Neonicotinoid pesticides were first introduced in the mid-1990s, and since then, their use has grown rapidly. They are now the most widely used class of insecticides in the world, with the majority of applications coming from seed dressings. Neonicotinoids are water-soluble, and so can be taken up by a developing plant and can be found inside vascular tissues and foliage, providing protection against herbivorous insects. However, only approximately 5% of the neonicotinoid active ingredient is taken up by crop plants and most instead disperses into the wider environment. Since the mid-2000s, several studies raised concerns that neonicotinoids may be having a negative effect on non-target organisms, in particular on honeybees and bumblebees. In response to these studies, the European Food Safety Authority (EFSA) was commissioned to produce risk assessments for the use of clothianidin, imidacloprid and thiamethoxam and their impact on bees. These risk assessments concluded that the use of these compounds on certain flowering crops poses a high risk to bees. On the basis of these findings, the European Union adopted a partial ban on these substances in May 2013. The purpose of the present paper is to collate and summarise scientific evidence published since 2013 that investigates the impact of neonicotinoids on non-target organisms. Whilst much of the recent work has focused on the impact of neonicotinoids on bees, a growing body of evidence demonstrates that persistent, low levels of neonicotinoids can have negative impacts on a wide range of free-living organisms. 相似文献
Global climate change, along with continued habitat loss and fragmentation, is now recognized as being a major threat to future
biodiversity. There is a very real threat to species, arising from the need to shift their ranges in the future to track regions
of suitable climate. The Important Bird Area (IBA) network is a series of sites designed to conserve avian diversity in the
face of current threats from factors such as habitat loss and fragmentation. However, in common with other networks, the IBA
network is based on the assumption that the climate will remain unchanged in the future. In this article, we provide a method
to simulate the occurrence of species of conservation concern in protected areas, which could be used as a first-step approach
to assess the potential impacts of climate change upon such species in protected areas. We use species-climate response surface
models to relate the occurrence of 12 biome-restricted African species to climate data at a coarse (quarter degree-degree
latitude-longitude) resolution and then intersect the grid model output with IBA outlines to simulate the occurrence of the
species in South African IBAs. Our results demonstrate that this relatively simple technique provides good simulations of
current species' occurrence in protected areas. We then use basic habitat data for IBAs along with habitat preference data
for the species to reduce over-prediction and further improve predictive ability. This approach can be used with future climate
change scenarios to highlight vulnerable species in IBAs in the future and allow practical recommendations to be made to enhance
the IBA network and minimize the predicted impacts of climate change. 相似文献
Major benefits were weighed against major costs associated with recent saltcedar control efforts along the Middle Pecos River,
New Mexico. The area of study was restricted to both sides of the channel and excluded tributaries along the 370 km between
Sumner and Brantley dams. Direct costs (helicopter spraying, dead tree removal, and revegetation) within the study area were
estimated to be $2.2 million but possibly rising to $6.4 million with the adoption of an aggressive revegetation program.
Indirect costs associated with increased potential for erosion and reservoir sedimentation would raise the costs due to increased
evaporation from more extensive shallows in the Pecos River as it enters Brantley Reservoir. Actions such as dredging are
unlikely given the conservative amount of sediment calculated (about 1% of the reservoir pool). The potential for water salvage
was identified as the only tangible benefit likely to be realized under the current control strategy. Estimates of evapotranspiration
(ET) using Landsat TM data allowed estimation of potential water salvage as the difference in ET before and after treatment,
an amount totaling 7.41 million m3 (6010 acre-ft) per year. Previous saltcedar control efforts of roughly the same magnitude found that salvaged ET recharged
groundwater and no additional flows were realized within the river. Thus, the value of this recharge is probably less than
the lowest value quoted for actual in-channel flow, and estimated to be < $63,000 per year. Though couched in terms of costs
and benefits, this paper is focused on what can be considered the key trade-off under a complete eradication strategy: water
salvage vs. erosion and sedimentation. It differs from previous efforts by focusing on evaluating the impacts of actual control
efforts within a specific system. Total costs (direct plus potential indirect) far outweighed benefits in this simple comparison
and are expected to be ongoing. Problems induced by saltcedar control may permanently reduce reservoir capacity and increase
reservoir evaporation rates, which could further deplete supplies on this water short system. These potential negative consequences
highlight that such costs and benefits need to be considered before initiating extensive saltcedar control programs on river
systems of the western United States. 相似文献
Abstract Passive samplers have been shown to be an inexpensive alternative to direct sampling. Diffusion denuders have been developed to measure the concentration of species such as ammonia (NH3), which is in equilibrium with particulate ammonium nitrate. Conventional denuder sampling that inherently requires air pumps and, therefore, electrical power. To estimate emissions of NH3 from a fugitive source would require an array of active samplers and meteorological measurements to estimate the flux. A recently developed fabric denuder was configured in an open tube to passively sample NH3 flux. Passive and active samplers were collocated at a dairy farm at the California State University, Fresno, Agricultural Research Facility. During this comparison study, NH3 flux measurements were made at the dairy farm lagoon before and after the lagoon underwent acidification. Comparisons were made of the flux measurements obtained directly from the passive flux denuder and those calculated from an active filter pack sampler and wind velocity. The results show significant correlation between the two methods, although a correction factor needed to be applied to directly compare the two techniques. This passive sampling approach significantly reduces the cost and complexity of sampling and has the potential to economically develop a larger inventory base for ambient NH3 emissions. 相似文献
Monitoring of cyclic volatile methylsiloxanes (cVMS) carried out at Anglian Water’s Broadholme sewage treatment plant (STP) is described. The method deployed used headspace gas chromatography/mass spectrometry (HS-GC/MS) and the addition of isotopically labelled cVMS to correct for partitioning in samples containing high levels of particulate and dissolved organic carbon. The method was capable of measuring cVMS in raw sewage samples, with recoveries of 80%, 85% and 71% respectively, for D4, D5 and D6. The limit of quantification was 0.2 μg L−1 for all three substances. Recoveries close to 100% were observed for all cVMS spiked into treated effluent (LOQ = 0.01 μg L−1). Despite the volatile nature of cVMS and its ubiquitous presence in the ambient atmosphere, the methods deployed showed excellent recoveries, reproducibility and quantification limits. A distinct diurnal variation in cVMS concentration, probably linked with the use of personal care products was observed for raw sewage but not in treated sewage effluent. The estimated per capita consumption of D5 (∼2.7 mg cap−1 d−1) derived for the population served by this plant was significantly lower than that derived in the Environment Agency (UK) risk assessment (11.6 mg cap−1 d−1). The cVMS were highly removed during sewage treatment with efficiencies greater than 98%. The methods and findings of this pilot study can be used as the basis for future studies on the fate of cVMS substances in STPs. 相似文献
Agriculture P management practices elevate the level of inorganic phosphates in soil that results in phosphorous (P) seepage into water-bodies. This is one of the key factors that have accelerated the menace of eutrophication. Phytic acid (phytate)-P-rich plant metabolite is infamous for its anti-nutrient activity and regularly oozing in to environment though discharge of mono-gastric animals. That has amplified the magnitudes of eutrophication. In this work, for catalysis of phytate-P, the metal-organic framework fabricated towards metal oxides (Fe3O4) and phytase in highly ordered microcosms of silica was employed. The synthesized framework was characterized through transmission electron microscopy (TEM) and nitrogen isotherm analysis. Average pore diameter of synthesized bisect oval shaped structures was measured around ≈200 nm. Herein, phytase and Fe3O4 nanoparticles were loaded to the cavities of microcosms through glutaraldehyde-mediated crosslinking. Whereas Fe3O4 nanoparticles act as nano-absorbents that adsorb P liberated from phytase-mediated catalysis of phytate. Kinetic analysis of free and loaded phytase has shown relatively small reduction in catalytic efficiency. These loaded microcosms have removed 60–80% of phytate-phosphate. The optimized process has reduced the growth of photoautotrophs by 50%. Additionally the magnet-assisted separation of loaded microcosms eased the reapplication of loaded microcosms tested for six independent instances. The primary studies conducted to evaluate the geno-toxicity of loaded microcosms have not shown any harmful effect on the process like cell division and seed germination. The efficacy of this method has evaluated towards on-field testing in Changa (Gujarat, India) lake.
There has been much recent interest in the concept of rewilding as a tool for nature conservation, but also confusion over the idea, which has limited its utility. We developed a unifying definition and 10 guiding principles for rewilding through a survey of 59 rewilding experts, a summary of key organizations’ rewilding visions, and workshops involving over 100 participants from around the world. The guiding principles convey that rewilding exits on a continuum of scale, connectivity, and level of human influence and aims to restore ecosystem structure and functions to achieve a self-sustaining autonomous nature. These principles clarify the concept of rewilding and improve its effectiveness as a tool to achieve global conservation targets, including those of the UN Decade on Ecosystem Restoration and post-2020 Global Biodiversity Framework. Finally, we suggest differences in rewilding perspectives lie largely in the extent to which it is seen as achievable and in specific interventions. An understanding of the context of rewilding projects is the key to success, and careful site-specific interpretations will help achieve the aims of rewilding. 相似文献