关键词： 树鼩   肝脏疾病   模型  

摘要： 肝脏疾病已经在世界范围内导致严重的致死率和死亡率,动物模型是研究肝脏疾病的有效工具,考虑到非人灵长类实际使用的限制,树鼩作为非人灵长类替代动物具有资源丰富,成本较低,且与人类亲缘关系较近等优势,本文对树鼩在肝脏疾病动物模型中的应用进行综述。

关键词： 动物类药材   药市   中药材专业市场   数  

摘要： 动物类药材为我国传统中药材之一，是我国中药材专业市场经销的重要组成部分，更是药市、药厂、药企、医院等不可或缺的品种之一。动物类药材的产量、销量、库存、价格、走势等一系列商情已引起商家和农家的密切关注。

关键词： Oribatid mites   Tree hollow   Oak   Soil   Carabodes   Biodiversity indicator  

摘要： Tree hollows are known to harbour a species-rich and specialized beetle fauna, while other invertebrates, such as for instance mites, have been much less studied. The importance of hollows in oak trees (Quercus robur) for local oribatid mite diversity was studied at three sites in south eastern Sweden. The qualitative and quantitative composition of the oribatid mite fauna was studied in hollows of fifteen 240-420 years old oak trees and compared to that in the surrounding soil. A total of 5,530 specimen of adult oribatid mites were determined belonging to 63 taxa. Taxonomic composition and community structure of the tree hollow communities differed markedly from the soil communities. The most dominant and frequent component of the tree hollow communities comprised a Carabodes species new to Sweden that accounted on average for 44 % of all Oribatida. This species, that closely resembles both Carabodes oenipontanus and Carabodes granulatus, was specific to the tree hollows. Dominance patterns in the soil communities were more even, with the most common taxa also occurring in the tree hollows but exhibiting a significant preference for the soil. Overall, there was little taxonomic overlap between the communities, suggesting that tree hollows harbour an independent mite community from the soil and therefore significantly contribute to the overall mite diversity on the landscape level. The present study therefore strongly supports the use of hollow trees as biodiversity indicators and also their conservation, which will preserve specialised invertebrate communities, including mites.

关键词： Egg parasitoid   Tritrophic interaction   Terpenoids   Green leaf volatiles   Herbivore-induced volatiles   Host location  

摘要： Parasitic insects use herbivore induced plant volatiles as signals for host location. However, their responses to these volatiles in the background of natural habitat odours need further evaluation for developing successful biological control strategies. Field elms (Ulmus minor Miller (Ulmaceae)) release a blend of volatiles in response to oviposition of the elm leaf beetle, Xanthogaleruca luteola Muller (Coleoptera: Chrysomelidae), a major urban and forest pest in the USA and Australia. This induced blend attracts the beneficial egg parasitoid Oomyzus gallerucae Fonscolombe (Hymenoptera: Eulophidae). Our olfactory assays showed that an odorous background of non-attractive host plant volatiles from feeding damaged elms or (Z)-3-hexenyl acetate masks the attractive effect of the host-induced (E)-beta-caryophyllene to O. gallerucae. Quantitative GC-MS analyses revealed decreased concentrations of (Z)-3-hexenyl acetate accompanied by highly increased concentrations of sesquiterpenes in oviposition and feeding treated elms compared to undamaged elms. This finding hints to how the parasitoid might distinguish between different odorous backgrounds. It is corroborated by the outcome of our field study in natural elm stands, where the egg parasitoid parasitized more host egg masses due to an artificially induced blend of elm terpenoids.

关键词： BEF China   Biodiversity   Ecosystem function   Invertebrate   Trophic interaction  

摘要： The effects of species loss on ecosystems depend on the community's functional diversity (FD). However, how FD responds to environmental changes is poorly understood. This applies particularly to higher trophic levels, which regulate many ecosystem processes and are strongly affected by human-induced environmental changes. We analyzed how functional richness (FRic), evenness (FEve), and divergence (FDiv) of important generalist predators-epigeic spiders-are affected by changes in woody plant species richness, plant phylogenetic diversity, and stand age in highly diverse subtropical forests in China. FEve and FDiv of spiders increased with plant richness and stand age. FRic remained on a constant level despite decreasing spider species richness with increasing plant species richness. Plant phylogenetic diversity had no consistent effect on spider FD. The results contrast with the negative effect of diversity on spider species richness and suggest that functional redundancy among spiders decreased with increasing plant richness through non-random species loss. Moreover, increasing functional dissimilarity within spider assemblages with increasing plant richness indicates that the abundance distribution of predators in functional trait space affects ecological functions independent of predator species richness or the available trait space. While plant diversity is generally hypothesized to positively affect predators, our results only support this hypothesis for FD-and here particularly for trait distributions within the overall functional trait space-and not for patterns in species richness. Understanding the way predator assemblages affect ecosystem functions in such highly diverse, natural ecosystems thus requires explicit consideration of FD and its relationship with species richness.

关键词： Elephant   Exclusion experiment   Herbivore   Phenology   Plant defence  

摘要： Carbon-based secondary metabolites (CBSMs) such as tannins are assumed to function as plant defences against herbivores. CBSMs are thought to be inversely related to growth rate and nutrient concentrations because a physiological trade-off exists between cellular growth and differentiation, but CBSM concentrations can be altered by herbivory-induced changes in the trade-off. We predicted that a significant interaction exists between herbivory and growth phase, such that the effects of large herbivores (or their exclusion) on nutrient or CBSM concentrations are greatest during phases of rapid shoot or leaf growth. Leaf samples were collected during phases of different growth rate from six woody species 4 years after establishment of a large-scale long-term herbivore exclusion experiment in Kruger National Park, South Africa. Samples were analysed for N, P, condensed tannins and total phenolics. Interactions between growth phase and herbivores were rare. However, the assumption that elevated nutrients and reduced CBSMs occurs during fast phases of growth was supported by four species (consistent with the growth-differentiation balance hypothesis), but not the other two. Large herbivores generally did not affect nutrients, but CBSMs in four species were reduced by large herbivores other than elephants, while CBSMs in two species were reduced by elephants. Carbon limitation ultimately prevailed among woody plants taller than 2 m under long-term browsing. Large herbivores and plant growth phase are independent and important determinants of nutrients or CBSMs in African savannas, but the effects depend on the interacting assemblages of species, which poses challenges to the application of current general hypotheses of plant defence.

关键词： LAND use -- Environmental aspects   SAVANNA ecology   NONFICTION   AFRICA  

摘要： [...]it carefully analyzes the balance between mutual conflict and co-existence between humans, wildlife, and livestock, and describes some of the current programs of community-based conservation that are designed to mitigate conflicts and enhance mutual gains for human livelihoods and wildlife conservation.

关键词： Adaptive dynamics   Finite population   Mast seeding   Predator satiation  

摘要： Many trees in forests show synchronized and intermittent reproduction, which is called "masting" or mast seeding. According to recent theoretical studies, the evolution of masting is promoted both by recruitment through the seedling bank and by seed predators. An important class of specialist seed predators (e.g., weevils and some moths) are parasitoids that oviposit on or in fruits from which the next generation emerges over the following several years. This staggered emergence is called "extended diapause". In this paper, we study the simultaneous evolution of tree masting and extended diapause of seed predators. If a fixed fraction of diapausing larvae matures every year, the evolution of trees results in masting (intermittent reproduction with a large fluctuation in reproductive activity) or non-masting (trees reproduce every year). The transition occurs discontinuously, showing evolutionary jumping. The range of seedling survivorship for which masting evolves is broader when the ovipositing efficiency and larval survivorship of the seed predators are large. Interestingly, the conditions for the evolution of masting are broadest for an intermediate fraction of extended diapause of seed predators. When both tree masting and the extended diapause of seed predators evolve simultaneously, the evolutionary end point of the fraction of extended diapause is clearly greater than the value that most favors masting evolution. The stochasticity caused by the finiteness of the number of trees tends to promote masting evolution. (C) 2013 Elsevier Ltd. All rights reserved.

关键词： Research Article  

摘要： Herbivores generally have strong structural and compositional effects on vegetation, which in turn determines the plant forage species available. We investigated how selected large mammalian herbivore assemblages use and alter herbaceous vegetation structure and composition in a southern African savanna in and adjacent to the Kruger National Park, South Africa. We compared mixed and mono-specific herbivore assemblages of varying density and investigated similarities in vegetation patterns under wildlife and livestock herbivory. Grass species composition differed significantly, standing biomass and grass height were almost twice as high at sites of low density compared to high density mixed wildlife species. Selection of various grass species by herbivores was positively correlated with greenness, nutrient content and palatability. Nutrient-rich Urochloa mosambicensis Hack. and Panicum maximum Jacq. grasses were preferred forage species, which significantly differed in abundance across sites of varying grazing pressure. Green grasses growing beneath trees were grazed more frequently than dry grasses growing in the open. Our results indicate that grazing herbivores appear to base their grass species preferences on nutrient content cues and that a characteristic grass species abundance and herb layer structure can be matched with mammalian herbivory types.

关键词： Bioturbation   Soil fauna   Microorganisms   Reclamation   Earthworms   Foliage chemistry  

摘要： The effects of tree species differing in foliage and litter chemistry on the chemical, micro-morphological, and biological properties of soil were studied on post-mining sites afforested with one of six tree species (spruce, pine, larch, oak, lime, and alder) and also on sites left to natural succession (dominated by willow). The sites were located on a large colliery spoil heap that had been produced by the mining of coal in alkaline tertiary clays near the city of Sokolov, Czech Republic. Because no topsoil had been applied to the sites, soil development resulted from in situ interactions among the deposited overburden (spoil), trees, and soil biota. Soil formation differed markedly among sites afforested with different tree species. On sites with trees producing litter with a low C/N ratio (the deciduous species), the organic Oe layer was narrow or absent and a thick organomineral A layer was evident. On sites with trees producing litter with a high C/N ratio (the evergreen species), in contrast, a thick Oe layer and a thin A layer were evident. Besides C/N ratio, earthworm abundance and earthworm bioturbation activity (measured as the amount of earthworm casts in the topsoil) were the strongest predictors of A layer thickness and C accumulation in the mineral topsoil. Sites with higher C accumulation in mineral soil had higher microbial biomass and lower microbial respiration, which may have contributed to the higher C storage. The gradient of bioturbaton was correlated with changes in the composition of the bacterial community and other soil biota, but partial correlation showed that the effects of litter quality and bioturbation were largely independent. Overall, the results indicate that the effect of tree species on soil development is substantially mediated by soil fauna activity and especially by earthworm bioturbation. (C) 2013 Elsevier B.V. All rights reserved.