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91.
Controls on coarse wood decay in temperate tree species: birth of the LOGLIFE experiment 总被引:1,自引:0,他引:1
Cornelissen JH Sass-Klaassen U Poorter L van Geffen K van Logtestijn RS van Hal J Goudzwaard L Sterck FJ Klaassen RK Freschet GT van der Wal A Eshuis H Zuo J de Boer W Lamers T Weemstra M Cretin V Martin R Ouden Jd Berg MP Aerts R Mohren GM Hefting MM 《Ambio》2012,41(Z3):231-245
Dead wood provides a huge terrestrial carbon stock and a habitat to wide-ranging organisms during its decay. Our brief review highlights that, in order to understand environmental change impacts on these functions, we need to quantify the contributions of different interacting biotic and abiotic drivers to wood decomposition. LOGLIFE is a new long-term 'common-garden' experiment to disentangle the effects of species' wood traits and site-related environmental drivers on wood decomposition dynamics and its associated diversity of microbial and invertebrate communities. This experiment is firmly rooted in pioneering experiments under the directorship of Terry Callaghan at Abisko Research Station, Sweden. LOGLIFE features two contrasting forest sites in the Netherlands, each hosting a similar set of coarse logs and branches of 10 tree species. LOGLIFE welcomes other researchers to test further questions concerning coarse wood decay that will also help to optimise forest management in view of carbon sequestration and biodiversity conservation. 相似文献
92.
Johannes H. C. Cornelissen Ute Sass-Klaassen Lourens Poorter Koert van Geffen Richard S. P. van Logtestijn Jurgen van Hal Leo Goudzwaard Frank J. Sterck René K. W. M. Klaassen Grégoire T. Freschet Annemieke van der Wal Henk Eshuis Juan Zuo Wietse de Boer Teun Lamers Monique Weemstra Vincent Cretin Rozan Martin Jan den Ouden Matty P. Berg Rien Aerts Godefridus M. J. Mohren Mariet M. Hefting 《Ambio》2012,41(3):231-245
Dead wood provides a huge terrestrial carbon stock and a habitat to wide-ranging organisms during its decay. Our brief review highlights that, in order to understand environmental change impacts on these functions, we need to quantify the contributions of different interacting biotic and abiotic drivers to wood decomposition. LOGLIFE is a new long-term ‘common-garden’ experiment to disentangle the effects of species’ wood traits and site-related environmental drivers on wood decomposition dynamics and its associated diversity of microbial and invertebrate communities. This experiment is firmly rooted in pioneering experiments under the directorship of Terry Callaghan at Abisko Research Station, Sweden. LOGLIFE features two contrasting forest sites in the Netherlands, each hosting a similar set of coarse logs and branches of 10 tree species. LOGLIFE welcomes other researchers to test further questions concerning coarse wood decay that will also help to optimise forest management in view of carbon sequestration and biodiversity conservation. 相似文献
93.
Structuring sustainability science 总被引:2,自引:2,他引:0
Anne Jerneck Lennart Olsson Barry Ness Stefan Anderberg Matthias Baier Eric Clark Thomas Hickler Alf Hornborg Annica Kronsell Eva L?vbrand Johannes Persson 《Sustainability Science》2011,6(1):69-82
It is urgent in science and society to address climate change and other sustainability challenges such as biodiversity loss, deforestation, depletion of marine fish stocks, global ill-health, land degradation, land use change and water scarcity. Sustainability science (SS) is an attempt to bridge the natural and social sciences for seeking creative solutions to these complex challenges. In this article, we propose a research agenda that advances the methodological and theoretical understanding of what SS can be, how it can be pursued and what it can contribute. The key focus is on knowledge structuring. For that purpose, we designed a generic research platform organised as a three-dimensional matrix comprising three components: core themes (scientific understanding, sustainability goals, sustainability pathways); cross-cutting critical and problem-solving approaches; and any combination of the sustainability challenges above. As an example, we insert four sustainability challenges into the matrix (biodiversity loss, climate change, land use changes, water scarcity). Based on the matrix with the four challenges, we discuss three issues for advancing theory and methodology in SS: how new synergies across natural and social sciences can be created; how integrated theories for understanding and responding to complex sustainability issues can be developed; and how theories and concepts in economics, gender studies, geography, political science and sociology can be applied in SS. The generic research platform serves to structure and create new knowledge in SS and is a tool for exploring any set of sustainability challenges. The combined critical and problem-solving approach is essential. 相似文献
94.
Lesschen JP Velthof GL de Vries W Kros J 《Environmental pollution (Barking, Essex : 1987)》2011,159(11):3215-3222
Nitrous oxide (N2O) direct soil emissions from agriculture are often estimated using the default IPCC emission factor (EF) of 1%. However, a large variation in EFs exists due to differences in environment, crops and management. We developed an approach to determine N2O EFs that depend on N-input sources and environmental factors. The starting point of the method was a monitoring study in which an EF of 1% was found. The conditions of this experiment were set as the reference from which the effects of 16 sources of N input, three soil types, two land-use types and annual precipitation on the N2O EF were estimated. The derived EF inference scheme performed on average better than the default IPCC EF. The use of differentiated EFs, including different regional conditions, allows accounting for the effects of more mitigation measures and offers European countries a possibility to use a Tier 2 approach. 相似文献
95.
Callaghan TV Tweedie CE Akerman J Andrews C Bergstedt J Butler MG Christensen TR Cooley D Dahlberg U Danby RK Daniëls FJ de Molenaar JG Dick J Mortensen CE Ebert-May D Emanuelsson U Eriksson H Hedenås H Henry H R G Hik DS Hobbie JE Jantze EJ Jaspers C Johansson C Johansson M Johnson DR Johnstone JF Jonasson C Kennedy C Kenney AJ Keuper F Koh S Krebs CJ Lantuit H Lara MJ Lin D Lougheed VL Madsen J Matveyeva N Mcewen DC Myers-Smith IH Narozhniy YK Olsson H Pohjola VA Price LW Rigét F Rundqvist S 《Ambio》2011,40(6):705-716
Understanding the responses of tundra systems to global change has global implications. Most tundra regions lack sustained environmental monitoring and one of the only ways to document multi-decadal change is to resample historic research sites. The International Polar Year (IPY) provided a unique opportunity for such research through the Back to the Future (BTF) project (IPY project #512). This article synthesizes the results from 13 papers within this Ambio Special Issue. Abiotic changes include glacial recession in the Altai Mountains, Russia; increased snow depth and hardness, permafrost warming, and increased growing season length in sub-arctic Sweden; drying of ponds in Greenland; increased nutrient availability in Alaskan tundra ponds, and warming at most locations studied. Biotic changes ranged from relatively minor plant community change at two sites in Greenland to moderate change in the Yukon, and to dramatic increases in shrub and tree density on Herschel Island, and in subarctic Sweden. The population of geese tripled at one site in northeast Greenland where biomass in non-grazed plots doubled. A model parameterized using results from a BTF study forecasts substantial declines in all snowbeds and increases in shrub tundra on Niwot Ridge, Colorado over the next century. In general, results support and provide improved capacities for validating experimental manipulation, remote sensing, and modeling studies. 相似文献
96.
The changes in the vascular plant flora of Tasiilaq, low arctic Southeast Greenland, between around 1900 and 2007 were studied
by comparing the data from historical literature with those of the field observations performed between the late 1960s and
2007. Since 1900, the percentage of widely distributed arctic species distinctly decreased, whereas that of the low arctic
species somewhat increased, and boreal species hardly increased. Vegetation monitoring revealed minor changes and showed that
several thermophilous and xerophilous species increased between 1968/1969 and 2007, whereas some hygrophilous species decreased.
Repeated vegetation mapping of a shallow pond revealed conspicuous changes suggesting increased evaporation/precipitation
ratios associated with environmental warming up and decreasing snow accumulation in winter, in line with results of previous
investigations. In spite of climate warming, expansion of the town and increasing human impact, flora and vegetation on the
whole appeared rather stable during the last 40 years without invading species or introductions. 相似文献
97.
Johannes A. Hagström Mario R. Sengco Tracy A. Villareal 《Journal of the American Water Resources Association》2010,46(1):187-198
Hagström, Johannes A., Mario R. Sengco, and Tracy A. Villareal, 2010. Potential Methods for Managing Prymnesium parvum Blooms and Toxicity, With Emphasis on Clay and Barley Straw: A Review. Journal of the American Water Resources Association (JAWRA) 46(1):187-198. DOI: 10.1111/j.1752-1688.2009.00402.x Abstract: Harmful algal bloom (HAB) control and mitigation is a complex problem in ecosystem management. Phytoplankton play an important role in aquatic ecosystems as primary producers and food sources for many commercially important shellfish and there are limited options for targeting just a single species within the community. Chemical treatments (e.g., algaecides), rotting barley straw, nitrogen and phosphorus manipulation, and clay and/or flocculants are but a few techniques tested or used to reduce fish kills or shellfish contamination during a HAB event. Prymnesium parvum control has focused on the use of chemicals, nutrient manipulation, and clay flocculation. However, many HAB control methods have been rejected due to their effects on ecosystems, high costs, or limited effects on target organisms. For example, rotting barley straw (Hordeum vulgare) is considered to be an environmentally friendly alternative, but has been found to have very different results on the phytoplankton community depending on the dominating taxa and is ineffective against P. parvum and dinoflagellate blooms. Clay flocculation is a useful control/mitigation technique during fish kills in marine aquaculture sites in South Korea and can be effective in freshwater if the correct combination of clay and flocculent is used. Toxins produced by P. parvum and Karenia brevis also bind to phosphatic clay, thereby removing and/or neutralizing the toxins, but there is concern that the clay will have a negative effect on sessile organisms. Some shellfish suffer high mortalities and significant impacts on somatic and reproductive tissue growth at high clay loads; however, benthic communities appear to be unchanged after five years of clay treatment in South Korea. There are likely site-specific and ecosystem-specific characteristics that make generalizations about control options difficult and require careful assessment of options at each location. 相似文献
98.
Gundersen P Laurén A Finér L Ring E Koivusalo H Saetersdal M Weslien JO Sigurdsson BD Högbom L Laine J Hansen K 《Ambio》2010,39(8):555-566
Riparian forests (RF) growing along streams, rivers and lakes comprise more than 2% of the forest area in the Nordic countries (considering a 10 m wide zone from the water body). They have special ecological functions in the landscape. They receive water and nutrients from the upslope areas, are important habitats for biodiversity, have large soil carbon stores, but may emit more greenhouse gases (GHG) than the uplands. In this article, we present a review of the environmental services related to water protection, terrestrial biodiversity, carbon storage and greenhouse gas dynamics provided by RF in the Nordic countries. We discuss the benefits and trade-offs when leaving the RF as a buffer against the impacts from upland forest management, in particular the impacts of clear cutting. Forest buffers are effective in protecting water quality and aquatic life, and have positive effects on terrestrial biodiversity, particularly when broader than 40 m, whereas the effect on the greenhouse gas exchange is unclear. 相似文献
99.
Modeling houses as two coupled chambers, namely, the living area and basement, predicts more accurately the total indoor radon source flux from building materials and geology than a one-chamber model in houses with disparate radon concentrations. Three regional surveys found mean radon concentration ratios between basement and living area to range from 1.4 to 4.2, implying weak interchamber coupling in most cases. The invariability of second-order system parameters under steady infiltration but different initial conditions confirms the adequacy of the two-chamber model. The presence of a characteristic radon source flux was detected within the basements of two houses, in one case across different infiltration, coupling, and initial conditions. One-chamber models fit to two-chamber tracer gas data in one house show a source flux variation of a factor of 6 across changing coupling, while the two-chamber source flux variation was only a factor of 1.5. A substantial fraction of the apparent one-chamber living area source flux in these cases is the variable convective radon flux from the basement. The technique is not sensitive enough to detect living area source fluxes if either the interchamber coupling is strong or if the basement source flux is substantially larger. 相似文献
100.
We have determined whether derivated fetal haemoglobin (dHbF, consisting of glycated and acetylated HbF) can be used as a cell age marker for fetal red blood cells (RBCs). Cord blood was obtained between 19 and 39 weeks of gestation from 28 alloimmunised anaemic fetuses (23 RhD+ and 5 Kell) and from 20 non-anaemic fetuses and newborns (controls). Density gradient centrifugation was applied to 36 samples (20 RhD+, 15 controls and 1 Kell) to obtain fractions of increasing cell age. Blood samples were used for measurements of mean cellular volume (MCV), mean cell haemoglobin (MCH), mean corpuscular haemoglobin concentration (MCHC), pyruvate kinase activity (PK) and derivated fetal haemoglobin (dHbF) by cation-exchange HPLC. Reticulocytes were counted only in the whole blood samples. In all density gradient separated RBC fractions, the values for MCV, MCH and PK activity decreased and those of MCHC and dHbF increased with increasing density (equivalent to increasing cell age). The mean density was lower for RBCs of the anaemic RHD group (1.072±0.007 g/ml) than for the non-anaemic controls (1.077±0.005 g/ml) (p<0.05) The RBC density of the Kell sensitised fetus did not differ from those of the controls. In the control group, the values of the cell age markers in whole blood changed significantly with the gestational age, showing an increase of mean age of the erythrocyte population. The best linear relationship was found for dHbF (y=6.28+0.17*weeks; r=0.84; p<0.001). In the anaemic RhD+ fetuses, the RBC age markers did not change with gestational age; the dHbF percentages were lower, and the MCV, MCH, PK values and the reticulocyte counts were higher than in the controls (0.05<p<0.001). The dHbF values of the Kell sensitised fetuses were above (p<0.01) and the reticulocyte counts were below normal (p<0.05) for gestational age. For the anaemic fetuses, a significant number of the dHbF values (86%) and of the reticulocyte counts (78%) differed from the values of the controls (p<0.01). The dHbF percentages in RhD+ fetuses showed the best correlation with the Hb deficit, which is a measure for anaemia (r=−0.81, p<0.0001). We conclude that the percentage derivated HbF may indicate whether the RBC production is normal for gestational age. It may in that sense reflect stimulated or impaired erythropoiesis in alloimmunised haemolytic anaemia. Copyright © 2001 John Wiley & Sons, Ltd. 相似文献