关键词： Carnivores   Forest management   Genet   Large old trees   Mediterranean landscape   Tree hollows  

摘要： Although tree hollows seem to be key structures for a wide range of forest mammals, their importance for Mediterranean forest carnivores remain poorly understood. Here we address this issue, by analysing daily resting site use by 21 radio-collared common genets. Tree hollows were used far more frequently during the wet season (October-April;73.1% of daily locations) than in the dry season (May-September;47.6%). Nests and underground dens were the second and third most frequently used resting sites, respectively, in both wet (17.5% and 9.4%) and dry (34.1% and 18.3%) seasons. Each individual reused a large percentage of its resting sites (65.7%). Some resting sites (17.3%) were used by more than one individual, but simultaneous sharing was exceedingly rare (0.56% of daily locations). Hollow use probability during the wet season varied little in relation to environmental variables, though there was a tendency to be higher away from riparian habitats (>50 m) and to be lower in sites with very high shrub cover (>80%). Environmental influences were responsible for more variability in the dry season, when hollow usage was highest in hot days, in days with precipitation, far from riparian habitats, close to sources of human disturbance, in landscapes dominated by continuous forest habitats, and in sites with low shrub cover. Results support the importance of tree hollows for Mediterranean forest carnivores, probably because they provide safe shelter against unfavourable weather, predators and human disturbance. However, results also revealed the importance of riparian trees, which offer support for building nests close to sources of water and food during the dry season. Considering home range size and the average number of hollow-bearing trees used by each genet, we recommend that management of cork and holm oak forests should strive to safeguard at least 4.6 hollow-bearing trees per 100 ha, while simultaneously maintaining large riparian trees. This will improve the resti

关键词： body size   climate   competition and facilitation   ecological field experiments   elephants   extinction   indirect species interactions   Kenya (East Africa)   rodents   top-down control   ungulate herbivory  

摘要： Assessing the direct and indirect consequences of nonrandom species removal within guilds of strongly interacting species, such as large mammalian herbivores, is an important goal in basic and applied ecology. The ecological impacts of such perturbations are often contingent on abiotic conditions, which have hindered efforts to generalize the results of field experiments. Thus, there is a need for experiments that selectively remove different species from ecologically important guilds and that are replicated across environmental gradients. In 2008, we constructed a series of size-selective large-herbivore exclosures across a natural rainfall gradient in semi-arid Kenyan savanna. This experiment (“UHURU”, for ungulate herbivory under rainfall uncertainty) aims to (a) characterize the effects of successively removing the largest size classes of herbivores from the system and (b) evaluate how the direction and magnitude of these effects are shaped by variation in precipitation regimes. UHURU consists of three electrically fenced herbivore-exclusion treatments and an unfenced control, applied to blocks of contiguous 1-ha plots. The three fenced treatments are: “Mega” (exclusion of elephants and giraffes only); “Meso” (exclusion of both megaherbivores and mesoherbivores, ∼40 kg and larger); and “Total” (exclusion of all herbivores ≥5 kg). Each block of treatments is replicated three times at each of three sites along the 20-km rainfall gradient (increasing from 439 mm/yr in the north to 639 mm/yr in the south, with little background variation in soil attributes and species composition). We present data, spanning 2008–2013, from (a) biannual surveys of understory plants at 49 staked grid points within each of the 36 1-ha plots (1764 total stakes); (b) annual woody-plant censuses within the central 0.36 ha of each plot; (c) annual and semi-annual monitoring of individually marked woody plants; (d) small-mammal capture–mark–recapture sessions conducted every other month in

关键词： Ungulates   Water   Piosphere   Rainfall variability   Mara-Serengeti ecosystem   Pastoralism   Zero-inflated models  

摘要： Water, forage and predation constrain ungulate distributions in savannas. To understand these constraints, we characterized distributions of 15 herbivore species from water, locations of peak density and degree of clustering around the peaks using zero-inflated count data models and mapping census data collected in the Mara reserve and the adjoining pastoral ranches in Kenya during a wet and dry year. Herbivores followed a humped pattern (n = 46), suggesting constrained foraging in which they balance the benefits of proximity to water with the costs of foraging where food is depleted near water and travelling to more abundant food distant from water;an exponentially decreasing pattern (n = 11), indicating strong attraction to water or vegetation near water;or a uniform (n = 3) pattern. The details rather than the types of these patterns varied between years. Herbivores concentrated farther from water and more tightly around locations of their peak densities in the ranches than the reserve. Herbivores were more abundant and widely distributed from water in the wet than the dry year, and segregated along the distance-to-water gradient, presumably to minimize interspecific competition for food. Pastoralism compressed herbivore distributions and partially excluded some species (warthog, hartebeest, topi, wildebeest, zebra, eland, buffalo and elephant) from, while attracting others (Grant's and Thomson's gazelles, impala, giraffe) to the ranches, relative to the reserve. Regulating cultivation, fencing, settlements and livestock stocking levels in the ranches would allow continued wildlife access to water, reduce competition with, displacement or harassment of wildlife by people, livestock and dogs near water.

关键词： Trees   Marsupials   Opossums   Forests   Species diversity   Conservation science   Ecosystems   Forest ecology  

摘要： A holy grail of conservation is to find simple but reliable measures of environmental change to guide management. For example, particular species or particular habitat attributes are often used as proxies for the abundance or diversity of a subset of other taxa. However, the efficacy of such kinds of species-based surrogates and habitat-based surrogates is rarely assessed, nor are different kinds of surrogates compared in terms of their relative effectiveness. We use 30-year datasets on arboreal marsupials and vegetation structure to quantify the effectiveness of: (1) the abundance of a particular species of arboreal marsupial as a species-based surrogate for other arboreal marsupial taxa, (2) hollow-bearing tree abundance as a habitat-based surrogate for arboreal marsupial abundance, and (3) a combination of species-and habitat-based surrogates. We also quantify the robustness of species-based and habitat-based surrogates over time. We then use the same approach to model overall species richness of arboreal marsupials. We show that a species-based surrogate can appear to be a valid surrogate until a habitat-based surrogate is co-examined, after which the effectiveness of the former is lost. The addition of a species-based surrogate to a habitat-based surrogate made little difference in explaining arboreal marsupial abundance, but altered the co-occurrence relationship between species. Hence, there was limited value in simultaneously using a combination of kinds of surrogates. The habitat-based surrogate also generally performed significantly better and was easier and less costly to gather than the species-based surrogate. We found that over 30 years of study, the relationships which underpinned the habitat-based surrogate generally remained positive but variable over time. Our work highlights why it is important to compare the effectiveness of different broad classes of surrogates and identify situations when either species- or habitat-based surrogates are likely t

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.