关键词： ecological sustainability   ecosystem heterogeneity   Kruger National Park   park management   protected areas   South Africa   vegetation structure  

摘要： African savannas are undergoing management intensification, and decision makers are increasingly challenged to balance the needs of large herbivore populations with the maintenance of vegetation and ecosystem diversity. Ensuring the sustainability of Africa's natural protected areas requires information on the efficacy of management decisions at large spatial scales, but often neither experimental treatments nor large-scale responses are available for analysis. Using a new airborne remote sensing system, we mapped the three-dimensional (3-D) structure of vegetation at a spatial resolution of 56 cm throughout 1640 ha of savanna after 6-, 22-, 35-, and 41-year exclusions of herbivores, as well as in unprotected areas, across Kruger National Park in South Africa. Areas in which herbivores were excluded over the short term (6 years) contained 38%-80% less bare ground compared with those that were exposed to mammalian herbivory. In the longer-term (> 22 years), the 3-D structure of woody vegetation differed significantly between protected and accessible landscapes, with up to 11-fold greater woody canopy cover in the areas without herbivores. Our maps revealed 2 scales of ecosystem response to herbivore consumption, one broadly mediated by geologic substrate and the other mediated by hillslope-scale variation in soil nutrient availability and moisture conditions. Our results are the first to quantitatively illustrate the extent to which herbivores can affect the 3D structural diversity of vegetation across large savanna landscapes.

关键词： Genes   Complete   prediction   novel   Performance  

摘要： We have developed a comprehensive gene orientated phylogenetic resource, EnsemblCompara GeneTrees, based on a computational pipeline to handle clustering, multiple alignment, and tree generation, including the handling of large gene families. We developed two novel non-sequence-based metrics of gene tree correctness and benchmarked a number of tree methods. The TreeBeST method from TreeFam shows the best performance in our hands. We also compared this phylogenetic approach to clustering approaches for ortholog prediction, showing a large increase in coverage using the phylogenetic approach. All data are made available in a number of formats and will be kept up to date with the Ensembl project.

关键词： antipredator behaviour   alternative reproductive tactics   corticosterone   male morph   ornate tree lizard   Urosaurus ornatus  

摘要： Most vertebrates respond to acute stressors with rapid plasma glucocorticoid elevations. Variation within species in this hormonal response should correlate with differences in physiological responses and behavioural tactics, yet this is rarely documented. We measured behavioural and hormonal responses of free-ranging male tree lizards (Urosaurus ornatus) during staged encounters with a collared lizard predator (Crotaphytus nebrius) or a control (stick). In our study population, males express alternate reproductive tactics that correlate with throat colour pattern: territorial males have a central blue patch on an orange background (OB males) and nonterritorial males lack the blue patch (O males). We also studied a previously uncharacterized male type with a mottled orange and blue throat (M males). A single encounter with an approaching predator initiated an elevation in plasma corticosterone that was similar among the male types (mean +/- SE 9.64 +/- 3.17 (OB), 9.72 +/- 2.49 (O), 10.19 +/- 2.82 (M)). Despite this similarity, male types differed behaviourally. Compared to OB and M males, O males initiated flight when the predator was further away and stayed hidden longer after seeking refuge. The M males showed responses similar to OB males and may functionally be the same morph. Among individuals of all morphs, total corticosterone levels after the predator encounter correlated strongly with their flight initiation distance and hiding duration during the encounter. We conclude that male tree lizards with alternative reproductive tactics show alternative antipredator behavioural tactics, and that individual variation in escape responses is directly correlated with corticosterone levels. (C) 2008 The Association for the Study of Animal Behaviour. Published by Elsevier Ltd. All rights reserved.

关键词： burning season   controlled burning   Cryptostegia grandiflora   fire management   introduced plants   reptiles   tropical savanna  

摘要： Fire is frequently used for land management purposes and may be crucial for effective control of invasive non-native plants. Nevertheless, fire modifies environments and may affect nontarget native biodiversity, which can cause conflicts for conservation managers. Native Australian reptiles avoid habitat invaded by the alien plant rubber vine (Cryptostegia grandiflora) and may be susceptible to the impacts of burning, a situation that provides a model system in which to examine possible conservation trade-offs between managing invasive plants and maintaining native biodiversity. We used replicated, experimental fire treatments (unburned, dry-season burned, and wet-season burned) in 2 habitats (riparian and adjacent open woodland) to examine the short- (within 12 months of fire) and longer-term (within 3 years of fire) changes of reptile assemblages in response to wet- and dry-season burning for weed management in tropical savannas of northern Australia. Within 12 months of fire, abundances of the skink Carlia munda (Scincidae) were higher in the burned sites, but overall reptile composition was structured by habitat type rather than by effects of burning. Within 3 years of a fire, the effects of fire were evident. Reptiles, especially the gecko Heteronotia binoei (Gekkonidae), were least abundant in dry-season burned sites;litter-associated species, including Carlia pectoralis (Scincidae), were rarely observed in burned habitat;and there were fewer species in the wet-season burned sites. Reptile abundance was associated with vegetation structure, which suggests that fire-induced changes detrimentally altered the availability of resources for some reptiles, particularly leaf-litter species. Invasive alien plants, such as rubber vine, have severe effects on native biodiversity, and control of such species is a fundamental land management objective. Nevertheless, fire management of invasive alien plants may adversely affect native biodiversity, creating a conservation

关键词： anatomy   colugos   Dermoptera   evolution   head muscles   homologies   mammals   primates   Scandentia   tree-shrews  

摘要： The colugos, or flying lemurs (Dermoptera), are arboreal gliding mammals that are commonly grouped with tree-shrews (Scandentia) and Primates in the superorder Euarchonta. However, little is known about the head and neck muscles of these gliding mammals. This raises difficulties for the discussion of not only the functional morphology and evolution of colugos, but also the origin, evolution, functional morphology, and phylogenetic relationships of the Euarchonta as a whole, and thus also of our own clade, the Primates. In this work, I describe the head and neck muscles of the colugo Cynocephalus volans, and compare these muscles with those of other mammals, either dissected by me or described in the literature. My observations and comparisons indicate that, with respect to the number of muscles, the plesiomorphic condition for euarchontans as well as for primates is more similar to that found in extant tree-shrews than in extant colugos. This is because various muscles that were probably plesiomorphically present in the euarchontan and primate clades, as, e.g., the stylohyoideus, mandibulo-auricularis, cleido-occipitalis, omohyoideus, and sternohyoideus, are not present as independent elements in extant colugos. These observations and comparisons also indicate that various laryngeal and facial muscles that are present in modern humans were absent in the last common ancestor of extant primates. J. Morphol. 270:14-51, 2009. (C) 2008 Wiley-Liss, Inc.

关键词： 树鼩   资源开发   标准化研究  

摘要： 树鼩(Tupaia belangeri)作为人类疾病动物模型,被应用于人类医学实验研究的多个领域,如各种类型的病毒性肝炎模型,流感病毒、登革热病毒、轮状病毒、疱疹病毒模型,糖尿病、胆结石、癌症病模型。但是,目前我国用于实验研究的树鼩几乎全都来自野外,对它们的微生物学、寄生虫学、遗传学、环境学等质量标准没有进行控制,它们本身携带的许多病原体会对实验结果的准确性造成影响,这既不符合国家对实验动物许可证管理的要求,也不利于我国实验动物科技工作与国际接轨的发展要求。因此,应该同步开展树鼩资源的开发利用和标准研究,使之纳入实验动物许可证的有效监控和管理,改变目前使用在前、质量控制标准研究在后的被动局面。

关键词： Biological control   herbivory   weed  

摘要： Understanding plant response to herbivory facilitates the prioritisation of guilds of specialist herbivores as biological control agents based on their potential impacts. Prickly acacia (Acacia nilotica ssp. indica) is a weed of national significance in Australia and is a target for biological control. Information on the susceptibility of prickly acacia to herbivory is limited, and there is no information available on the plant organ (i.e. leaf, shoot and root in isolation or in combination) most susceptible to herbivory. We evaluated the ability of prickly acacia seedlings, to respond to different types of simulated herbivory (defoliation, shoot damage, root damage and combinations), at varying frequencies (no herbivory, single, two and three events of herbivory) to identify the type and frequency of herbivory that will be required to reduce the growth and vigour. Defoliation and shoot damage, individually, had a significant negative impact on prickly acacia seedlings. For the defoliation to be effective, more than two defoliation events were required, whereas a single bout of shoot damage was enough to cause a significant reduction in plant vigour. A combination of defoliation + shoot damage had the greatest negative impact. The study highlights the need to prioritise specialist leaf and shoot herbivores as potential biological control agents for prickly acacia.

关键词： HBx   突变Kras   睾丸生精小管内注射   脂质体   精原细胞   转基因树鼩  

摘要： 目的在构建重组质粒pcDNA3.1-HBx和pEGFP-N1-Kras的基础上,采用直接注射的方法,将脂质体包裹的重组质粒注入动物睾丸中,探讨利用睾丸内生精小管微注射精子载体法建立转HBx、突变Kras基因树鼩的可行性,为建立转HBx、突变Kras基因树鼩肝癌动物模型并进一步研究两种基因在肝细胞癌发生发展过程中的作用打下基础。 方法首先用多聚酶链式反应(PCR)扩增含NheⅠ和KpnⅠ酶切位点的Kras基因序列,对pEGFP-N1载体及Kras基因PCR产物双酶切,用连接酶将两者连接并转化大肠杆菌DH5α,筛选阳性克隆,并对其进行双酶切和测序鉴定,构建Kras基因真核表达载体pEGFP-N1–Kras;成年雄雌树鼩按1:1或1:2配对,根据动物间的适应和受孕情况调整成相对固定的繁殖对。给所有动物建立档案,记录树鼩的生产情况,计算母树鼩的总产仔数、平均年产仔数及平均每次妊娠的合笼天数。记录仔动物的每日体重、进食量和健康情况。对仔树鼩用三种方法进行喂养,即配方乳喂养、被动和主动母乳喂养。16只雄性成年树鼩随机分为pcDNA3.1-HBx组、pEGFP-N1-Kras组、pcDNA3.1-HBx + pEGFP-N1-Kras组和生理盐水对照组,利用脂质体2000包裹已构建的pcDNA3.1-HBx和pEGFP-N1-Kras重组质粒,按3:1比例混合(V/W),DMEM稀释后按分组用微量注射器多位点注射入16只雄性树鼩睾丸,每周一次,连续注射四次后再隔三周与成年雌性树鼩合笼自然交配。对合笼交配后4个月内生产的仔树鼩进行肝活检,提取活检肝组织总DNA,PCR技术对基因整合进行鉴定,免疫组化检测其蛋白表达情况。C57BL/6小鼠转基因试验方法同树鼩,剪取一周龄仔鼠尾巴提取总DNA,PCR检测目的基因。 结果双酶切pEGFP-N1-Kras后,琼脂糖电泳可分别见到大小约为567bp的片段和几kb的大片断,说明Kras亚克隆入pEGFP-N1,经序列测定其含有完整的Kras基因片段; 20个月的实验期内共进行三次转基因后的雄性树鼩,均具有正常的繁殖能力,三轮实验观察期内共生产仔树鼩128只,其中成活58只。仔树鼩存活率为45.3%;PCR检测128只仔树鼩肝、肾等组织中的HBx基因,其中4只为阳性(单独注射组3只,联合注射组1只)。PCR产物经DNA测序证实为HBx基因。阳性率为3.57%。EGFP基因均为阴性。经转基因后的小鼠12个月的观察期内共获得HBx基因阳性动物3只(单独注射组2只,联合注射组1只),EGFP基因阳性动物1只(联合注射组)。对活检肝组织进行常规HE染色和免疫组化检测,显示3只树鼩(E9478、E9242、E9256)部分肝细胞有HBxAg阳性颗粒分布。两只树鼩(E9260、E9252)活检肝组织出现EGFP蛋白表达。 结论成功构建了真核表达载体pEGFP-N1-Kras;睾丸内注射精原细胞介导法构建转HBx基因树鼩动物模型是可行的,用此方法建立转突变Kras基因树鼩是否可行还需进一步研究。

关键词： Browser   Grazer   Kruger Park   Mixed feeder   Mixing model  

摘要： We tested the reliability of herbivore faecal delta C-13 and delta N-15 values for reconstructing diet through review of an extensive database derived from a 3-year study of ungulates in South Africa's Kruger National Park. Faeces are a useful material for stable isotope studies of diet because they record dietary turnover at very short time scales, and because sampling is non-invasive. However, the validity of faecal isotope proxies may be questioned because they represent only undigested food remains. Results from Kruger Park confirm that free-ranging browsers have faecal delta C-13 consistent with C-3 feeding, grazer faeces are C-4, and mixed-feeder faeces intermediate. Although the respective ranges do not overlap, there is significant variation in faecal delta C-13 of browsers and grazers (similar to 2.0-4.0%o) across space and through time. We demonstrate that most (similar to 70%) of this variation can be ascribed to corresponding patterns of variation in the delta C-13 of C-3 and C-4 plants, respectively.. re-enforcing the fidelity of faecal isotope proxies for diet but highlighting a need for mixing models that control for variations in plant delta C-13 in order to achieve accurate diet reconstructions. Predictions for the effects of climate (rainfall) and ecophysiology on delta N-15-abundance variations in mammals do not persist in faeces. Rather, faecal delta N-15 tracks changes in plant delta N-15, with further fractionation occurring primarily due to variations in dietary protein (reflected by %N). Controlling for these effects, we show that a dual-isotope multiple source mixing model (Isosource) can extend diet reconstructions for African savanna herbivores beyond simplified C-3/C-4 distinctions, although further understanding of variations in mammal delta N-15 are needed for greater confidence in this approach. (C) 2008 Deutsche Gesellschaft fur Saugetierkunde. Published by Elsevier GmbH. All rights reserved.

关键词： BARNACLES   MOLLUSKS   ARCOIDA   BIOLOGY -- Classification   SPECIES distribution   PHYLOGENY  

摘要： A previously undescribed heteralepadomorph genus and species is recorded as attached to the inside of the shell of the living epibenthic bivalve Arca navicularis, dredged from the waters of Moreton Bay, Queensland. The combination of anatomical features exhibited by the barnacle match some of the characteristics of Malacolepas. However, several characters are distinctive and a new genus and species is, therefore, proposed and named Arcalepas brucei sp. nov. Occurring in groups of up to ten individuals inside each host, Arcalepas brucei sp. nov. clearly benefits from the protection afforded by inhabiting the living bivalve and the flow of oxygenated water created by Arca navicularis. However, the barnacle also exploits the ciliary rejection currents of its host and appears to collect the pseudofaeces the bivalve removes from its mantle cavity along the rejectory tracts that internally occupy each ventral mantle margin. It does this by expanding its cirral net into the rejectory tracts and plucking up the unwanted particles collected by the suspension feeding activities of the bivalve. The barnacle's relationship with its host is thus best described as commensal. This is the first record of such an association from Australian waters.