The monoculture vs. rotation strategies in forestry: formalization and prediction by means of Markov-chain modelling

The monoculture strategy of forest management, where the same tree species (e.g., Picea abies) is cultivated in a number of successive planting-growing-felling cycles, is generally considered to be economically efficient, yet not sustainable as it reduces biodiversity in the forest. The sound alternative suggests a long-term strategy of forest management in which different forest types rotate either with planting after clear cutting, or by natural forest succession, yet the commercial output remains dubious. We suggest an approach to formalization and modelling forest dynamics in the long-term by means of Markov chains, the monoculture strategy resulting in an absorbing chain and the rotation one in a regular chain. The approach is illustrated with a case study of Russkii Les, a managed forest located in the Moscow Region, Russia, and the nearby forest reserve having been used as a data source for undisturbed forest dynamics. Starting with conceptual schemes of transitions among certain forest types (states of the chain) in the monoculture and rotation cases, we estimated the transition probabilities by an original method based on average duration of the corresponding states and on the likelihood of alternative transitions from a state into the next one. Formal analysis of the regular chain reveals an opportunity to achieve particular management objectives within the rotation strategy, in particular, to get the distribution of forest types in accordance with an adopted hierarchy of their commercial values, i.e. more valuable types have greater shares.     

Double trouble: health risks of accidental sewage release

Occupational health risks from long-term exposure to sewage are well documented [Am J. Ind. Med. 25 (1994) 59; Ann. Agric. Environ. Med. 81 (2001) 39; Am J. Ind. Med. 40 (2001) 170]. Some studies suggest an increase in the incidence of specific cancers [Am J. Ind. Med. 19 (1991) 75; J. Occup. Med. 36 (1994) 31]. There are also many reports of acute fatalities in confined spaces (sewage chambers and pipes) [H&S at Work 13 (1991), 10; FACE report: sewer worker dies when inflatable sewer plug bursts in Washington, DC, Performer, National Institute For Occupational Safety and Health, 19th July 1990]. In a residential area incidents of sudden sewage release can be regarded as double trouble because both the emergency service personnel and the local residents may be exposed to a galaxy of chemical and microbiological agents present in sewage. However, data on the effects of acute non-occupational exposure due to accidental sewage releases is still very limited. The incidents investigated here took place at two different locations in the southern part of the UK. In both incidents the symptoms experienced by those exposed were more serious than expected by the public health experts.     

Landscape--wildfire interactions in southern Europe: implications for landscape management

Every year approximately half a million hectares of land are burned by wildfires in southern Europe, causing large ecological and socio-economic impacts. Climate and land use changes in the last decades have increased fire risk and danger. In this paper we review the available scientific knowledge on the relationships between landscape and wildfires in the Mediterranean region, with a focus on its application for defining landscape management guidelines and policies that could be adopted in order to promote landscapes with lower fire hazard. The main findings are that (1) socio-economic drivers have favoured land cover changes contributing to increasing fire hazard in the last decades, (2) large wildfires are becoming more frequent, (3) increased fire frequency is promoting homogeneous landscapes covered by fire-prone shrublands; (4) landscape planning to reduce fuel loads may be successful only if fire weather conditions are not extreme. The challenges to address these problems and the policy and landscape management responses that should be adopted are discussed, along with major knowledge gaps.     

A multi‐level investigation of psychological contract breach and organizational identification through the lens of perceived organizational membership: Testing a moderated–mediated model

Drawing on the perceived organizational membership theoretical framework and the social identity view of dissonance theory, I examined in this study the dynamics of the relationship between psychological contract breach and organizational identification. I included group‐level transformational and transactional leadership as well as procedural justice in the hypothesized model as key antecedents for organizational membership processes. I further explored the mediating role of psychological contract breach in the relationship between leadership, procedural justice climate, and organizational identification and proposed separateness–connectedness self‐schema as an important moderator of the above mediated relationship. Hierarchical linear modeling results from a sample of 864 employees from 162 work units in 10 Greek organizations indicated that employees' perception of psychological contract breach negatively affected their organizational identification. I also found psychological contract breach to mediate the impact of transformational and transactional leadership on organizational identification. Results further provided support for moderated mediation and showed that the indirect effects of transformational and transactional leadership on identification through psychological contract breach were stronger for employees with a low connectedness self‐schema. Copyright © 2012 John Wiley & Sons, Ltd.     

Sex allocation and secondary sex ratio in Cuban boa (Chilabothrus angulifer): mother’s body size affects the ratio between sons and daughters

The Science of Nature - By working together, social insects achieve tasks that are beyond the reach of single individuals. A striking example of collective behaviour is self-assembly, a process in...     

High-Biomass Forests of the Pacific Northwest: Who Manages Them and How Much is Protected?

To examine ownership and protection status of forests with high-biomass stores (>200 Mg/ha) in the Pacific Northwest (PNW) region of the United States, we used the latest versions of publicly available datasets. Overlay, aggregation, and GIS-based computation of forest area in broad biomass classes in the PNW showed that the National Forests contained the largest area of high-biomass forests (48.4 % of regional total), but the area of high-biomass forest on private lands was important as well (22.8 %). Between 2000 and 2008, the loss of high-biomass forests to fire on the National Forests was 7.6 % (236,000 ha), while the loss of high-biomass forest to logging on private lands (364,000 ha) exceeded the losses to fire across all ownerships. Many remaining high-biomass forest stands are vulnerable to future harvest as only 20 % are strictly protected from logging, while 26 % are not protected at all. The level of protection for high-biomass forests varies by state, for example, 31 % of all high-biomass federal forests in Washington are in high-protection status compared to only 9 % in Oregon. Across the conterminous US, high-biomass forest covers <3 % of all forest land and the PNW region holds 56.8 % of this area or 5.87 million ha. Forests with high-biomass stores are important to document and monitor as they are scarce, often threatened by harvest and development, and their disturbance including timber harvest results in net C losses to the atmosphere that can take a new generation of trees many decades or centuries to offset.     

Humic-like substances extracted from composts can promote the photodegradation of Irgarol 1051 in solar light

Humic-like substances (HLS) were extracted from a mixture of sewage sludges and trimmings (70-30%, w/w) after different times of composting (0, 70 days and 130 days). HLS were analyzed by elemental analysis, UV-visible and fluorescence spectroscopy and also tested for their ability to photosensitize the degradation of Irgarol. The rate of Irgarol photodegradation in artificial solar light was found to be 2.5- to 4.3-fold higher in the presence of HLS than in buffered Milli-Q water. These results were confirmed by experiments in solar light that evidenced the photodegrading properties of HLS in a more striking way. Using 2-propanol as hydroxyl radical scavenger, we could show that hydroxyl radicals contributed to the photosensitized Irgarol degradation for about 25%. The photodegrading activity of HLS, their absorbance and their emissive properties were all found to increase between 0 and 70 days of composting and to remain quite constant between 70 and 130 days. The degree of humification varied in the same way, linking all these properties to the humification process.     

Pesticide exposure and lung cancer mortality in Leningrad province in Russia

This study was carried out to examine the association between pesticide exposure and lung cancer mortality. We conducted an autopsy based case-control study in Leningrad Province in Russia. A total of 540 lung cancer cases and 582 controls were identified among subjects who had died in the hospitals of the Leningrad province between 1993 and 1998. Using work history records, we assessed exposure to pesticide at the level of industry and job title. Unconditional logistic regression was used to calculate adjusted odds ratio for pesticide exposure and lung cancer mortality. There was no association between ever exposure to pesticide and lung cancer mortality overall (odds ratio=1.06, 95% confidence interval=0.82-1.36) and in both men (odds ratio=1.11, 95% confidence interval=0.84-1.46) and women (odds ratio=0.74, 95% confidence interval=0.37-1.46). We observed no statistically significant odds ratio by duration of pesticide exposure, intensity of pesticide exposure, and cumulative pesticide exposures with lung cancer mortality in both smokers and nonsmokers. Odds ratio also did not differ when the analysis was restricted to individuals who had exposure data with high confidence scores. Our findings suggest no associations between pesticide exposures and mortality of lung cancer in the population of the Leningrad province in Russia that deserves further evaluation.     

Physiological and biochemical characteristic of Miscanthus × giganteus grown in heavy metal – oil sludge co-contaminated soil

The effect of oil sludge and zinc, present in soil both separately and as a mixture on the physiological and biochemical parameters of Miscanthus × giganteus plant was examined in a pot experiment. The opposite effect of pollutants on the accumulation of plant biomass was established: in comparison with uncontaminated control the oil sludge increased, and Zn reduced the root and shoot biomass. Oil sludge had an inhibitory effect on the plant photosynthetic apparatus, which intensified in the presence of Zn. The specific antioxidant response of M. × giganteus to the presence of both pollutants was a marked increase in the activity of superoxide dismutase (mostly owing to oil sludge) and glutathione-S-transferase (mostly owing to zinc) in the shoots. The participation of glutathione-S-transferase in the detoxification of both the organic and the inorganic pollutants was assumed. Zn inhibited the activity of laccase-like oxidase, whereas oil sludge promoted laccase and ascorbate oxidase activities. This finding suggests that these enzymes play a part in the oxidative detoxification of the organic pollutаnt. With both pollutants used jointly, Zn accumulation in the roots increased 6-fold, leading to increase in the efficiency of soil clean-up from the metal. In turn, Zn did not significantly affect the soil clean-up from oil sludge. This study shows for the first time the effect of co-contamination of soil with oil sludge and Zn on the physiological and biochemical characteristics of the bioenergetic plant M. × giganteus. The data obtained are important for understanding the mechanisms of phytoremediation with this plant.     

Seasonal peculiarities of PCDD/Fs levels in bank voles inhabiting sites in the vicinity of the landfill with municipal wastes (Moscow,Russia)

Environmental Science and Pollution Research - Differences in PCDD/Fs concentrations were registered among adult bank voles (Myodes glareolus) inhabiting forest in the vicinity of the Landfill...