青藏高原东部地区田鼠物种的分子鉴定

以线粒体细胞色素b基因序列（Cyt b）为分子标记,结合系统发育分析（最大似然法和贝叶斯法）和遗传距离统计（JC遗传距离模型）等方法,分析青藏高原东部地区田鼠类动物的物种组成和地理分布特征。从16个样点共采集到189个田鼠样品,成功获得所有个体的Cyt b全序列,长度为1 143 bp,共检测到248个变异位点和65个单倍型。系统发育分析显示,最大似然树和贝叶斯树的结构基本一致,将65个单倍型分为三组（G1-G3）,分别与已知的柴达木根田鼠（Microtus limnophilus）、青海松田鼠（Neodon fuscus）和高原松田鼠（N. irene）聚为单系群,支持率都为100%。遗传距离统计显示,G1、G2、G3组内两两单倍型之间的遗传距离范围分别为0.09%~3.04%、0.09%~0.70%、0.18%~1.95%;同时,G1与柴达木根田鼠参考序列之间、G2与青海松田鼠参考序列之间、G3与高原松田鼠参考序列之间遗传距离范围分别为0.61%-2.49%、0.53%-0.97%、1.77%-2.22%。结合系统发育和遗传距离分析结果,本研究中采集到的田鼠个体可以鉴定为3个物种：柴达木根田鼠（n = 135）、青海松田鼠（n = 30）和高原松田鼠（n = 24）。其中,柴达木根田鼠分布最广（10个地点）,青海松田鼠（4个地点）和高原松田鼠（3个地点）的分布区则相对狭小;3种动物在分布区上重叠度很小,仅河南县同时发现有柴达木根田鼠和青海松田鼠分布。研究表明,青藏高原东部地区至少有3种田鼠分布,种间遗传界限清晰,空间分布具有一定规律性。研究结果为了解青藏高原东部地区田鼠类动物的物种分布提供可靠的基础资料,同时,为这一地区的田鼠类动物的分子鉴定方法提供参考。     

祁连山北麓高原鼢鼠栖息地选择要素

Studying the habitat characteristics and habitat selection of the plateau zokor in different grassland types is very important to understand the function and position of the zokor in these grassland ecosystems. We selected the plateau zokor inhabiting in the alpine meadow, alpine shrub meadow and alpine grassland located in northern Qilian Mountain to describe habitatcharacteristics and study its habitat selection by dividing five plots in each grassland according to the zokor’s mounds densities, which can be regarded as relative population density of zokors. We investigated soil compaction, soil moisture, soil temperature, soil pH, as well as plant community structure in each plot of three grassland types. One-Way ANOVAs showed that there were significant differences in vegetation and soil among the three grassland types. Soil compaction, soil temperature, and total plant species number in alpine meadow were the highest (P<0.05), soil moisture and total vegetation coverage in alpine shrub meadow were the highest (P<0.05), soil pH in alpine grassland was the highest (P<0.05). Correlation analysis showed that soil compaction was negatively correlated with the relative population density of the zokor (P<0.05). Stepwise linear regression analysis showed that the plateau zokor preferred habitat with lower compaction, richer forbs in alpine meadow, lower compaction in alpine shrub meadow, and lower compaction, higher soil moisture, richer sedges in alpine grassland. In the three grassland types, we found that the soil compaction was the key factor of habitat selection of the plateau zokor and food resources was the secondary factor.     

基于BIOMOD的青海湖流域高原鼠兔分布模拟

随着统计模型及空间信息数据的不断发展和完善,物种分布模型已经成为全球变化背景下研究大尺度物种分布情况的重要工具。高原鼠兔(Ochotona curzoniae)是青藏高原特有的关键物种,在青藏高原生态系统中占有重要地位。通过采集高原鼠兔的分布点数据及环境变量数据,基于R语言中BIOMOD包中的7个模型对其在青海湖流域的分布进行了模拟。结果表明,高原鼠兔主要分布于青海湖西岸和北岸、天峻县周边及布哈河流域上游,影响高原鼠兔分布的主要环境因子为距道路距离、距居民点距离、最暖月最高气温、NDVI标准差、最冷季和最干季降水量。BIOMOD组合模型中,推进式回归树模型(GBM)和最大熵模型(MAXENT)的模拟效果最好,广义线性回归模型(GLM)结果较差。而优化后的结果显示,模拟结果的集成和筛选能有效提高模型的精度和效果。     

鄂尔多斯蓑羽鹤小群体的GPS-GSM跟踪初步分析

在内蒙古鄂尔多斯遗鸥国家级自然保护区已多次发现有一个孤立的蓑羽鹤(Anthropoides virgo)小种群在此地繁殖和度夏。2015年7月,在该地区为5只成年蓑羽鹤(3只繁殖,2只非繁殖)佩戴了中国湖南生产的GPS-GSM发射器。截止到5只蓑羽鹤全部离开鄂尔多斯高原,共获得7 794个GPS位点信息。通过跟踪信息了解到1只个体在9月18日死于鄂尔多斯高原的中西部,其余个体于9月末至10月初先后迁出鄂尔多斯高原。迁徙过程中的最快瞬时速度为93.1 km/h。4只个体迁出鄂尔多斯高原的时间和路线均略有不同。     

Intensified wind pollination mediated by pollen dimorphism after range expansion in an ambophilous biennial Aconitum gymnandrum

Pollination systems and associated floral traits generally differ between core and marginal populations of a species. However, such differences are rarely examined in plants with a mixed wind‐ and bumblebee‐pollination system, and the role of wind pollination during range expansion in ambophilous plants remains unclear. We compared floral traits and the contributions of bumblebee and wind pollination in refugium and marginal populations of the ambophilous plant Aconitum gymnandrum. We found that most floral traits differed between the two populations, and those traits associated with the shift to wind pollination were pronounced in the marginal population. Bumblebee visitation rates varied significantly, but were generally low in the marginal population. Wind pollination occurred in both populations, and the efficiency was lower than that of bumblebee pollination. Two types of pollen grains, namely round and fusiform pollen, were transported to a stigma by bumblebees and wind, but fusiform pollen contributed to wind pollination to a larger degree, especially in the marginal population. Our results suggest that wind pollination was enhanced by pollen dimorphism in the marginal population of A. gymnandrum, and wind pollination may provide reproductive assurance when bumblebee activity is unpredictable during range expansion, indicating that ambophily is stable in this species and shift in pollination system could be common when plants colonize new habitats.     

Elevational diversity gradients of Tibetan loaches: The relative roles of ecological and evolutionary processes

It is widely believed that species richness patterns (SRPs) are shaped by both ecological and evolutionary processes. However, the relative roles of these processes remain unclear, especially for aquatic organisms. In this study, we integrated ecological and evolutionary measures to tease apart the relative influences of these factors on the SRP of Tibetan loaches along an extensive elevational gradient. We found that the Tibetan loaches displayed a richness pattern that peaked at midelevations. The mean annual temperature (MAT), mid‐domain effect (MDE), and summed age of colonization (SAC, complex of colonization age and colonization frequency) were the main drivers, accounting for 85%, 51%, and 88% of the variations in the SRP, respectively. The three predictors had very high combined effects (MAT‐MDE‐SAC, MAT‐SAC, and MDE‐SAC were 44%, 38%, and 6%, respectively). Our analyses suggested that energy input, time‐for‐speciation, and species dispersal may directly guide the SRP or mediate it by geometric constraints. Conclusively, the SRP of the Tibetan loaches with elevation is the outcome of interactions between biogeographical processes and regional ecological conditions.     

实验增温对藏北高寒草甸植物繁殖物候的影响

全球气候变暖对高寒和极地地区的植物物候产生强烈的影响。该研究主要关注增温条件下藏北高寒草甸不同功能型植物繁殖时间(生殖物候)的改变。实验采用开顶箱式增温方法, 对3个主要功能群浅根-早花、浅根-中花和深根-晚花植物的现蕾、开花、结实时间进行观测。研究结果表明: (1)增温导致了土壤水分胁迫, 显著推迟了浅根-早花植物高山嵩草(Kobresia pygmaea)的繁殖时间; (2)增温显著提前了浅根-中花植物钉柱委陵菜(Potentilla saundersiana)和深根晚花植物紫花针茅(Stipa purpurea)和矮羊茅(Festuca coelestis)的繁殖时间; (3)增温没有显著影响浅根-中花植物楔叶委陵菜(Potentilla cuneata)和深根-晚花植物无茎黄鹌菜(Youngia simulatrix)的繁殖时间; (4)增温缩短了3种类型植物的开花持续时间。这些结果显示增温改变了藏北高寒草甸群落中多数物种的繁殖时间, 这预示着在未来更热更干的生长季, 青藏高原高寒草甸系统的植物物候格局可能会被重塑。     

The spatial pattern of grassland aboveground biomass on Xizang Plateau and its climatic controls

Aims Grassland is the most widely distributed vegetation type on the Xizang Plateau. Accurate remote sensing estimation of the grassland aboveground biomass (AGB) in this region is influenced by the types of vegetation indexes (VIs) used, the grain size (resolution) of the remote sensing data and the targeted ecosystem features. This study attempts to answer the following questions: (i) Which VI can most accurately reflect the grassland AGB distribution on the Xizang Plateau? (ii) How does the grain size of remote sensing imagery affect AGB reflection? (iii) What is the spatial distribution pattern of the grassland AGB on the plateau and its relationship with the climate?Methods We investigated 90 sample sites and measured site-specific AGBs using the harvest method for three grassland types (alpine meadow, alpine steppe and desert steppe). For each sample site, four VIs, namely, Normalized Difference VI (NDVI), Enhanced VI, Normalized Difference Water Index (NDWI) and Modified Soil-Adjusted VI (MSAVI) were extracted from the Moderate Resolution Imaging Spectroradiometer (MODIS) products with grain sizes of 250 m and 1 km. Linear regression models were employed to identify the best estimator of the AGB for the entire grassland and the three individual grassland types. Paired Wilcoxon tests were applied to assess the grain size effect on the AGB estimation. General linear models were used to quantify the relationships between the spatial distribution of the grassland AGB and climatic factors.Important findings The results showed that the best estimator for the entire grassland AGB on the Xizang Plateau was MSAVI at a 250 m grain size (MSAVI 250 m). For each individual grassland type, the best estimator was MSAVI at a grain size of 250 m for alpine meadow, NDWI at a grain size of 1 km for alpine steppe and NDVI at a grain size of 1 km for desert steppe. The explanation ability of each VI for the grassland AGB did not significantly differ for the two grain sizes. Based on the best fit model (AGB =^-10.80 + 139.13 MSAVI 250 m), the spatial pattern of the grassland AGB on the plateau was characterized. The AGB varied from 1 to 136g m ?2. Approximately 59% of total spatial variation in the AGB for the entire grassland was explained by the combination of the mean annual precipitation (MAP) and mean annual temperature. The explanatory power of MAP was weaker for each individual grassland type than that for the entire grassland. This study illustrated the high efficiency of the VIs derived from MODIS data in the grassland AGB estimation on the Xizang Plateau due to the vegetation homogeneity within a 1×1 km pixel in this region. Furthermore, MAP is a primary driver on the spatial variation of AGB at a regional scale.     

Survival and reproduction of plant species in the Qinghai–Tibet Plateau

The Qinghai–Tibet Plateau (QTP) is the highest and largest plateau in the world. It covers correspondingly wide geological, topographical, and climatic gradients, and thus hosts greater biodiversity than surrounding lowlands and other high elevation regions. Due to its extreme environmental and biological diversity, the QTP is an ideal region for studying adaptations of plant species under harsh environmental conditions at multiple evolutionary levels. Many recent ecological studies have revealed functions of distinctive morphological features of various plants in the region that improve their reproductive success. Examples include large and showy bracts, hairy inflorescences, and drooping flowers. Numerous other investigations have examined QTP plants' sexual systems, patterns of biomass allocations, and biotic interactions. This paper summarizes recent advances in understanding of morphological adaptations, plant–plant interactions, plant–pollinator interactions, floral color patterns, pollination adaptations, and resource allocation patterns of alpine plants of the QTP. The overall aim is to synthesize current knowledge of the general mechanisms of plant survival and reproduction in this fascinating region.     

青藏高原20种灌木抗旱形态和生理特征

该研究以青藏高原地区采集的柠条锦鸡儿(Caragana korshinskii)等20种灌木树种为研究对象, 将其二年生幼苗移栽至苗圃培育, 通过田间试验测定三年生苗木生物量根冠比(RSR)、叶片蒸腾速率(T_r)、瞬时水分利用效率(WUE_i)、稳定碳同位素组成(δ¹³C)、叶片解剖结构特征和根系特征(长度、表面积、体积和根尖数)指标, 综合分析其抗旱性能差异, 为青藏高原干旱地区灌木树种抗逆性(耐旱)评价指标的建立、优良抗逆性树种的筛选及各种灌木树种的合理立地配置提供必要的理论依据。研究结果表明: 所选20种灌木为适应长期的干旱逆境, 不同植物种具有不同的抗旱策略。研究中将灌木抗旱机制划分为6个类型: 根系特征抗旱型、叶片旱生结构型、叶片旱生形态型、生物量分配型、节水型、高水分利用效率型。不同属和同属不同种灌木抗旱性有所差异, 沙棘属(Hippophae)植物总体抗旱性不佳, 而金露梅(Potentilla fruticosa)、豪猪刺(Berberis julianae)、树锦鸡儿(Caragana arborescens)、绣线菊(Spiraea salicifolia)和蒙古沙棘(Hippophae rhamnoides ssp. mongolica)综合抗旱性能较好, 总体上属于根系和叶片抗旱特征明显、低耗水、高生产效率的抗旱性强树种, 可以在青藏高原地区植被恢复树种筛选时优先考虑。根系特征值之间存在极显著正相关关系, 叶片结构特征指标之间也存在不同程度的相关关系, 但RSR、T_r、WUE_i和δ¹³C与根系特征值和叶片解剖结构特征指标之间总体上相关性不显著。主成分分析结果显示灌木全根和细根的长度、表面积、体积、根尖数和叶片栅栏组织厚度、海绵组织厚度、瞬时水分利用效率因子载荷较高, 能较好地反映青藏高原灌木树种抗旱性差异相关信息。此外, 灌木树种原产地与抗旱性也存在一定的联系, 青海西宁地区采集的灌木树种总体抗旱性优于甘肃天水和西藏拉萨地区。