Understanding the environmental drivers of radial growth in the Pinus massoniana (lamb.) is essential for improving forest productivity and carbon sequestration in subtropical ecosystems. This study used the basal area increment (BAI) as an indicator of radial growth to investigate the main factors affecting the radial growth rate of P. massoniana and the changes in BAI with these factors. A total of 58 high quality tree ring series were analyzed. Six common methods were used to comprehensively analyze the importance of nine factor variables on the BAI, including tree age, competition index, average temperature, and so on. Generalized additive models (GAMs) were developed to explore the nonlinear relationships between each selected variable and the BAI. The results revealed the following: (1) Age and Competition Index was identified as the primary driving force; (2) BAI increased with Age when tree age was below 69 years; (3) from the overall trend, the BAI of P. massoniana decreased with the increase in the Competition Index. These findings provide a scientific basis for developing management plans for P. massoniana forests.

In order to reduce modeling workload and improve the accuracy of wood density measurement, a modeling method for establishing an overall model for multiple tree species was studied. Firstly, the wood cores and drill resistance of 9 tree species were collected. The absolute dry density, wood moisture content, and average drill resistance for each wood core were calculated. Secondly, the random forest algorithm was used to rank the relative importance of each factor affecting wood density, and factors with relative importance higher than 0.05 were selected as independent variables for building the overall mathematical model for total tree species and sub model for individual tree species. The results showed that: (1) the relative importance of tree species and drill resistance on wood density was higher than 0.05; (2) the relative importance of moisture content and drill usage frequency (less than 150 times) on wood density was lower than 0.05; (3) the average estimation accuracy of overall model was 91.42

The Eurasian Goshawk (Accipiter gentilis schvedowi) is widely distributed across Russia and East Asia and is a second-class key protected wild animal species in China. There have been few studies on the migration routes of this species. Here, we present data from solar-powered satellite transmitters we placed on 4 goshawks at Changdao Island, Shangdaong Province, China, to follow them over the period of 2008-2013 and document their migratory routes and site fi delity. We obtained 7 spring and 9 autumn migration trajectories. We identified Shangdong and Anhui in China as wintering sites and Inner Mongolia, China, and Russia as breeding areas of Eurasian Goshawks. The spring migration fl ights covered 1,936 +/- 847.08 km and took 27 +/- 11.20 d (n 1 / 4 3), and the autumn migration covered 2,382.50 +/- 781.35 km and took 39 +/- 15.56 d (n 1 / 4 2). We found no significant difference in migration distance covered or number of traveling days between autumn and spring. We identified 7 stopover sites during spring and 21 stopover sites during autumn migration. Goshawks had strong site fi delity to breeding and wintering sites, and the arrival dates at wintering and breeding sites were similar among years. Our data will aid in the conservation of this species, including guiding decision- making and conservation action plans by providing basic data for the protection of goshawk populations and habitats. Received 11 August 2023. Accepted 14 August 2024.

To achieve a micro-destructive and rapid measurement of the wood density of standing trees, this study investigated the possibility of the unified modeling of multiple tree species, the reliability of the micro drilling resistance method for measuring wood density, the relationship between drilling needle resistance and wood density, and whether moisture content has a significant impact on the model. First, 231 tree cores and drill resistance data were sampled from Pinus massoniana, Cunninghamia lanceolate, and Cryptomeria fortunei. The basic density and moisture content of each core were measured, and the average value of each resistance data record was calculated. Second, the average drill resistance, the natural logarithm of average drill resistance, and absolute moisture content were used as independent variables, while the basic wood density was used as the dependent variable. Third, the total model of the three tree species and sub-model for each tree species were established through a stepwise regression method. Finally, the accuracy of each model was compared and analyzed with that of using the average basic density of each tree species as an estimated density. The estimated accuracy of the total model, sub model, and average wood density modeling data were 90.070%, 93.865%, and 92.195%, respectively. The results revealed that the estimation accuracy of the sub-model was 1.670 percentage points higher than that of the average wood density modeling data, while the estimation accuracy of the total model was 2.125 percentage points lower than that of the average wood density modeling data. Additionally, except for Cryptomeria fortunei, the natural logarithm of drill resistance significantly influenced the wood density model at a significance level of 0.05. Moreover, moisture content significantly affected the total model and sub-models of Pinus massoniana at a significance level of 0.05. The results indicated the feasibility of using the micro-drilling resistance method to measure the wood density of standing trees. Moreover, the relationship between wood density and drill resistance did not follow a linear pattern, and moisture content slightly influenced the drill needle resistance. Furthermore, the establishment of a mathematical model for each tree species was deemed essential. This study provides valuable guidance for measuring the wood density of standing trees through the micro-drilling resistance method.

Drill feed speed significantly affects the measurement accuracy and efficiency of the micro drill resistance instrument. Generally, different speeds are set according to the density of the wood to be drilled. It is necessary to convert the resistance data measured at different drill feed speeds into resistance data at a uniform speed to properly analyze resistance data. In this study, drill resistance data for a Paulownia wood block was measured with a self-made micro drill resistance instrument at different drill feed speeds. We found that the drill resistance is positively correlated with changes in its feed speed and the natural logarithm of change times for feed speed. We developed a conversion algorithm for the micro drill resistance instrument measurements at different feed speeds. The accuracy of the conversion algorithm is up to 95%. The algorithm can be used to convert the drill resistance of Paulownia wood measured at different drill feed speeds; it has reference value for the mutual conversion of other tree species’ drill resistance data measured at different feed speeds. This work may provide a feasible solution to improving micro drill resistance instrument accuracy when drill feed speed error is high.

Wood density is an important attribute that is positively correlated with many wood quality parameters. How to express wood density with drill resistance is a challenge. In this study, we determined the optimal resistance expression using the current, voltage, and power of the DC (Direct-Current) motor. Nine wood blocks crossing over the pith, with widths and heights of 2 cm and 5 cm, respectively, were obtained from three larch (Larix spp.) trees. The microdensity of each wood block at every 0.1-mm length was measured, and the average current, voltage, and power of the DC motor was recorded when the drill fed forward at every 0.1 mm by a self-manufactured resistance drill. The drill path was parallel to the lengthwise direction of the block. The linear models between the current, voltage, and power of the DC motor and wood microdensity were subsequently established, and the model with the highest R2adj was selected to express the resistance. The adjusted R2adj of the forward stepwise regression models between the current, voltage, and power of the DC motor and wood microdensity were determined as 0.2943. This suggests that the drilling needle resistance expressed with the current, voltage, and power or other combination may be optimal.

针对前期研制的微钻阻力仪存在钻针钻入树木方向偏离直线方向、无法准确获取树木年轮宽度等问题,对微钻阻力仪的机械结构和软件算法进行了改进,提出了改进钻针形状和增加钻针支撑挡片的改进措施,给出了年轮宽度的计算方法.分别使用自制微钻阻力仪、Resistograph 650-s型微钻阻力仪、Lintab 6型高精度树木年轮分析仪测量9个马尾松圆盘的年轮信息,以Lintab 6型树木年轮分析仪测试结果作为真值,分别计算自制微钻阻力仪和Resistograph 650-s型微钻阻力仪的年轮识别错误率和年轮宽度测量精度.结果表明:2个微钻阻力仪的平均年轮宽度的测量精度达85％左右,说明使用微钻阻力法测量树木年轮宽度可行;自制微钻阻力仪的年轮识别错误率比Resistograph 650-s型微钻阻力仪低12.7个百分点,年轮宽度测量精度比Resistograph 650-s型微钻阻力仪高1.47个百分点,说明自制微钻阻力仪机械结构设计合理,年轮识别方法可行.

低温对鸟类的生长发育、新陈代谢和生活状态有显著的影响,鸟类往往通过改变行为模式来适应温度的变化.朱鹮(Nipponia nippon)是东亚特有的濒危鸟类,2018年从秦岭南麓的陕西洋县引入到河北北戴河,建立了全球纬度最高的野化种群.本文以北戴河和洋县两个野化种群为研究对象,采用瞬时扫描法观察分析了季节和温度等因素对朱鹮休息行为的影响.结果 表明,双腿站立露喙是朱鹮在游荡期最常见的休息行为(70.9％),但在越冬期显著降低(55.6％),而单腿站立和隐喙行为比例相应升高.温度对双腿站立隐喙、单腿站立露喙和单腿站立隐喙3种行为的比例有显著影响.可见,朱鹮在冬季通过增加保护裸露部位的行为比例来适应低温.在冬季,随着温度的下降,朱鹮趴卧在树干上的夜宿行为比例逐渐增加,而这一行为在白天没有记录到.温度对成鸟和幼鸟冬季的休息行为有显著影响.由此表明,趴卧行为很可能是朱鹮对极端耐受低温的一种应对,在保护监测过程中需警惕.朱鹮在北戴河越冬过程中没有使用网笼中的遮挡伞棚和庇护场所,表明其能够自主适应-20℃的低温.为了确保野化朱鹮顺利越冬,建议在野化网笼中增加一些松科等常绿树种,为朱鹮提供更加优良的夜宿环境,并用稻草搭建风挡,减少夜间大风的负面影响.

鸟类环志是种群监测和迁徙研究的重要手段.基于秦皇岛鸟类环志站1999～2019年的环志数据,对黄胸鹀(Emberiza aureola)和蓝歌鸲(Larvivora cyane)两种鸟类在21年间的种群动态和迁徙时序进行了分析.结果表明,迁徙途经秦皇岛的黄胸鹀种群数量以4或5年为周期呈规律性的波动下降,年均降幅达17.3％,21年间种群数量累计下降了97.7％.近年来我国加强了对黄胸鹀及其栖息地的保护管理,并于2021年初将其列为国家Ⅰ级重点保护动物,有望促进其种群的逐步恢复.蓝歌鸲种群数量的年均降幅为4.2％,但下降过程主要集中在1999至2003年间,其后种群指数趋于稳定.黄胸鹀春季网捕高峰短暂而集中,持续约15 d;秋季网捕高峰则较为分散,持续约47 d.这表明黄胸鹀春季迁徙进程明显较为集中和快速,可能是出于繁殖需求采取了时间最短的迁徙策略.蓝歌鸲成年雄鸟、成年雌鸟和亚成鸟春季的网捕高峰在日期上有明显的差异,间隔4或5 d先后出现,表明蓝歌鸲不同年龄和性别的个体在春季进行差别迁徙,有利于减小停歇地的种内竞争,并确保雄鸟提前到达繁殖地占领优质的繁殖领域.

环境温度变化通过影响鸟类的行为进而使其活动区也发生变化,探讨三者之间的关联性有助于理解鸟类是如何通过行为调整以适应周围环境的变化,来满足自身的生理需求.本研究通过卫星跟踪的方法获得了在河南三门峡湿地越冬的31只大天鹅(Cygnus cygnus)详细位点数据,在ArcGIS和R语言中采用核密度估计法计算大天鹅的活动区面积,在SPSS中采用Spearman分析平均温度与活动区面积的相关性;并利用瞬时扫描法获得大天鹅越冬行为观察数据,采用非参数Kruskal Wallis检验对大天鹅行为的差异性进行分析,探讨了环境温度与大天鹅越冬行为和活动区三者之间相互作用的模式.研究表明,从越冬初期至后期,随着环境温度的先下降后升高,大天鹅的取食、运动、静息等主要行为发生了较大的变化,静息和取食行为先增加后减少,运动行为则先减少后增加.越冬不同时期的核心区和活动区面积与温度呈显著性正相关.大天鹅在不同时段的活动区面积大小整体上均呈现出先减少后增加的趋势.随着环境温度的变化,大天鹅的越冬行为也随之发生了调整,进而使活动区面积发生改变,主要体现在越冬初期大天鹅通过增加活动区面积及时补充能量增加体能,越冬中期减少活动保持能量需求,越冬后期增加盘旋飞行使得活动区面积增大等.大天鹅这一系列行为和活动区的调整都是为了更好地满足越冬不同时期的生理需求.

The crested ibis Nipponia nippon formerly occurred throughout East Asia, but since 1981 its unique population has been confined to a narrow band in transborder area of Yangxian, Chenggu and Xixiang County of Shaanxi Province, Central China, on the south slope of the Qinling Mountains. During 2004-2005, 23 crested ibises were experimentally reintroduced to an isolated basin in Qinling Mountains, where they and their offspring exhibited breeding variation never observed in wild population in the following 9 breeding seasons. Crested ibis has been considered a monogamous species, and breeding pair is solitary and territorial. However, 3.4% of breeding females exhibited polyandry and 43.1% of nests were observed colonial in single tree in the reintroduced population, probably due to male-biased sex ratio and better nesting conditions. First nest failure in reintroduced population occurred much earlier than that in wild, which resulted in significantly higher probability of re-nesting. The phenotypic plasticity in crested ibis may play important role in future reintroduction of this critically endangered species under a changing environment.

为提高树木年轮测量仪的测量精度,提出了一种自适应低通滤波算法对年轮测量仪的直流电机电流信号进行滤波处理.普通低通滤波算法滤波系数固定,当树木年轮宽度发生变化时,既可能保留了部分噪声信号,又可能滤去部分有效的树木年轮信号,因此降低了年轮测量仪的测量精度.自适应低通滤波算法的滤波系数可随滤波器输入值和输出值的变化自动进行调整,提高了噪声滤除效果,减少了有效信号损失.使用自主研发的年轮测量仪测量了大、中、小3种径阶的60个落叶松圆盘,记录直流电机原始电流信号,分别采用自适应低通滤波算法和普通低通滤波算法对原始电流进行滤波处理,根据滤波后的电流波形图,预估圆盘年龄,并计算2种滤波算法的年轮识别正确率.结果 表明,自适应低通滤波器年轮识别正确率的平均值为89.66％,普通低通滤波器年轮识别正确率的平均值为75.84％;当平均年轮宽度变窄时,自适应低通滤波器的年轮识别正确率从95.61％下降到82.02％,下降了13.59个百分点,而普通低通滤波器的年轮识别正确率从86.37％下降到62.30％,下降了24.07个百分点.表明自适应低通滤波器年轮识别正确率高,自适应能力强,年轮识别精度稳定.

Five novel H5N6 influenza viruses, including four highly pathogenic avian influenza viruses and one low pathogenic avian influenza virus, were isolated from migratory birds in Ningxia, China, in November 2017. To understand the genetic origination of the novel H5N6 virus, and the infectivity and pathogenicity of the four highly pathogenic avian influenza viruses in mammals, phylogeographic analyses and infection studies in mice were performed. The phylogenetic and phylogeographic analyses showed that the H5N6 isolates, which are closely related to the viruses from Korea, Japan and the Netherlands, originated from reassortant virus between H5N8 and HxN6 viruses from western Russia. The animal study revealed that the SBD-87 isolate presented moderate virulence in mice, suggesting a potential public risk to humans and a potential threat to public health.

To further protect the breeding population of black-faced spoonbills (Platalea minor), it is important to understand the current conservation status of breeding distribution sites and migration routes, especially for important stopover and wintering sites of black-faced spoonbills. Six individuals were tagged with satellite transmitters at Zhuanghe, Liaoning Province, northeastern China, in July of 2017 and 2018 to identify important distribution sites during the breeding period and detailed migration routes. The results showed that Zhuanghe Bay, Qingduizi Bay and Dayang Estuary were important feeding and roosting sites for black-faced spoonbills from August to October. Jiaozhou Bay, Shandong Province, and Lianyungang and Yancheng, Jiangsu Province, were important stopover sites during fall migration, and the coastal areas of Yancheng, Jiangsu; Hangzhou Bay, Zhejiang Province; and Tainan, Taiwan of China; and the inland areas of Poyang Lake, Jiangxi Province, and Nanyi Lake, Anhui Province, were important wintering sites. This is the first study to report the inland migration routes of black-faced spoonbills in China. Our findings on the key breeding distribution sites, fall migration routes and current threats (such as aquaculture, mudflat reclamation and dam construction) have important implications for the conservation of and global action plan development for the endangered black-faced spoonbill.

冬季幼鸟与成鸟面临着不同的生存压力,成鸟负责照顾幼鸟使其获得最大的生存率,这使得它们的行为选择不同.2016年12月-2017年3月,在河南省三门峡湿地,采用瞬时扫描法记录了成、幼大天鹅Cygnus cygnus的行为类型,并对越冬期成、幼大天鹅昼间行为选择的差异进行了分析.结果 表明,在整个越冬期,成鸟占比最高的行为是警戒(29.1％),并高于幼鸟(18.5％);幼鸟占比最高的行为是运动(22.7％),并高于成鸟(18.2％).对不同越冬阶段的行为差异分析表明,成鸟在越冬初期占比最高的行为是警戒(27.6％),幼鸟的是觅食(26.5％).在越冬初期,幼鸟经过长时间的迁徙,急需补充能量,因此觅食行为占比最高,此时成鸟为保护幼鸟的安全,在警戒上的时间较其他行为更多;进入越冬中期,成、幼鸟的警戒行为均有所增加(成鸟:32.3％;幼鸟:20.8％),占比最高,此时湖面结冰,大天鹅受到天敌攻击的几率增加,因此成、幼鸟警戒行为均有所增加,且此时天然食物减少,成、幼鸟的觅食行为有所下降(成鸟:8.8％;幼鸟:13.5％),并增加了休息时间,以减少能量消耗来抵御严寒;到了越冬后期,成鸟的警戒行为(27.2％)仍是占比最高的行为,但与前期、中期相比,后期有所下降,幼鸟占比最高的行为是运动(26.3％),如飞行等,此时春季迁徙即将来临,幼鸟需要增加运动来锻炼飞行能力;成鸟此时也需积累能量,因此警戒行为与其他2个时期相比有所下降.在整个越冬阶段,成鸟警戒的比例都是最高的,表明成鸟始终以减少觅食和休息时间来保证幼鸟的安全作为首要任务.

The spread of highly pathogenic avian influenza (HPAI) H5N1 virus is associated with wild fowl migration in East Asian-Australasian (EA) and Central Asian (CA) flyways. However, the spread of H5N1 virus between the two flyways is still unclear. Here, the movements of wild waterfowl were obtained from satellite tracking data covering seven bar-headed geese and three great black-headed gulls breeding in the Qinghai Lake area (along the EA flyway), and 20 whooper swans wintering in the Sanmenxia Reservoir area (at the CA flyway). From the 2688 samples that were screened from wild birds at Qinghai Lake after an outbreak of HSN1 in July 2015, four genomes of HSN1 virus were obtained from bar-headed geese. The results of phylogenetic analysis indicated that these H5N1 viruses belonged to Glade 2.3.2.1c and their gene fragments were highly homologous with A/whooper swan/Henan/SMX1/2015 (HSN1) virus (ranging from 99.76% to 100.00%) isolated from a dead whooper swan from the Sanmenxia Reservoir area along the EA flyway in January 2015. Furthermore, the coincidental timing of the HSN1 outbreak with spring migration, together with phylogenetic evidence, provided new evidence of the east-to-west spread of HPAI H5N1 between the EA and CA migratory flyways of China. [GRAPHICS] .

Home range and habitat use are the central components of avian ecology, and studies on these aspects will be helpful for the conservation and management of avian populations. Sixty-seven swans were global positioning system tagged at Sanmenxia Wetland of Henan Province to obtain detailed location data in winter from 2015 to 2016. The home range size of swans was the largest in the middle wintering period and followed by the early period and late period, and sizes were significantly different among the three wintering periods. There were significant differences in habitat use among the different wintering periods. In the early period, the swans mainly used the aquatic grasses and emergent plants zones, and they mainly relied on artificial supplementation because of a lack of natural feeding habitats in the middle period. In the late period, the swans mainly used the newly emerged terrestrial grasses zone. Except for the deep water, the use of other water levels was significantly different among the different wintering periods. In the early wintering period, the swans tended to prefer the low and high water level areas; in the middle period, they were mainly in the intermediate and high water level areas and they used all the water level areas except the deep water level in the late wintering period. It was concluded that some plants are preferred by the swans, such as reeds, cattails and barnyard grass, and that water depth should be suitable for the swans, with the water levels varying over a gradient.

Physiological stress in captive wild animals may be caused by stressors such as capture, handling, and transport. Continuous strong stimulation may induce a long-term physiological stress in captive wild animals after transport. Fecal Glucocorticosteroid Metabolites (FGM), vital signs and behavioral changes were used to establish stress responses of white rhinoceros during a translocation process. The result indicated that the overall FGM increased significantly (p < 0.05) during transport compared to FGM baseline concentration established in two rhino breeding centers. Respiratory rate, heart rate, and body temperature were significantly increased during capture and transport. Grouping and aggressive behavior increased after transport, reflecting the acclimatization to the new social environment. Feeding also increased probably due to increased energy consumption during transport. The overall FGM concentration increased during capture and transport but normalized within an average period of 32 days after transport. Individual differences were attributed to previous transport experience and the ability of intrinsic control through increased adrenaline levels. Recommendations to improve the management and welfare of captive white rhinoceros on transport are provided. (C) 2019 The Authors. Published by Elsevier B.V.

BackgroundThe Black-necked Crane (Grus nigricollis) is an internationally threatened crane living on the plateau, mainly in winter, in the Yarlung Tsangpo River basin in Tibet, western China. In the past five years, some economic development projects have been conducted in this area, posing potential threats to the wintering populations of the cranes and their habitats. Therefore, the current population dynamics of wintering Black-necked Cranes and habitat suitability in the Yarlung Tsangpo River basin were investigated.MethodsTwenty counties were surveyed using the line transect method in December 2017 and January 2018, and we recorded the location, flock size, number of individuals, habitat types and presence of human disturbance in which they occurred. We compared the results from the middle wintering period in this survey with those from 2014.ResultsThe highest number of cranes recorded was 8291, and the results showed that the cranes were mainly distributed in Lhaze, Namling, Samzhubze, and Lhunzub. A total of 577 and 495 flocks were recorded in the early and middle wintering periods, respectively. In the early wintering period, there were significant differences in the number of individuals across the different habitats, with crop stubble land and plowed land representing more than 30% of the total habitat utilization. In the middle wintering period, there were also significant differences in the number of individuals, and the utilization of crop stubble land represented over 60% of the total.ConclusionsWintering Black-necked Cranes mainly fed on spilled grains in stubble habitat after harvest. In the middle wintering period, some of the farmlands were plowed and irrigated, which resulted in food shortages in these areas, and the cranes tended to gather in mixed flocks of large size instead of as a single family. There were still considerable regional wintering populations decreases in Quxu, Nedong, and Sakya in 2018 compared with 2014, and these decreases were mainly due to some recently emerging threats, including farmlands being converted into areas of greenhouse cultivation, highway and railway construction, river dredging, the rapid development of the manufacturing and mining industries, and the lack of protection of important wintering sites.