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1.
The potential of alpine moss-sedge heath to recover from elevated nitrogen (N) deposition was assessed by transplanting Racomitrium lanuginosum shoots and vegetation turfs between 10 elevated N deposition sites (8.2-32.9 kg ha−1 yr−1) and a low N deposition site, Ben Wyvis (7.2 kg ha−1 yr−1). After two years, tissue N of Racomitrium shoots transplanted from higher N sites to Ben Wyvis only partially equilibrated to reduced N deposition whereas reciprocal transplants almost matched the tissue N of indigenous moss. Unexpectedly, moss shoot growth was stimulated at higher N deposition sites. However, moss depth and biomass increased in turfs transplanted to Ben Wyvis, apparently due to slower shoot turnover (suggested to result partly from decreased tissue C:N slowing decomposition), whilst abundance of vascular species declined. Racomitrium heath has the potential to recover from the impacts of N deposition; however, this is constrained by the persistence of enhanced moss tissue N contents.  相似文献   
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The spectral reflectance of recently formed salt marshes at the mouth of the Yangtze River, which are undergoing invasion by Spartina alterniflora, were assessed to determine the potential utility of remotely sensed data in assessing future invasion and changes in species composition. Following a review of published research on remote sensing of salt marshes, 53 locations along three transects were sampled for paired data on plant species composition and spectral reflectance using a FieldSpec™ Pro JR Field Portable Spectroradiometer. Spectral data were processed concerning reflectance, and the averaged reflectance values for each sample were reanalysed to correspond to a 12-waveband bandset of the Compact Airborne Spectral Imager. The spectral data were summarised using principal components analysis (PCA) and the relationships between the vegetation composition, and the PCA axes of spectral data were examined. The first PCA axis of the reflectance data showed a strong correlation with variability in near infrared reflectance and ‘brightness’, while the second axis was correlated with visible reflectance and ‘greenness’. Total vegetation cover, vegetation height, and mudflat cover were all significantly related to the first axis. The implications of this in terms of the ability of remote sensing to distinguish the various salt marsh species and in particular the invasive species S. alterniflora were discussed. Major differences in species with various physiognomies could be recognised but problems occurred in separating early colonising S. alterniflora from other species at that stage. Further work using multi-seasonal hyperspectral data might assist in solving these problems.  相似文献   
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Bonamia ostreae is a protozoan parasite of the native oyster, Ostrea edulis. The parasite can be transmitted directly from infected to uninfected oysters. Though direct transmission of the parasite can occur between oysters it is unclear if this represents the complete life cycle of the parasite, and the involvement of a carrier/reservoir cannot be ruled out. A survey of benthic macroinvertebrate and zooplankton survey was carried out in the North Channel, Cork Harbour, Ireland, an area where B. ostreae is endemic and the parasite has been present since the 1980s. This was compared to several European surveys of benthic macroinvertebrate and zooplankton species found in other B. ostreae endemic areas. The objective was to identify any species that were common to these sites and could act as possible carrier/reservoir hosts for the pathogen. Species that were found to be common in two or more sites were included in two comparison tables. These species will be targeted in future studies investigating the possible role of macroinvertebrates and zooplankton in the complete life cycle of B. ostreae.  相似文献   
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Analyses of ecological regime shifts primarily focus on abrupt, long-term and significant changes that trigger fundamental reorganisation in ecosystem structure and function. There remains limited empirical work on the relationship between regime shifts and social inequities, power imbalances, and social and environmental injustices. Inadequate attention to this social context restricts our ability to predict and avert impending regime shifts, or to effectively navigate where thresholds have been crossed. In this paper, we offer an initial empirical assessment of politics and power in two coastal lagoons in India and Vietnam experiencing abrupt change. We adopt a realist view of power to: (1) assess the social relations structuring human–environment interactions in both lagoons; (2) characterise the dominant framings and narratives that influence if and how regime shifts are understood; (3) consider who wins and loses if and when regime shifts and other forms of rapid environmental change take place; and (4) reflect on the implications of power and politics for the governance of regime shifts in linked human–ocean settings.  相似文献   
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We present two new software implementations of the BETR Global multimedia contaminant fate model. The model uses steady-state or non-steady-state mass-balance calculations to describe the fate and transport of persistent organic pollutants using a desktop computer. The global environment is described using a database of long-term average monthly conditions on a 15° × 15° grid. We demonstrate BETR Global by modeling the global sources, transport, and removal of decamethylcyclopentasiloxane (D5).  相似文献   
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Ozgul A  Armitage KB  Blumstein DT  Oli MK 《Ecology》2006,87(4):1027-1037
Spatiotemporal variation in age-specific survival rates can profoundly influence population dynamics, but few studies of vertebrates have thoroughly investigated both spatial and temporal variability in age-specific survival rates. We used 28 years (1976-2003) of capture-mark-recapture (CMR) data from 17 locations to parameterize an age-structured Cormack-Jolly-Seber model, and investigated spatial and temporal variation in age-specific annual survival rates of yellow-bellied marmots (Marmota flaviventris). Survival rates varied both spatially and temporally, with survival of younger animals exhibiting the highest degree of variation. Juvenile survival rates varied from 0.52 +/- 0.05 to 0.78 +/- 0.10 among sites and from 0.15 +/- 0.14 to 0.89 +/- 0.06 over time. Adult survival rates varied from 0.62 +/- 0.09 to 0.80 +/- 0.03 among sites, but did not vary significantly over time. We used reverse-time CMR models to estimate the realized population growth rate (lamda), and to investigate the influence of the observed variation in age-specific survival rates on lamda. The realized growth rate of the population closely covaried with, and was significantly influenced by, spatiotemporal variation in juvenile survival rate. High variability in juvenile survival rates over space and time clearly influenced the dynamics of our study population and is also likely to be an important determinant of the spatiotemporal variation in the population dynamics of other mammals with similar life history characteristics.  相似文献   
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Sustainable environmental planning and management require effective integration of ecological, socioeconomic, and institutional elements. This paper presents an integrative methodological framework for sustainable environmental planning and management. The development of this integrative framework is accomplished by combining two complementary analytical approaches—Hufschmidt's conceptual framework for watershed planning and management and the ABC resource survey method. The combined methodological framework seeks to delineate and synthesize essential ecological information utilizing an integrative resource survey method. This method generates classifications of environmental significance and constraint. Areas of environmental significance and constraint are then linked to appropriate and acceptable resource management actions, implementation tools (e.g., education, technical assistance), and institutional and organizational arrangements. The integrative methodological framework was developed for application in the Rio Fortuna watershed in Costa Rica's Arenal Conservation Area. The watershed is characterized by a variety of land and resource uses, including biologically diverse and ecologically fragile protected areas, small-parcel agriculture, cattle ranching, and tourism.  相似文献   
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In this policy perspective, we outline several conditions to support effective science–policy interaction, with a particular emphasis on improving water governance in transboundary basins. Key conditions include (1) recognizing that science is a crucial but bounded input into water resource decision-making processes; (2) establishing conditions for collaboration and shared commitment among actors; (3) understanding that social or group-learning processes linked to science–policy interaction are enhanced through greater collaboration; (4) accepting that the collaborative production of knowledge about hydrological issues and associated socioeconomic change and institutional responses is essential to build legitimate decision-making processes; and (5) engaging boundary organizations and informal networks of scientists, policy makers, and civil society. We elaborate on these conditions with a diverse set of international examples drawn from a synthesis of our collective experiences in assessing the opportunities and constraints (including the role of power relations) related to governance for water in transboundary settings.  相似文献   
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