Comparison of growth-climate relationship of Sabina przewalskii at different timberlines along a precipitation gradient in the northeast Qinghai-Xizang Plateau,China

为了了解青藏高原东北部不同降水梯度下, 高山林线处的树木径向生长与气候关系是否存在差异, 在青海东北部从西北到东南沿降水梯度设置3个高山林线采样点: 乌兰县哈里哈图国家森林公园(HL, 年降水量217 mm)、都兰县曲什岗(QS, 281 mm)和同德县河北林场(HB, 470 mm), 运用树轮年轮学方法分析林线优势种祁连圆柏(Sabina przewalskii)的径向生长-气候关系随降水梯度的变化规律。结果表明: 不同降水梯度下, 降水对祁连圆柏径向生长的限制作用差异不明显, 但温度对祁连圆柏径向生长的影响存在显著差异。在低降水区域(HL), 冬、夏季最低气温主要限制祁连圆柏径向生长, 并且在不同气候特征年中无明显变化; 在中降水区域(QS), 祁连圆柏的径向生长明显受冬季最低气温影响, 与低降水区域相比, 春、夏季最低气温对祁连圆柏径向生长的限制作用减弱, 并且主要限制因子在不同气候特征年存在显著变化; 在高降水区域(HB), 冬、夏季最低气温对祁连圆柏径向生长的限制作用不显著, 而春、秋季最低气温对祁连圆柏径向生长的抑制作用显著增加, 并且主要集中在高温年和干旱年。该研究结果并未支持干旱(湿润)区高山林线树木径向生长主要由水分(温度)限制的假说, 但是林线处降水量会影响树木生长与温度的关系。随着青藏高原东北部暖湿化加剧, 不同地区林线处树木生长的气候限制因子可能存在复杂化趋势。     

基于叶绿体DNA trnT-trnF序列研究祁连圆柏的谱系地理学

由于青藏高原的地貌效应,第四纪冰期气候的反复变化应对现今该地区生物的地理分布及其居群遗传结构产生重大影响。本文对这一地区特有分布物种祁连圆柏Juniperus przewalskii Kom.整个分布区内20居群392个个体的trnT-trnF序列变化进行了研究;共发现3种单倍型(haplotype),构成两种地理区域:高原台面上的居群主要固定Hap A,而Hap A、Hap B和Hap C在高原边缘居群均有分布。所有居群总的遗传多样性HT = 0.511,GST= 0.847。在低海拔的高原边缘,Hap A、Hap B和Hap C高频率固定在不同的居群中,表明可能存在多个不同的避难所,居群反复缩小和扩张的瓶颈效应造成了遗传多样性的丢失。而边缘的一个居群含有两种相似单倍型频率则可能是冰期后迁移融合而成或者该居群在冰期经受的瓶颈作用更弱。高原台面东部间断分布的居群只固定Hap A,表明它们可能经历了冰期后共同的回迁过程和由此产生的奠基者效应。我们的研究结果表明祁连圆柏在冰期可能存在多个避难所,瓶颈效应和奠基者效应造成了这些居群现在的遗传多样性分布式样。     

Comparison of growth-climate relationship of sabina przewalskii at different timberlines along a precipitation gradient in the northeast Qinghai-Xizang Plateau,China北大核心CSCD

Aims To test the hypothesis that water is the main limiting factor of tree growth at the arid alpine timberline, and to explore the effects of water on growth-climate relationships of Sabina przewalskii along a precipitation gradient in the northeast Qinghai-Xizang Plateau. Methods Three sides were selected to sample the alpine timberline along a precipitation gradient in the northeast Qinghai-Xizang Plateau: Halihatu National Forest Park in Wulan County (HL, annual precipitation 217 mm), Qushigang in Dulan County (QS, 281 mm) and Hebei Forest Farm in Tongde County (HB, 470 mm). The correlation and response analysis at seasonal and extreme climate year scales were used to examine the spatial variations of the growth-climate relationship of S. przewalskii at different timberlines. Important findings Our results do not support the hypothesis that water is the main limiting factor of tree growth at the arid alpine timberline. The effect of precipitation on the radial growth of S. przewalskii were consistent across all three sampling sites, while the effects of temperature were different across sites. At HL site (low precipitation), the winter and summer minimum temperature were the main limiting factor of S. przewalskii radial growth, and this relationship did not significantly change in different extreme climate years. At QS site (middle precipitation), the radial growth of S. przewalskii was mainly limited by the minimum temperature in spring and summer, but its effect was weaker than that at low precipitation site. At HB site (high precipitation), the spring temperature had a significant negative effect on tree growth, and the positive effect of spring precipitation on tree growth was significantly enhanced in comparison with those at low and middle precipitation sites, especially in extreme high temperature and drought years. Summer precipitation did not significantly affect tree growth at high precipitation site. Our results did not support the hypothesis that the radial growth of trees at alpine timberline in arid/humid area is mainly limited by water/temperature. However, precipitation at timberline will affect the relationship between tree growth and temperature at different seasons. With the warming and humidification of the northeastern Qinghai-Xizang Plateau, the climatic limiting factors of tree growth in different timberline areas may be complicated. © 2018 Editorial Office of Chinese Journal of Plant Ecology. All rights reserved.     

坡向对海拔梯度上祁连圆柏树木生长的影响

选择青海省同德县南部河北林场的一个连续坡面,根据不同海拔和坡向设置4个采样点,采集祁连圆柏(Sabina przewalskii)树轮数据,分析不同海拔和坡向对树木生长的影响。结果表明:坡面上部3个采样点的树轮年表特征值均呈一定的变化规律——平均敏感值(MS)和标准差(SD)随海拔升高而增大,一阶自相关(AC)随海拔升高而递减,下限年表特征值均表现出与其他3点的不同,都是最值(MS和SD均最大,AC最小);年表间相关和主成分分析结果都显示出海拔梯度上的变化规律,但下限差异显著;树轮指数与当年6–8月平均气温的相关系数呈增强趋势,森林上限受当年7、8月平均气温影响较大,下限树轮指数不仅与当年6月和前一年11月的气温显著负相关,而且受前一年8月和当年5月的月降水量影响显著。与通常情况"下限树木生长受降水制约"比较,这里的温度作用增强而降水限制减弱。显然,坡向扭转是海拔梯度上影响祁连圆柏生长变化的重要因子。     

Phylogeography and conservation genetics of Lake Qinghai scaleless carp Gymnocypris przewalskii

The objective of this study was to examine the spatial genetic relationships of the Lake Qinghai scaleless carp Gymnocypris przewalskii within the Lake Qinghai system, determining whether genetic evidence supports the current taxonomy of Gymnocypris przewalskii przewalskii and Gymnocypris przewalskii ganzihonensis and whether Gymnocypris przewalskii przewalskii are returning to their natal rivers to spawn. Comparison of mitochondrial (control region) variation (42 haplotypes in 203 fish) of G. przewalskii with the postulated ancestral species found in the Yellow River, Gymnocypris eckloni (10 haplotypes in 23 fish), indicated no haplotype sharing, but incomplete lineage sorting. Consistent with the sub-species status, an AMOVA indicated that the Ganzi River population was significantly different from all other river populations (F(ST) = 0·1671, P < 0·001). No genetic structure was found among the other rivers in the Lake Qinghai catchment. An AMOVA of amplified fragment length polymorphism (AFLP) loci, however, revealed significant genetic differences between most spawning populations (F(ST) = 0·0721, P < 0·001). Both mitochondrial and AFLP data found significant differences among G. p. przewalskii, G. p. ganzihonensis and G. eckloni (F(ST) values of 0·1959 and 0·1431, respectively, P < 0·001). Consistent with the incomplete lineage sorting, Structure analysis of AFLP loci showed evidence of five clusters. One cluster is shared among all sample locations, one is unique to G. p. ganzihonensis and G. eckloni, and the others are mostly found in G. p. przewalskii. Genetic evidence therefore supports the current taxonomy, including the sub-species status of G. p. ganzihonensis, and is consistent with natal homing of most Lake Qinghai populations. These findings have significant implications for the conservation and management of this unique and threatened species. The evidence suggests that G. p. przewalskii should be treated as a single population for conservation purposes. Exchangeability of the populations, however, should not be used to promote homogenization of fish spawning in the different rivers. As some degree of genetic divergence was detected in this study, it is recommended that the spawning groups be treated as separate management units.     

气候变化情景下祁连圆柏在青海省的适宜分布区预测

祁连圆柏具有良好的水土保持功能,是青海省高寒干旱地区造林绿化的优良乡土树种之一,预测未来气候变化情景下祁连圆柏在青海省的潜在地理分布将为祁连圆柏的经营管理和引种栽培提供理论指导。本研究基于实地调查和资料搜集获得88个有效地理分布样点,利用Maxent模型和ArcGIS空间分析技术对当前气候条件下祁连圆柏在青海省的潜在地理分布进行模拟,综合Jackknife检验和相关系数,分析影响祁连圆柏潜在分布的主导限制因子,同时结合第六次国际耦合模式比较计划(CMIP6)的气候模式数据,预测祁连圆柏在3种(SSP126、SSP245、SSP585)气候变化情景下2061—2080年潜在适生区的变化。结果表明:Maxent模型受试者工作特征曲线下面积(AUC)都大于0.92,具有较好的预测能力。在当前气候条件下,祁连圆柏的适宜分布区主要位于青海省东部,总适宜区面积占比为11.2%,影响其地理分布的主导因子是海拔、年均降水量、极端最低温和坡度,累计贡献率为85.9%。未来3种气候情景对祁连圆柏适宜区的影响存在差异,SSP245气候情景的适宜区面积将会缩减,SSP126和SSP585气候情景下则会不同程度地扩张,SSP126气候情景的扩张最明显,其扩张区域主要位于泽库县、河南蒙古族自治县中北部和祁连县东南部地区。在未来3种气候情景下,祁连圆柏适宜分布区逐渐向高海拔地区迁移,但在经纬度方向分布变化较小,适宜区总体稳定。     

甘西鼠尾草一新变型

2004年8月份,我们在巴颜喀拉山南坡考察时,在四川省的壤塘县发现了甘西鼠尾草的一个白花变型,生境为海拔3350m的沟谷林缘灌丛,现报道如下。     

掌裂橐吾的胚胎学

首次报道了掌裂橐吾的胚胎发育过程。药壁发育双子叶型;绒毡层发育属、The Cosmos bipinnatus”型,成熟花粉为3细胞型;单珠被,薄珠心,倒生胚珠;具发达的珠被绒毡层;胚囊发育为4孢子型,类似德鲁撒型（Drusa);胚乳发育为核型,胚胎发育为紫菀型千里光变型。     

沙柳河青海湖裸鲤早期资源发生量及时空分布

为了掌握青海湖裸鲤(Gymnocypris przewalksii)资源补充状况, 于2019年5月26日至9月2日逐日在青海湖第二大支流沙柳河开展了青海湖裸鲤早期资源丰度时空变化特征的调查研究, 共采集青海湖裸鲤鱼卵3386粒, 仔鱼4690尾。调查发现, 亲鱼自5月底开始洄游, 鱼卵6月初出现, 6月底至7月初达到高峰, 随后逐渐下降, 至8月中旬基本消失。仔鱼数量自7月初呈波动式上升, 8月达到高峰, 9月初逐渐消失。经估算, 沙柳河鱼卵径流量为25.58×106粒, 仔鱼径流量为62.00×106尾。鱼卵仔鱼空间分布为从河口往上丰度依次递减, 断面水平分布为右岸>左岸>中心。Kruskal-Wallis检验表明, 昼夜鱼卵丰度存在显著差异(P<0.05); 昼夜仔鱼丰度存在极显著性差异(P<0.01), 鱼卵仔鱼漂流高峰期均集中在夜间。鱼卵丰度与流速呈显著正相关(P<0.05), 仔鱼丰度与流速呈极显著正相关(P<0.01), 与径流量日上涨率呈极显著正相关(P<0.01)。研究报道了沙柳河青海湖裸鲤早期资源现状, 填补了该水域青海湖裸鲤早期资源研究的空缺, 为青海湖裸鲤上溯亲本资源量和入湖幼鱼资源量估算提供了数据支撑, 可为青海湖裸鲤资源管理与保护提供科学依据。