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81.
Using historical ecology to reassess the conservation status of coniferous forests in Central Europe 下载免费PDF全文
Péter Szabó Petr Kuneš Helena Svobodová‐Svitavská Markéta Gabriela Švarcová Lucie Křížová Silvie Suchánková Jana Müllerová Radim Hédl 《Conservation biology》2017,31(1):150-160
Forests cover approximately one‐third of Central Europe. Oak (Quercus) and European beech (Fagus sylvatica) are considered the natural dominants at low and middle elevations, respectively. Many coniferous forests (especially of Picea abies) occur primarily at midelevations, but these are thought to have resulted from forestry plantations planted over the past 200 years. Nature conservation and forestry policy seek to promote broadleaved trees over conifers. However, there are discrepancies between conservation guidelines (included in Natura 2000) and historical and palaeoecological data with regard to the distribution of conifers. Our aim was to bring new evidence to the debate on the conservation of conifers versus broadleaved trees at midelevations in Central Europe. We created a vegetation and land‐cover model based on pollen data for a highland area of 11,300 km2 in the Czech Republic and assessed tree species composition in the forests before the onset of modern forestry based on 18th‐century archival sources. Conifers dominated the study region throughout the entire Holocene (approximately 40–60% of the area). Broadleaved trees were present in a much smaller area than envisaged by current ideas of natural vegetation. Rather than casting doubt on the principles of Central European nature conservation in general, our results highlight the necessity of detailed regional investigations and the importance of historical data in challenging established notions on the natural distribution of tree species. 相似文献
82.
M Calabi-Floody G Velásquez L Gianfreda S Saggar N Bolan C Rumpel ML Mora 《Chemosphere》2012,89(6):648-655
The high P retention of acidic Andisols makes necessary to increase our technological approaches in pasture management in the animal system production. Here, we evaluated the clay- or nanoclay-acid phosphatase complexes for improving phosphorus mineralization from degraded cattle dung. We implemented an immobilization mechanism of acid phosphatase (AP) using natural clays (allophanic and montmorillonite) and nanoclays as support materials. Also, we evaluated the mineralization of organic P containing in decomposed cattle dung with clay- and nanoclay-AP complexes by incubation studies. Clays and nanoclays were characterized by microscopy techniques as atomic force and confocal-laser scanning microscopy. We found that these support materials stabilized AP by encapsulation. Our results showed that immobilization on allophanic or montmorillonite materials improved both the specific activity (4-48%) and the Vmax (28-38%) of AP. Moreover, the enzyme had a better performance when immobilized on clay and nanoclay from Andisol than on montmorillonite materials. Phosphorous mineralization of cattle dung was regulated by water-soluble P present in the dung and P re-adsorption on allophanic materials. However, we were able to detect a potential capacity of AP immobilized on allophanic nanoclays as the best alternative for P mineralization. Further research with initially low water-soluble P containing organic materials is required to quantify the P mineralization potential and bioavailability of P from dung. 相似文献
83.
Elizabeth Vega Elizabeth Reyes Hugo Ruiz José García Gabriela Sánchez Gerardo Martínez-Villa 《Journal of the Air & Waste Management Association (1995)》2013,63(7):786-798
Abstract During the last 10 years, high atmospheric concentrations of airborne particles recorded in the Mexico City metropolitan area have caused concern because of their potential harmful effects on human health. Four monitoring campaigns have been carried out in the Mexico City metropolitan area during 2000-2002 at three sites: (1) Xalos-toc, located in an industrial region; (2) La Merced, located in a commercial area; and (3) Pedregal, located in a residential area. Results of gravimetric and chemical analyses of 330 samples of particulate matter (PM) with an aerodynamic diameter less than 2.5 μm (PM2.5) and PM with an aerodynamic diameter less than 10 μm (PM10) indicate that (1) PM2.5/PM10 average ratios were 0.42, 0.46, and 0.52 for Xalostoc, La Merced, and Pedregal, respectively; (2) the highest PM2.5 and PM10 concentrations were found at the industrial site; (3) PM2.5 and PM10 concentrations were lower at nighttime; (4) PM2.5 and PM10 spatial averages concentrations were 35 and 76 μg/m3, respectively; and (5) when the PM2.5 standard was exceeded, nitrate, sulfate, ammonium, organic carbon, and elemental carbon concentrations were high. Twenty-four hour averaged PM2.5 concentrations in Mexico City and Sao Paulo were similar to those recorded in the 1980s in Los Angeles. PM10 concentrations were comparable in Sao Paulo and Mexico City but 3-fold lower than those found in Santiago. 相似文献
84.
Civeira Gabriela Lado Liares Marcos Vidal Vazquez Eva Paz Gonzlez Antonio 《Environmental management》2020,65(3):355-368
Environmental Management - This work quantified ecosystem services (ES) and the geographic gross product (GGP) at municipal level in the Metropolitan Region of Buenos Aires (MRBA), Argentina. The... 相似文献
85.
Prediction of manure nitrogen availability to crops is key to ensuring adequate production while minimizing potential adverse environmental impacts. This field study estimated first-year and residual N availability from several manures subjected to various levels of processing, and evaluated the applicability of the pre-sidedress soil N test (PSNT) in fields receiving the different manures using corn (Zea mays L.) as the test crop. Plots received several rates of fresh (FP), dried (DP), or composted (CP) poultry (Gallus gallus domesticus) manure, composted cow (Bos taurus) (CC) manure, ammonium nitrate (AN), or no N. Crop yields and N uptake from plots where CC was applied were undistinguishable from controls in most years, whereas poultry manures significantly increased corn production. Average apparent first-year N availability, as measured by fertilizer equivalence, was 57, 53, 14, and 4% for FP, DP, CP, and CC respectively. Apparent second-year N availability, as measured by relative effectiveness, was 18, 19, 12, and 7% for FP, DP, CP, and CC; however, for CC both first- and second-year estimates of apparent N recovery (ANR) could statistically not be separated from the controls. Apparent nitrogen avail-ability was greater for less processed manures and for CP compared to CC, emphasizing that producers should know the source and level of compost stability when these materials are used as a primary nutrient source. The PSNT successfully (87% correct) identified sites with a critical value of 24 mg kg(-1) that were N sufficient across a variety of N amendments from those that would have benefitted from additional N input. 相似文献
86.
Gabriela Kalčíková Janja Babič Aleksander Pavko Andreja Žgajnar Gotvajn 《Waste management (New York, N.Y.)》2014,34(4):798-803
The aim of our study was to evaluate biotreatability of mature municipal landfill leachate by using white rot fungus and its extracellular enzymes. Leachates were collected in one active and one closed regional municipal landfill. Both chosen landfills were operating for many years and the leachates generated there were polluted by organic and inorganic compounds. The white rot fungus Dichomitus squalens was able to grow in the mature leachate from the closed landfill and as it utilizes present organic matter as a source of carbon, the results were showing 60% of DOC and COD removal and decreased toxicity to the bacterium Aliivibrio fischeri. On the other hand, growth of the fungus was inhibited in the presence of the leachate from the active landfill. However, when the leachate was introduced to a crude enzyme filtrate containing extracellular ligninolytic enzymes, removal levels of COD and DOC reached 61% and 44%, respectively. Furthermore, the treatment led to detoxification of the leachate to the bacterium Aliivibrio fischeri and to reduction of toxicity (42%) to the plant Sinapis alba. Fungal and enzymatic treatment seems to be a promising biological approach for treatment of mature landfill leachates and their application should be further investigated. 相似文献
87.
Jesus Silva Rodrigo Nardoto Gabriela Bielefeld Schor Tatiana da Silva Marcia Regina Farias Martinelli Luiz Antônio 《Environment, Development and Sustainability》2022,24(1):1010-1030
Environment, Development and Sustainability - Urbanization has threatened rural communities’ livelihoods worldwide, changing their agro-food systems from locally produced traditional items to... 相似文献
88.
Metal availability and uptake by sorghum plants grown in soils amended with sludge from different treatments 总被引:6,自引:0,他引:6
Several factors depending on the sludge, the soil, or the combination of both substrates, may affect element availability to plants. In this study, an assessment was done of the effect of two sludges obtained by different processes (activated sludge and facultative stabilization pond) on heavy-metal availability and uptake by sorghum plants in soils with high and low copper contents. Results obtained for DTPA-extractable metal indicated higher metal availability in sludge-amended soils. In addition, sludges caused changes in copper and zinc distribution in soil, indicating in most cases a discrete increase in the more labile metal forms. However, observed changes did not increase heavy metal concentration in plant leaves, indicating that assessment of metal availability by a chemical procedure (single extraction or metal fractionation) would not permit a good prediction of metal bioavailability. On the other hand, sludge application at a rate of 100 t ha−1 to high-copper agricultural soils would not imply greater mobility of this metal on account of a greater sorbing capacity provided by the sludges. Such results would indicate that sludges from wastewater treatment plants, meeting the standards of heavy metal contents, regardless of the process by which they were obtained, may be applied to several kinds of soil, even to high-copper soils, with no risk of increasing heavy metal bioavailability to phytotoxic levels in the short range. 相似文献
89.
Hatchery rearing of the scallop Argopecten purpuratus has resulted in successive generations of scallops not exposed to predators that are less sensitive to and escape more slowly
from predators than wild scallops. The present study examined whether conditioning hatchery-reared A. purpuratus to its natural predator, the sea star Meyenaster gelatinosus, improved its escape responses. Both juvenile and adult A. purpuratus from Tongoy Bay, Chile, were exposed for 7 days to different conditions: (1) continuous predator odor, (2) predator contact
for 30 min three times a day, (3) a combination of the two previous conditions, and (4) no exposure to the predator (control).
After conditioning, we evaluated scallop’s escape responses: reaction time, total clap number, duration of the clapping response,
clapping rate, and the time scallops spent closed when exhausted. Conditioning with contact and odor plus contact (i.e., high
predation risk) resulted in 25 and 50% shorter reaction times of juveniles and adults, respectively. Further, these stimuli
caused juveniles to increase the number of claps and clapping rate. For adults, the time spent closed after exhaustion decreased
by 50 and 63% after conditioning with contact and odor plus contact, respectively. Therefore, it is shown for the first time
that exposure of scallops to increasing predator stimuli enhances escape responses, evidence of threat-sensitive predator
avoidance. 相似文献
90.
The purpose of this work was to investigate the impact of user’s positions in close space over the variations of SAR distribution
in human head induced from mobile phone under the worst case conditions. The “worst case” considered in this paper refers
to conditions that include (1) a half-wavelength dipole antenna, placed near the model of human head—SAM phantom; (2) a vertically
oriented dipole antenna, parallel to the side walls of closed space for maximum reflection; (3) metallic closed space acts
as a resonant cavity; and (4) 360 randomly selected observation points. We also used a free space model for comparative purposes.
The maximum 1- and 10-g average SAR and average SAR in whole-exposed object probability density function curves have been
derived to illustrate the percentage of SAR values that have been induced inside SAM for different locations of user in the
closed space. The obtained results show that in more than 86.7% of all investigated user’s positions in the metallic closed
space, the induced maximum 1-g average SAR in user’s head is in the boundaries of ±10% of maximum 1-g average SAR, when the
user use mobile phone in free space. This relationship keep still at maximum 10-g average SAR, where in 85.9% from all investigated
user’s positions, SAR values are in boundaries of ±10% of maximum 10-g average SAR in free space. The results showed that
closed space causes more significant changes on average SAR in whole-exposed object than maximal SAR values. When we estimated
the average SAR in whole-exposed SAM in 85% from all investigated user’s position in closed space, the induced SAR is higher
than SAR values in free space model. It can be noted that the highest obtained SAR values in closed space were with 8.5% (for
1 g), 6.7% (for 10-g average SAR), and 15.1% (for average SAR in whole SAM) higher than these of the free space. 相似文献