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21.
The maintenance of biodiversity by securing representative and well-connected habitat networks in managed landscapes requires a wise combination of protection, management, and restoration of habitats at several scales. We suggest that the integration of natural and social sciences in the form of "Two-dimensional gap analysis" is an efficient tool for the implementation of biodiversity policies. The tool links biologically relevant "horizontal" ecological issues with "vertical" issues related to institutions and other societal issues. Using forest biodiversity as an example, we illustrate how one can combine ecological and institutional aspects of biodiversity conservation, thus facilitating environmentally sustainable regional development. In particular, we use regional gap analysis for identification of focal forest types, habitat modelling for ascertaining the functional connectivity of "green infrastructures", as tools for the horizontal gap analysis. For the vertical dimension we suggest how the social sciences can be used for assessing the success in the implementation of biodiversity policies in real landscapes by identifying institutional obstacles while implementing policies. We argue that this interdisciplinary approach could be applied in a whole range of other environments including other terrestrial biota and aquatic ecosystems where functional habitat connectivity, nonlinear response to habitat loss and a multitude of economic and social interests co-occur in the same landscape.  相似文献   
22.
Disappearance rate constants are reported for the reductive transformation of 17 halogenated aliphatic hydrocarbons in anaerobic sediment-water samples. Statistical experimental design in combination with multivariate chemical characterization of their chemical properties was used to select the compounds. Degradation followed pseudo first-order kinetics through at least two half-lives for 15 of the 17 compounds. Of all the compounds investigated, 1,2,3-trichloropropane and dichloromethane were unique in that they were dehalogenated according to zero-order kinetics. Reductive dehalogenation was the sole transformation reaction taking place.  相似文献   
23.
Sperm number is often a good predictor of success in sperm competition; however, it has become increasingly clear that, for some species, variation in probability of paternity cannot be explained by sperm number alone. Intraspecific variation in ejaculate characteristics, such as the number of viable sperm and sperm longevity, may play an equally important role in determining fertilization success. Here, we assess variation among ejaculates in three factors that may contribute to fertilization success (number of sperm per ejaculate, viability, and longevity), in a population of Peron’s tree frog (Litoria peronii). We detected large variation among males in the number of sperm per ejaculate and the proportion of viable sperm within ejaculates, which could not be explained by variation in either male size or body condition. However, the proportion of viable sperm released by males increased over the season. Finally, we assessed sperm longevity (proportion viable sperm determined using a dual-fluorochrome vital dye) at two different temperatures. At 23°C, on average, 75% of sperm remained viable after 2 h, but there were significant differences amongst males with the percentage of viable sperm ranging from 43% to 95%. For sperm incubated at 4°C, ejaculates varied fivefold in sperm longevity with some males having 50% viable sperm after 5 days. Our data suggest that ejaculate characteristics (sperm number, viability, and longevity) vary widely in Peron’s tree frog and may therefore play an important role in determining siring success both in the presence and absence of sperm competition. We discuss the results in relation to selection on ejaculate traits via natural and sexual selection in this and other amphibians.  相似文献   
24.
Elevated concentrations of endotoxin in indoor air due to cigarette smoking   总被引:1,自引:0,他引:1  
Exposure to environmental tobacco smoke (ETS) is an important worldwide public health issue. The present study demonstrates that cigarette smoke can be a major source of endotoxin (lipopolysaccharide, LPS) in indoor environments. Gas-chromatography/mass-spectrometry was used to determine 3-hydroxy fatty acids as markers of endotoxin in air-borne house dust in homes of smokers and non-smokers. Air concentrations of endotoxin were 4-63 times higher in rooms of smoking students than in identical rooms of non-smoking students. The fact that cigarette smoke contains large amounts of endotoxin may partly explain the high prevalence of respiratory disorders among smokers and may also draw attention to a hitherto neglected risk factor of ETS.  相似文献   
25.
This study was conducted in the Swedish sub-Arctic, near Abisko, in order to assess the direction and scale of possible vegetation changes in the alpine–birch forest ecotone. We have re-surveyed shrub, tree and vegetation data at 549 plots grouped into 61 clusters. The plots were originally surveyed in 1997 and re-surveyed in 2010. Our study is unique for the area as we have quantitatively estimated a 19% increase in tree biomass mainly within the existing birch forest. We also found significant increases in the cover of two vegetation types—“birch forest-heath with mosses” and “meadow with low herbs”, while the cover of snowbed vegetation decreased significantly. The vegetation changes might be caused by climate, herbivory and past human impact but irrespective of the causes, the observed transition of the vegetation will have substantial effects on the mountain ecosystems.  相似文献   
26.
With rising concentrations of both atmospheric carbon dioxide (CO2) and tropospheric ozone (O3), it is important to better understand the interacting effects of these two trace gases on plant physiology affecting land-atmosphere gas exchange. We investigated the effect of growth under elevated CO2 and O3, singly and in combination, on the primary short-term stomatal response to CO2 concentration in paper birch at the Aspen FACE experiment. Leaves from trees grown in elevated CO2 and/or O3 exhibited weaker short-term responses of stomatal conductance to both an increase and a decrease in CO2 concentration from current ambient level. The impairement of the stomatal CO2 response by O3 most likely developed progressively over the growing season as assessed by sap flux measurements. Our results suggest that expectations of plant water-savings and reduced stomatal air pollution uptake under rising atmospheric CO2 may not hold for northern hardwood forests under concurrently rising tropospheric O3.  相似文献   
27.
Phenylurea herbicides are used worldwide, and often pollute surface- and groundwater in concentrations exceeding the limit value for drinking water (0.1 μg l−1). Bacteria degrade phenylurea herbicides by successive N-dealkylation to substituted aniline products. Little is known about the corresponding fungal pathways, however. We here report degradation of chlorotoluron, diuron, isoproturon and linuron by the soil fungus Mortierella sp. Gr4. Degradation was fastest with linuron and resulted in successively dealkylated metabolites and 3,4-dichloroaniline. A major new metabolite was detected that has not yet been fully identified. Thin layer chromatography and nuclear magnetic resonance spectroscopy indicate that it is a non-aromatic diol. Degradation of isoproturon, chlorotoluron and diuron involved successive N-demethylation and, in the case of isoproturon and chlorotoluron, additional hydroxylation. A new hydroxylated isoproturon metabolite was detected. The study thus shows that the fungal pathways differ from the bacterial pathways and yield new metabolites of possible environmental concern.  相似文献   
28.
This article analyzes and carries out an econometric test of the explanatory power of economic and attitude variables for occurrences of the nonnative signal crayfish in Swedish waters. Signal crayfish are a carrier of plague which threatens the native noble crayfish with extinction. Crayfish are associated with recreational and cultural traditions in Sweden, which may run against environmental preferences for preserving native species. Econometric analysis is carried out using panel data at the municipality level with economic factors and attitudes as explanatory variables, which are derived from a simple dynamic harvesting model. A log-normal model is used for the regression analysis, and the results indicate significant impacts on occurrences of waters with signal crayfish of changes in both economic and attitude variables. Variables reflecting environmental and recreational preferences have unexpected signs, where the former variable has a positive and the latter a negative impact on occurrences of waters with signal crayfish. These effects are, however, counteracted by their respective interaction effect with income.  相似文献   
29.
Green radicalism among local environmental officials in Sweden is examined with the aims of theoretically elaborating on different dimensions of Green radicalism in the context of public administration, exploring the dimensionality of Green radicalism among officials, and examining the extent to which Green radicalism is associated with policy influence. Three types of Green radicalism are identified: Green ethics, Green institutional change, and Green activism. Survey data (N = 701) show that the three theoretical dimensions are present among officials, and that there is no negative association between radicalism and influence. It is primarily officials with Green activism beliefs who perceive themselves as able to influence policy. These findings suggest a need for more nuanced understanding of and further studies into the role of public administration in the quest for more radical Green reforms.  相似文献   
30.
A promising approach for addressing sustainability problems is to recognize the unique conditions of a particular place, such as problem features and solution capabilities, and adopt and adapt solutions developed at other places around the world. Therefore, research and teaching in international networks becomes critical, as it allows for accelerating learning by sharing problem understandings, successful solutions, and important contextual considerations. This article identifies eight distinct types of research and teaching collaborations in international networks that can support such accelerated learning. The four research types are, with increasing intensity of collaboration: (1) solution adoption; (2) solution consultation; (3) joint research on different problems; and (4) joint research on similar problems. The four teaching types are, with increasing intensity of collaboration: (1) adopted course; (2) course with visiting faculty; (3) joint course with traveling faculty; and (4) joint course with traveling students. The typology is illustrated by extending existing research and teaching projects on urban sustainability in the International Network of Programs in Sustainability, with partner universities from Europe, North America, Asia, and Africa. The article concludes with challenges and strategies for extending individual projects into collaborations in international networks.  相似文献   
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