Understanding the complex effects of biotic and abiotic factors on the composition of vegetation is very important for developing and implementing strategies for promoting sustainable grassland development. The vegetation–disturbance–environment relationship was examined in degraded alpine grasslands in the headwater areas of three rivers on the Qinghai–Tibet Plateau in this study. The investigated hypotheses were that (1) the heterogeneity of the vegetation of the alpine grassland is due to a combination of biotic and abiotic factors and that (2) at a small scale, biotic factors are more important for the distribution of alpine vegetation. On this basis, four transects were set along altitudinal gradients from 3,770 to 3,890 m on a sunny slope, and four parallel transects were set along altitudinal gradients on a shady slope in alpine grasslands in Guoluo Prefecture of Qinghai Province, China. It was found that biological disturbances were the major forces driving the spatial heterogeneity of the alpine grassland vegetation and abiotic factors were of secondary importance. Heavy grazing and intensive rat activity resulted in increases in unpalatable and poisonous weeds and decreased fine forages in the form of sedges, forbs, and grasses in the vegetation composition. Habitat degradation associated with biological disturbances significantly affected the spatial variation of the alpine grassland vegetation, i.e., more pioneer plants of poisonous or unpalatable weed species, such as Ligularia virgaurea and Euphorbia fischeriana, were found in bare patches. Environmental/abiotic factors were less important than biological disturbances in affecting the spatial distribution of the alpine grassland vegetation at a small scale. It was concluded that rat control and light grazing should be applied first in implementing restoration strategies. The primary vegetation in lightly grazed and less rat-damaged sites should be regarded as a reference for devising vegetation restoration measures in alpine pastoral regions. 相似文献
Environmental Science and Pollution Research - Aquaculture is an activity with economic and social importance since it generates food, employment, and income. However, like other human activities,... 相似文献
Abstract: We examined the decisions women make in their collection of fuelwood within a protected area in Malawi. We used law enforcement data and behavioral observations of fuelwood harvesting practices to examine the risk of detection and penalties posed by law enforcement activities. Our results indicate that, at their current levels, law enforcement patrols have little effect on wood collection practices. The low risk of detection and light penalties appear to favor illegal wood collection, which is practiced by the majority of women. Alternative strategies should be pursued to enhance the conservation of the woodland and its management as a fuelwood resource for local communities. 相似文献
Commonly occurring natural events become natural disasters when they affect the population through death and injury, and/or
through the destruction of natural and physical capital on which people rely for their livelihood and quality of life. Climate
change plays a role in that it tends to increase the frequency and intensity of weather-related natural disasters. Additionally,
climate change may put people at risk by influencing access to water, coastal flooding, disease and hunger, and leaving them
with a more degraded environment, leading, in turn, to increased vulnerability. The purpose of this paper is to present a
review and synthesis of the literature and case studies addressing differential impacts of climate change-related natural
disasters on a society and its economy. Developed and developing countries show different vulnerabilities to natural disasters.
Even within countries, impacts vary significantly across population and economic sectors. When losses from natural disasters
are large, their cumulative effect can have notable macroeconomic impacts, which feed back to further pronounce existing income
inequalities and lower income levels. Impacts tend to be most pronounced for women, the young and elderly, and people of ethnic
or racial minorities.
Economic appraisal and technical effectiveness of adaptation options are key criteria for judging climate change adaptation investment decisions in all sectors. Yet relatively little methodological guidance exists for determining the most appropriate appraisal techniques for different adaptation options. This paper provides adaptation options and scopes relevant appraisal methods in agriculture focussing on livestock production specifically. We find that for many adaptation options for livestock agriculture, standard (expected) cost-benefit analysis is an appropriate tool. For adaptation options requiring long lead times or those with long lifetimes, techniques incorporating uncertainty (‘robust’ methods) are more suitable, including real options analysis, portfolio analysis and robust decision-making. From a comprehensive list of adaptation options in the livestock sector, we identify the most appropriate appraisal technique for each option and describe how the robust appraisal tools could be applied to heat stress, flood risk and water management.
A recently designed two-chamber-lysimeter-test-system allows the detailed investigation of degradation, transport and transfer
processes of 14C-labeled substances in soil–plant–atmosphere-systems under outdoor conditions. With this test system it is feasible to distinguish
between 14C-emissions from soil surfaces and 14C-emissions from plant surfaces in soil monoliths under real environmental conditions. Special soil humidity sensors allow
the measurement of soil water content near to the soil surface, in 1 and 5 cm depth. The behavior of organic chemicals can
be followed for a whole vegetation period and a mass balance for the applied chemical can be established. Some selected results
of the herbicides isoproturon and glyphosate – using the two-chamber-lysimeter-test-system – are presented to demonstrate
its applicability for the identification and quantification of the processes that govern pesticide behavior in soil–plant-systems.
Mineralization of 14C-isoproturon was very different in four different soils; the mineralization capacity of the soils ranged from 2 to 60%. Leaching
of isoproturon in general was very low, but depending on the soil type and environmental conditions isoproturon and its metabolites
could be leached via preferential flow, especially shortly after application. For the herbicide 14C-glyphosate no accumulation of residues in the soil and no leaching of the residues to deeper soil layers could be observed
after three applications. Glyphosate was rapidly degraded to AMPA in the soil. Glyphosate and AMPA were accumulated in soy
bean nodules. 相似文献
The development of effective agricultural monitoring networks is essential to track, anticipate and manage changes in the social, economic and environmental aspects of agriculture. We welcome the perspective of Lindenmayer and Likens (J. Environ. Monit., 2011, 13, 1559) as published in the Journal of Environmental Monitoring on our earlier paper, "Monitoring the World's Agriculture" (Sachs et al., Nature, 2010, 466, 558-560). In this response, we address their three main critiques labeled as 'the passive approach', 'the problem with uniform metrics' and 'the problem with composite metrics'. We expand on specific research questions at the core of the network design, on the distinction between key universal and site-specific metrics to detect change over time and across scales, and on the need for composite metrics in decision-making. We believe that simultaneously measuring indicators of the three pillars of sustainability (environmentally sound, social responsible and economically viable) in an effectively integrated monitoring system will ultimately allow scientists and land managers alike to find solutions to the most pressing problems facing global food security. 相似文献
The evolution of graduated licensing systems in the past 25 years has resulted in dramatic growth in research on this topic. The most recent summary reports have covered the period up to 2007. In the present article more recent and ongoing research is categorized, summarized, and discussed. 相似文献
The incorporation of antimicrobial metals such as silver is an alternative to protect the material against microbial attack. However, loaded polymer can lose its antimicrobial properties after some time of use, and the additive may even leak out into the environment becoming harmful to non-target organisms. This study aims to evaluate the mechanical properties and antimicrobial activity of silver containing thermoplastic elastomer (TPE) samples exposed to weathering and the influence of additive incorporation in material biodegradation in the soil. For this purpose, silver ions (Ag+_bentonite, Ag+_phosphate) and silver nanoparticles (AgNp_silica) based additives were blended in a formulation of SEBS, polypropylene and mineral oil. The test samples were exposed to natural ageing over nine months, and were then evaluated according to their mechanical properties, antimicrobial activity, and degree of crystallinity and surface characteristics. The biodegradation process before and after natural ageing was evaluated through the generation of carbon dioxide. The results show that the action of natural ageing reduced the mechanical properties of loaded and unloaded TPE, and modified the degree of crystallinity and the chemical characteristic of the TPE surface. The presence or type of additive did not influence material resistance after being exposed to weathering. A decrease in antimicrobial activity in samples after natural ageing was observed. At a variable level and according to the chemical content, generation of carbon dioxide from TPE samples was greater in aged samples than in unexposed ones. 相似文献
Olive oil mill wastewater (OOMW) environmental impacts minimization have been attempted by developing more effective processes,
but no chemical or biological treatments were found to be totally effective to mitigate their impact on receiving systems.
This work is the first that reports simultaneously the efficiency of three different approaches: biological treatment by two
fungal species (Trametes versicolor or Pleurotus sajor caju), enzymatic treatment by laccase, and chemical treatment by photo-Fenton oxidation on phenols removal. 相似文献