时也影响生物的生长发育及其分布。该文以广泛分布于中国的观花植物四照花为研究对象,通过植物标本库查询和野外实地调查确定四照花在中国的分布情况,利用MaxEnt模型和ArcGIS软件模拟四照花的历史分布格局、当前分布格局及未来的分布趋势,计算不同时期物种分布面积的变化并分析物种分布变化产生的原因。研究结果显示:四照花当前的分布主要受降水量变异系数、最冷月份最低温、最冷季节平均温度和温度季节变化4个生物气候因子影响。此外,基于四照花在末次盛冰期、全新世中期和当前的分布格局的变化推测:冰期来临时,中西部的大巴山地区和东部天目山地区是四照花潜在分布的核心区,为四照花的冰期避难所。     

洮河自然保护区大峪沟林区紫果云杉群落木本植物种群生态位特征

基于群落调查数据,以样地代表多种资源的综合状态,物种重要值作为生态位的计测指标,利用Levins和Shannon生态位宽度,Schoener生态位相似和Pianka生态位重叠对洮河自然保护区大峪沟林区的紫果云杉群落木本植物种群生态位进行定量研究。结果表明：紫果云杉群落乔木层共有树种8种,隶属于4科6属,紫果云杉占绝对优势,岷江冷杉为次优势种;灌木层共有植物50种,隶属于16科25属,忍冬科的蓝靛果、葱皮忍冬和唐古特忍冬等以及蔷薇科的峨眉蔷薇和银露梅等构成了灌木层的主体,紫果云杉幼苗优势不明显,但生态位宽度最大。本研究表明,生态位宽度受物种生态特性及其分布和生境共同影响,重要值大的物种生态位宽度一般较大,生态位宽度大的物种之间生态位相似性和重叠性一般较大,并与其它物种重叠的概率高、重叠程度大,生态位宽度小的物种集中出现时也会出现较大的生态位重叠,同科或同属的物种间常有较大生态位相似和重叠。生态位宽度反映着种群的扩散潜力,生态位相似反映着群落的稳定性,生态位重叠反映着物种间存在或潜在的竞争程度。紫果云杉在乔、灌木层均有最大的生态位宽度,生态适应性最强,群落结构稳定,具有进一步扩散的可能。     

沙地云杉与其近缘种间的GISH分析

以沙地云杉(Picea mongolica(H.Q.Wu)W.D.Xu)、白杄(P.meyeri Rehd.et Wils.)、红皮云杉(P.koraiensis Nakai)3种云杉属植物为材料,利用基因组原位杂交技术(GISH),用白杄和红皮云杉基因组DNA分别作探针与沙地云杉中期染色体进行杂交,分析3种云杉的亲缘关系,旨在进一步探讨沙地云杉的起源。结果表明:(1)3种云杉的染色体数目均为2n=24,核型类型为1A,大部分染色体为亚中部着丝粒;白杄和红皮云杉核型不对称系数分别为57.78%、57.64%,小于沙地云杉(58.75%)。(2)以白杄基因组DNA为探针时,在沙地云杉14条染色体上有明显杂交信号,信号位点主要位于着丝粒区、次缢痕处和短臂部位;以红皮云杉DNA为探针时,12条染色体上有明显杂交信号,主要位于着丝粒区、次缢痕处和长臂上,杂交信号分布范围和强度明显弱于白杄。研究认为,沙地云杉与白杄的亲缘关系较近,而与红皮云杉较远,该研究首次阐明沙地云杉非起源于白杄和红皮云杉的种间杂交。     

Two Robin Populations

Capsule This study is the first ever documented evidence of an interglacial refugium during the Last Interglacial for birds in Anatolia and suggests the need of a re-examination of the effects of the Last Interglacial on the geographic distribution and genetic structure of species.

Aims We tested whether, in accordance with the ‘refugia within refugia’ model, multiple refugia existed for Kruper's Nuthatch Sitta krueperi during the Last Glacial Maximum or the species survived along the coastal belt of Anatolia through the Late Quaternary glacial–interglacial cycles.

Methods An ecological niche model was developed to predict the geographic distribution of Kruper's Nuthatch under reconstructed past (the Last Interglacial and the Last Glacial Maximum), present, and projected future bioclimatic conditions. Also, robust coalescent-based analyses were used to assess demographic events over the history of Kruper's Nuthatch.

Results Kruper's Nuthatch survived the Last Glacial Maximum almost along the coastal belt of Anatolia, but not in multiple refugia, and surprisingly, contrary to expectations, it survived the Last Interglacial in southern Anatolia, but not along the coastal belt of Anatolia.

Conclusion A kind of the ‘refugia within refugia’ model (i.e. the ‘refugium within refugium’ model) was supported because range shifts took place within Anatolia (itself also a refugium) for Kruper's Nuthatch.     

Origin and demographic history of the endemic Taiwan spruce (Picea morrisonicola)

Taiwan spruce (Picea morrisonicola) is a vulnerable conifer species endemic to the island of Taiwan. A warming climate and competition from subtropical tree species has limited the range of Taiwan spruce to the higher altitudes of the island. Using seeds sampled from an area in the central mountain range of Taiwan, 15 nuclear loci were sequenced in order to measure genetic variation and to assess the long‐term genetic stability of the species. Genetic diversity is low and comparable to other spruce species with limited ranges such as Picea breweriana, Picea chihuahuana, and Picea schrenkiana. Importantly, analysis using approximate Bayesian computation (ABC) provides evidence for a drastic decline in the effective population size approximately 0.3–0.5 million years ago (mya). We used simulations to show that this is unlikely to be a false‐positive result due to the limited sample used here. To investigate the phylogenetic origin of Taiwan spruce, additional sequencing was performed in the Chinese spruce Picea wilsonii and combined with previously published data for three other mainland China species, Picea purpurea, Picea likiangensis, and P. schrenkiana. Analysis of population structure revealed that P. morrisonicola clusters most closely with P. wilsonii, and coalescent analyses using the program MIMAR dated the split to 4–8 mya, coincidental to the formation of Taiwan. Considering the population decrease that occurred after the split, however, led to a much more recent origin.     

Interglacial genetic diversification of Moussonia deppeana (Gesneriaceae), a hummingbird‐pollinated,cloud forest shrub in northern Mesoamerica

Recent empirical work on cloud forest‐adapted species supports the role of both old divergences across major geographical areas and more recent divergences attributed to Pleistocene climate changes. The shrub Moussonia deppeana is distributed in northern Mesoamerica, with geographically disjunct populations. Based on sampling throughout the species range and employing plastid and nuclear markers, we (i) test whether the fragmented distribution is correlated with main evolutionary lineages, (ii) reconstruct its phylogeographical history to infer the history of cloud forest in northern Mesoamerica and (iii) evaluate a set of refugia/vicariance scenarios for the region and demographic patterns of the populations whose ranges expanded and tracked cloud forest conditions during the Last Glacial Maximum. We found a deep evolutionary split in M. deppeana about 6–3 Ma, which could be consistent with a Pliocene divergence. Comparison of variation in plastid and nuclear markers revealed several lineages mostly congruent with their isolated geographical distribution and restricted gene flow among groups. Results of species distribution modelling and coalescent simulations fit a model of multiple refugia diverging during interglacial cycles. The demographic history of M. deppeana is not consistent with an expanding–contracting cloud forest archipelago model during the Last Glacial Maximum. Instead, our data suggest that populations persisted across the geographical range throughout the glacial cycles, and experienced isolation and divergence during interglacial periods.     

Adding ecology into phylogeography: ecological niche models and phylogeography in tandem reveals the demographic history of the subalpine warbler complex

Capsule: This study documents evidence of interglacial refugia during the Last Interglacial for birds in the Mediterranean region, and emphasizes the importance of the Last Interglacial on the geographic distribution and genetic structure of Mediterranean species.

Aims: We focused on the historical biogeography of the subalpine warbler complex: Subalpine Warbler Sylvia cantillans and Moltoni’s Warbler Sylvia subalpina; we tested if this Mediterranean bird complex shared a similar demographic fate as the present-day widespread species in the temperate zones of Europe, through the late Quaternary glacial-interglacial cycles.

Methods: An ecological niche model was developed to predict the geographic distribution of the subalpine warblers under the past (the Last Interglacial and the Last Glacial Maximum) and the present bioclimatic conditions. Additionally, Bayesian Skyline Plot analysis was used to assess effective population size changes over the history of the subalpine warbler complex.

Results: During the Last Glacial Maximum, the subalpine warblers almost reached their current distribution in the Mediterranean region; yet, unlike the widespread temperate bird species, they survived the Last Interglacial in allopatric refugia in the Mediterranean region.

Conclusion: A unique biogeographic pattern was revealed, indicating the importance of the Last Interglacial on current distributional patterns and demographic histories of common bird species in the Mediterranean region. This study suggests that Mediterranean biogeography is far more complex than previously assumed, and so deserves further study and more attention.     

Interprétation paléogéographique des données palynologiques du site du Paléolithique supérieur de Mezhyrich (Ukraine)

The results of palynological study of the Upper Paleolithic Mezhyrich site in central Ukraine are presented. Four local pollen zones were identified. The results of the palynological investigations allow us to hypothesize that the plant cover during Upper Paleolithic had a mosaic structure. The pollen record shows the presence of a few tree species with the predominance of herbaceous plants. We suggest that the river valleys and other local favorable sites were natural refugia where forest elements could survive even during the Last Glacial Maximum. These favorable landscapes to the existence of prehistoric hunters may have persisted during the Last Pleniglacial.     

Phylogeography and ecological niche modelling implicate coastal refugia and trans‐alpine dispersal of a New Zealand fungus beetle

The Last Glacial Maximum (LGM) severely restricted forest ecosystems on New Zealand’s South Island, but the extent of LGM distribution for forest species is still poorly understood. We used mitochondrial DNA phylogeography (COI) and ecological niche modelling (ENM) to identify LGM refugia for the mycophagous beetle Agyrtodes labralis (Leiodidae), a forest edge species widely distributed in the South Island. Both the phylogenetic analyses and the ENM indicate that A. labralis refuged in Kaikoura, Nelson, and along much of the South Island’s west coast. Phylogeography of this species indicates that recolonization of the largely deforested east and southeast South Island occurred in a west–east direction, with populations moving through the Southern Alps, and that the northern refugia participated little in interglacial population expansion. This contradicts published studies of other New Zealand species, in which recolonization occurs in a north–south fashion from many of the same refugia.     

The critical role of local refugia in postglacial colonization of Chinese pine: joint inferences from DNA analyses,pollen records,and species distribution modeling

The importance of long‐distance migration from low to high latitudes relative to local spread from northern refugia after the Last Glacial Maximum (LGM) remains a focus of debate for many temperate tree species. We assessed the dynamics of Chinese pine Pinus tabulaeformis, a widespread species endemic to northern China, since the LGM by integrating cytoplasmic DNA data, mapped pollen records and ecological niche modeling. Genetic variation among 544 individuals from 50 populations spanning the entire natural species range revealed eight genetic clusters with distinct geographic distribution, indicating glacial lineages likely originating from multiple local microrefugia. Palynological evidence suggested that the northernmost part of the natural distribution originated from local postglacial spread. Niche modeling indicated high probability of the species being present in the area of the Loess Plateau and coastal areas north of the Yangtze River during the LGM. The three lines of evidence jointly suggest that the species persisted through the last glaciation in the mountains surrounding the Loess Plateau of northern China and that the current distribution of the species originated primarily from the spread of local refugial populations, instead of long‐distance migration. These results cast doubt on the notion that Chinese pine migrated from areas south of the Yangtze River and underscore the importance of northern refugia.     

Multiple ice-age refugia in a southern beech of South America as evidenced by chloroplast DNA markers

Chloroplast DNA polymorphisms were analysed to infer the post-glacial history of Nothofagus nervosa (Phil.) Dim. et Mil., a species endemic to South American Temperate Forests. Two hypotheses were postulated to explain the current distribution of the species in relation to the refugia proposed after palynological studies and the time elapsed since Last Glacial Maximum. If refugia were located only in the Coastal Mountains, as pollen records suggests, long-distance dispersal events should be invoked to explain the current occurrence of the species in southern latitudes. The alternative hypothesis is the existence of cryptic refugia in southern latitudes. A total of 26 populations covering the entire geographical range of the species in Chile and Argentina were analysed through PCR–RFLP. Five haplotypes were identified, and a very low intrapopulation variation was observed together with a high gene differentiation (G _ST=0.93). The haplotypes showed a highly structured geographic distribution, separating populations located in the Pacific Coastal Mountains from those coming from the easterly located Andes Mountains. Moreover, among the populations of the Andes Mountains a north–south variation in the distribution of haplotypes was found. The results strongly suggest the persistence of the species in several ice-age refugia. The possible location of such refugia is discussed in combination with the available palynological data.     

The crested newt Triturus cristatus recolonized temperate Eurasia from an extra‐Mediterranean glacial refugium

We assess the role of the Carpathians as an extra‐Mediterranean glacial refugium for the crested newt Triturus cristatus. We combine a multilocus phylogeography (one mitochondrial protein‐coding gene, three nuclear introns, and one major histocompatibility complex gene) with species distribution modelling (projected on current and Last Glacial Maximum climate layers). All genetic markers consistently show extensive genetic variation within and genetic depletion outside the Carpathians. The species distribution model suggests that most of the current range was unsuitable at the Last Glacial Maximum, but a small suitable area remained in the Carpathians. Triturus cristatus dramatically expanded its postglacial range, colonizing much of temperate Eurasia from a glacial refugium in the Carpathians. Within the Carpathians, T. cristatus persisted in multiple geographically discrete regions, providing further support for a Carpathian ‘refugia within refugia’ scenario. © 2015 The Linnean Society of London, Biological Journal of the Linnean Society, 2015, 114 , 574–587.