生态补偿对大熊猫栖息地周边农户生态足迹的影响

大熊猫栖息地正面临破碎化和人类活动干扰的威胁,如何减少这些威胁成为保护大熊猫这一生态旗舰物种的关键.通过实施生态补偿项目,充分考虑当地弱势群体生存和发展的权利,帮助其进行生计替代和能源替代,以减小生态系统所承受的压力.以120个项目农户作为研究对象,利用生态足迹方法,探讨了生态补偿项目对生活在关键生态区域内农村人口的影响.结果表明,在各种生态生产性土地中,农户对林地和草地生态占用最大,能源替代可以大幅降低农户的薪柴消耗水平,从而降低农户对林地的生态占用.通过调整农户的牲畜养殖模式,减小了放牧对草地资源的压力和对草地的生态占用.农户人均生态足迹由2005年的2.7346hm2减小至2007年的1.6325 hm2,对周边环境的压力降低,有利于保护和恢复珍稀野生动植物栖息地.     

Quantifying ecological filters: the relative impact of herbivory, neighbours, and sediment on an oligohaline marsh

The objective of this experiment was to quantify the relative importance of herbivory, interactions with neighbours and sediment addition as filters in controlling the species present in an oligohaline marsh in southeastern Louisiana, USA. We planted 16 species of wetland plants in 3×3 m plots either inside or outside herbivore exclosures, with or without presence of established vegetation, and with or without added sediment. These species, representing 12 families and diverse morphologies, included herbaceous and woody plants. At the end of the growing season above‐ and below ground biomass were measured. In cleared plots (no neighbours) inside herbivore exclosures, 12 of the 16 species grew well, indicating that they could tolerate the physical conditions in the habitat. Competition significantly reduced the biomass of four of these species (A. calamus, C. occidentalis, P. hemitomon, P. cordata), suggesting that it is the strongest species‐specific filter operating in the marsh. These results confirm the general consensus that competition from existing plants is the strongest filter operating in high biomass habitats, and further imply that competition has the potential to remove 33% of the species from the community. Facilitation occurred for one species, R. corniculata. Herbivory had the largest general effect of reducing biomass, as determined in the full ANOVA model, but on a species‐specific basis, significantly reduced the biomass of only two species (T. distichum, T. domingensis). These results support the emerging view that herbivory is an important filter in coastal wetlands. Although several other studies have argued for the importance of sedimentation in controlling plant species composition in wetlands, we found no effect of sediment addition. Competition and herbivory appear to be two critical biological filters that control plant composition of coastal wetlands, and they must be considered in future studies and restoration efforts along the Gulf of Mexico.     

Winter social behaviour of dark-eyed juncos: Communication,social organization,and ecological implications

This paper reports on winter social behaviour in free-living and captive flocks of dark-eyed juncos (Junco hyemalis). Visual and vocal signals used by flocked juncos are analysed structurally and functionally. An examination is made of the frequency and form of agonistic behaviour in several social and environmental contexts in an attempt to provide insight into the relationship between junco communication and social organization. A system of classification of signals, based upon the meaning of cues to the signaller, is proposed. Evidence is given to suggest that the behaviour of subordinate, rather than of dominant, individuals controls the operation of the social system in junco flocks. Some ecological implications of junco social behaviour are discussed.     

The social and reproductive biology of Humpback Whales: an ecological perspective

Existing knowledge of the social organization, mating system and reproduction of Humpback Whales (Megaptera novaeangliae) is reviewed to assess how our current understanding of this wide-ranging marine mammal fits into the predictive framework developed from ecological studies of more accessible terrestrial taxa. The small unstable groups characteristic of this species on its summer feeding grounds appear to be a function of absence of predation and of the patchy, mobile nature of most prey; the absence of territoriality and the minimal importance of kinship in associations are also predictable consequences of the latter. The mating system is similar to both leks and to male dominance polygyny, in which males display (sing) or directly compete (perhaps sometimes in coalitions) for access to females. However, the rigid spatial structure characteristic of classic leks is absent. The mating system of this species is sufficiently different to merit a novel category, and ‘floating lek’ is proposed. The widespread distribution of females resulting from absence of both predation and resources during the breeding season preclude simultaneous monopolization by males of more than one potential mate. Furthermore, these factors, together with a male-biased operational sex ratio, minimize the possibility of competition among females. The intensity of intrasexual competition among males conforms to predictions derived from information on testis size and from expectation of future reproductive success. Female choice and, to a lesser extent, differential allocation of competitive effort by males, appears likely. Lack of interpopulation variation in social and mating behaviour, and in general reproductive biology, is likely a response to similarity of marine environmental conditions. Year-to-year variation in reproductive rates may be linked to variations in the abundance of prey. The invariably uniparous nature of female Humpback Whales is assumed to be related to the energetic demands of lactation, and the lower ratio of available energy partitioned to reproduction that is characteristic of larger mammals. The reversed sexual size dimorphism of this species may reflect different selective pressures on males and females. Finally, there is now evidence that, as in some other taxa, offspring sex ratio is related to maternal condition.     

#SayHerName: a case study of intersectional social media activism

Social media activism presents sociologists with the opportunity to develop a deeper understanding of how groups form and sustain collective identities around political issues throughout the course of a social movement. This paper contributes to a growing body of sociological literature on social media by applying an intersectional framework to a content analysis of over 400,000 tweets related to #SayHerName. Our findings demonstrate that Twitter users who identified with #SayHerName engage in intersectional mobilization by highlighting Black women victims of police violence and giving attention to intersections with gender identity. #SayHerName is a dialogue that centres Black cisgender and transgender women victims of state-sanctioned violence. Additionally, #SayHerName is a space for highlighting Black women victims of non-police violence. Therefore, we propose that future research on social media activism should incorporate intersectionality as a basis for understanding the symbols and language of twenty-first century social movements.     

Monitoring microbial aeroflora using vegetable waste media: an ecological aspect

For isolation of aeromicroflora in ecologically different zones, a liquid vegetable waste, deproteinised leaf juice (DLJ) was used instead of usual media. DLJ samples from three different plants, cowpea (Vigna sinensis), turnip (Brassica campestris) and radish (Raphanus sativus), were used in order to determine their efficiency as potential growth media for different types of microbes. Four different ecological zones of West Bengal, India were selected to study the aeromicroflora. The zones were as follows: (i) densely populated and industrially polluted Calcutta (CAL); (ii) plateau region of western part of the state (WEST); (iii) Terai region of Northern Bengal (TER); (iv) sandy coastal zone of Midnapore district of Southern Bengal (SB). Each zone was subdivided into three subzones. The variation in population of fungi, bacteria and actinomycetes among these zones was studied. The relative abundance and species diversities of microbes were noted. The study indicates that pollution and ecological diversity both play important roles in controlling the above two factors.     

The impact of an exotic social wasp (Vespula germanica) on the native arthropod community of north-west Patagonia, Argentina: an experimental study

Abstract 1. Biological invasions are usually thought to have a negative impact on native communities. However, data supporting this idea are often based on comparative studies between invaded and non‐invaded areas, and are spatially and temporally limited. 2. The present study experimentally assessed the impact of an exotic wasp, Vespula germanica, on the native arthropod community of north‐west Patagonia during 3 years in an area of 80 ha. Vespula germanica is an exotic social vespid that invaded north‐west Patagonia 20 years ago. It has been suggested that its populations affect native arthropods because of its broad diet and also because Patagonia lacks natural enemies and potential competitors for these wasps. 3. Using wasp‐specific toxic baits, V. germanica abundance was reduced in five sites of native woodlands during 3 consecutive years. The abundance, species richness, and composition of arthropods between non‐poisoned (control) and poisoned sites was then compared, both before and after the wasps were poisoned. 4. Wasp abundance represented 6% of the total arthropod catches in non‐poisoned sites and was reduced, on average, by 50% in the treated areas. The abundance, species richness, and composition of the arthropod community (305 species, 24 600 individuals) did not differ between control areas and areas where the abundance of V. germanica was reduced. Significant differences in response variables were found only before wasp poisoning had begun and were related to variations among sites. 5. These results suggest that V. germanica is not affecting the local arthropod assemblages, contradicting past work in other regions. The low relative abundance of wasps in Patagonia, when compared with other invaded regions, might explain the findings. 6. The present study provides further evidence for the importance of large‐scale experimental work with before/after comparisons to fully understand the impact of invaders on natural communities.     

湿地生态环境影响评价初步探讨

探讨了湿地生态环境影响评价的理论框架 ,指出由于湿地生态环境的特殊性 ,应将非污染型生态环境影响评价放到重要位置。应重视工程项目对湿地水文条件、植物区系、动物种群改变以及移民和诱导开发的影响分析。从湿地分类开始 ,以湿地功能为核心建立评价指标体系 ,把湿地潜在的生态环境效益和工程项目可能产生影响有机结合在一起 ,评价建设项目的急性和慢性影响 ,提出减缓影响的措施和替代方案。着眼于维持现存的生态过程和自然系统 ,保护湿地的生态效益和功能 ,为湿地可持续利用服务