Latitudinal and temporal shifts in the radial growth-climate response of Siberian larch in the Polar Urals

This paper presents a dendroclimatic analysis of Siberian larch trees sampled along a latitudinal 260-km transect located in the Polar Urals,Russia. Three standardised chronologies were built over a length of 230–293 years using 79 individual tree-ring chronologies collected in the southern,middle and northern parts of the Polar Urals.Bootstrapped correlation functions showed that the annual growth of the larches was mainly influenced by the air temperatures in June and July. The relative role of the temperatures increased from south to north. Daily air temperature data analysis revealed that the duration of the growing season in the northern part of the Polar Urals is 24 days less than that in the southern part. At the present time, air temperatures exceeded threshold of 8~℃, 5 days earlier than it did in the beginning of the 20 th century In response to the increase in the duration of the growing season and the changing winter conditions in the Polar Urals over the last 130 years, radial growth–temperature relationships in larches have weakened;this effect was strongly pronounced in the southern part of the Polar Urals.

Root structure syndromes of four families of monocots in the Middle Urals

The present article tests the following general assumption:plant taxa with different specializations towards mycorrhizal interactions should have different root syndromes.Roots of 61 species common in boreal zone were studied:16 species of Poaceae,24 species of Cyperaceae,14 species of Orchidaceae,and 7 species of Iridaceae.Using a fixed material of 5 individuals of each species,the following was determined:number of orders of branching roots;transverse dimensions of root,stele and cortex;number of primary xylem vessels and exodermis layers;length of root hairs;abundance of mycorrhiza.Species of each family had well-defined syndromes.Roots of Orchidaceae and Iridaceae were thick with a large stele and developed exodermis.Orchidaceae had no branching roots and had long root hairs.In Iridaceae,roots were branched,and root hairs were short.Roots of Poaceae and Cyperaceae were thin with a relatively thin stele.Root hairs were short in Poaceae and long in Cyperaceae.Our finding that root syndromes of four families of monocots differed is a new and unexpected discovery.The high specificity of root syndromes in Cyperaceae,Iridaceae,Poaceae,and Orchidaceae indicates that species of these families use different strategies to obtain water and soil nutrients.

Expansion of Juniperus sibirica Burgsd.as a response to climate change and associated effect on mountain tundra vegetation in the Northern Urals

Shrub expansion into arctic and alpine tundra is one of the prominent vegetation changes currently underway.We studied the expansion of shrub vegetation into high elevation tundra in the Kvarkush Range of the Northern Ural mountains,Russia.Age structure analysis of the dominant shrub Juniperus sibirica Burgsd.seems to support ongoing upslope advance of shrubs,a process particularly active in the second half of the 20 th century.We found a close connection between the expansion of shrub vegetation and the general change in climatic conditions of the cold season(months with mean airtemperature below 0°Сfrom November to March).In general,the greatest influence on the distribution of J.sibirica is exerted by the climate conditions of the beginning(November-January)and the end(March)of the cold season.With increasing elevation,the correlation coefficients between the establishment of J.sibirica shrubs and the precipitation of the beginning of the cold season increased,and reached maximum values at the top elevation level of the study area.However,the upwards shift of J.sibirica into typical mountain tundra does not lead to changes in the ecological structure of vegetation at this stage,but simply a decrease in the area of mountain tundra.

Climate change evidence in tree growth and stand productivity at the upper treeline ecotone in the Polar Ural Mountains

Background:Recent warming is affecting species composition and species areal distribution of many regions.However,although most treeline studies have estimated the rates of forest expansion into tundra,still little is known about the long-term dynamic of stand productivity at the forest-tundra intersection.Here,we make use of tree-ring data from 350 larch(Larix sibirica Ledeb.)and spruce(Picea obovata Ledeb.)sampled along the singular altitudinal treeline ecotone at the Polar Urals to assess the dynamic of stand establishment and productivity,and link the results with meteorological observations to identify the main environmental drivers.Results:The analysis of stand instalment indicated that more than 90%of the living trees appeared after 1900.During this period,the stand became denser and moved 50m upward,while in recent decades the trees of both species grew faster.The maximum afforestation occurred in the last decades of the twentieth century,and the large number of encountered saplings indicates that the forest is still expanding.The upward shift coincided with a slight increase of May-August and nearly doubling of September-April precipitation while the increase in growth matched with an early growth season warming(June+0.27°C per decade since 1901).This increase in radial growth combined with the stand densification led to a 6-90 times increase of biomass since 1950.Conclusion:Tree-ring based twentieth century reconstruction at the treeline ecotone shows an ongoing forest densification and expansion accompanied by an increased growth.These changes are driven by climate change mechanism,whereby the leading factors are the significant increase in May-June temperatures and precipitation during the dormant period.Exploring of phytomass accumulation mechanisms within treeline ecotone is valuable for improving our understanding of carbon dynamics and the overall climate balance in current treeline ecosystems and for predicting how these will be altered by global change.

Previously unknown behavior in parasitic cuckoo females:male-like vocalization during migratory activity

Background:In the last decade,enigmatic male-like cuckoo calls have been reported several times in East Asia.These calls exhibited a combination of vocal traits of both Oriental Cuckoo(Cuculus optatus)and Common Cuckoo(Cuculus canorus)advertising calls,and some authors therefore suggested that the enigmatic calls were produced by either Common×Oriental Cuckoo male hybrids or Common Cuckoo males having a gene mutation.However,the exact identity of calling birds are still unknown.Methods:We recorded previously unknown male-like calls from three captive Oriental Cuckoo females,and compared these calls with enigmatic vocalizations recorded in the wild as well as with advertising vocalizations of Common and Oriental Cuckoo males.To achieve this,we measured calls automatically.Besides,we video-recorded captive female emitting male-like calls,and compared these recordings with the YouTube recordings of calling males of both Common and Oriental Cuckoos to get insight into the mechanism of call production.Results:The analysis showed that female male-like calls recorded in captivity were similar to enigmatic calls recorded in the wild.Therefore,Oriental Cuckoo females might produce the latter calls.Two features of these female calls appeared to be unusual among birds.First,females produced male-like calls at the time of spring and autumn migratory activity and on migration in the wild.Because of this,functional significance of this call remained puzzling.Secondly,the male-like female call unexpectedly combined features of both closed-mouth(closed beak and simultaneous inflation of the‘throat sac')and open-mouth(prominent harmonic spectrum and the maximum neck extension observed at the beginning of a sound)vocal behaviors.Conclusions:The Cuculus vocalizations outside the reproductive season remain poorly understood.Here,we found for the first time that Oriental Cuckoo females can produce male-like calls in that time.Because of its rarity,this call might be an atavism.Indeed,female male-like vocalizations are still known in non-parasitic tropical and apparently more basal cuckoos only.Therefore,our findings may shed light on the evolution of vocal communication in avian brood parasites.

FungalTraits:a user-friendly traits database of fungi and fungus-like stramenopiles

The cryptic lifestyle of most fungi necessitates molecular identification of the guild in environmental studies.Over the past decades,rapid development and affordability of molecular tools have tremendously improved insights of the fungal diversity in all ecosystems and habitats.Yet,in spite of the progress of molecular methods,knowledge about functional properties of the fungal taxa is vague and interpretation of environmental studies in an ecologically meaningful manner remains challenging.In order to facilitate functional assignments and ecological interpretation of environmental studies we introduce a user friendly traits and character database FungalTraits operating at genus and species hypothesis levels.Combining the information from previous efforts such as FUNGuild and FunFun together with involvement of expert knowledge,we reannotated 10,210 and 151 fungal and Stramenopila genera,respectively.This resulted in a stand-alone spreadsheet dataset covering 17 lifestyle related traits of fungal and Stramenopila genera,designed for rapid functional assignments of environmental stud-ies.In order to assign the trait states to fungal species hypotheses,the scientific community of experts manually categorised and assigned available trait information to 697,413 fungal ITS sequences.On the basis of those sequences we were able to summarise trait and host information into 92,623 fungal species hypotheses at 1%dissimilarity threshold.

Correction to:FungalTraits:a user friendly traits database of fungi and fungus-like stramenopiles

Correction to:Fungal Diversity(2020)105:116 https://doi.org/10.1007/s13225-020-00466-2 There were errors in the name of author LászlóG.Nagy and in affiliation no.31 in the original publication.The original article has been corrected.

从木材解剖学视角看公元6世纪中期晚古小冰期的开始时间

公元536~540年间的大规模火山喷发使得晚古小冰期成为过去两千年最为寒冷的时期.然而,受限于现有气候代用资料的时间分辨率和空间覆盖度,晚古小冰期的开始时间和空间范围仍存有争议.本文分析了全球23个森林样点、20个树种的106个树轮样本资料,从细胞尺度揭示了公元530~550年间北半球发生的短暂夏季冷却现象.经过交叉定年和染色处理后,在北半球的树轮样品中共识别出89个蓝轮(缺失细胞壁木质化过程)、9个霜轮(细胞分裂受阻)和93个浅轮(细胞壁增厚减弱).研究结果表明,公元536年7月中旬至8月初期间整个北美和欧亚大陆均发生了最剧烈的温度下降,而更多的区域性“冷夏”出现于公元532年、540~543年和548年.然而,本研究在南半球的树轮资料中并未发现异常的解剖结构,其原因可能与南半球的海洋热惯性减缓了火山降温效应有关,也或与南半球其时正值非生长季有关.相较于传统的树轮年代学方法,本研究的木材解剖学的方法能为地球系统模式提供更为精细的参考标准,有望服务于气候与人类历史交叉学科研究,同时对“全球气候平均”概念的使用提出质疑.