Sex differences in emigration and mortality affect optimal management of deer populations

Populations of red deer that are limited by food, like those of many other ungulates, commonly include more females than males. We assessed the contribution of variation in sex- and age-specific rates of mortality and emigration to density-dependent changes in the adult sex ratio, using long-term observations and demographic experiments involving the red deer population on Rum, Scotland. We incorporated these effects in a stochastic model of local populations under different management regimes to show here that, when female numbers are allowed to increase to more than 60% of the ecological carrying capacity, the sustainable annual harvest of males from local deer populations will fall. Because males are typically culled by fee-paying hunters and generate more income than females, income will decrease as the male harvest falls. Because numbers of female deer throughout much of the Highlands probably exceed the threshold at which male density starts to be affected, many managers might be able to raise income from local deer populations by reducing female numbers, with potential benefits to the vegetation of Scottish Highland environments.     

Nonlinear effects of large-scale climatic variability on wild and domestic herbivores

Large-scale climatic fluctuations, such as the North Atlantic Oscillation (NAO), have been shown to affect many ecological processes. Such effects have been typically assumed to be linear. Only one study has reported a nonlinear relation; however, that nonlinear relation was monotonic (that is, no reversal). Here we show that there is a strong nonlinear and non-monotonic (that is, reversed) effect of the NAO on body weight during the subsequent autumn for 23,838 individual wild red deer (Cervus elaphus) and 139,485 individual domestic sheep (Ovis aries) sampled over several decades on the west coast of Norway. These relationships are, at least in part, explained by comparable nonlinear and non-monotonic relations between the NAO and local climatic variables (temperature, precipitation and snow depth). The similar patterns observed for red deer and sheep, the latter of which live indoors during winter and so experience a stable energy supply in winter, suggest that the (winter) climatic variability (for which the index is a proxy) must influence the summer foraging conditions directly or indirectly.     

Phytohaemagglutinin activation of T cells through the sheep red blood cell receptor

Expression of receptors for sheep red blood cells and the ability to proliferate in response to phytohaemagglutinin (PHA) are the traditional properties of human T cells, but the function of the sheep red cell receptor (the T11 antigen) is controversial and the mechanism of PHA-induced mitogenesis unclear. Mitogenesis involves a complex series of cell-mediated and factor-dependent interactions, but a rise in intracellular free calcium concentration, [Ca2+]i, seems to be an important primary event in T-cell activation. We have now investigated the effects of three monoclonal antibodies, previously shown to inhibit mitogen-induced proliferation, on T-cell [Ca2+]i. We find that anti-LFA-2 and OKT11, which react with the sheep red cell receptor, have no effect on [Ca2+]i, nor do they inhibit the rise in [Ca2+]i induced by concanavalin A (Con A) or the mitogenic anti-T3 monoclonal antibody UCHT1 (ref. 11). They do, however, block PHA-induced Ca2+ mobilization. Anti-LFA-1, which reacts with the lymphocyte function-associated antigen, has no effect on intracellular Ca2+. These studies suggest that the sheep red blood cell receptor is an activation pathway for T cells and that the effects of PHA are mediated through this pathway.     

应用E_2P_4浓度比判断雌性多浪绵羊和塔里木马鹿血浆P_4含量的波动

为了找出能够准确反映雌性哺乳动物体内血浆孕酮(P4)波动的检测方法,实验以多浪绵羊和塔里木马鹿为实验动物,分别对其发情周期各阶段的血液样本外周血雌二醇(E2),P4与促黄体生成素(LH)含量进行了放射免疫分析(RIA)测定。发现,应用E2 P4比值比传统的方法更能准确反映雌性哺乳动物体内血浆孕酮含量的波动情况。     

全球森林及林产品碳科学研究进展与前瞻

森林和木质林产品是全球碳循环系统中的一个重要组成部分,能够对大气层温室气体的浓度造成重大影响。研究发现全球森林在最近几十年平均每年从大气中吸收二、三十亿吨碳,而毁林和森林退化又造成每年10多亿吨的碳排放。全球森林碳汇并不平衡,由于森林面积的增加,美国、加拿大、中国、欧盟等国家和地区的森林碳汇在近几十年里有了巨大的增长,而在南美洲、中美洲、非洲、南亚和东南亚,毁林却造成了森林碳汇大量减少。相对于森林碳汇来说,木质林产品碳储量较小,但在全球尺度上木质林产品碳储的持续增加对减排的贡献却非常重要。近10年的研究发现,使用木质林产品替代高能耗非林产品可以对林业整体的减排效益做出重要贡献,而生命周期分析法的引入使得这种替代减排效应的核算更为准确。主流研究强调使用集成评估,将经营森林和源于这些森林的木质林产品看作一个整体,从而把两者的碳储及碳排放系统结合,集成评估能够更全面准确地核算整体林业的净温室气体效应。林业碳科学的研究前沿在以下重要领域仍需着力拓展:充分考虑气候变化对森林生长及森林碳汇的影响; 积极推进并完善各国的森林资源清单; 可持续管理和优化使用森林资源以使林业在减缓气候变化方面的贡献最大化; 构建和完善林产品生命周期数据库; 加强全球林业减排效应的集成评估和系统研究。     

江西桃红岭国家级自然保护区梅花鹿种群生存力分析

梅花鹿华南亚种(Cervus nipponkopschi)是我国Ⅰ级重点保护野生动物。目前仅分布于江西、浙江、安徽等狭窄的区域内,形成多个孤立种群。根据梅花鹿种群的相关参数,借助漩涡模型Vortex 9.99,以江西桃红岭国家级自然保护区梅花鹿种群为研究对象,对其梅花鹿种群在1983年后100 a内的动态及敏感性进行了模拟分析。模型结果表明,在自然情况下,该种群在100 a内灭绝概率为0。第1阶段(1983-1998年)种群数量从60只快速增长至226只,第2阶段(1998-2011年)种群数量从226只增长到341只,第3阶段(2011-2083年)种群数量维持在352只左右,年均增长率分别为9.25%、3.32%、0.04%。虽然高死亡率、灾害延缓了种群增长的速度,近亲繁殖导致近100 a内基因杂合率下降了7.46%,但这些因素并没有显著影响桃红岭梅花鹿种群近100 a内的命运。在不考虑其它条件的情况下,环境容纳量对梅花鹿种群遗传多样性损失具有明显的影响,是限制该梅花鹿种群发展的重要因素。因此,改善生境质量,提高环境容纳量是促进该梅花鹿种群增长的有效途径。有计划的火烧、植被矮化以及开辟生境走廊,可以有效地改善鹿类环境容纳量,是当前梅花鹿保护亟待开展的工作。同时,应进一步提高当地社区居民的保护意识,杜绝偷猎盗猎,降低人类生产经营活动对梅花鹿的影响。     

The phylogenetic position of the 'giant deer' Megaloceros giganteus

The giant deer, or 'Irish elk', has featured extensively in debates on adaptation, sexual selection, and extinction. Its huge antlers--the largest of any deer species, living or extinct--formed a focus of much past work. Yet the phylogenetic position of the giant deer has remained an enigma. On the basis of its flattened antlers, the species was previously regarded as closely related to the living fallow deer. Recent morphological studies, however, have challenged that view and placed the giant deer closer to the living red deer or wapiti. Here we present a new phylogenetic analysis encompassing morphological and DNA sequence evidence, and find that both sets of data independently support a sister-group relationship of giant and fallow deer. Our results include the successful extraction and sequencing of DNA from this extinct species, and highlight the value of a joint molecular and morphological approach.     

我国铝的社会蓄积量分析

给出了金属物质社会蓄积量的分析方法.分析了在金属消费量保持不变、线性变化及指数变化3种情况下,金属消费量对金属物质社会蓄积量及其回收率的影响.计算得到了我国2006～2009年期间铝的社会蓄积量变化情况:在此期间,铝社会蓄积量增长很快,2009年时达到了8 890万t;铝社会蓄积量回收率的均值为1.45%;随着未来我国铝消费量增速的降低,铝社会蓄积量回收率会逐步提高.对金属物质的社会蓄积量分析,可以为金属工业的资源战略、产业政策和环境政策的制定提供一定依据.     

Climatic influence on a marine fish assemblage

Understanding the fluctuations in marine fish stocks is important for the management of fisheries, and attempts have been made to demonstrate links with oceanographic and climatic variability, including the North Atlantic Oscillation (NAO). The NAO has been correlated with a range of long-term ecological measures, including certain fish stocks. Such environmental influences are most likely to affect susceptible juveniles during estuarine residency, as estuaries are critical juvenile nursery or over-wintering habitats. Here we show that, during a 16-year period, climatic forcing (by means of the NAO) is consistently the most important parameter explaining variation in assemblage composition, abundance and growth of juvenile marine fish during estuarine residency. A possible mechanism for the effect of the NAO is a temperature differential between estuarine and marine waters that allows fish to facultatively exploit optimal thermal habitats. The connection has potentially important implications for the size and numbers of individuals recruited to the fishery, for understanding and predicting the composition of juvenile fish stocks using estuaries, and for the appropriate conservation of estuarine systems in relation to fish stocks.     

Roaring by red deer stags advances the date of oestrus in hinds

Some male mammals call loudly and repeatedly during the breeding season. Although the song of male birds is known to have effects on male-male competition, mate selection and ovulation, until now the loud calls of male mammals have been shown to affect only competition between males. Although it has been suggested that loud calling could also serve to attract females, the possibility that it has a direct effect on reproduction in females has not previously been investigated for any mammal. Here I report that roaring in red deer (Cervus elaphus) advances ovulation and that harem-holding males can improve their mating success by regular calling.     

In vitro effects of high molecular weight forms of ACTH on the fetal sheep adrenal

The direct involvement of the pituitary-adrenal axis in birth has been well established, at least in sheep, and its removal prolongs pregnancy. As part of the process the fetal sheep adrenal grows rapidly during the 10-15 d prepartum and is associated with a large rise in the plasma corticosteroid concentration. This does not seem to result from an increased ACTH secretion. The fetal adrenal in vivo seems refractory to circulating ACTH and shows poor response to elevation of plasma concentration. Thus the signal for the adrenal hypertrophy and the initiation of parturition remains unclear. The responsiveness of the fetal adrenal to ACTH has been re-examined using isolated adrenal cells. The study shows that in the fetal sheep these are not inherently unresponsive to ACTH, but that high-molecular-weight forms of ACTH block the action of ACTH. These peptides may be responsible for controlling the activity of the adrenal in situ.     

Control of haemoglobin switching by a developmental clock?

The pattern of haemoglobin production changes at the embryonic, fetal and postnatal stages of human development, reflecting the expression of different globin genes in both the alpha-like and beta-like gene clusters. Recent studies have identified alterations in the state of DNA methylation and sensitivity to nuclease digestion associated with developmental expression of the globin genes in red blood cell precursors, but the mechanism initiating these changes remains unknown. Despite the screening of large numbers of blood samples from newborn infants, no mutants have been found which affect the timing of these changes (with one possible exception involving a chromosomal translocation), thus necessitating alternative approaches to analysing the cellular basis for the timing of haemoglobin switching. Although many mechanisms are possible, the initiation of the switch from fetal to adult haemoglobin could be regulated essentially either by a developmental clock inherent to haematopoietic stem cells or by an inductive environment, and in an attempt to distinguish between these possibilities, we have transplanted sheep fetal haematopoietic tissue into adult animals. Although previous experiments of this type produced conflicting results, the accumulated results presented here demonstrate that the pattern of haemoglobin production after transplantation is determined largely by the gestational age of the fetal donor cells.     

Sexually antagonistic genetic variation for fitness in red deer

Evolutionary theory predicts the depletion of genetic variation in natural populations as a result of the effects of selection, but genetic variation is nevertheless abundant for many traits that are under directional or stabilizing selection. Evolutionary geneticists commonly try to explain this paradox with mechanisms that lead to a balance between mutation and selection. However, theoretical predictions of equilibrium genetic variance under mutation-selection balance are usually lower than the observed values, and the reason for this is unknown. The potential role of sexually antagonistic selection in maintaining genetic variation has received little attention in this debate, surprisingly given its potential ubiquity in dioecious organisms. At fitness-related loci, a given genotype may be selected in opposite directions in the two sexes. Such sexually antagonistic selection will reduce the otherwise-expected positive genetic correlation between male and female fitness. Both theory and experimental data suggest that males and females of the same species may have divergent genetic optima, but supporting data from wild populations are still scarce. Here we present evidence for sexually antagonistic fitness variation in a natural population, using data from a long-term study of red deer (Cervus elaphus). We show that male red deer with relatively high fitness fathered, on average, daughters with relatively low fitness. This was due to a negative genetic correlation between estimates of fitness in males and females. In particular, we show that selection favours males that carry low breeding values for female fitness. Our results demonstrate that sexually antagonistic selection can lead to a trade-off between the optimal genotypes for males and females; this mechanism will have profound effects on the operation of selection and the maintenance of genetic variation in natural populations.     

麝的分类研究概述

麝（Moschus spp.）是亚洲地区特产野生动物,具有非常重要的经济和生态价值,为我国一级重点保护物种,已被列入CITES附录Ⅰ中.麝一直颇为中外学者所关注.目前,麝作为独立的科已广泛被接受,但种及种下的分类仍处于＂广泛争论＂状态.本文从形态、分子生物学等特征对麝的分类研究进行了简要概述,提出了一些尚待解决的问题,并对将来的研究工作做出展望.     

VIE架构下企业资金回流新解

VIE模式(Variable interest entities,译为"可变利益实体")又称协议控制模式。近年来在外商投资受限制的互联网通信或电子商务领域应用广泛,外国投资者通过VIE协议而不是股权来控制国内牌照公司。但是由于受到外商投资行业、资本项目资金使用和跨境担保等管理要求限制,VIE架构下境外募集资金回流使用在实务中一直有一定难度。建设银行通过充分研究相关管理政策,结合企业实际需求,为VIE架构境外投资资金探索了一套行之有效的使用方案,取得了良好的实践效果。该方案在合法合规前提下,有力促进VIE构架互联网企业的发展。     

香港股市与美国、英国股市的联动性

通过多变量协整理论，检验香港股票市场和世界上主要的股票市场一美国、英国股票市场的联动关系。结果表明，在1993年1月至1995年12周期间，香港市场与这些世界主要发达国家市场存在着弱的协整关系；而在1999年6月至2002年5月，香港股市与美、英股市之间不存在着协整关系。这一结果意味着分散投资于美、英市场与香港市场存在着长期的获利机会。     

毛冠鹿人工饲养及繁殖初探

毛冠鹿主要产于我国，生性胆小，人工饲养及繁殖困难．成都动物园饲养有1雄3雌4只成年毛冠鹿，多年没有繁殖．通过设置专门的饲养场地，并在其中种植大量毛冠鹿喜食的小叶女贞、毛叶丁香等植物，将4只毛冠鹿放入这样一个僻静无干扰的环境中饲养．提供多样化的饲料和足够的能量，每只毛冠鹿日平均摄入能量〉4604．6kJ，同时毛冠鹿还能自由采食场地中的植物，很快适应了环境，使多年未繁殖的毛冠鹿开始繁殖．2003年有一只雌性毛冠鹿产仔，2004年3只雌性毛冠鹿全部产仔并存活．产仔率和存活率都达到了100％．     

Natural diet and food habitat use of the Tarim red deer,Cervus elaphus yarkandensis

In order to determine the natural diet and food habitat use of Tarim red deer (Cervus elaphus yarkandensis), a study was carried out in Qiemo, Xinjiang , China from October 2000 to June 2001. Direct observation combined with faecal analysis method was used to determine the natural diet of red deer. 15 different species of plant were identified as food items. Among them, 13 species of plants were identified in winter diet and 9 species in summer. Red deer consumed a wider range of species in winter because of their nutrient requirement as well as the shortage of food and the scarcity of high-quality forage in the study area. Phragmites communis, Glycyrrhiza inflata and populus diversifo-lia were frequently present in the deer's diet whenever in winter and summer. Among them, Phragmites communis was the most abundant plant in the area and was included in the deer's diet. Observation on food selection frequency of captive Tarim red deer showed that Populus diversifolia was the first preferred species. However, this food was limited in the study area. Five food habitat types were found in the study area according to plant association: (1) Phragmites communis-Tamarix ramosissima association, (2) Tamarix ramosissima-Halostachys cas-pica association, (3) Tamarix ramosissima-Phragmites communis association, (4) Populus diversifolia-Phragmites communis association, (5) Burned area. Among them, Phragmites communis-Tamarix ramosissima association (reed meadow and reed marsh) was preferred to other types within the study area whenever in summer and winter. Dense reed cover could reduce the chance of detection from predator and obstruct attack from predator. Furthermore, under the cover of the reed, Tarim red deer was protected from direct solar radiation during the hours of hot day in summer. The reed meadow and marsh was preferred, presumably because the red deer could minimize their movements while searching for food, water and cover.     

Mammalian sex ratios and variation in costs of rearing sons and daughters

In red deer, the sex ratio of calves at birth (calculated as the proportion of calves born that are male) increases with the dominance rank of the mother, whereas opposite trends exist in several populations of macaques and baboons. Here we show that the subsequent survival and reproductive success of subordinate female red deer is depressed more by rearing sons than by rearing daughters, whereas the subsequent fitness of dominant females is unaffected by the sex of their present offspring. By contrast, among subordinate female macaques, the rearing of daughters has greater costs to the mother's subsequent fitness than does the rearing of sons, although again, no difference in the costs of rearing sons and daughters is found among dominant mothers. These findings indicate that both differences in the relative fitness of sons and daughters and differences in the relative costs of rearing male and female offspring can favour variation in the sex ratio.     

苏南山地园林的叠石与理水

苏南山地园林历史远，是江南私家园林宝库中的一部分；古代造园师们依山就势；恰地处理了人造景观与自然山水环境的关系，在叠石与理水方面留下许多宝贵的经验。通过对几座现存苏南山地园林的考察以及有关园记的研究，可以了解：山地造园的叠石形态不求怪异，而是作为主山余脉的延续或导引入园之不的堤岸。