关键词： Biodiversity and ecosystem function   Host specialization   Plant species richness   Sustainable forest management   Trophic interactions  

摘要： Stand diversification is considered a promising management approach to increasing the multifunctionality and ecological stability of forests. However, how tree diversity affects higher trophic levels and their role in regulating forest functioning is not well explored particularly for (sub)tropical regions. We analyzed the effects of tree species richness, community composition, and functional diversity on the abundance, species richness, and beta diversity of important functional groups of herbivores and predators in a large-scale forest biodiversity experiment in south-east China. Tree species richness promoted the abundance, but not the species richness, of the dominant, generalist herbivores (especially, adult leaf chewers), probably through diet mixing effects. In contrast, tree richness did not affect the abundance of more specialized herbivores (larval leaf chewers, sap suckers) or predators (web and hunting spiders), and only increased the species richness of larval chewers. Leaf chemical diversity was unrelated to the arthropod data, and leaf morphological diversity only positively affected oligophagous herbivore and hunting spider abundance. However, richness and abundance of all arthropods showed relationships with community-weighted leaf trait means (CWM). The effects of trait diversity and CWMs probably reflect specific nutritional or habitat requirements. This is supported by the strong effects of tree species composition and CWMs on herbivore and spider beta diversity. Although specialized herbivores are generally assumed to determine herbivore effects in species-rich forests, our study suggests that generalist herbivores can be crucial for trophic interactions. Our results indicate that promoting pest control through stand diversification might require a stronger focus on identifying the best-performing tree species mixtures.

关键词： adenocarcinoma   amphibia   carcinoma   lymphosarcoma   mast-cell tumour   neoplasia  

摘要： Four cases of spontaneous neoplasia in different species of Amphibia at two zoological collections in the United Kingdom (2009–2016) are described: disseminated lymphosarcoma with leukaemia in an Alpine newt Ichthyosaura alpestris, nasal adenocarcinoma in a Red-eyed tree frog Agalychnis callidryas, pulmonary carcinoma in a Common frog Rana temporaria and cutaneous mast-cell tumour in a Puerto Rican crested toad Peltophryne lemur. History, and gross and histological findings are presented. In particular, mast-cell tumours in Anura and respiratory tumours of amphibians have rarely been reported. © 2017 The Zoological Society of London

关键词： PREDATION (Biology)   BEETLES   SPATIO-temporal variation   POPULATION dynamics   FOREST ecology  

摘要： Resolving linkages between local-scale processes and regional-scale patterns in abundance of interacting species is important for understanding long-term population stability across spatial scales. Landscape patterning in consumer population dynamics may be largely the result of interactions between consumers and their predators, or driven by spatial variation in basal resources. Empirical testing of these alternatives has been limited by the lack of suitable data. In this study, we analyzed an extensive network of spatially replicated time series to characterize the local and regional processes affecting spatio-temporal dynamics of a tree-killing bark beetle (Dendroctonus frontalis or SPB) and its key predator (Thanasimus dubius) across the southeastern United States. We first used a mechanistic model to evaluate factors affecting the stability of 95 predator-prey time series and then conducted spatial analyses to evaluate scale dependence in the factors affecting the geographical patterning of this system. Across the region, population fluctuations of both species were correlated in space beyond 400 km but there was notable spatial variation in the deterministic and stochastic processes influencing forest-scale (local) fluctuations. Time series analyses indicated that local dynamics of SPB and T. dubius are not cyclical. Instead, the abundance of T. dubius responded almost instantaneously to changes in SPB abundance. Spatial variation in long-term forest-scale abundance of both species was linked most strongly to the abundance of pine habitat indicating a stronger role for resource availability in SPB population dynamics than top-down effects. Our results are consistent with other studies indicating that animal populations tend to be synchronized in space via spatially correlated processes such as weather;yet local dynamics tend to be linked to smaller-scale host patterns. Our study provides a rare empirical assessment of how local processes scale up to produce la

关键词： grazing   Great Plains   oak savannas   regeneration   Quercus macrocarpa Michx  

摘要： Oak savanna remnants contribute substantially to the biodiversity of graminoid-dominated landscapes in the Great Plains Region. Most of these ecologically important ecosystems have either been altered or lost altogether since the arrival of Europeans in the early to mid-1800s. Changes in land use have been accompanied by reduced oak regeneration, which may be attributable to grazing and other management practices. At present, numbers of surviving oak seedlings are insufficient for sustaining the recruitment of oaks into savanna overstory strata. Herbivore exclosures were used to distinguish sources of mortality in first-year bur oak (Quercus macrocarpa) seedlings to determine the impacts of large mammalian herbivores, small mammals, and drought on oak regeneration in savanna remnants in Custer County, Nebraska. Results suggested an uncertain future for extant oak savannas on private land in central Nebraska. Seedlings without exclosures exhibited 97% mortality over the first growing season, and 100% mortality was observed during the subsequent dormant season in seedlings without exclosures that had survived the growing season. Although drought and small mammals contributed to overall oak seedling mortality, cattle and deer impacts were the leading causes of mortality in seedlings without exclosures. Trampling, grazing, and browsing may compromise efforts to restore and sustain these ecologically valuable ecosystems. However, effects of these factors may be reduced through management involving exclosures and limiting grazing to seasons when young oaks are less susceptible to damage.

关键词： Conservation   forest management   habitat variables   tracks  

摘要： We examined the influence of tree thinning on the abundance of mammals in a Japanese larch Larix kaempferi plantation in Mt Gariwang, Pyeongchang, South Korea. In 2014 and 2015, from April to October, we recorded the presence of tracks as a proxy for abundance, for the following seven mammalian species: Korean hare Lepus coreanus, raccoon dog Nyctereutes procyonoides, Siberian weasel Mustela sibirica, Eurasian badger Meles meles, water deer Hydropotes inermis, roe deer Capreolus pygargus, and wild boar Sus scrofa. We also assessed how the intensity of tree thinning affected vegetation cover;there were significant differences in number of standing trees, basal area, coverage of vegetation layers, and number and volume of downed trees among the control, moderately thinned, and intensively thinned stands. We found significant differences in the abundance of tracks among the stands for three mammal species. In four mammal species, the abundance of track was significantly correlated with volume of downed trees, coverage of ground vegetation, number of downed trees, and number of standing trees, according to stepwise analysis. The presence and abundance of mammals is linked to habitat variables and forest managers should consider how habitat modifications will affect wildlife.

关键词： Anti-cancer   Anti-inflammatory   Analgesic   Ethnopharmacology   Traditional medicines   Animal models  

摘要： Ethnopharmacological relevance: Phytochemicals with anti-oxidative and anti-inflammatory properties are known to inhibit tumour initiation, promotion and progression. Hence, there is an increasingly-convincing rationale for employing remedies containing those phytochemicals in the treatment of cancers and also as analgesic and anti-inflammatory adjuvants in therapy. The plants Garcinia kola Heckel (Clusiaceae), stem bark;Uvaria chamae P. Beauv. (Annonaceae), root;and Olax subscorpioidea Oliv. (Olacaceae), root, have been documented to be part of various indigenous anti-cancer regimens. Aim of the study: To determine if the three plants exhibit significant anti-oxidative and anti-inflammatory properties. Materials and methods: Using established models, the analgesic and anti-inflammatory activities of the three plants were investigated. Results: Pre-treatment with the plant extracts at 100, 200 and 400 mg/kg produced inhibition of writhes;G. kola and U. chamae showed no significant effect on formalin-induced pain, but O. subscorpioidea produced inhibition in both phases of the formalin test. Similarly, while G. kola and U. chamae did not produce any significant inhibitory effect in the xylene-induced ear oedema model, the oedema was significantly reduced by O. subscorpioidea pre-treatment. However, all the three plants significantly inhibited the time-dependent increase in paw circumference in the carrageenan- and formaldehyde-induced rat paw oedema tests, with peak effects observed at 400 mg/kg, 6 h after the induction of oedema, comparable in some cases to the effects of two standard drugs, the non-steroidal anti-inflammatory drug diclofenac and the anti-inflammatory antibiotic doxycycline. Conclusion: We conclude that the three plant extracts possess analgesic and anti-inflammatory properties, thus providing a scientific rationale for their inclusion in some traditional anti-cancer regimens.

关键词： 树鼩   小型哺乳动物   模式动物  

摘要： 树鼩作为一类具有潜在应用价值的新型模式动物,已越来越多地受到人们的关注。简述树鼩的形态学特征、生存环境、活动特征及研究价值。

关键词： INVERTEBRATE communities   BIOMASS   HONEY mesquite   BIODIVERSITY   INVERTEBRATES  

摘要： Effects of frequency of prescribed burning on invertebrate abundance, diversity, and biomass were investigated in a shortgrass prairie encroached by mesquite, Prosopis glandulosa Torr., at Cross Bar Management Area in Potter County, TX. Invertebrates were collected from three burn treatments (frequencies of 2-3, 4-6, and 8-12 years) by using pitfall traps in 2007 and 2008. Analysis of variance was used to compare abundance, diversity, and biomass at the order and family levels using fire frequency, season, and year as main effects. In general, the season and year had more effect on abundance, diversity, and biomass than did burn frequency. These patterns are consistent with the idea that weather has more impact than fire on invertebrate biomass in shortgrass prairie. Longer-term monitoring of the effects of fire frequency is necessary to better elucidate long-term effects of burning on invertebrate communities in mesquite-encroached shortgrass prairie.

关键词： Savanna ecosystems   Cause and effect mechanisms   Complex systems   Fires   Loop analysis   Positive feedback  

摘要： The dynamics of savanna ecosystems depends on the interplay between multiple factors such as grazing, browsing, fires, rainfall regime and interactions between grass and woody vegetation. In most modelling applications this interplay may not be fully understood because some of these drivers enter the models as dynamically independent factors. In this paper we consider such factors as dynamic variables. To analyze their interplay we focus on the structure of the interactive network of variables and exploit the properties of signed digraphs using the algorithm of Loop Analysis. Qualitative signed digraphs for the savanna ecosystem are developed and their predictions used to interpret patterns of abundance observed in case studies selected from the literature. The outcomes of this exercise unveil that: 1) the structure of the interactions is appropriate locus for the explanation of patterns observed in savannas;2) signed digraph can help disentangling causative mechanisms by linking correlation patterns, source of change and network structure. This study highlights that central to the understanding of savanna dynamics is our ability to diagram the important relationships and understand how they interrelate with sources of variations to cause ecosystem change. (C) 2016 Elsevier B.V. All rights reserved.

关键词： amphibians   areas of endemism   biodiversity   biotic elements   distributional patterns   Neotropical region   open areas   regionalization   reptiles  

摘要： Aim To analyse ranges of endemic squamates and anurans in the Cerrado hotspot, searching for coincident distributional patterns in two ecologically distinct clades, and proposing a testable and comprehensive regionalization scheme for the richest and most threatened savanna on the planet. Location Cerrado region, central South America. Methods We updated previous point-locality compilations for endemic species of the Cerrado herpetofauna, gathering 4588 unique occurrence records. Using a 1 degrees grid cell, we compared regionalization results of biotic element ( BE) and endemicity analyses. To search for a unified regionalization pattern, we compared analyses with a combined dataset ( anurans + squamates) with those obtained in single-group analyses. Results The analysis with the combined dataset recovered more complete results than those in taxon-specific analyses. We found 13 main biogeographical units formed by anurans and squamates that were recovered in both analyses with the combined dataset, and formed our general regionalization scheme. In general, biogeographical units defined by BEs correspond to those recovered by endemicity analysis with the combined dataset. Most recovered biogeographical units were formed both by anurans and squamates, with fewer areas determined solely by one group. Main conclusions Common regionalization processes operated on both anurans and squamates, shaping general biogeographical patterns for the Cerrado. The general regionalization pattern recovered with anurans and squamates may be valid for other taxa, and should be tested in future studies. As in previous results, most biogeographical units are found over ancient plateaus, separated by peripheral depressions. These major topographical barriers may explain major coincident patterns, linking the evolution of Cerrado biotas to the geomorphological history of the Brazilian shield.