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841.
We examine the wider social knowledge domain that complements technical and environmental knowledge in enabling adaptive practices through two case studies in Tanzania. We are concerned with knowledge production that is shaped by gendered exclusion from the main thrusts of planned adaptation, in the practice of irrigation in a dryland village and the adoption of fast-maturing seed varieties in a highland village. The findings draw on data from a household survey, community workshops, and key informant interviews. The largest challenge to effective adaptation is a lack of access to the social networks and institutions that allocate resources needed for adaptation. Results demonstrate the social differentiation of local knowledge, and how it is entwined with adaptive practices that emerge in relation to gendered mechanisms of access. We conclude that community-based adaptation can learn from engaging the broader social knowledge base in evaluating priorities for coping with greater climate variability. 相似文献
842.
Gunnar Rundgren 《Journal of Agricultural and Environmental Ethics》2016,29(1):103-121
Our food and farming system is not socially, economically or ecologically sustainable. Many of the ills are a result of market competition driving specialization and linear production models, externalizing costs for environmental, social and cultural degradation. Some propose that market mechanisms should be used to correct this; improved consumer choice, internalization of costs and compensation to farmers for public goods. What we eat is determined by the path taken by our ancestors, by commercialization and fierce competition, fossil fuels and demographic development. Based on those, governments and the food industry are the choice architects who determine what we eat; consumer choice plays a marginal role. Using market mechanisms to internalize cost and compensate farmers for public goods has been proposed for decades but little progress has been made. There are also many practical, ethical and theoretical objections to such a system. The market is not a good master for a sustainable food system. Instead we need to find new ways of managing the food system based on food as a right and farming as a management system of the planet Earth. The solutions should be based on relocalization of food production and de-commodification of food and our symbionts, the plants and animals we eat. 相似文献
843.
Detecting Temporal Change in Watershed Nutrient Yields 总被引:1,自引:1,他引:1
Meta-analyses reveal that nutrient yields tend to be higher for watersheds dominated by anthropogenic uses (e.g., urban, agriculture) and lower for watersheds dominated by natural vegetation. One implication of this pattern is that loss of natural vegetation will produce increases in watershed nutrient yields. Yet, the same meta-analyses also reveal that, absent land-cover change, watershed nutrient yields vary from one year to the next due to many exogenous factors. The interacting effects of land cover and exogenous factors suggest nutrient yields should be treated as distributions, and the effect of land-cover change should be examined by looking for significant changes in the distributions. We compiled nutrient yield distributions from published data. The published data included watersheds with homogeneous land cover that typically reported two or more years of annual nutrient yields for the same watershed. These data were used to construct statistical models, and the models were used to estimate changes in the nutrient yield distributions as a result of land-cover change. Land-cover changes were derived from the National Land Cover Database (NLCD). Total nitrogen (TN) yield distributions increased significantly for 35 of 1550 watersheds and decreased significantly for 51. Total phosphorus (TP) yield distributions increased significantly for 142 watersheds and decreased significantly for 17. The amount of land-cover change required to produce significant shifts in nutrient yield distributions was not constant. Small land-cover changes led to significant shifts in nutrient yield distributions when watersheds were dominated by natural vegetation, whereas much larger land-cover changes were needed to produce significant shifts when watersheds were dominated by urban or agriculture. We discuss our results in the context of the Clean Water Act. 相似文献
844.
Luke Holman 《Behavioral ecology and sociobiology》2009,63(11):1679-1688
The causes and consequences of variation in sperm quality, survival and ageing are active areas of research in ecology and
evolution. In order to address these topics, many recent studies have measured sperm viability using fluorescent staining.
Although sperm viability staining has produced a number of interesting results, it has some potential pitfalls that have rarely
been discussed. In the present paper, I review the major findings of ecology and evolution studies employing sperm viability
staining and outline the method’s principle limitations. The key problem is that the viability assay may itself kill sperm,
which is likely to confound many common experimental designs in addition to producing artificially low estimates of sperm
viability. I further suggest that sperm number should be routinely measured in sperm viability studies, as it may be an important
but overlooked source of spurious results. I provide methodological advice on sperm viability staining aimed at minimising
artefacts and producing robust conclusions, and discuss possible avenues for future research.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
845.
Phytoremediation is the use of plants to decontaminate and improve waters and soils. Pleustonic macrophytes are plant models for research in waters. In a phytoremediation study, the elicitation of Pistia stratiotes with methyl jasmonate or salicylic acid suggests that oxytetracycline modification rate coefficients could be increased more than threefold. Here we present the elicitation of Pistia stratiotes apical primary root tips. We detected reactive oxygen species generation by X-band electron paramagnetic resonance spectroscopy, using the spin trap α-(4-pyridyl-1-oxide)-N-tert-butylnitrone (POBN). Elicitation using 0.8 mM methyl jasmonate during 1 h increased the relative spin-trapped radical concentration by +12 %. Further, results indicate acute plant toxicity above 0.24 mM salicylic acid. 相似文献
846.
Panos Hadjinicolaou Christos Giannakopoulos Christos Zerefos Manfred A. Lange Stelios Pashiardis Jos Lelieveld 《Regional Environmental Change》2011,11(3):441-457
We present climate change projections and apply indices of weather extremes for the Mediterranean island Cyprus using data
from regional climate model (RCM) simulations driven by the IPCC A1B scenario within the ENSEMBLES project. Daily time-series
of temperature and precipitation were used from six RCMs for a reference period 1976–2000 and for 2026–2050 (‘future‘) for
representative locations, applying a performance selection among neighboring model grid-boxes. The annual average temperatures
of the model ensemble have a ±1.5°C bias from the observations (negative for maximum and positive for minimum temperature),
and the models underestimate annual precipitation totals by 4–17%. The climatological annual cycles for the observations fall
within the 1σ range of the 6-model average, highlighting the strength of using multi-model output. We obtain reasonable agreement
between models and observations for the temperature-related indices of extremes for the recent past, while the comparison
is less good for the precipitation-related extremes. For the future, the RCM ensemble shows significant warming of 1°C in
winter to 2°C in the summer for both maximum and minimum temperatures. Rainfall is projected to decrease by 2–8%, although
this is not statistically significant. Our results indicate the shift of the mean climate to a warmer state, with a relatively
strong increase in the warm extremes. The precipitation frequency is projected to decrease at the inland Nicosia and at the
coastal Limassol, while the mountainous Saittas could experience more frequent 5–15 mm/day rainfall. In future, very hot days
are expected to increase by more than 2 weeks/year and tropical nights by 1 month/year. The annual number of consecutive dry
days shows a statistically significant increase (of 9 days) in Limassol. These projected changes of the Cyprus climate may
adversely affect ecosystems and the economy of the island and emphasize the need for adaptation strategies. 相似文献
847.
848.
Mehrzad Keshavarzifard Farid Moore Behnam Keshavarzi Reza Sharifi 《Environmental geochemistry and health》2018,40(2):721-735
Surface sediment samples were collected from intertidal zone of Asaluyeh, Persian Gulf, to investigate distribution, sources and health risk of sixteen polycyclic aromatic hydrocarbons (PAHs). Total PAH concentrations ranged from 1.8 to 81.2 μg kg?1 dry weight, which can be categorized as low level of pollution. Qualitative and quantitative assessments showed that PAHs originated from both petrogenic and pyrogenic sources with slight pyrogenic dominance. Source apportionment using principal component analysis indicated that the main sources of PAHs were fossil fuel combustion (33.59%), traffic-related PAHs (32.77%), biomass and coal combustion (18.54%) and petrogenic PAHs (9.31%). According to the results from the sediment quality guidelines, mean effects range-median quotient (M-ERM-Q) and benzo[a]pyrene toxic equivalents (BaPeq), low negative ecological risks related to PAH compounds would occur in the intertidal zone of Asaluyeh. The total benzo[a]pyrene (BaP) toxic equivalent quotient (TEQcarc) for carcinogenic compounds ranged from 0.01 to 7 μg kg?1-BaPeq, indicating low carcinogenic risk. The human health risk assessment of PAH compounds via ingestion and dermal pathways suggests low and moderate potential risk to human health, respectively. 相似文献
849.
Dariusz Dobrzyński Anna Boguszewska-Czubara Kenji Sugimori 《Environmental geochemistry and health》2018,40(4):1355-1375
Germanium is considered to be a non-essential element; however, little is still known about its significance for living organisms. It exerts prophylactic and therapeutic effects in the treatment of serious diseases such as cancer, HIV infection, and others. Germanium does not exhibit acute toxicity, but, as it tends to accumulate in various organs and tissues, undesirable and even dangerous side effects have been reported after prolonged and/or high dosage application. In general, inorganic compounds of germanium are more toxic than its organic compounds. Further studies should be performed to elucidate the exact molecular mechanism of germanium action, to determine the safe and effective dose of germanium via curative/mineral waters, and to understand the applications and benefits of using germanium-enriched waters in balneotherapy. The geochemistry of curative (cold CO2-rich, thermal) waters from spas in the Sudetes (Poland) was clarified in terms of components and mineral phases which might govern germanium. Germanium and silicon in thermal (above 20 °C) waters presumably result from the solubility of silicates in crystalline (granites, gneisses) aquifer rocks and might be controlled by neo-formed quartz. The cold CO2-rich waters revealed a significant diversity of aqueous chemistry and relationships of germanium with iron, silicon, or arsenic. Locally, both in sedimentary (sandstones) and metamorphic (gneisses) aquifer rocks, primary (silicates) and/or secondary (oxides) iron-containing minerals likely release germanium into solution. In the CO2-rich waters of the western part of the K?odzko Region, germanium distinctly correlates with arsenic. It is hypothesized that both elements are co-sourced from crystalline basement and/or migration of substances of post-magmatic origin along deep-seated dislocations related to the seismically active Po?í?í-Hronov fault zone. This area was proposed as the most prospective one for finding waters rich in germanium in the Sudetes. 相似文献
850.
We investigated the type and extent of degradation at three sites on the Agulhas Plain, South Africa: an old field dominated
by the alien grass Pennisetum clandestinum Pers. (kikuyu), an abandoned Eucalyptus plantation, and a natural fynbos community invaded by nitrogen fixing—Australian Acacia species. These forms of degradation are representative of many areas in the region. By identifying the nature and degree
of ecosystem degradation we aimed to determine appropriate strategies for restoration in this biodiversity hotspot. Vegetation
surveys were conducted at degraded sites and carefully selected reference sites. Soil-stored propagule seed banks and macro-
and micro-soil nutrients were determined. Species richness, diversity and native cover under Eucalyptus were extremely low compared to the reference site and alterations of the soil nutrients were the most severe. The cover of
indigenous species under Acacia did not differ significantly from that in reference sites, but species richness was lower under Acacia and soils were considerably enriched. Native species richness was much lower in the kikuyu site, but soil nutrient status
was similar to the reference site. Removal of the alien species alone may be sufficient to re-initiate ecosystem recovery
at the kikuyu site, whereas active restoration is required to restore functioning ecosystems dominated by native species in
the Acacia thicket and the Eucalyptus plantation. To restore native plant communities we suggest burning, mulching with sawdust and sowing of native species. 相似文献