In peripheral parts of Europe such as the West of Ireland, where environment-development tensions may be particularly sensitive, environmental sustainability principles need to be integrated into all policy and programme areas, as the Fifth Environmental Action programme requires. This paper examines the small but significant LEADER rural development initiative to assess how much its operation integrates sustainability considerations. While LEADER-supported projects are often environmentally benign, there is little evidence of proactive application in LEADER group strategies of sustainability criteria which are other than weak. Economic imperatives dominate LEADER programmes, and many actors are sanguine about potential environmental problems arising from development. 相似文献
Some recently emerged brook charr (Salvelinus fontinalis) inhabiting still-water pools along the sides of streams are sedentary and eat crustaceans from the lower portion of the
water column. Others are more active and eat insects from the upper portion of the water column. We provide evidence that
this divergent foraging behavior reflects short-term divergent selection brought about by intraspecific competition in the
presence of alternative food sources. Rates of encounters and interactions between individuals were density dependent, and
encounter and interaction events were closely timed with prey capture attempts. In addition, aggressive fish made more foraging
attempts per minute than nonaggressive fish. Aggressive fish were also either inactive or very active, while nonaggressive
fish exhibited intermediate levels of activity. Growth rate potential, an important component of fitness during the early
life stages of brook charr, was assessed using tissue concentrations of RNA and found to be highest for sedentary fish and
for active fish making frequent foraging attempts, and lower for fish exhibiting intermediate levels of activity. Our findings
support contentions that individual behavior plays an important role during initial steps in the evolution of resource polymorphisms.
Received: 27 July 1998 / Accepted after revision: 16 November 1998 相似文献
We present a model of error-prone female choice on leks, and investigate the effects of different degrees of error on the
distribution of mating success among males present at leks of different sizes. At higher levels of error, the best male is
predicted to gain a smaller share of matings, while low-ranking males gain a larger share. Males who are of high rank but
not the most desirable on the lek do best at intermediate levels of error, since the top-ranked male does not then claim all
the matings, but assessment is still sufficiently accurate for females to discriminate between high-ranking and low-ranking
competitors. The effects of error are shown to be more pronounced on larger leks, due to smaller expected differences in mating
value between males of adjacent ranks. This interaction between lek size and error suggests that observed negative relationships
between lek size and mating skew need not be attributed solely to intrasexual competition, as previously suggested, but could
also be a result of imperfect choice.
Received: 20 February 1998 / Accepted after revision: 25 October 1998 相似文献
Abstract: There is little information on the effects of tree harvest on salamander populations in the midwestern United States. We present data on plethodontid salamander densities in replicated stands of three forest age classes in the southeastern Ozarks of Missouri. Forest age classes consisted of regeneration-cut sites <5 years old, second-growth sites 70–80 years old, and old-growth sites> 120 years old. Salamander abundance on 21, 144-m2 plots was determined by area- and time-constrained searches. We also compared age-class habitat characteristics, including downed woody debris, canopy cover, ground area cover, herbaceous vegetation, and woody vegetation. Salamander density was lowest in newly regenerated forests and highest in forests> 120 years old. Comparisons of recently regenerated forests with mature forests> 70 years old indicated that terrestrial salamanders were reduced to very low numbers when mature forests had been intensively harvested. This reduction may result from a decrease in microhabitat availability. Forest age-class comparisons further indicated that salamander abundance slowly increased over time after forests had regenerated. Management decisions that take into account plethodontid salamander abundance and their response to forest structural diversity are important components in sustaining ecosystem integrity while maximizing economic yield. 相似文献
Climate change issues are calling for advanced methods to produce materials and fuels in a carbon–neutral and circular way. For instance, biomass pyrolysis has been intensely investigated during the last years. Here we review the pyrolysis of algal and lignocellulosic biomass with focus on pyrolysis products and mechanisms, oil upgrading, combining pyrolysis and anaerobic digestion, economy, and life cycle assessment. Products include oil, gas, and biochar. Upgrading techniques comprise hot vapor filtration, solvent addition, emulsification, esterification and transesterification, hydrotreatment, steam reforming, and the use of supercritical fluids. We examined the economic viability in terms of profitability, internal rate of return, return on investment, carbon removal service, product pricing, and net present value. We also reviewed 20 recent studies of life cycle assessment. We found that the pyrolysis method highly influenced product yield, ranging from 9.07 to 40.59% for oil, from 10.1 to 41.25% for biochar, and from 11.93 to 28.16% for syngas. Feedstock type, pyrolytic temperature, heating rate, and reaction retention time were the main factors controlling the distribution of pyrolysis products. Pyrolysis mechanisms include bond breaking, cracking, polymerization and re-polymerization, and fragmentation. Biochar from residual forestry could sequester 2.74 tons of carbon dioxide equivalent per ton biochar when applied to the soil and has thus the potential to remove 0.2–2.75 gigatons of atmospheric carbon dioxide annually. The generation of biochar and bio-oil from the pyrolysis process is estimated to be economically feasible.
Environmental Chemistry Letters - Declining mineral resources, high fertilizer production cost and widespread eutrophication are calling for the recovery of nitrogen and phosphorus from wastewaters... 相似文献
Water pollution and the unsustainable use of fossil fuel derivatives require advanced catalytic methods to clean waters and to produce fine chemicals from modern biomass. Classical homogeneous catalysts such as sulfuric, phosphoric, and hydrochloric acid are highly corrosive and non-recyclable, whereas heterogeneous catalysts appear promising for lignocellulosic waste depolymerization, pollutant degradation, and membrane antifouling. Here, we review the use of sulfonated graphene and sulfonated graphene oxide nanomaterials for improving membranes, pollutant adsorption and degradation, depolymerization of lignocellulosic waste, liquefaction of biomass, and production of fine chemicals. We also discuss the economy of oil production from biomass. Sulfonated graphene and sulfonated graphene oxide display an unusual large theoretical specific surface area of 2630 m2/g, allowing the reactants to easily enter the internal surface of graphene nanosheets and to reach active acid sites. Sulfonated graphene oxide is hydrophobic and has hydrophilic groups, such as hydroxyl, carboxyl, and epoxy, thus creating cavities on the graphene nanosheet’s surface. The adsorption capacity approached 2.3–2.4 mmol per gram for naphthalene and 1-naphthol. Concerning membranes, we observe an improvement of hydrophilicity, salt rejection, water flux, antifouling properties, and pollutant removal. The nanomaterials can be reused several times without losing catalytic activity due to the high stability originating from the stable carbon–sulfur bond between graphene and the sulfonic group.
This paper seeks to understand evacuation behaviour in a case of spontaneous evacuation. During the Second Lebanon War of 2006, more than one‐third of residents in north Israel spontaneously evacuated—the remainder stayed in situ. Using a telephone survey of 665 respondents residing in north Israel, we were able to characterise the behaviour of evacuees and non‐evacuees. The main reasons cited for evacuating were fear of injury to self or family, the effect on children, inability to remain in a protective space, and family pressure. The main reasons cited for remaining at home were no suitable alternative, did not perceive a high level of danger, had to go to work, and there is no place like home. There were no significant differences with regard to most socio‐demographic characteristics of the population. These findings should aid emergency managers in preparing the population for a future emergency and in engaging in effective dialogue with the population during an emergency on the evacuation option. 相似文献
Two important contributions to the understanding of voluntary turnover are the ideas that employees become embedded in a net or web of restraining forces on- and off-the-job and that they experience varying degrees of control and desire that yield proximal withdrawal states explaining turnover motivations. We build on these ideas in two multi-wave studies to study job insecurity, one of the most common work stressors and top concerns among employees around the world. Study 1 demonstrates that job search mediates the positive relationship between job insecurity and voluntary turnover, and that employees higher in on-the-job embeddedness are less likely to search for jobs despite job insecurity. Study 2 demonstrates that turnover intention mediates the positive relationship between job insecurity and voluntary turnover, and that employees higher in on-the-job embeddedness are less likely to contemplate quitting despite job insecurity. However, off-the-job embeddedness had opposite interactive effects, exacerbating the relationship of job insecurity with turnover. 相似文献