首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 15 毫秒
1.
Israeli environmental non-government organizations (ENGOs) are assessed in light of Resource Mobilization Theory, introducing a new method for dividing ENGOs according to strategic orientation. Based on a national survey, 85 groups are categorized as consensus ENGOs that seek understanding aim at finding common grounds, or as conflict ENGOs working “outside the system.” Results show that conflict ENGOs are more grassroots in orientation and consensus ENGOs are more professionalized. Conflict ENGOs operate primarily in local arenas. Consensus ENGOs appear more stable, with larger annual budgets and paid staff, but with fewer registered members. Consensus ENGOs enjoy a wider variety of income sources; receive more funding from government, foreign, and private donations; and have a broader range of self-generated income sources. Conflict ENGOs depend more on membership fees. Both groups are highly dependent on foundation grants. In general, greater resources are associated with consensus activity than among organizations utilizing conflict tactics.  相似文献   

2.
Afforestation is inserted in the urban environment and interferes directly in the surface runoff. In order to quantify the rainfall interception by tree species, an experiment was carried out in the city of Uruaçu, Goiás, Brazil, with the four most common tree species in the urban afforestation of the region. The species chosen were the Mangifera indica (mango tree), the Caesalpinia peltophoroides (sibipiruna tree), the Pachira aquatica (munguba tree) and the Licania tomentosa (oiti). In order to register precipitation, ten pluviographs were used. They are capable of measuring precipitation over time in terms of duration, volume, and intensity. For events with a mean cumulative precipitation of 16.7 mm, the mean values of interception found in each species were: Mangifera indica - 8.0 mm; Pachira aquatica - 7.4 mm; Licania tomentosa - 7.2 mm; and Caesalpinia peltophoroides - 4.8 mm. The research confirms the importance of studies related to the identification of the species’ individual characteristics that interfere in the rainfall interception capacity and that can consequently contribute to urban drainage actions. In addition, it proves the existence of variations of rainfall interception in relation to rainfall events and during their occurrences and emphasizes the need for a careful definition of the species that will compose the urban afforestation.  相似文献   

3.
We investigated the drivers of street tree transpiration in boreal conditions, in order to better understand tree water use in the context of urban tree planning and stormwater management. Two streets built in Helsinki in 2002, hemiboreal zone that had been planted either with Tilia?×?vulgaris or Alnus glutinosa f. pyramidalis were used as the study sites. Tree water use was measured from sap flow over the 2008–2011 period by the heat dissipation method. Penman-Monteith based evapotranspiration models of increasing complexity were tested against the tree water use measurements to assess the role of environmental and tree related factors in tree transpiration. Alnus and Tilia respectively used 1.1 and 0.8 l of water per m2 of leaf area per day under ample water conditions, but the annual variation was high. The Penman-Monteith evapotranspiration estimate and soil water status changes explained over 80 % of the variation in tree transpiration when the model was parameterized annually. The addition of tree crown surface area in the model improved its accuracy and diminished variation between years and sites. Using single parameterization over all four years instead of annually varying one did not produce reliable estimates of tree transpiration. Tree transpiration, scaled to different canopy cover percentages, implied that the columnar Alnus trees could transpire as much as all annual rainfall at or less than 50 % canopy cover.  相似文献   

4.
Growing human populations make it imperative for ecologists to identify strategies to conserve biodiversity in human-dominated landscapes, such as cities. Effects of urbanization on birds are particularly well-studied, but questions remain regarding the best conservation approaches. Debate about the relative utility of focusing conservation efforts on nature reserves versus developed lands has focused largely on comparing species abundance or presence, with few studies addressing underlying behavioral or demographic mechanisms. Here we evaluated differences in avian reproductive success in nature reserves and matrix habitats to test the assumption that nest predation is lower within areas protected from development. Specifically, we investigated 1) whether nest survival differed in replicated pairs of forest parks and residential neighborhoods and 2) whether differences in nest survival were associated with changes in which species most frequently depredated nests. From April–August 2007–2014, we monitored nests of two native birds, American robin (Turdus migratorius) and northern cardinal (Cardinalis cardinalis), and video-documented nest predators in paired forest-matrix habitats in the Columbus, Ohio metropolitan area. We found similar rates of nest survival in the two habitats for both robins (Χ21?=?0.715, p?=?0.398, n?=?741 nests) and cardinals (Χ21?=?0.926, p?=?0.336, n?=?1156 nests), but interactions between predators and prey differed. In particular, domestic cats (Felis catus) were over five times as likely to depredate cardinal nests in matrix habitats versus forest parks (Χ21?=?7.24, simulated p?=?0.010; nforest?=?3, nmatrix?=?7). Our results suggest that at least in some circumstances, nest success of native birds may be equivalent between nature reserves and adjacent residential matrix habitats, and thus residential neighborhoods may contribute positively to bird conservation in urban landscapes.  相似文献   

5.
This study examines whether there are multiple joint trajectories of depression and problem gambling co-development in a sample of emerging adults. Data were from the Manitoba Longitudinal Study of Young Adults (n = 679), which was collected in 4 waves across 5 years (age 18–20 at baseline). Parallel process latent class growth modeling was used to identified 5 joint trajectory classes: low decreasing gambling, low increasing depression (81%); low stable gambling, moderate decreasing depression (9%); low stable gambling, high decreasing depression (5%); low stable gambling, moderate stable depression (3%); moderate stable problem gambling, no depression (2%). There was no evidence of reciprocal growth in problem gambling and depression in any of the joint classes. Multinomial logistic regression analyses of baseline risk and protective factors found that only neuroticism, escape-avoidance coping, and perceived level of family social support were significant predictors of joint trajectory class membership. Consistent with the pathways model framework, we observed that individuals in the problem gambling only class were more likely using gambling as a stable way to cope with negative emotions. Similarly, high levels of neuroticism and low levels of family support were associated with increased odds of being in a class with moderate to high levels of depressive symptoms (but low gambling problems). The results suggest that interventions for problem gambling and/or depression need to focus on promoting more adaptive coping skills among more “at-risk” young adults, and such interventions should be tailored in relation to specific subtypes of comorbid mental illness.  相似文献   

6.
Urbanization is a major global change inducing complex and multiple modifications of landscapes and ecosystems. The spatial distributions of organisms experiencing these modifications will likely shift specifically, depending on each species’ response to each environmental modification induced by urbanization. We sampled two ant genera (Lasius and Tetramorium) at 1248 locations along an urbanization gradient in Lyon, France and used high resolution spatial layers for 18 spatial (e.g., open habitat fragmentation, bioclimatic data and surface temperatures) and temporal (e.g., comparison of Normalized Difference Vegetation Index between 1986 and 2015) environmental variables associated with urbanization. Coupling two different analytical methods (Outlying Mean Index and Boosted Regression Trees), we showed that each species’ distribution was influenced by its own combination of environmental factors. Two morphologically cryptic Tetramorium species (T. sp.E and T. sp.U2) were both highly abundant but with opposite responses to urbanization: while T. sp.E was favored by urbanized habitat, T. sp.U2 avoided urbanized areas. Among Lasius species, we detected 63 occurrences of the invasive ant Lasius neglectus, the distribution of which was favored only by embankments along roads. We found that, even at this reduced spatial scale, climatic effects influenced most species and interacted with urbanization factors.  相似文献   

7.
Understanding the factors determining the occupancy and detection probability of birds in human dominated environments is important for their conservation. In this study we investigated various environmental variables believed to influence the site occupancy and detection probability of Trumpeter Hornbill (Bycanistes bucinator) in urban-forest mosaics of KwaZulu-Natal, South Africa. Presence/absence data were collected from a total of 50 point count stations established between September 2014 and March 2015 in urban-forest mosaics of Durban, Eshowe and Mtunzini. Mean occupancy rate of Trumpeter Hornbill was 0.40 ± 0.09 with a low detection probability of 0.28 ± 0.04. For Trumpeter Hornbills, large trees influenced their occupancy positively (sum AIC weight (ω i ) = 79%) while relative human abundance negatively influenced their occupancy (ω i = 91%). Model selection suggested that housing density had a strong negative influence on detection probability of Trumpeter Hornbills (ω i ?=?82?%?) and availability of fruiting trees influenced their detection positively (ω i ?=?29%). With continued changing land use in KwaZulu-Natal, these finding are important for conservation of Trumpeter Hornbills as we provide insight into landscape variables or features that influence Trumpeter Hornbill’s occupancy and detection in areas of urban-forest mosaics.  相似文献   

8.
This study is a first attempt to estimate the degree of tritrophic association between the common dandelion Taraxacum officinale complex, the herbivorous weevil Glocianus punctiger and its parasitoid Entedon costalis, as an environmental marker in urban ecosystems. The study was conducted on 3926 dandelion flowering stems spread across 24 sample plots situated within the municipal borders of Kyiv (Ukraine). Eighteen plots were infested by the weevils, and 14 plots were infested by E. costalis. Of all the examined dandelion stems, 359 (9.1 %) were infested by weevils, and 21.4 % of these weevil-infested stems were parasitized by E. costalis. Thirty-two incidents of superparasitism were registered in nine sample plots. Seven environmental variables were chosen for characterization of the sample plots and for testing their possible effects on the tritrophic association. The results indicate that the infestation of dandelions by weevils is strongly limited by the grasslands’ mowing. Apart from that, the presence of anthropogenic barriers bounding the study areas negatively affected the parasitism of G. punctiger by E. costalis. This is regarded as an example of the crucial effect of habitat fragmentation on the specialist herbivore and the specialist parasitoid of this tritrophic system. Both the mowing and habitat fragmentation are linked with human land-use regimes on the sample plots.  相似文献   

9.
As urbanization in the landscape increases, some urban centers are setting aside habitat for wildlife. This habitat may be particularly valuable to declining or conservation-priority species. One group in particular need of conservation actions that may benefit from habitat located in urban areas is grassland birds. Declines of grassland bird species have been particularly severe in the Midwestern U.S., where most grassland cover has been lost, fragmented, and surrounded by unsuitable habitat. Conservation efforts have focused on protecting large grasslands surrounded by minimal amounts of trees and development. Although urban development is considered hostile to grassland birds, this assumption has received little attention. In heavily fragmented landscapes where habitat is limited, urban grasslands may be of significant value to grassland birds. We examined grassland bird response to development and additional landscape and habitat variables in the greater Chicago metropolitan area. In 2012 and 2013, we surveyed bird communities in grassland patches along a gradient of urbanization and patch sizes. Density of Savannah Sparrows (Passerculus sandwichensis) increased with amount of development, while density of Sedge Wrens (Cistothorus platensis) decreased. Development did not appreciably impact Bobolinks (Dolichonyx oryzivorus), Dickcissels (Spiza americana), Eastern Meadowlarks (Sturnella magna), Grasshopper Sparrows (Ammodramus savannarum), or Henslow’s Sparrows (Ammodramus henslowii). Patch size had a positive effect on species densities. These results indicate that for many conservation-priority grassland birds, urban landcover surrounding grasslands generally has neutral rather than negative effects on habitat use. Therefore, grasslands in developed landscapes may provide valuable contributions to regional conservation efforts.  相似文献   

10.
Time of peak bat activity during the night differs among bat species due to temperature, prey availability, habitat availability, and/or interactions between species. Habitat availability is altered in urban areas, which may affect insect prey availability and interspecies interactions. Our objectives were to use mobile acoustic monitoring to determine when bat species were active in a single night in urban and nonurban sites and if nightly bat activity patterns differed in urban versus nonurban sites. Bat echolocation call sequences were recorded using Anabat acoustic detectors while driving transects through the night at five sites (three “urban” and two “nonurban”) located in the Piedmont region of north-central North Carolina from May through August 2016. Transects were driven three times per night starting 45 min, 180 min, and 300 min after sunset. Recorded echolocation call sequences were analyzed manually using AnalookW and automatically using Bat Call Identification and Echoclass software. Total bat activity was not different between urban and nonurban sites. However, total bat activity was lower later in the night in urban sites, but stayed the same in nonurban sites. Species specifically, there were more Eptesicus fuscus, Lasionycteris noctivagans, and Tadarida brasiliensis call sequences and fewer Lasiurus borealis, Nycticeius humeralis, and Perimyotis subflavus call sequences in urban sites than nonurban sites. There were also fewer E. fuscus, L. noctivagans, and N. humeralis call sequences later in the night in both urban and nonurban sites. Only Lasiurus borealis activity in urban sites later in the night reduced and L. borealis activity in nonurban sites remained at the same. These results suggest that bats in urban areas partition time differently, which is important to consider for urban conservation efforts and planning.  相似文献   

11.
Studies were carried out in two mining pond complexes in an industrial landscape. The first complex (consisting of six ponds) was located in an urban area and the second one (consisting of six ponds) in a woodland area. The aims of the study were to assess the diversity of benthic oligochaetes and to evaluate which environmental variables are most important in determining variations in the community structure in ponds of varying location. In total, 21 oligochaete species were recorded (7–11 in the urban ponds, 11–15 in the woodland ponds). Aulodrilus pluriseta, Aulodrilus japonicus and Ophidonais serpentina were only found in the woodland ponds, while Potamothrix bavaricus only occurred in the urban ponds. Limnodrilus hoffmeisteri, Limnodrilus claparedeanus, Chaetogaster diaphanus and Ophidonais serpentina dominated in the woodland ponds, whereas Limnodrilus hoffmeisteri, Limnodrilus claparedeanus, Potamothrix bavaricus and Tubifex tubifex prevailed in the urban ponds. The total density of oligochaetes was higher in the urban ponds thought the values of the diversity indices were higher in the woodland ponds. The local diversity of the ponds was high, while the among-site diversity made only a small contribution to the regional diversity. Nonetheless, a cluster analysis divided all of the ponds into two distinct groups depending on their location. CCA analysis showed that conductivity, pH, total hardness, alkalinity, the concentration of chlorides and the content of organic matter in the bottom sediments were most associated with the distribution of some oligochaete species among the ponds studied.  相似文献   

12.
Social movement theories provide a framework for explaining the post-1990 rise in China’s citizen-organized environmental nongovernmental organizations (ENGOs), which consisted of at least 128 organizations as of 2004. We use a political process model, which is based on favorable political opportunities, cognitive liberation, and indigenous organizational strength, to explain the sharp growth in citizen organized ENGOs. In addition, we employ a world society perspective to help clarify why the political environment in China became favorable for ENGO growth, and how international ENGO practices were diffused within China. Our analysis shows that the relatively high status of ENGO founders together with their personal and professional networks also played important roles in ENGO growth.
Jiang RuEmail:
  相似文献   

13.
Urbanization has caused the local extinction of several butterfly species around the world, while others have managed to thrive in urban areas. Butterflies of the genus Eumaeus are among the most striking and colorful lycaenid butterflies in the Americas, but their neurotoxic hostplants, cycads, are a highly threatened plant group. The main threats for cycads are the loss and modification of their habitats and their removal for ornamental purposes, which in addition to their slow growth rate, make them highly vulnerable. Ornamental cycads are taken from natural habitats to urban areas, where they are playing an important role for Eumaeus reproduction. We here report two cases in which two Eumaeus species (E. childrenae, E. atala) are following and utilizing ornamental cycads to reproduce in urban areas, showing how significant urban areas can be, ecologically speaking. Aside from having enormous potential as flagship species for conservation in urban areas, these butterfly and plant species, and their interactions, shed encouraging light on the idea of putting reconciliation ecology ideas into action.  相似文献   

14.
Aim: Psychological risk assessments at work serve to identify psychological risk factors and their relation to health and well-being outcomes. Objective of the present study is to investigate which work characteristics predict commitment and turnover intentions of employees.Design: Based on the guidelines of the GDA (Joint German Occupational Safety and Health Strategy), a questionnaire was developed that captures psychological risk factors at work. Additionally, people were asked to indicate their commitment and their turnover intentions. Based on the guidelines of the Joint German Occupational Safety and Health Strategy we assessed four domains of psychological job demands (job content, work organization, social relationships and environmental demands) as well as affective commitment and turnover intention in a sample of 453 full-time employees. Using hierarchical regression analyses, we tested the predictive power of the psychological demands for the different indicators of employee retention.Results: Work content and social relationships were found to be significant predictors for commitment and turnover intentions, whereas work organisation and work context did not predict the outcomes. A detailed analysis of the single risk factors identified autonomy as the strongest predictor for both commitment and turnover intentions.Limitations: The single predictors are not independent and the cross sectional design does not allow for causality interpretations.Practical implications: Based on the assessment of critical psychological risk factors, it is possible to take individual and structural measures to promote commitment and to reduce turnover intentions.  相似文献   

15.
Using three recent data sets (ALLBUS 2016, GLES 2016, ESS 2016), we show that the affinity for the AfD is a socially stratified phenomenon. Actors with minimal education and low income, the unemployed, workers, and actors who feel deprived in socioeconomic terms have a stronger tendency towards supporting the AfD than those actors with a higher socioeconomic status. This finding contrasts with previous research, which describes the rise of right-wing populism in Germany as the result of some kind of clash of idealistic cultures lacking any foundation in the economic basis of society.  相似文献   

16.
Mycorrhizal fungi symbioses can be critical determining if established seedlings survive or not. Currently, in remnant forests, plants and their fungal symbionts are exposed to varied anthropomorphic effects related to urbanization, however, little is known about their impact on this association. We investigated the relationship between mycorrhizal fungi and tree seedling survival along an urbanization gradient. We planted three species of temperate tree seedlings (Acer rubrum, Carya ovata, and Quercus rubra) in three landscapes: urban, suburban, and rural. We measured the percent of root length colonized by mycorrhizal fungi and monitored survival during their first growing season. We analyzed mycorrhizal colonization as a function of landscape type (urban-rural) and additional variables known to contribute to mycorrhizal colonization (phosphorus, nitrogen, initial plant height). We then analyzed seedling survival as a function of the degree of mycorrhizal fungi colonization associated with the landscape gradient and of additional environmental factors (light and soil moisture). Within a species we found no changes in the levels of mycorrhizal fungi colonization across the urbanization gradient. Each species, however, had markedly different levels of colonization. Survival of A. rubrum was independent of mycorrhizal colonization, while C. ovata and Q. rubra had a significant positive response to increased mycorrhizal fungi. These findings highlight the resilience of mycorrhizal communities across the rural-urban gradient typical of this region, but they also underscore the potential sensitivity of some tree species to lower levels of mycorrhizal fungi colonization.  相似文献   

17.
Human social interaction is enriched with synchronous movement which is said to be essential to establish interactional flow. One commonly investigated phenomenon in this regard is facial mimicry, the tendency of humans to mirror facial expressions. Because studies investigating facial mimicry in face-to-face interactions are lacking, the temporal dynamics of facial mimicry remain unclear. We therefore developed and tested the suitability of a novel approach to quantifying facial expression synchrony in face-to-face interactions: windowed cross-lagged correlation analysis (WCLC) for electromyography signals. We recorded muscle activations related to smiling (Zygomaticus Major) and frowning (Corrugator Supercilii) of two interaction partners simultaneously in 30 dyadic affiliative interactions. We expected WCLC to reliably detect facial expression synchrony above chance level and, based on previous research, expected the occurrence of rapid synchronization of smiles within 200 ms. WCLC significantly detected synchrony of smiling but not frowning compared to a control condition of chance level synchrony in six different interactional phases (smiling: d z s = .85–1.11; frowning: d z s = .01–.30). Synchronizations of smiles between interaction partners predominantly occurred within 1000 ms, with a significant amount occurring within 200 ms. This rapid synchronization of smiles supports the notion of the existence of an anticipated mimicry response for smiles. We conclude that WCLC is suited to quantify the temporal dynamics of facial expression synchrony in dyadic interactions and discuss implications for different psychological research areas.  相似文献   

18.
Urbanization affects the availability and diversity of floral resources (pollen and/or nectar) for wild pollinating insects. For example, urban green areas are characterized by an abundance of ornamental plant species. Increasingly, trees are planted to improve the aesthetics of urban streets and parks. These urban trees might offer important floral resources to pollinating insects. To examine the suitability of urban trees as resources for pollinating insects, we investigated the chemical composition of pollen and nectar as well as the amount of nectar produced by the nine major insect-pollinated tree species planted in cities of Western Europe, namely Acer pseudoplatanus, Aesculus carnea, A. hippocastanum, Robinia pseudoacacia, Tilia cordata, T. x euchlora, T. x europaea, T. platyphyllos and T. tomentosa. The analyses revealed that globally the Tilia trees provide pollen with lower contents of polypeptides, amino acids and phytosterols compared with the other species. Urban tree flowers offer abundant nectar with relatively high sugar contents (0.16–1.28 mg/flower); sucrose was the predominant sugar in all nectars. The investigated tree species could therefore be considered in future city plantings.  相似文献   

19.
In recent years, INGO legitimacy has been subject to growing scrutiny from analysts and practitioners alike. Critics have highlighted a backlash against INGOs in the Global South, a growing mismatch between INGO capacities and contemporary global challenges, and diminishing support for norms such as democracy and human rights that underpin INGOs’ work. Although these problems have attracted significant attention within the academic literature, this article argues that existing explorations of INGO legitimacy have broadly conformed either to a top-down approach focused on global norms and institutions or a bottom-up approach focused on the local dynamics surrounding states and populations in the Global South. We suggest that this divide is unhelpful for understanding the current predicament and propose a new approach, which pays closer attention to the interaction between bottom-up and top-down dimensions, and to historical context. This new approach can provide important insights into current debates about the future roles and internal structures of INGOs.  相似文献   

20.
We study claims problems in which a certain amount of indivisible units (of an homogeneous good) has to be distributed among a group of agents, when this amount is not enough to fully satisfy agents’ demands. Our aim is to find solutions fulfilling procedural and fairness properties. To do that, we define the M-down methods, which are the unique robust (composition down and consistency) and fair (balancedness and conditional full compensation) rules. Besides, we also establish the relationship between these M-down methods and the constrained equal awards rule.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号