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41.
During migrations, birds have to cope with varying meteorological conditions, which shape their migratory routes and affect their performance. Amongst these, wind is the main meteorological agent influencing behaviour of birds in their migration journeys. Here we analyze the effect of winds during migrations of adult individuals of two raptor species tracked with satellite telemetry, the Montagu’s harrier (Circus pygargus) and the lesser kestrel (Falco naumanni). While harriers use mostly soaring flight, kestrels principally use flapping flight and thus, wind can differently affect these birds. We found that both forward and perpendicular winds significantly affected the movements of the Montagu’s harrier, which were drifted from their intended direction but also took advantage of tailwinds. On the contrary, lesser kestrels moved more regardless of forward winds, despite they were highly drifted by crosswinds. Our results also support that the drifting effect of winds at the onset of the spring migration may explain the loop migration observed for both species, with birds compensating later the effect of crosswinds to arrive to their breeding areas. Results presented here illustrate how winds can differently affect migrating birds according to their flight modes.  相似文献   
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Long-term studies to understand biodiversity changes remain scarce—especially so for tropical mountains. We examined changes from 1911 to 2016 in the bird community of the cloud forest of San Antonio, a mountain ridge in the Colombian Andes. We evaluated the effects of past land-use change and assessed species vulnerability to climate disruption. Forest cover decreased from 95% to 50% by 1959, and 33 forest species were extirpated. From 1959 to 1990, forest cover remained stable, and an additional 15 species were lost—a total of 29% of the forest bird community. Thereafter, forest cover increased by 26% and 17 species recolonized the area. The main cause of extirpations was the loss of connections to adjacent forests. Of the 31 (19%) extirpated birds, 25 have ranges peripheral to San Antonio, mostly in the lowlands. Most still occurred regionally, but broken forest connections limited their recolonization. Other causes of extirpation were hunting, wildlife trade, and water diversion. Bird community changes included a shift from predominantly common species to rare species; forest generalists replaced forest specialists that require old growth, and functional groups, such as large-body frugivores and nectarivores, declined disproportionally. All water-dependent birds were extirpated. Of the remaining 122 forest species, 19 are vulnerable to climate disruption, 10 have declined in abundance, and 4 are threatened. Our results show unequivocal species losses and changes in community structure and abundance at the local scale. We found species were extirpated after habitat loss and fragmentation, but forest recovery stopped extirpations and helped species repopulate. Land-use changes increased species vulnerability to climate change, and we suggest reversing landscape transformation may restore biodiversity and improve resistance to future threats.  相似文献   
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Economic liberalization in former socialist countries may have various implications for their environmental sustainability. Positive effects of this process are potentially associated with improved efficiency, investments into cleaner technologies, responsiveness to environmentally aware markets, and ending subsidies to heavy industries. On the other hand, market liberalization may result in weaker environmental controls, economic instabilities distracting attention from environmental issues, and increasing orientation towards profit-making leading to more intensive exploitation of natural resources. In addition, trade liberalization may result in shifts towards more pollution and resource-intensive industries. This article seeks to quantify effects of economic restructuring in Russia on air pollution from productive economic sectors in the 1990s. Air pollution in Russia had significantly declined in 1991-1999, however, this decline was largely due to economic decline, as the overall pollution intensity of the economy had decreased only slightly. The factors that affected the pollution intensity are: (1) a decrease in the combined share of industrial and transport activities in the economy and (2) changing pollution intensities of the industrial and transport sectors. The pollution intensity of the Russian industry had remained relatively stable during the 1990s. This was the result of the two opposite and mutually canceling trends: (a) increasing shares of pollution-intensive branches such as metal smelting and oil production vs. less pollution intensive manufacturing and (b) decline in pollution intensities within the industrial branches. The article proposes a methodology by which the contribution of both factors to the overall pollution intensity of the industrial sector can be quantified. The pollution intensity of the Russian transport sector appears to have declined in the first half of the 1990s and increased in the second half. The most recent trend can be explained by a rising proportion of private motorcars used for transportation of people and goods instead of traditional rail and other public transport. The findings of the paper demonstrate that shifts towards more pollution-, resource- and energy-intensive industries as a result of economic liberalization emerges as a significant negative factor of the process of economic transition threatening sustainability of emerging market economies. A research agenda to further investigate these impacts is proposed.  相似文献   
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In order to evaluate the water quality at the surface/groundwater interface (hyporheic zone), the pattern of microcrustacean assemblages in response to environmental stress caused by urban industrial contamination was studied in the Jarama River basin (central Spain) during high water discharges (March and April 2011). The clustering of biological variables and the concentration of urban contaminants in hyporheic waters showed that pristine hyporheic waters have moderate species diversity (two to seven species) and dominance of k strategist stygobites, whereas excessively contaminated sites are devoid by crustaceans. An intermediate level of disturbance in hyporheic waters is associated with a peak of species taxonomic diversity (four to nine species) and proliferation of r strategist more tolerant species. Typical species found in hyporheic zone, e.g., Paracyclops imminutus (Copepoda, Cyclopoida), Cryptocandona vavrai (Ostracoda) and Herpetocypris chevreuxi (Ostracoda), were good indicators of high concentrations of Cr, Mn, Ni, Cd, Pb and VOCs; whereas the stygobites do not show any significant correlation. The effectiveness of hyporheic crustaceans as efficient bioindicators for assessing the current ecological status of river ecosystems is emphasised.  相似文献   
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The pressure exerted by shallow water hydrothermal vents on edible gastropods and their cellular responses triggered by these stresses are almost unknown. The aims of this study were to evaluate the bioavailability of metals in the Macaronesian endemic limpet Patella candei gomesii living close to shallow water hydrothermal vents, and the structural differences in their digestive gland as well as the levels of apoptosis in that organ. Limpets were sampled in four sites, two with the presence of hydrothermalism and the other two without it. Whole body concentrations of several metals (Ca, Cd, Cs, Co, Cu, Fe, Hg, Mg, Mn, Pb, Rb, Se, Sr, and Zn) were obtained, morphometry analysis of the digestive gland and TUNEL test for apoptosis were also performed. Results revealed that the presence of shallow water hydrothermal vents is a source of chronic metal stress to limpets, imposing modifications in the morphometry and cell composition of the digestive gland of those limpets that may constitute cell and tissue adaptations to the environment they live in. This study sets up new baseline data for further research on the influence of shallow water hydrothermal vents over communities living in these habitats.  相似文献   
49.
Ex‐ante measures to improve risk preparedness for natural disasters are generally considered to be more effective than ex‐post measures. Nevertheless, most resources are allocated after an event in geographical areas that are vulnerable to natural disasters. This paper analyses the cost‐effectiveness of ex‐ante adaptation measures in the wake of earthquakes and provides an assessment of the future role of private and public agencies in disaster risk management. The study uses a simulation model approach to evaluate consumption losses after earthquakes under different scenarios of intervention. Particular attention is given to the role of activity diversification measures in enhancing disaster preparedness and the contributions of (targeted) microcredit and education programmes for reconstruction following a disaster. Whereas the former measures are far more cost‐effective, missing markets and perverse incentives tend to make ex‐post measures a preferred option, thus occasioning underinvestment in ex‐ante adaptation initiatives.  相似文献   
50.
In the tradition of the study of materials flows through society, the Substance Flow Analysis (SFA) method and its software tool SFINX are presented. SFA aims at providing the relevant information for a country’s overall management strategy regarding single substances or coherent groups of substances. Three modelling techniques and their possibilities and limitations are discussed: Bookkeeping, static modelling, and dynamic modelling. The computer program SFINX can be used for varoius purposes: (1) to obtain an overview of stocks and flows of a substance in, out and through a nation’s economy and environment for a specific year, (2) to trace the origins of specific pollution problems, and (3) to estimate the effectiveness of certain abatement measures. Each application has its own requirements with regard to data and modelling.  相似文献   
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