首页 | 官方网站   微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 15 毫秒
1.
Changes in boreal climate of the magnitude projected for the 21st century have always caused vegetation changes large enough to be societally important. However, the rates and patterns of vegetation change are difficult to predict. We review evidence suggesting that these vegetation changes may be gradual at the northern forest limit or where seed dispersal limits species distribution. However, forest composition may be quite resilient to climate change in the central portions of a species range until some threshold is surpassed. At this point, changes can be rapid and unexpected, often causing a switch to very different ecosystem types. Many of these triggers for change are amenable to management, suggesting that our choice of policies in the coming decades will substantially influence the ecological and societal consequences of current climatic change.  相似文献   

2.
3.
Environmental Science and Pollution Research - The pandemic shock puts the world on quarantine and paused economic operations that affected energy consumption and economic output. This study...  相似文献   

4.
Abstract

The distribution and persistence of aerially applied mexacarbate were studied in a New Brunswick aquatic forest environment after spraying twice at a dosage of 70 g A.l./ha using a fixed‐wing aircraft. Average droplet density (drops/cm2) and ground deposition (g A.1./ha) between the two applications differed considerably. The values for the first and second applications were 1.7 and 0.73, and 5.2 and 2.0, respectively; but the average NMD (20 μm) and VMD (36 μm) for both applications were nearly the same. The maximum 1‐h postspray concentrations of mexacarbate in the stream and pond waters were 0.73 and 18.74 ppb, respectively. Concentrations fell rapidly to below detection limits within 12 h in stream and within 3 d in pond water. Cattails (Typha latifolia), manna grass (Glyceria borealis) and bog moss (Sphagnum sp.) collected from the pond contained peak 1‐h postspray concentrations of 720, 482 and 81 ppb, respectively. The concentration levels decreased rapidly and the average half‐lives of the chemical in them were about 3.9, 8.5 and 2.0 h. Bog moss, stream moss (Fontinalis sp.), watercress (Nasturtium officinalis), buttercup (Ranunculus aquatilis) and green alga (Drapamaldia sp.) sampled from the stream sites did not contain measurable levels of mexacarbate. Also, caged and wild tadpoles (Rana clamitans melanota) from the pond, and brook trout (Salvelinus fontinalis) (caged and wild), Atlantic salmon (Salmo salar) (wild) and mayfly nymphs (Ephemeralla sp.) collected from the stream did not contain any of the material. Mexacarbate was not detected in stream and pond sediments. The demethylated products, 4‐methylamino and 4‐amino‐3,5‐xylyl methylcarbamates and the phenol, 4‐dimethylamino‐3,5‐xylenol, were frequently detected as metabolites in water and in the aquatic plants. The presence of these compounds showed that demethylation and hydrolytic routes are the major metabolic pathways for the dissipation of mexacarbate from these substrates.  相似文献   

5.
6.
Sediment characteristics are well known to interfere with toxicity, mainly through differences in terms of bioaccumulation. Here, with chironomids exposed to zinc in an artificial and a field sediment, we investigated the differences of zinc accumulation and of effects on the life cycle, at individual and population level. We used biology and energy-based modeling to analyze the data at all the levels of biological organization. This permits a reliable estimation of thresholds values for tissue residues. Differences in zinc tissue residues accounted for most of the differences between the results for both sediments (a factor of 11 for differences from 20 to 100 depending on the parameter which is considered). Taking into account accumulation and background variability, the differences relative to thresholds could be accounted for. However, it appeared that, once the threshold was passed, effects were much more pronounced for organisms exposed to artificial sediment compared to field sediment. We concluded that some sediment characteristics can enhance toxicity, in addition to their influence on the compound accumulation, even if the latter was the major source of differences in our study.  相似文献   

7.
Environmental Science and Pollution Research - Climate change is severely damaging the agricultural system of many food producing regions worldwide. Small/subsistent livestock herders are the most...  相似文献   

8.
9.
Will species that are sensitive/tolerant to Zn pollution still have the same sensitivity/tolerance in a future climate? To answer this question we analysed the response of constructed grassland communities to five levels of zinc (Zn) supply, ranging from 0 to 354 mg Zn kg−1 dry soil, under a current climate and a future climate (elevated CO2 and warming). Zn concentrations increased in roots and shoots with Zn addition but this increase did not differ between climates. Light-saturated net CO2 assimilation rate (Asat) of the species, on the other hand, responded differently to Zn addition depending on climate. Still, current and future climate communities have comparable biomass responses to Zn, i.e., no change in root biomass and a 13% decrease of above-ground biomass. Provided that the different response of Asat in a future climate will not compromise productivity and survival on the long term, sensitivity is not altered by climate change.  相似文献   

10.
Environmental Science and Pollution Research - This research attempts to evaluate the linkage among climatic change factors such as average temperature and rainfall patterns and non-climatic...  相似文献   

11.
Carlsson L  Lazdinis M 《Ambio》2004,33(6):366-370
After the break-up of the Soviet system, the divergence in forest management among Soviet republics became obvious. While the forest sectors of the Baltic States have been fundamentally changed, Russia has not been able to develop an institutional framework that would fit the prerequisites for social-ecological resilience. It is argued that sustainable development requires institutional frameworks that have the capacity to adapt and learn, and thus to treat policies as experiments that are constantly assessed and readjusted. This, however, requires a participatory approach and in this respect the Baltic States are believed to be on a more promising track. Finally, it is concluded that only to the extent that suitable institutional frameworks will be developed will social-ecological resilience be a significant feature of the natural resources management in the former communist countries.  相似文献   

12.
Environmental Science and Pollution Research - In developing countries like Pakistan, agriculture constitutes the primary source of support for the majority of rural and the adjacent urban...  相似文献   

13.
14.
Ehrich  Dorothée  Schmidt  Niels M.  Gauthier  Gilles  Alisauskas  Ray  Angerbjörn  Anders  Clark  Karin  Ecke  Frauke  Eide  Nina E.  Framstad  Erik  Frandsen  Jay  Franke  Alastair  Gilg  Olivier  Giroux  Marie-Andrée  Henttonen  Heikki  Hörnfeldt  Birger  Ims  Rolf A.  Kataev  Gennadiy D.  Kharitonov  Sergey P.  Killengreen  Siw T.  Krebs  Charles J.  Lanctot  Richard B.  Lecomte  Nicolas  Menyushina  Irina E.  Morris  Douglas W.  Morrisson  Guy  Oksanen  Lauri  Oksanen  Tarja  Olofsson  Johan  Pokrovsky  Ivan G.  Popov  Igor Yu.  Reid  Donald  Roth  James D.  Saalfeld  Sarah T.  Samelius  Gustaf  Sittler  Benoit  Sleptsov  Sergey M.  Smith  Paul A.  Sokolov  Aleksandr A.  Sokolova  Natalya A.  Soloviev  Mikhail Y.  Solovyeva  Diana V. 《Ambio》2020,49(3):801-804
Ambio - In the original published article, some of the symbols in figure 1A were modified incorrectly during the typesetting and publication process. The correct version of the figure is provided...  相似文献   

15.
Environmental Science and Pollution Research - Excessive cobalt exposure has been shown to induce various adverse health effects in animal and human toxicity studies. However, the relationships...  相似文献   

16.
This study intended to determine whether the redox state in plants of Nicotiana tabacum ‘Bel-W3’ fluctuates in response to the environmental factors in a sub-tropical area contaminated by ozone (São Paulo, SE - Brazil) and which environmental factors are related to this fluctuation, discussing their biomonitoring efficiency. We comparatively evaluated the indicators of redox state (ascorbic acid, glutathione, superoxide dismutase, ascorbate peroxidase, and glutathione reductase) and leaf injury in 17 field experiments performed in 2008. The redox state was explained by the combined effects of chronic levels of O3 and meteorological variables 4-6 days prior to the plant sampling. Moderate leaf injury was observed in most cases. The redox state of tobacco decreases few days after their placement in the sub-tropical environment, causing them to become susceptible to oxidative stress imposed by chronic doses of O3. Its bioindicator efficiency would not be diminished in such levels of atmospheric contamination.  相似文献   

17.
The study aimed to assess morphological, structural and compositional alterations in Scrobicularia plana nacre environmentally exposed to mercury in order to seek out the possibility of the assessed alterations as a monitoring tool to handle complexity and interactions of metals in the environment involving a non-invasive methodology. Bivalves were collected from a mercury contaminated site (Laranjo basin – Ria de Aveiro, Portugal) and a reference site in the same aquatic system. The combination of scanning electron microscopy (SEM) with energy-dispersive X-ray spectroscopy (EDS) technique depicted a sheet like morphology of bivalve nacre collected from the reference site. Moreover, EDS plot exhibited the presence of potassium, oxygen, calcium, and carbon elements. Shells collected from the contaminated area depicted lamellar patches like structures with particle like morphology composition. SEM images corresponding to the elemental analysis by EDS plot clearly denoted the presence of mercury. SEM images from the other locations of the contaminated shells depicted large surface area, a broken or ruptured symmetry of organic matrix as well as crack-like gaps. The influence of environmental mercury affecting the surface morphology of S. plana nacre showed dimple like morphology (as proved by transmission electron microscopy, TEM). The possible explanation may be the replacement of calcium elements with other elements or alloys from the nacre composite collected from contaminated region. Therefore, the nacre fingerprint may be useful as innovative knowledge and applicable tool aiming at risk reduction from noxious mercury present in the environment. Overall results suggested the use of shell as an indelible fingerprint of metal exposure.  相似文献   

18.
Short-term elevated O3 reduces photosynthesis, which reduces stomatal conductance (g(s)) in response to increased substomatal CO2 concentration (Ci). Further exposure causes stomata to become sluggish in response to environmental stimuli. Exposure to elevated CO2 stimulates rapid stomata closure in response to increased Ci. This reduction in g(s) may not be sustained over time as photosynthesis down-regulates and with it, g(s). The relationship between g(s) and photosynthesis may not be constant because stomata respond more slowly to environmental changes than photosynthesis, and because elevated CO2 may alter guard cell sensitivity to other signals. Also, reduced stomatal density (and g(s)) in response to long-term CO2 enrichment suggests sustained reduction in g(s). Elevated CO2 is believed to ameliorate the deleterious O3 effects by reducing g(s) and thus the potential O3 flux into leaves. Confirmation that g(s) acclimation to CO2 enrichment does not lessen over time is critical for developing meaningful O3 flux scenarios.  相似文献   

19.
Pharmaceuticals are commonly found both in the aquatic and the agricultural environments as a consequence of the human activities and associated discharge of wastewater effluents to the environment. The utilization of treated effluent for crop irrigation, along with land application of manure and biosolids, accelerates the introduction of these compounds into arable lands and crops. Despite the low concentrations of pharmaceuticals usually found, the continuous introduction into the environment from different pathways makes them ‘pseudo-persistent’. Several reviews have been published regarding the potential impact of veterinary and human pharmaceuticals on arable land. However, plant uptake as well as phytotoxicity data are scarcely studied. Simultaneously, phytoremediation as a tool for pharmaceutical removal from soils, sediments and water is starting to be researched, with promising results. This review gives an in-depth overview of the phytotoxicity of pharmaceuticals, their uptake and their removal by plants. The aim of the current work was to map the present knowledge concerning pharmaceutical interactions with plants in terms of uptake and the use of plant-based systems for phytoremediation purposes.  相似文献   

20.
The changing Arctic environment is affecting zooplankton that support its abundant wildlife. We examined how these changes are influencing a key zooplankton species, Calanus finmarchicus, principally found in the North Atlantic but expatriated to the Arctic. Close to the ice-edge in the Fram Strait, we identified areas that, since the 1980s, are increasingly favourable to C. finmarchicus. Field-sampling revealed part of the population there to be capable of amassing enough reserves to overwinter. Early developmental stages were also present in early summer, suggesting successful local recruitment. This extension to suitable C. finmarchicus habitat is most likely facilitated by the long-term retreat of the ice-edge, allowing phytoplankton to bloom earlier and for longer and through higher temperatures increasing copepod developmental rates. The increased capacity for this species to complete its life-cycle and prosper in the Fram Strait can change community structure, with large consequences to regional food-webs.Supplementary InformationThe online version contains supplementary material available at 10.1007/s13280-021-01667-y.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司    京ICP备09084417号-23

京公网安备 11010802026262号