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241.
The USDA’s Conservation Reserve Program (CRP) has predominantly used only a few species of dominant prairie grasses (CP2 practice)
to reduce soil erosion, but recently has offered a higher diversity planting practice (CP25) to increase grassland habitat
quality. We quantified plant community composition in CP25 and CP2 plantings restored for 4 or 8 years and compared belowground
properties and processes among restorations and continuously cultivated soils in southeastern Nebraska, USA. Relative to cultivated
soils, restoration increased soil microbial biomass (P = 0.033), specifically fungi (P < 0.001), and restored soils exhibited higher rates of carbon (C) mineralization (P = 0.010). High and low diversity plantings had equally diverse plant communities; however, CP25 plantings had greater frequency
of cool-season (C3) grasses (P = 0.007). Older (8 year) high diversity restorations contained lower microbial biomass (P = 0.026), arbuscular mycorrhizal fungi (AMF) biomass (P = 0.003), and C mineralization rates (P = 0.028) relative to 8 year low diversity restorations; older plantings had greater root biomass than 4 year plantings in
all restorations (P = 0.001). Low diversity 8 year plantings contained wider root C:N ratios, and higher soil microbial biomass, microbial community
richness, AMF biomass, and C mineralization rate relative to 4 year restorations (P < 0.050). Net N mineralization and nitrification rates were lower in 8 year than 4 year high diversity plantings (P = 0.005). We attributed changes in soil C and N pools and fluxes to increased AMF associated with C4 grasses in low diversity plantings. Thus, reduced recovery of AMF in high diversity plantings restricted restoration of belowground
microbial diversity and microbially-mediated soil processes over time. 相似文献
242.
Jean-Michel Roberge Hjalmar Laudon Christer Björkman Thomas Ranius Camilla Sandström Adam Felton Anna Sténs Annika Nordin Anders Granström Fredrik Widemo Johan Bergh Johan Sonesson Jan Stenlid Tomas Lundmark 《Ambio》2016,45(2):109-123
The rotation length is a key component of even-aged forest management systems. Using Fennoscandian forestry as a case, we review the socio-ecological implications of modifying rotation lengths relative to current practice by evaluating effects on a range of ecosystem services and on biodiversity conservation. The effects of shortening rotations on provisioning services are expected to be mostly negative to neutral (e.g. production of wood, bilberries, reindeer forage), while those of extending rotations would be more varied. Shortening rotations may help limit damage by some of today’s major damaging agents (e.g. root rot, cambium-feeding insects), but may also increase other damage types (e.g. regeneration pests) and impede climate mitigation. Supporting (water, soil nutrients) and cultural (aesthetics, cultural heritage) ecosystem services would generally be affected negatively by shortened rotations and positively by extended rotations, as would most biodiversity indicators. Several effect modifiers, such as changes to thinning regimes, could alter these patterns. 相似文献
243.
Replacing monocultures with mixed-species stands: Ecosystem service implications of two production forest alternatives in Sweden 总被引:2,自引:0,他引:2
Adam Felton Urban Nilsson Johan Sonesson Annika M. Felton Jean-Michel Roberge Thomas Ranius Martin Ahlström Johan Bergh Christer Björkman Johanna Boberg Lars Drössler Nils Fahlvik Peichen Gong Emma Holmström E. Carina H. Keskitalo Maartje J. Klapwijk Hjalmar Laudon Tomas Lundmark Mats Niklasson Annika Nordin Maria Pettersson Jan Stenlid Anna Sténs Kristina Wallertz 《Ambio》2016,45(2):124-139
Whereas there is evidence that mixed-species approaches to production forestry in general can provide positive outcomes relative to monocultures, it is less clear to what extent multiple benefits can be derived from specific mixed-species alternatives. To provide such insights requires evaluations of an encompassing suite of ecosystem services, biodiversity, and forest management considerations provided by specific mixtures and monocultures within a region. Here, we conduct such an assessment in Sweden by contrasting even-aged Norway spruce (Picea abies)-dominated stands, with mixed-species stands of spruce and birch (Betula pendula or B. pubescens), or spruce and Scots pine (Pinus sylvestris). By synthesizing the available evidence, we identify positive outcomes from mixtures including increased biodiversity, water quality, esthetic and recreational values, as well as reduced stand vulnerability to pest and pathogen damage. However, some uncertainties and risks were projected to increase, highlighting the importance of conducting comprehensive interdisciplinary evaluations when assessing the pros and cons of mixtures. 相似文献
244.
The recent browning (increase in color) of surface waters across much of the northern hemisphere has important implications for light climate, ecosystem functioning, and drinking water treatability. Using log-linear regressions and long-term (6–21 years) data from 112 Swedish watercourses, we identified temporal and spatial patterns in browning-related parameters [iron, absorbance, and total organic carbon (TOC)]. Flow variability and lakes in the catchment were major influences on all parameters. Co-variation between seasonal, discharge-related, and trend effects on iron, TOC, and absorbance were dependent on pH, landscape position, catchment size, latitude, and dominant land cover. Large agriculture-dominated catchments had significantly larger trends in iron, TOC, and water color than small forest catchments. Our results suggest that while similarities exist, no single mechanism can explain the observed browning but show that multiple mechanisms related to land cover, climate, and acidification history are responsible for the ongoing browning of surface waters. 相似文献
245.
Anh L. Nguyen Vinh H. Dang Roel H. Bosma Johan A. J. Verreth Rik Leemans Sena S. De Silva 《Ambio》2014,43(8):1059-1068
In Vietnam, culturing striped catfish makes an important contribution to the Mekong Delta’s economy. Water level rise during rainy season and salt intrusion during dry season affect the water exchange and quality for this culture. Sea level rise as a consequence of climate change will worsen these influences. In this study, water level rise and salt water intrusion for three sea level rise (SLR) scenarios (i.e., +30, +50, and +75 cm) were simulated. The results showed that at SLR +50, the 3-m-flood level would spread downstream and threaten farms located in AnGiang, DongThap and CanTho provinces. Rising salinity levels for SLR +75 would reduce the window appropriate for the culture in SocTrang and BenTre provinces, and in TienGiang’s coastal districts. Next to increasing dikes to reduce the impacts, the most tenable and least disruptive option to the farming community would be to shift to a salinity tolerant strain of catfish. 相似文献
246.
Per Angelstam Jean-Michel Roberge Robert Axelsson Marine Elbakidze Karl-Olof Bergman Anders Dahlberg Erik Degerman Sönke Eggers Per-Anders Esseen Joakim Hjältén Therese Johansson Jörg Müller Heidi Paltto Tord Snäll Ihor Soloviy Johan Törnblom 《Ambio》2013,42(2):229-240
Assessing ecological sustainability involves monitoring of indicators and comparison of their states with performance targets that are deemed sustainable. First, a normative model was developed centered on evidence-based knowledge about (a) forest composition, structure, and function at multiple scales, and (b) performance targets derived by quantifying the habitat amount in naturally dynamic forests, and as required for presence of populations of specialized focal species. Second, we compared the Forest Stewardship Council (FSC) certification standards’ ecological indicators from 1998 and 2010 in Sweden to the normative model using a Specific, Measurable, Accurate, Realistic, and Timebound (SMART) indicator approach. Indicator variables and targets for riparian and aquatic ecosystems were clearly under-represented compared to terrestrial ones. FSC’s ecological indicators expanded over time from composition and structure towards function, and from finer to coarser spatial scales. However, SMART indicators were few. Moreover, they poorly reflected quantitative evidence-based knowledge, a consequence of the fact that forest certification mirrors the outcome of a complex social negotiation process. 相似文献
247.
Robert Axelsson Per Angelstam Lennart Myhrman Stefan Sädbom Milis Ivarsson Marine Elbakidze Kenneth Andersson Petr Cupa Christian Diry Frederic Doyon Marcus K. Drotz Arne Hjorth Jan Olof Hermansson Thomas Kullberg F. Henry Lickers Johanna McTaggart Anders Olsson Yurij Pautov Lennart Svensson Johan Törnblom 《Ambio》2013,42(2):241-253
To implement policies about sustainable landscapes and rural development necessitates social learning about states and trends of sustainability indicators, norms that define sustainability, and adaptive multi-level governance. We evaluate the extent to which social learning at multiple governance levels for sustainable landscapes occur in 18 local development initiatives in the network of Sustainable Bergslagen in Sweden. We mapped activities over time, and interviewed key actors in the network about social learning. While activities resulted in exchange of experiences and some local solutions, a major challenge was to secure systematic social learning and make new knowledge explicit at multiple levels. None of the development initiatives used a systematic approach to secure social learning, and sustainability assessments were not made systematically. We discuss how social learning can be improved, and how a learning network of development initiatives could be realized. 相似文献
248.
Burnout is considered to be a long‐term reaction to occupational stress. It is characterized by emotional exhaustion, depersonalization, and diminished personal accomplishment. The most widely used instrument to measure burnout is the Maslach Burnout Inventory (MBI), developed by Maslach and Jackson (1986). From this instrument, Schaufeli and van Dierendonck (1995a) developed a somewhat modified Dutch version: the MBI‐NL. Burnout among dentists has hardly been studied. Since the professions that the MBI‐NL was developed upon are quite different from dentistry, the aim of this study was to test the three‐factor structure of the MBI‐NL against alternative structures among dentists. Both principal components analysis (PCA) and confirmatory factor analysis (CFA) were examined in a representative sample of 709 Dutch general dental practitioners (75 per cent response rate). The three‐factor structure shows the best fit to the underlying data, while other psychometric qualities are very satisfactory. It is concluded that the three‐factor structure of the MBI‐NL is superior to alternative structures, and that the MBI‐NL is a highly suitable instrument to measure burnout among dentists. Copyright © 1999 John Wiley & Sons, Ltd. 相似文献
249.
250.
Franke Alastair Falk Knud Hawkshaw Kevin Ambrose Skip Anderson David L. Bente Peter J. Booms Travis Burnham Kurt K. Ekenstedt Johan Fufachev Ivan Ganusevich Sergey Johansen Kenneth Johnson Jeff A. Kharitonov Sergey Koskimies Pertti Kulikova Olga Lindberg Peter Lindström Berth-Ove Mattox William G. McIntyre Carol L. Mechnikova Svetlana Mossop Dave Møller Søren Nielsen Ólafur K. Ollila Tuomo Østlyngen Arve Pokrovsky Ivan Poole Kim Restani Marco Robinson Bryce W. Rosenfield Robert Sokolov Aleksandr Sokolov Vasiliy Swem Ted Vorkamp Katrin 《Ambio》2020,49(3):762-783
Ambio - The peregrine falcon (Falco peregrinus) and the gyrfalcon (Falco rusticolus) are top avian predators of Arctic ecosystems. Although existing monitoring efforts are well established for both... 相似文献