关键词： 作品集   现代   动画   连环画   中国  

ISBN: (纸本)7802200520

摘要： 本书由四个独立小故事配以大幅彩图组成的经典动物童话合集。

关键词： Joshua tree   scatter hoarding   seed caching   seed dispersal   Yucca brevifolia  

摘要： Joshua tree (Yucca brevifolia) is a distinctive and charismatic plant of the Mojave Desert. Although floral biology and seed production of Joshua tree and other yuccas are well understood, the fate of Joshua tree seeds has never been studied. We tested the hypothesis that Joshua tree seeds are dispersed by seed-caching rodents. We radioactively labelled Joshua tree seeds and followed their fates at five source plants in Potosi Wash, Clark County, Nevada, USA. Rodents made a mean of 30.6 caches, usually within 30 in of the base of source plants. Caches contained a mean of 5.2 seeds buried 3-30 mm deep. A variety of rodent species appears to have prepared the caches. Three of the 83 6 Joshua tree seeds (0.4%) cached germinated the following spring. Seed germination using rodent exclosures was nearly 15%. More than 82% of seeds in open plots were removed by granivores, and neither microsite nor supplemental water significantly affected germination. Joshua tree produces seeds in indehiscent pods or capsules, which rodents dismantle to harvest seeds. Because there is no other known means of seed dispersal, it is possible that the Joshua tree-rodent seed dispersal interaction is an obligate mutualism for the plant.

关键词： Forestry  

摘要： Non-lethal management methods for reducing mammal browsing damage to Eucalyptus seedlings during plantation establishment are currently being investigated in Tasmania, Australia. One method is use of selective retention of non-seedling vegetation in plantations. To assess its potential, information is needed on how herbivores use such vegetation and whether it has positive or negative effects on browsing and growth of commercial tree seedlings. We quantified the populations of five mammalian herbivore species in and around a spot-herbicided E. nitens plantation during its establishment. We also investigated several aspects of the interactions between those mammalian herbivores, insect herbivores, tree seedlings and non-seedling vegetation. We found that overall population densities were high for red-bellied pademelons (Thylogale billardierii) and red-necked wallabies (Macropus rufogriseus rufogriseus), but very low for common brushtail possums (Trichosurus vulpecula), common wombats (Vombatus ursinus) and the introduced European rabbit (Oryctolagus cuniculus). Population densities of the five mammalian species did not change in response to planting E. nitens seedlings. Dominant vegetation in the plantation was grass, then forbs and non-grass monocots. Herbivores ate a large proportion of available plantation vegetation in unfenced plots. Mammal browsing had little effect on survival of E. nitens seedlings 15 weeks after planting, but significantly reduced their growth. In unfenced plots, insects, mainly Heteronyx spp., caused twice as much damage to seedlings as browsing mammals. The absence of mammalian browsing in fenced plots, which resulted in high grass cover, was associated with reduced insect damage to seedlings.

关键词： Ghana   hunting   duality   sustainability   bushmeat   livelihoods  

摘要： This article argues that insufficient attention has been paid in the recent literature to the social and environmental factors which regulate hunting in Ghanaian savannas, and to how this may influence the sustainability of their livelihoods. Despite the vital significance of this issue, the emphasis in the literature and media has been on the destructive impacts of hunting and the bushmeat trade on wildlife. Taking a case study from the coastal savanna of Ghana, a region commonly regarded as a degraded relict of former deciduous forest with a richer wildlife past, it investigates the hypothesis that structure/actor dualities, manifested by socio-cultural change, local environmental knowledge and livelihood activity options, are the primary regulators of hunting intensity and possible sustainability. Such an evaluation is effective if done from a structuration perspective. The integrated methodology incorporates social surveys, GIS based time series image analysis, ecological field methods and statistical analysis. The results provide evidence that the direct and indirect regulatory functions of the socioenvironmental context provide a core feature of the sustainability of hunting. It is concluded that local strategies of resource management may provide an effective complement to conservation policy. (c) 2005 Elsevier Ltd. All rights reserved.

关键词： ants   Batesian mimicry   staphylinid beetle   predation  

摘要： Some myrmecophilous animals show myrmecomorphy, however, its adaptive significance is still controversial. We investigated a possible benefit of Batesianmimicry between a myrmecophilous staphylinid beetle, Pella comes, and its host ant, Lasius (Dendrolasius) spathepus, by using a common ant predator, the Japanese treefrog, Hyla japonica. In the field, H. japonica were found to feed on numerous ants and other insects, but in laboratory experiments they refused feeding on L. spathepus. L. spathepus was highly repellent to these frogs, while P. comes was potentially palatable. After repeated contacts with L. spathepus which led to its avoidance the treefrogs started to reject P. comes as well . This suggests that myrmecomorphy is beneficial to P. comes, reducing the risk of predation, and that it , may represent a case of Batesian mimicry. may represent a case of Batesian mimicry.

关键词： C : N : P ratio   floods   invertebrate   litter quality   Populus   Rio Grande   riparian vegetation   river floodplain  

摘要： 1. We examined the role of flooding on the leaf nutrient content of riparian trees by comparing the carbon : nitrogen : phosphorus (C : N : P) ratio of leaves and litter of Rio Grande cottonwood (Populus deltoides ssp. wislizenii) in flood and non-flood sites along the Middle Rio Grande, NM, U.S.A. The leaf C : N : P ratio was also examined for two non-native trees, saltcedar (Tamarix chinensis) and Russian olive (Elaeagnus angustifolia), and six species of dominant riparian arthropods. 2. Living leaves and leaf litter of cottonwoods at flood sites had a significantly lower leaf N : P ratio and higher %P compared with leaves and litter at non-flood sites. A non-flood site downstream from wastewater effluent had a significantly lower litter C : N ratio than all other sites, suggesting N fertilisation through ground water. The non-native trees, saltcedar and Russian olive, had higher mean leaf N content, N : P ratio, and lower C : N ratio compared with cottonwoods across study sites. 3. Riparian arthropods ranged from 5.2 to 7.1 for C : N ratio, 56-216 for C : P ratio, and 8.9-34 for N : P ratio. C content ranged from 25 to 52% of dry mass, N content from 4.7 to 10.8%, and P content from 0.59 to 1.2%. Differences in stoichiometry between high C : nutrient leaf litter and low C : nutrient invertebrates suggests possible food-quality constraints for detritivores. 4. These results suggest that spatial and temporal variation in the C : N : P ratio of cottonwood leaves and leaf litter is influenced by surface and subsurface hydrologic connection within the floodplain. Reach-scale variation in the elemental composition of riparian organic matter inputs may have important implications for decomposition, nutrient cycling, and food webs in river floodplain systems.

关键词： water management   wildlife management   semi-arid savannas   artificial water sources   water source heterogeneity   rainfall   Kruger National Park  

摘要： Savanna water management is predicated on the hypothesis that surface water availability can be manipulated at scales that influence herbivore distributions. Using a case study in the Kruger National Park, South Africa, we assess the contribution of perennial and ephemeral water sources to surface water availability in the dry season. We posit that surface water availability in savanna ecosystems exists along a continuum of being determined primarily by perennial or ephemeral water sources and propose that locating an ecosystem along this continuum provides a means to evaluate the utility of water management. We also develop general hypotheses about the relative response of herbivore species to ephemeral water sources. (c) 2005 Elsevier Ltd. All rights reserved.

关键词： Chile   climbing ability   habitat use   marsupial   rodent   small mammal  

摘要： Climbing ability can be a major component of the capability of terrestrial mammals to use vertical habitats. Previous studies Suggest that small mammals from central Chile have low climbing capabilities. However, those Studies have not disentanaled the influence of tree diameter in natural habitats from true climbing ability of different species. We carried Out a laboratory experiment by Studying the climbing ability of 4 central Chilean small mammals, 2 octodontid rodents (Octodon bridgesi and O. degus), I murid rodent (Phyllotis darwini), and I marsupial (Thylamys elegans), in situations with different stern diameters. Species showed distinctive climbing abilities. The marsupial T. elegans showed efficient climbing ability independent of stem diameter. P. darwini and O. bridgesi were both influenced by stein diameter, but the former species used smaller-diameter stems less frequently. O. degus showed the lowest climbing ability.

关键词： AFLP   dispersal   spatial genetic structure   microsatellites   tropical forest  

摘要： Simarouba amara (Simaroubaceae) is a vertebrate-dispersed, insect-pollinated Neotropical tree found in lowland moist forest from upper Mesoamerica to the Amazon basin. We assessed the spatial genetic structure of S. amara within the 50-ha Forest Dynamics Plot on Barro Colorado Island in the Republic of Panama. A total of 300 individuals were genotyped using five microsatellite loci, representing 100 individuals with a dbh >= 10 cm, 100 individuals of 1-10 cm dbh, and 100 individuals of <1 cm dbh. The 200 individuals in the two larger size classes were also genotyped with 155 AFLP loci. Spatial autocorrelation analysis using Moran's Index detected significant genotypic association at the smallest distance classes for 1-10 cm dbh (0-20 m) and 410 cm dbh (0-40 m) size categories. Significant spatial autocorrelations were detected over larger scales (0-140 m) in <1 cm dbh individuals. The relatively weak genetic structure of S. amara, in comparison to other recent studies, may be explained by pollen and seed dispersal over the 50 ha plot, overlapping seed shadows, and postrecruitment mortality.

关键词： PASTEURELLA   BACTERIAL diversity   MICROBIAL diversity   BACTERIAL genetics   MICROBIAL genetics   RECOMBINANT DNA  

摘要： To reveal the genetic diversity of Pasteurella pneumotropica, the 16S rDNA sequence and multiple alignments were performed for 35 strains (from 17 mice, 13 rats, 3 hamsters, 1 rabbit, and 1 guinea pig) identified as P. pneumotropica using a commercial biochemical test kit or PCR test and two reference strains (ATCC 35149 and CNP160). Each strain showed a close similarity with one of the following organisms: P. pneumotropica (M75083), Bisgaard taxon22 (AY172726), Pasteurella sp. MCCM00235 (AF224300), Pasteurellaceae gen. sp. Forsyth A3 (AF224301), and Actinobacillus muris (AF024526) on GenBank, and were divided into six clusters on a phylogenic tree. Two reference strains, P. pneumotropica biotype Jawetz and Heyl, were classified at both ends of the clusters. Our conclusion is that P. pneumotropica should be reclassified because of the very wide genetic diversity that exists.