Effects of Long-Term Trampling on the Above-Ground Forest Vegetation and Soil Seed Bank at the Base of Limestone Cliffs

Exposed limestone cliffs in central Europe harbor a highly divers flora with many rare and endangered species. During the past few decades, there has been increasing recreational use of these cliffs, which has caused local environmental disturbances. Successful restoration strategies hinge on identifying critical limitations. We examined the composition of aboveground forest vegetation and density and species composition of seeds in the soil seed bank at the base of four limestone cliffs in mixed deciduous forests that are intensively disturbed by human trampling and at four undisturbed cliffs in the Jura Mountains in northwestern Switzerland. We found that long-term human trampling reduced total aboveground vegetation cover at the base of cliffs and caused a significant shift in the plant-species composition. Compared with undisturbed cliffs, total seed density was lower in disturbed cliffs. Human trampling also altered the species composition of seeds in the soil seed bank. Seeds of unintentionally introduced, stress-tolerant, and ruderal species dominated the soil seed bank at the base of disturbed cliffs. Our findings indicate that a restoration of degraded cliff bases from the existing soil seed bank would result in a substantial change of the original unique plant composition. Active seed transfer, or seed flux from adjacent undisturbed forest areas, is essential for restoration success.     

Luzernemehl-induzierte Aktivitätserhöhung (LIA) in ökotoxikologisch-mikrobiologischen Tests

In previous trials, lucerne-meal induced increase in microbial activities (=LIA) was used as a new ecotoxicological indicator of pesticide effects on soil microorganisms. In the following, this technique has been applied to measure and compare the effects of the two dinitrophenol herbicides ‘Flüssig Herbogil’ (active ingredient dinoterb) and ‘Aretit flüssig’ (active ingredient dinoseb acetate) used as reference compounds. A loamy sand soil known for its sensitive microflora was treated with the herbicides and incubated up to 90 days under laboratory conditions. In order to ensure the comparison of the specific effects, equal amounts of the active ingredients of the two formulated herbicides, based on the field rate of ‘Flüssig Herbogil’, were applied. In a parallel trial, the soil was additionally amended with lucerne meal to enable the determination of its specific stimulatory effect on microbial activity. The two biomass-related microbial activities dehydrogenase (=DHA) and glucose-induced short-term respiration (=KZA) were measured, as well as the nitrogen mineralization (=N_min). Depending on the dosage, the activities of LIA-DHA, LIA-KZA and LIA-N_min as increased by lucerne meal, were affected by the herbicides. Normally, the biomass-related activities were inhibited with exception of LIA-DHA at the single dosage. However, the nitrogen mineralization was enhanced. In most cases, the effects caused by ‘Flüssig Herbogil’ (dinoterb) were more pronounced than those of ‘Aretit flüssig’ (dinoseb agetate) when the same amount of the active ingredients had been applied. The LIA of the tested microbial activities proved to be a sensitive indicator for pesticide effects on soil microorganisms. It enabled the differentiation of the ecotoxic effects of chemically similar pesticides. Using this indicator will support results from separate trials run with or without lucerne meal, because marked losses of microbial biomass will become more pronounced. In addition, this improves the interpretation of ecotoxicological effects of pesticides in soil.     

Temporal analysis of airborne particulate matter reveals a dose-rate effect on mortality in El Paso: indications of differential toxicity for different particle mixtures

One of two topics explored is the limitations of the daily average in summarizing pollutant hourly profiles. The daily average of hourly measurements of air pollutant constituents provides continuity with previous studies using monitoring technology that only provided the daily average. However, other summary statistics are needed that make better use of all available information in 24-hr profiles. The daily average reflects the total daily dose, obscuring hourly resolution of the dose rate. Air pollutant exposures with comparable total daily doses may have very different effects when occurring at high levels over a few hours as opposed to low levels over a longer time. Alternative data-based choices for summary statistics are provided using principal component analysis to capture the exposure dose rate, while preserving ease of interpretation. This is demonstrated using the earliest hourly particle concentration data available for El Paso from archived records of particulate matter (PM)10. In this way, a significant association between evening PM10 exposures and nonaccidental daily mortality is found in El Paso from 1992 to 1995, otherwise missed using the daily average. Secondly, the nature and, hence, effects of particles in the ambient aerosol during El Paso sandstorms is believed different from that of particles present during still-air conditions resulting from atmospheric temperature inversions. To investigate this, wind speed (ws) is used as a surrogate variable to label PM10 exposures as Low-ws (primarily fine particles), High-ws (primarily coarse particles), or Mid-ws (a mixture of fine and coarse particles). A High-ws evening is significantly associated with a 10% lower risk of mortality on the succeeding third day, as compared with comparable exposures at Low- or Mid-ws. Although this analysis cannot be used to form firm conclusions because it uses a very small data set, it demonstrates the limitations of the daily average and suggests differential toxicity for different particle compositions.     

Mikrobiologisch-ökotoxikologische Bodenuntersuchungen von zwei im Pflanzenschutz eingesetzten Öl-Präparaten

Goal and Scope

Since many years mineral and plant oils have been applied with relatively high doses to control noxious insects in sevral agricultural and horticultural crops. In addition they have also been used with low doses as adjuvants (additives) together with herbicides to improve their efficacy. Their ecotoxicological effets on soil microorganisms as an important part of the soil fertility, however, have been insufficiently investigated.

Methods

Under laboratory conditions two agricultural soils were treated with a rapeseed oil and a paraffin oil as well as in some cases with biocidal reference compounds (e.g. dinitrophenol herbicides). The applied dosage were related to the concentrations in soil reached after simulated penetration of practical field amounts into upper soil layers. In some cases green manuring was simulated by adding lucerne meal to the soil. During incubation for several weeks biomass-related microbial activities (dehydrogenase activity, substrate-induced short-term respiration) as well as the mineralization of carbon and nitrogen (including nitrification) were measured. In addition some combinations of these activities were investigated.

Results and Conclusion

As compared to ‘normal’ pesticides both oil products differed in their effects on soil microorganisms. Those effects typical for strongly biocidal compounds including plant protection products, namely a dose-related inhibition of microbial biomass and stimulated mineralization (especially of nitrogen) failed with the tested oily compounds. Depending on the high input of organic carbon by these oils and their rapid decomposition a dose-dependent increase of biomass-related parameters and of the carbon mineralization occurred especially with the high doses, whereas the nitrogen mineralization was reduced or even the available nitrate content was nearly eliminated for some time by microbiological immobilization. In comparison with the reference products the two oil preparations caused only little microbiological-ecotoxicological impacts on the soil and even some stimulations of important microbial soil parameters when tested with the extended test system (including the dosages used).

Recommendation and Perspective

As a result of these investigations and of the existing literature we recommend an extension of the test spectrum for those formulated preparations and adjuvants which should be applied at high dosages or if they contain higher amounts of well decomposable organic substances. This is necessary to distinguish dose-related enhanced activities induced by biocidal effects and the subsequent mineralization of this death material (=indirect effects) from ‘real’ stimulations directly produced by the substrate.     

Indonesia’s forest conversion moratorium assessed with an agent-based model of Land-Use Change and Ecosystem Services (LUCES)

The Indonesian government recently confirmed its Intended Nationally Determined Contributions (INDCs) to mitigate global climate change. A forest moratorium policy that protects forest and peatland is a significant part of the INDCs; however, its effectiveness is unclear in the face of complex land-use and land-cover change. This study aims to assess the dynamics of land-use change and ecosystem service supply as a function of local decision-making. We developed an agent-based model, Land-Use Change and Ecosystem Services (LUCES), and used it to explore the possible effects of the forest moratorium policy on the land-use decisions of private companies and communities. Our simulations for two districts in Central Kalimantan show that the current implementation of the forest moratorium policy is not effective in reducing forest conversion and carbon emissions. This is because companies continue to invest in converting secondary forest on mineral soils and the moratorium does not affect community decision-making. A policy that combines a forest moratorium with livelihood support and increases farm-gate prices of forest and agroforestry products could increase the local communities’ benefits from conservation. Forest and agroforestry areas that are profitable and competitive are more likely to be conserved and reduce potential carbon emission by about 36 %. The results for the two districts, with different pressures on local resources, suggest that appropriate additional measures require local fine-tuning. The LUCES model could be an ex ante tool to facilitate such fine-tuning and help the Indonesian government achieve its INDC goals as part of a wider sustainable development policy.     

Sustainable metal management exemplified by copper in the USA

A sustainable management of non-renewable metals calls for scientific-ecological understanding of the regional material household. The copper household in the USA between 1900 and 2100 was chosen to illustrate mathematical modelling of such systems. Relatively limited and inaccurate sets of data already allow a first approximation of the metal management system. The copper fluxes of the 20th century have contributed to the formation of two new ore deposits of the same order of magnitude as the currently still available reservoir (90 million tons), i.e. copper stock in consumption products (approx. 70 million tons) and in landfills (approx. 40 million tons). The “landfill”, therefore, contains copper whose potential use is lost due to dilution. The long-term copper consumption stock is greater than the short-term stock. Scenarios show that the current economically mineable Cu-stocks will be exhausted in 30 to 50 years if a change in the existing management system does not occur. In case of a reorientation, the use of copper as a “new resource” in the consumption stocks appears to be the most promising strategy. The future waste management processes will have to increase their copper recycling rates. Received: 24 February 1999 · Accepted: 8 June 1999     

Establishing best practice for microbially aided phytoremediation

The dispersal of industrial and municipal wastes leads to an increase of contaminated soils and is one of the large concerns in many countries throughout Europe regarding environmental issues. This article proposes a sequence of the microbially aided phytoremediation (phytoextraction and phytostabilization) procedure with the following most important steps: (1) risk assessment, (2) site investigation, (3) determination of the remediation strategy, (4) realization of remediation measures, (5) monitoring, and (6) reuse of the remediated site. UMBRELLA's innovative approach is a proposal of methods to evolve a tool-box which supports phytoremediation by means of microbes and enhances the efficiency of the remediation process at low and heterogeneously metal contaminated sites.