圈养麇鹿冬季昼间行为及活动规律

2008年11-12月在济南动物园,采用瞬时扫描取样法、焦点动物取样法和全事件取样法,对9只圈养麋鹿的行为及活动规律进行了研究。结果表明,麇鹿冬季行为时间分配比例依次为卧息（36．45％±7．34％）、取食（24．79％±8．11％）、运动（18．67％±5．93％）、反刍（17．50％±5．52％）、其他（2．59％±0．87％）。在冬季麋鹿的卧息在1d内有1个高峰期（12：30～14：30）,取食在1d中有2个高峰期（8：30～9：30和17：30～18：30）,占糜鹿各种行为比例最多的2种行为在1d中是交替出现的,运动在10：30和15：30各有1个较为明显的高峰期,反刍在1d中有1个高峰期（9：30～11：30）,其他行为在1d中发生的较为随机,没有明显的高峰期。年龄因素对糜鹿冬季昼间的卧息、取食和运动行为的影响差异极显著（P〈0．01）,对其他行为影响显著（P〈0．05）,对反刍行为影响不显著（P〉0．05）;性别因素对糜鹿冬季昼间的行为影响不显著（P〉0．05）。     

Estimating Fine-Root Production and Mortality in the Biomass Plantations

Loblolly pine (Pinus taeda L.), silver maple (Acer saccharinum L.), and cottonwood (Populus deltoides Bartr.) are short-rotation woody crops with potential use for biomass plantations. The study of fine-root production and mortality in these intensively managed crops is important to understand carbon and nutrient cycling in these systems. We used minirhizotrons to measure monthly fine-root production and mortality of each species in a biomass plantation during the second growing season in Collins, Arkansas, USA. Images were taken and digitized on a monthly basis from March 2008 to February 2009 to calculate volumes and were converted into dry-weight biomass. Data analysis showed that net fine-root production varied among the species and the time of year. Loblolly pine had significantly greater net fine-root production and mortality than others. Overall fine-root production was greatest during fall months, whereas fine-root mortality showed no seasonal difference.     

饥饿补偿对中国林蛙肌肉生化组成的影响

【目的】研究饥饿补偿对中国林蛙肌肉生化组成的影响。【方法】在室内环境条件下,将1 000只供试中国林蛙随机分成饥饿0(CK),3,6,9,12d5组,每组200只,饥饿结束后恢复投喂饵料,试验时间均为22d,比较各组中国林蛙饥饿结束和试验结束时的粗蛋白、脂肪、糖原含量以及体质量和摄食率的变化,并对中国林蛙补偿生长过程中的能量来源进行分析。【结果】饥饿不同时间后,各饥饿组中国林蛙肌肉中的糖原、蛋白质含量均有所降低,其中糖原含量与对照组相比差异均达极显著水平,蛋白质含量差异不显著;各饥饿组中国林蛙的脂肪含量均低于对照组,其中饥饿12d组与对照组的差异达极显著水平,其他各组差异均不显著,但饥饿6,9d组的脂肪含量与3d组相比不降反升。试验结束后,中国林蛙各饥饿组的体质量均接近对照组,且差异不显著,呈现出完全补偿生长现象;中国林蛙肌肉中的脂肪含量均有所升高,但各组间无显著差异;除饥饿6d组林蛙的糖原含量略有增加外,其余各饥饿组林蛙肌肉中的糖原含量与试验前相比均有所降低,且与对照组有极显著差异;除饥饿6d组林蛙的蛋白质含量与对照相比极显著下降外,其他各组林蛙的蛋白质含量均极显著升高。【结论】中国林蛙具有完全补偿生长现象,其补偿生长效应是通过提高摄食率实现的。补偿生长过程中中国林蛙的能量消耗主要来源于肌糖原,其次是蛋白质和脂肪,即饥饿时中国林蛙首先动用糖原提供能量。     

甘肃产“蛤蟆油”的品质

甘肃产蛤蟆油膨胀度在５１．５～７０．５之间，水分、无机物、总糖、粗脂肪、粗蛋白含量与东北地区产品差异不大，甘肃武威市的产品人体必需氨基酸含量较高。     

Cercis siliquastrum L., Malus trilobata Schneid and Acer syriacum Boin and Gaill water use as affected by two fertilizer rates

There has been an increased demand for landscaping plants in Lebanon as a result of numerous reconstruction projects. Sustainable landscape regulations have created a need for regionally adapted taxa, especially those with low water requirements. Therefore, water use of container-grown plants and the impact of fertilization on water use were studied in the following native species: Cercis siliquastrum L. (six mother trees), Malus trilobata Schneid (two mother trees) and Acer syriacum Boin and Gaill (one tree). Two-year-old containerized seedlings were grown at The Ohio State University (Columbus, USA) under two fertilizer rates: 25 or 100 mg N L⁻¹ of 21 N–3.1 P–5.9 K water soluble fertilizer. Water use estimates were made by saturating the containers early in the morning, allowing them to drain for 1 h, weighing them and re-weighing approximately 5 h later. Although there were differences in seedling heights, those grown at 25 mg N L⁻¹ were taller than those at 100, there were few differences in water use per seedling. In August, Cercis seedlings grown under 100 mg N L⁻¹ had higher height adjusted water use (g water cm⁻¹ height h⁻¹, a method for standardizing water use among different sized plants) than those grown under 25 mg L⁻¹. However, there were no differences in height adjusted water use in September attributed to fertilizer rates. In September, Acer seedlings had higher water use cm⁻² leaf surface area under 25 than 100 mg N L⁻¹. There were no differences in water use among the progeny from the six Cercis mother trees. However, the seedlings from one Malus tree had higher water use cm⁻² leaf surface area than those from the other tree, even though the extant trees were separated by less than 20 m.     

Cattle Grazing Distribution in Shortgrass Steppe: Influences of Topography and Saline Soils

The distribution of livestock across heterogeneous landscapes is often uneven, which has important implications for vegetation dynamics and how rangeland managers achieve desired outcomes from these landscapes. Here, we use data from widely available digital elevation models to classify a landscape in the shortgrass steppe with subtle topographic variation using two different approaches: topographic wetness index (TWI) and topographic position classes (TPCs) derived from topographic position indices. We used global positioning system collars to track the grazing locations of cattle within replicate pastures and fit generalized linear mixed models to their locations to quantify the influence of topography on grazing distribution. In addition, we examine the influence of the presence of saline vegetation communities on cattle use of lowlands. The resulting models indicate that TPC more effectively predicts grazing distribution than TWI and that the patterns are strongest in the second half of the growing season (August ? October). Model performance was improved with the inclusion of saline vegetation communities, although the magnitude of cattle grazing time in these communities was not consistent across multiple pastures. These models, in combination with local knowledge, can be used by managers to predict and manage livestock distribution even in landscapes with relatively subtle topographic variability.     

Elevation dependent sensitivity of northern hardwoods to Ca addition at Hubbard Brook Experimental Forest,NH, USA

Acidic deposition has caused a depletion of calcium (Ca) in the northeastern forest soils. Wollastonite (Ca silicate) was added to watershed 1 (WS1) at the Hubbard Brook Experimental Forest (HBEF) in 1999 to evaluate its effects on various functions of the HBEF ecosystem. The effects of Ca addition on foliar soluble (extractable in 5% HClO₄) ions, chlorophyll, polyamines, and amino acids were studied in three hardwood species, namely sugar maple, yellow birch, and American beech. We further analyzed these effects in relation to elevation at Ca-supplemented WS1 and reference WS3 watersheds. Foliar soluble Ca increased significantly in all species at mid and high elevations at Ca-supplemented WS1. This was accompanied by increases in soluble P, chlorophyll, and two amino acids, glutamate and glycine. A decrease in known metabolic indicators of physiological stress (i.e., the amino acids, arginine and γ-aminobutyric acid (GABA), and the diamine, putrescine) was also observed. In general, these changes were species-specific and occurred in an elevation dependent manner. Despite an observed increase in Ca at high elevation for all three species, only sugar maple exhibited a decrease in foliar putrescine at this elevation indicating possible remediation from Ca deficiency. At higher elevations of the reference WS3 site, foliar concentrations of Ca and Mg, as well as Ca:Mn ratios were lower, whereas Al, putrescine, spermidine, and GABA were generally higher. Comparison of metabolic data from these three species reinforces the earlier findings that sugar maple is the most sensitive and American beech the least sensitive species to soil Ca limitation. Furthermore, there was an increase in sensitivity with an increase in elevation.     

石首麋鹿自然保护区草本植物功能群研究

石首麋鹿国家级自然保护区是世界上最大的麋鹿野生种群栖息地,也是长江中游保存较为完好的一块湿地。本研究以石首麋鹿保护区草本植物群落为研究对象,垂直于故道选取典型样地进行群落学调查。以χ^2检验为基础,结合联结系数AC和共同出现百分率PC来测定草本优势种的种间联结及相关性。根据优势种间的联结性在不同生境中的变化来划分植物功能群。结果表明:以优势种为主体对石首麋鹿保护区草本植物进行功能群划分可行性较高。对12种草本植物优势种共划分了3组植物功能群:“阳性湿生型”、“阳性湿中生型”和“阴性湿中生型”。每组植物功能群都有其特定的优势种和分布区,较好地反映了水、热生态因子与植被的关系。研究石首麋鹿保护区的草本植物功能群,不仅有助于揭示保护区植被格局的变化,同时也可为保护区正在开展的湿地修复工程提供一定的理论依据。     

Relationships between elm spanworm, Ennomos subsignaria, juvenile density and defoliation on mature sycamore maple in an urban environment

Using field surveys, we established sampling procedures for estimating defoliation resulting from elm spanworm, Ennomos subsignaria (Hübner) (Lepidoptera: Geometridae), feeding on mature sycamore maple, Acer pseudoplatanus L. (Aceraceae), in St. John's, Newfoundland and Labrador. We also determined whether densities of E. subsignaria eggs, egg masses, early- or late-instar larvae could predict the amount of defoliation at the end of the larval feeding period. Defoliation estimates acquired by sampling branches from only the lower, mid or upper crown explained ≥80% of the variation in tree-level defoliation, suggesting that density–defoliation relationships established using defoliation data from any crown level would also be useful for predicting tree-level defoliation. In linear regressions, egg and egg mass densities explained ≤20% of variation in defoliation and thus only provide a crude relative estimate of the amount of defoliation that will occur. Early- and late-instar larval density in the lower crown explained 53 and 29%, respectively, of the variation in defoliation in the lower crown, where defoliation levels were highest. Thus monitoring early-instar density in the lower crown should provide pest managers with reliable information for decisions regarding whether to apply suppression tactics while allowing enough time to implement these tactics, if necessary.     

Effects of fragmentation on juvenile morphology of Acer saccharum Marsh. (sugar maple) in temperate forests of northeastern Ohio,USA

The influence of forest fragmentation on population and community dynamics of woody plants has been well established worldwide, but rarely at the level of an individual plant. We evaluated the influence of fragmentation on juvenile stem morphology of Acer saccharum Marsh. (sugar maple), while also examining light levels and considering possible confounding effects attributed to elevation gradients in temperate forests of northeastern Ohio, USA. At two sites, plant stem dimensions, canopy openness, and relative ground level elevation were measured using randomly positioned plots in forest edge and interior habitats that were within 25 and 60–100 m from a forest edge, respectively. Ratios of stem length to stem basal diameter were greater in forest interiors than near forest edges. These differences in stem morphology between habitats were likely a result of stem elongation in relation to a shade avoidance response in forest interiors that were consistently darker than forest edge areas across study sites. By contrast, such morphological differences were likely not related to variation in relative ground level elevation since a subtle elevation gradient was detected at only one site. We encourage experimentation to identify mechanisms that affect plant stem morphology of young individuals and its influence, in turn, on plant population dynamics in fragmented forests.