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111.
Current knowledge on the abundance and distribution patterns of different soft coral species is relatively limited when compared to other benthic suspension feeders such as gorgonians and hard coral species. To overcome this scarcity of information, the distribution patterns of the soft corals Alcyonium acaule and Alcyonium palmatum were investigated in northwestern Mediterranean benthic communities over a wide geographical (60 km of coastline) and bathymetrical (0–70 m depth) extent using a remotely operated vehicle. A. acaule was the most abundant species in the study area with highest recorded density of 18 col m?2 found at depths of 35–45 m in areas that are directly exposed to strong near-bottom currents. Conversely, A. palmatum was only found as scattered solitary colonies at greater depths in soft bottoms, with maximum density of 2.4 col m?2. Medium and large colonies of A. acaule were preferentially found on sloping and vertical rocky bottoms where they form dense patches. High-density patches of A. acaule were preferentially found on vertical rocky bottom, while isolated colonies were preferentially observed on coralligenous substrata as well as on flat soft and maërl substrates. A. acaule biomass distribution showed highest values between 40 and 45 m depth, and between 60 and 65 m depth. This suggests that deeper populations are formed by colonies that are bigger than the equivalent shallower ones. Although both species are almost genetically identical, ecologically they are very different. For this reason, conservation plans should consider the differential ecological traits shown by these two soft coral species.  相似文献   
112.
Several attempts for evaluating environmental impact of active agents allowed in organic olive farming against Bactrocera oleae have been made, but very few studies were performed contemporaneously on more than one of them. Insects were chosen as indicators because they are known to react very quickly to environmental perturbations, mainly at the community level. In fact, the coenosis is the functional unit interacting with biotic and abiotic environmental parameters. Seven taxa, known for their sensitivity to habitat alterations, were sampled and grouped in functional groups: predators and parasitoids, phytophagouses and pollinators. The coenotic balance between these two functional groups was analyzed. The study was carried out in an organic olive orchard in the municipality of Terranova da Sibari, Cosenza, Southern Italy. The tested active agents (Azadirachtin, Rotenone, Copper Oxychloride) were sprayed twice (end of September and middle October). During the treatments the population dynamics of all the taxa were knocked-down. No one tested compound seems to be harmless to the entomocoenosis, particularly on phytophagouses and pollinators. In truly organic farming it is necessary to provide natural refuge areas to beneficial insects (i.e. pest antagonists) in which no active agents are sprayed and alternative preys could be found.  相似文献   
113.
Conservation and enhancement of ecosystem services have become a priority of rural policies. Feedback loops from rural policies on ecosystem service supply have often been highlighted in the literature, but only vaguely investigated. In this paper, we model feedback loops from rural policies through an agent-based model, and we analyse whether feedback loops can indirectly create a system in which voluntarily landscape enhancement emerges from the interactions between farmers and rural tourists. The results suggest that, in certain conditions, feedback loops from policies can be a relevant element to take into account, but that greater attention to the ecosystem service demand is required.  相似文献   
114.
115.
We determined genetic variation and metal and polycyclic aromatic hydrocarbon concentrations in Leptodon smithii moss collected in holm oak stands at cities, outskirts and remote areas of Campania and Tuscany(Italy) to investigate if anthropogenic pressure(pollutant emissions and land use change) affects moss genetic richness. In both regions, metal and polycyclic aromatic hydrocarbon concentrations reflected the trend urban 〉 outskirts 〉 remote areas, excepting Tuscany remote site. In both regions,the moss gene diversity increased from urban to remote areas. The findings suggest the extent and the fragmentation of urban green areas, as drivers of moss genetic richness.  相似文献   
116.
We conducted a study of the institutional barriers to introducing urine source separation in the urban area of Kunming, China. On the basis of a stakeholder analysis, we constructed stakeholder diagrams showing the relative importance of decision-making power and (positive) interest in the topic. A hypothetical decision-making process for the urban case was derived based on a successful pilot project in a periurban area. All our results were evaluated by the stakeholders. We concluded that although a number of primary stakeholders have a large interest in testing urine source separation also in an urban context, most of the key stakeholders would be reluctant to this idea. However, the success in the periurban area showed that even a single, well-received pilot project can trigger the process of broad dissemination of new technologies. Whereas the institutional setting for such a pilot project is favorable in Kunming, a major challenge will be to adapt the technology to the demands of an urban population. Methodologically, we developed an approach to corroborate a stakeholder analysis with the perception of the stakeholders themselves. This is important not only in order to validate the analysis but also to bridge the theoretical gap between stakeholder analysis and stakeholder involvement. We also show that in disagreement with the assumption of most policy theories, local stakeholders consider informal decision pathways to be of great importance in actual policy-making.  相似文献   
117.
At a very early age several mammals establish a first dominance hierarchy, which often persists into adulthood. Social wasps offer an excellent opportunity to study such a phenomenon in insects. Indeed, foundresses of several paper wasps meet in clusters to hibernate from September to March. In spring, wasps found new associative nests where linear hierarchies occur. In the first phase of hibernation, clustering Polistes dominulus wasps show most of the social interactions occurring on the nest 6 months later. At the emergence from diapause, some females already show some behavioral and physiological traits typical of dominant individuals. Here, we investigated the significance of the interactions in the autumnal clusters. We demonstrated that in a given pair, it is more likely that the dominant wasp in autumn becomes the alpha female in spring after the nest foundation phase occurred. Moreover, we showed that dominant females in clusters have both larger body size and ovaries. As ovarian development mainly depends on the social context, our findings seem to indicate that social factors affect the tendency to dominate in aggregations. Furthermore, we suggest that some females may reinforce their physiological status by dominating in clusters, thus increasing the probability to become dominant in spring.  相似文献   
118.
Extreme climate events produce simultaneous changes to the mean and to the variance of climatic variables over ecological time scales. While several studies have investigated how ecological systems respond to changes in mean values of climate variables, the combined effects of mean and variance are poorly understood. We examined the response of low-shore assemblages of algae and invertebrates of rocky seashores in the northwest Mediterranean to factorial manipulations of mean intensity and temporal variance of aerial exposure, a type of disturbance whose intensity and temporal patterning of occurrence are predicted to change with changing climate conditions. Effects of variance were often in the opposite direction of those elicited by changes in the mean. Increasing aerial exposure at regular intervals had negative effects both on diversity of assemblages and on percent cover of filamentous and coarsely branched algae, but greater temporal variance drastically reduced these effects. The opposite was observed for the abundance of barnacles and encrusting coralline algae, where high temporal variance of aerial exposure either reversed a positive effect of mean intensity (barnacles) or caused a negative effect that did not occur under low temporal variance (encrusting algae). These results provide the first experimental evidence that changes in mean intensity and temporal variance of climatic variables affect natural assemblages of species interactively, suggesting that high temporal variance may mitigate the ecological impacts of ongoing and predicted climate changes.  相似文献   
119.
This paper summarises the results of the EU funded MEAD project, an interdisciplinary study of the effects of atmospheric nitrogen deposition on the Kattegat Sea between Denmark and Sweden. The study considers emissions of reactive nitrogen gases, their transport, transformations, deposition and effects on algal growth together with management options to reduce these effects. We conclude that atmospheric deposition is an important source of fixed nitrogen to the region particularly in summer, when nitrogen is the limiting nutrient for phytoplankton growth, and contributes to the overall eutrophication pressures in this region. However, we also conclude that it is unlikely that atmospheric deposition can, on its own, induce algal blooms in this region. A reduction of atmospheric nitrogen loads to this region will require strategies to reduce emissions of ammonia from local agriculture and Europe wide reductions in nitrous oxide emissions.  相似文献   
120.
Summary This paper outlines the second phase of an ecotourism project undertaken in the Santa Elena community, in the Monteverde region of Costa Rica. The community originally established a rainforest reserve with the help of Youth Challenge International in an attempt to provide a wider economic base and employment for the area. The project has been successful in the first phase in that it is now drawing an annual income of US$40 000 and it employs guides and management from the local community. In terms of the underlying principles usually aligned with ecotourism it has been successful but it is now necessary to evaluate the impacts this project is having on the community. The second phase of the project was to assess the sociocultural impacts of ecotourism on that community and the paper outlines this phase.Stephen Wearing is a lecturer in the School of Leisure and Tourism Studies at the University of Technology, Sydney. He lectures and consults in the area of tourism and environmental planning, and parks and protected area management. His particular interest is in ecotourism projects with local communities and he has spent much of the last 4 years working on the Santa Elena Project. He is linked with Youth Challenge International and people interested in becoming involved or looking for assistance with community projects of this nature can contact him at the above address. Libby Larson recently graduated with a BA in Leisure Studies at the University of Technology, Sydney, focusing on social sciences in natural resource management. She has also worked in Costa Rica with Youth Challenge International and is particularly interested in ecotourism.  相似文献   
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