Using ecological memory as an indicator to monitor the ecological restoration of four forest plantations in subtropical China

A large area of plantations has been established worldwide and especially in China. Evaluating the restoration status of these plantations is essential for their long-term management. Based on our previous work, we used an ecological memory (EM) approach to evaluate four 26-year-old plantations that represent four common kinds of plantations in subtropical China, i.e., mixed broad-leaved plantation (MBP), mixed coniferous plantation (MCP), eucalyptus plantation (EP), and mixed legume plantation (MLP). Comparing them with the regional climax community, i.e., monsoon evergreen broad-leaved forest (BF), all four plantations accumulated nearly the same pattern of EM during succession. EM was >50 % for soil minerals, light conditions, soil age, soil animals, and soil microbes. EM was about 25 % for soil pollen and 10 % for birds, soil seed bank, and plant species. The total EM value of the four plantations ranged from 50.96 to 52.54, which indicated that all four plantations were in the regional, natural trajectory of succession and between the early and medium successional stages. The results indicated that natural succession processes are unlikely to be accelerated by planting late-stage tree species without sufficient EM. The results also demonstrated that all four plantations were in positive successional trajectories, and the positive succession dynamics were greater in the MLP and MCP. We suggest that the entire natural succession trajectory be used to evaluate the restoration of a site and that the ultimate restoration target be divided into several milestones along the reference trajectory to monitor progress. Forest restoration may be accelerated by starting with a minimum dynamic unit supporting sufficient EM.     

Spiders in mountain habitats of the Giant Mountains

Ground-living spiders were studied using modified pitfall traps during several years in four characteristic habitats in Giant Mountains (Krkono?e Mts.), the High Sudetes, Czech Republic: alpine tundra, subalpine mire, tall-herb stand at the bottom of a glacial corrie, and decaying mountain spruce forest. Ecological and zoogeographical aspects of spider communities were analysed. The spider communities of alpine tundra, subalpine mire, and glacial corrie exhibited long-term stability, whereas the community of decaying mountain forest changed during observations. Small linyphiid spiders, dominating in mature forest, were gradually replaced by larger Iycosid and gnaphosid species. Zoogeographic characterization of mountain habitats was made based on species exhibiting disjunctive area. In contrast to plants, for spiders of boreal origin alpine tundra is the most important habitat for survival, followed by screes, mires, spruce forests, and corries.     

A phenomenological approach shows a high coherence of warming patterns in dimictic aquatic systems across latitude

To predict the coherence in local responses to large-scale climatic forcing among aquatic systems, we developed a generalized approach to compare long-term data of dimictic water bodies based on phenomenologically defined hydrographic events. These climate-sensitive phases (inverse stratification, spring overturn, early thermal stratification, summer stagnation) were classified in a dual code (cold/warm) based on threshold temperatures. Accounting for a latitudinal gradient in seasonal timing of phases derived from gradients in cumulative irradiation (2.2?days per degree latitude), we found a high spatial and temporal coherence in warm–cold patterns for six lakes (84?%) and the Baltic Sea (78?%), even when using the same thresholds for all sites. Similarity to CW-codes for the North Sea still was up to 72?%. The approach allows prediction of phase-specific warming trends and resulting instantaneous or time-delayed ecological responses. Exemplarily, we show that warming during early thermal stratification controls food-web-mediated effects on key species during summer.     

Analysis of two schemes using micro hydroelectric power (MHPs) in the Amazon with environmental sustainability and energy and economic feasibility

A major problem for sustainable development in the Amazon is the difficulty of supplying electric power to isolated communities, which represent a considerable share of the population. This problem has been a major obstacle to productive activities (especially extractive and agricultural) in such communities, thus significantly contributing to rural drift and creating social problems in larger cities. In that case, one way to supply electric power would be to use the huge network of small rivers in the region by implementing Micro Hydroelectric Power Plants (MHPs). However, this type of hydropower project requires a set of technical assessments in order to obtain better value for its cost-effectiveness from the perspective of sustainable development. Thus, based on a survey of energy demand and the local hydrological and topographical characteristics, two possible MHP designs for the hydrological site under analysis were suggested. Assessments of hydropower, economic and environmental aspects were developed. MHP designs were compared with the diesel generator design of the community under focus. Comparison showed that the MHP designs are feasible in terms of energy to meet local demand; economically, they are more feasible than the diesel generator and are environmentally sustainable, mainly because such designs involve low-head, run-of-river MHPs and the flooded areas were simulated and are not larger than 0.02 km². Therefore, the information provided by these assessments constitutes important data, serving as subsidies for MHP implementation projects, which shall contribute to sustainable development in the region.     

Deriving environmental quality standards in European surface waters: when are there too few data?

Recent technical guidance has been published by the European Commission that outlines methodologies for the derivation of Environmental Quality Standards (EQS) in European surface waters under the Water Framework Directive (WFD). The guidance allows the derivation of a long-term EQS from a small dataset. Specifically an EQS can be derived from just three acute data points, although the safety factors built into such an EQS are large (e.g. up to a factor of 1,000). Large safety factors make such EQS uncertain, and often difficult to achieve in practice. We examine dataset requirements for the derivation of EQS and specifically the minimum number of tests needed for setting EQS for long-term chemical exposures that result in reduced relative uncertainty, as assessed simply through the reduction in standard deviation of the means of the values derived. Using ecotoxicity datasets for four example chemicals, for which EQS have been derived in many jurisdictions, we show that variation in the EQS is greatest when using the minimum dataset allowable under the WFD guidance, but decreases rapidly when seven or more datapoints are available. Increasing the minimum number of ecotoxicity data in deriving an EQS results in a greater understanding of ecotoxicological effects. With this knowledge, the mitigating effects of water chemistry can be accounted for in deriving an EQS, even with relatively limited datasets. The new guidance suggests “simplistic” approaches to account for chemical availability, but does not detail how this might be undertaken. We provide examples of ways by which water chemistry effects can be included in deriving implementable EQS for metals with relatively few reliable and relevant data.     

Reduction in toxicity and generation of slag in secondary lead process

This paper focuses on the improvement of a secondary lead recycling processing plant, giving special attention to the generation of lead slag. The study was conducted using two different industrial rotary furnaces that together produce three different slag types, which depend on charge composition and lead-containing raw material obtained from a lead-acid battery recycling process. First, characterization of three slag types from different batches was performed, and such characterization included chemical, mineralogical, and structural analyses. By analyzing these data and the operational conditions of the process, it was possible to identify certain deficiencies in the recycling process and implement modifications in order to improve it. A reduction of up to 25% in the quantity of slag generated could be achieved with certain charges. In addition to this process improvement, it was possible to reduce the toxicity of the slag produced when processing a charge containing the same proportion of paste and grid as the lead-acid battery. This improvement lessens the overall environmental impact of the process. By applying this methodology, it was possible to determine some principles of cleaner production in the lead recycling process. So, waste generation could be reduced via improvements in the process and slag characteristics were modified to decrease its toxicity (as determined by lead content in leaching tests).     

Book Reviews

ION‐SELECTIVE ELECTRODES IN ANALYTICAL CHEMISTRY, Vol. 2 by H. Freiser (ed.), Plenum Press, New York, 1980.

CARCINOGENESIS AND MUTAGENESIS by Myron A. Mehlman, Morris F. Cranmer and Raymond E. Shapiro, from the Journal of Environmental Pathology and Toxicology (Official Organ of the American College of Toxicology), 388 pages and 135 tables and figures, 1977, linen, format 261 × 178 mm, ISBN 0–930376–02–1, printed by Pathotox Publishers, Inc., Park Forest South, Illinois 60466, $23.00.     

Environmental and social determinants of anuran lekking behavior: intraspecific variation in populations at thermal extremes

Environmental and social factors are critical to determine the timing and duration of lekking behavior since they provide species with signs to maximize benefits over costs in sexual displays. However, these factors have rarely been studied under different environmental conditions, and thus, it remains unclear whether exogenous factors affecting group displays show a general species-specific pattern or whether they are population-specific. Using audio-trapping techniques, we compared factors influencing the daily occurrence and duration of lekking behavior in two populations of Hyla molleri and two populations of Hyla meridionalis located at the thermal extremes (coldest vs. hottest) of their Iberian distribution range. From 12,240 hourly recordings over one season, multimodel inference revealed that the major determinants of chorus occurrence were similar between populations and species (i.e., chorus size the previous day, daytime air temperature, relative humidity, and barometric pressure), and accounted for 51–79 % of its deviance. In contrast, the major determinants of chorus duration differed between populations and species (i.e., chorus size, number of day, and air temperature and relative humidity at the onset of the chorus), and accounted for 38–69 % of its variance. Our findings suggest that the decision making related to lek attendance is environment-dependent, takes place at time between lekking events, and is associated with exogenous factors that may be both stable across species ranges and population-specific when populations are under different climatic conditions. This intraspecific variation might be underlain by plasticity mechanisms providing tree frogs with means to cope with changing environments. Moreover, social facilitation related to male-male acoustic competition seems to play a relevant role on the daily time invested by males in lek attendance.