Territorial defense in a group-living solitary forager: who,where, against whom?

Territoriality is of great significance for many species and a characteristic of most group-living animals. Territoriality is thought to lead to increased reproductive success by defending a particular area containing critical resources. I describe several factors that influence territorial aggression in free-ranging striped mice (Rhabdomys pumilio), a group-living solitary forager. I induced territorial aggression by attracting mice of different groups using bait either at territory boundaries or in front of nests. Striped mice are territorial and make decisions about whether or not to attack a mouse from another group based upon several factors: (1) the sex of the opponent: males are much more likely to attack strange males than strange females, whereas no sex specific aggression was observed in females; (2) the body size of the opponent: striped mice are much more likely to attack a strange mouse that is lighter than themselves; and (3) the location of encounters: striped mice are much more likely to attack strangers, even those significantly heavier than themselves, in front of the nest than at territory boundaries. These variations in territorial responses between different types of individuals may be due to the different ultimate consequences of territorial aggression for different animals.Communicated by S. Alberts     

Non-timber forest product dependency in the Central Himalayan foot hills

Rural households throughout the Himalayas are regarded as dependent on non-timber forest products (NTFPs), but very few studies have quantified this dependency. This case study, undertaken in two villages in the Central Himalayan foot hills in Nepal, documents the absolute and relative importance of commercial NTFPs to rural household economies. Data were collected in a one-year period and included interviews with 250 households using a semi-structured questionnaire and monthly interviews with four sub-local NTFP traders, two local traders and two central wholesalers. The conservative estimate of NTFP-derived cash income showed this to be a cornerstone in poorer household livelihood strategies and thus in poverty prevention. An annual average of 578 kg of commercial NTFPs was collected in the wild per household, providing poorer households with a cash income share of 44–78%. Better off households are not NTFP dependent but rely on income from crop production and livestock. Based on a net marketing margin analysis, showing that harvesters capture a large share of the Indian wholesaler price, it is argued that there is scope for pursuing NTFP-based strategies for poverty reduction through leasehold forestry and agroforestry. Both these options are compatible with conserving forest cover and forest corridor functions and may thus present a win–win scenario for livelihood improvement and conservation.     

Pulsed gas injection: A minimum effort approach for enhanced natural attenuation of chlorobenzene in contaminated groundwater

Chlorobenzene-contaminated groundwater was used to assess pulsed gas sparging as a minimum effort aeration strategy to enhance intrinsic natural attenuation. In contrast to existing biosparging operations, oxygen was supplied at minimum rate by reducing the gas injection frequency to 0.33 day^?1. Field tests in a model aquifer were conducted in a 12 m long reactor, filled with indigenous aquifer material and continuously recharged with polluted groundwater over 3 years. The closed arrangement allowed yield balances, cost accounting as well as the investigation of spatial distributions of parameters which are sensitive to the biodegradation process. Depending on the injection frequency and on the gas chosen for injection (pure oxygen or air) oxygen-deficient conditions prevailed in the aquifer. Despite the limiting availability of dissolved oxygen in the groundwater, chlorobenzene degradation under oxygen-deficient conditions proved to be more effective than under conditions with dissolved oxygen being available in high concentrations.     

Multi-generation studies with Chironomus riparius--effects of low tributyltin concentrations on life history parameters and genetic diversity

While toxicological data are available for numerous chemicals from standard tests, little is known on effects of pollutants over several generations or regarding chronic effects of chemicals on genetic diversity. Within the experiments, effects of the model pollutant tributyltin (TBT) were investigated over eleven generations at a sublethal TBT concentration of 4.46 μg as Sn kg⁻¹ sediment dw on life-cycle parameters and genetic variability of Chironomus riparius. Moreover, the adaptation potential towards TBT was determined. This experimental design enables the identification of TBT effects on life-cycle parameters and the determination of a potential extinction risk caused by chronic exposure. Furthermore, effects on the genetic structure can be determined, which are not predictable based solely on knowledge of the toxic mode of action of the chemical.

Genetic variety was determined via microsatellite analysis, measuring individual length differences of highly variable satellite DNA fragments. For the identification of changes in tolerances towards the stressor, acute and chronic toxicity experiments were conducted.

During the multi-generation study, significant effects on development and reproduction were determined. For some generations, the emergence was significantly (p < 0.05) delayed under TBT exposure. Reproduction seems to be a sensitive parameter as well, whereby females laid significantly larger egg masses (p < 0.05) in the latter generations. TBT did not affect the population growth rate nor the genetic variability, while clear deviations from the Hardy–Weinberg equilibrium appeared. The study also provides strong evidence for the acquirement of a higher tolerance towards the stressor in the TBT-exposed group.     

Degradation of biochanin A in soil

Degradation of biochanin A, 400 μg (1.41 μmol) per gram of dry soil, was studied and the initial degradation products, dihydrobiochanin A, pratensein and genistein were identified and quantified. The maximum concentrations of these compounds were determined as 166 pmol/g dry soil after 2 days of incubation, 175 pmol/g dry soil after 1 day and 1,236 pmol/g dry soil after 1 day, respectively. Biochanin A and the initially formed products degrade too fast to be responsible for clover soil sickness (DT₉₀ <20 days), but could be precursors for the responsible compounds. The immediate degradation products from biochanin A are all biologically active and are the prime candidates for a reduction of weed pressure caused by clover.     

Niche complementarity for nitrogen: an explanation for the biodiversity and ecosystem functioning relationship?

The relationship between plant diversity and productivity has largely been attributed to niche complementarity, assuming that plant species are complementary in their resource use. In this context, we conducted an 15N field study in three different grasslands, testing complementarity nitrogen (N) uptake patterns in terms of space, time, and chemical form as well as N strategies such as soil N use, symbiotic N fixation, or internal N recycling for different plant species. The relative contribution of different spatial, temporal, and chemical soil N pools to total soil N uptake of plants varied significantly among the investigated plant species, within and across functional groups. This suggests that plants occupy distinct niches with respect to their relative N uptake. However, when the absolute N uptake from the different soil N pools was analyzed, no spatial, temporal, or chemical variability was detected, but plants, and in particular functional groups, differed significantly with respect to their total soil N uptake irrespective of treatment. Consequently, our data suggest that absolute N exploitation on the ecosystem level is determined by species or functional group identity and thus by community composition rather than by complementary biodiversity effects. Across functional groups, total N uptake from the soil was negatively correlated with leaf N concentrations, suggesting that these functional groups follow different N use strategies to meet their N demands. While our findings give no evidence for a biodiversity effect on the quantitative exploitation of different soil N pools, there is evidence for different and complementary N strategies and thus a potentially beneficial effect of functional group diversity on ecosystem functioning.     

Veränderungen des NO/NO2-Verhältnisses in Nordrhein-Westfalen (1984–2004) und mögliche Ursachen

Objective and Background

The nitrogen oxides NO and NO₂ and, in particular, their ratio (NO/NO₂), play important roles in the radical-system of the atmospheric boundary layer. There were various indications upon a dropping NO/NO₂-ratio in citiex over the last years, however, no proof has been given yet Especially in densely populated areas such as the federal state of North Rhine-Westphalia (NRW), such a change can have significant influences upon various atmospheric reactions. The objective of this investigation was to prove the existence of a systematic change of the NO/NO₂-ratio, to describe the development of NO_x over the past 2 decades at different locations and to determine the causes for this development.

Methods

To detect changes of the NO/NO₂-ratio we processed the data of 11 continuously operating air quality stations of the State Environment Agency (LUA NRW) with time series reaching back up to 20 years. We investigated rural stations, stations in the urban background and heavily traffic influenced locations. It was possible to calculate and assess the NO/NO₂-ratio under consideration of the fast reaction of ozone with NO. There were clear indications towards existing trends and they could be determined as statistically significant using the nonparametric Mann-Kendall Test. The analysis of possible causes for the change of the NO/NO₂-ratio focused upon the change of the global radiation, the change of the patterns of the atmosphetic circulation, and the frequency of cyclones and anticyclones meteorological conditions in Central Europe, the introduction of automotive catalytic converters, and the development of the atmospheric oxidation-capacity.

Results and conclusions

The results are indicating a decline of the ratio at traffic-influenced stations with a statistical significance over 95%. The negative trend can also be detected at most urban background stations. It was problematic to perform the trend-analysis of the rural background station in the Egge-Mountains because of the fragmentary character of the dataset. Regional differences in the development of the NO/NO₂-ratio indicate towards various causes. Crucial for the situation at the rural areas are the changed trajectories of cyclones and anticyclones as well as the decline of the atmospheric oxidation-capacity, while the traffic plays another important role at urban stations. The negative trend at the traffic-stations was intensified by the introduction of catalytic converters, which lead to a reduction in emissions of NO_x

Recommendations and prospects

The significance of the NO/NO₂-ratio for the oxidation capacity of the atmosphere shows the necessity to further monitor this development. Previous investigations detected a decline in total NO_x without examining the relative development of the two nitrogen oxides towards each other. Gaining insight into the local differences of this ratio helps to allocate sources and to develop understanding of the atmospheric processes.     

Multi tracer test for the implementation of enhanced in-situ bioremediation at a BTEX-contaminated megasite

At the Centre for Environmental Research Leipzig-Halle (UFZ) research site in Zeitz, Germany, benzene contaminates the lower of two aquifers with concentrations of up to 20 mg/l. Since the benzene plume has a minimum length of approximately 1 km, enhanced natural attenuation measures are being considered as a remediation strategy. This study describes the performance and evaluation of a multi-species reactive tracer test using the tracers fluorescein and bromide as conservative tracers and toluene as reactive tracer. Sampling was performed over a period of six months using a detailed network of multilevel sampling wells. Toluene was only slightly retarded in comparison to bromide, whereas fluorescein was retarded considerably stronger. Therefore, it was not possible to use fluorescein as an in situ tracer for the determination of groundwater velocities. The ionic nature of fluorescein is assumed to be the major reason for its retardation. The results show that the infiltration conditions were suitable to produce a wide spreading of the tracer front along the full thickness of the aquifer. Thus, a large aquifer volume can be treated in future enhanced bioremediation measures. The total quantity of infiltrated toluene (24 l) was degraded under sulfate-reducing conditions over a flow path of 50 m. Benzylsuccinate was identified as a metabolite of toluene degradation under sulfate-reducing conditions at this site. The modelling results show that toluene degradation was described more accurately using Monod kinetics than first-order kinetics. Since toluene was only slightly retarded in comparison to bromide, sorption and desorption processes were considered to be negligible.     

Mitigation of CO2 Emissions from the EU-15 Building Stock. Beyond the EU Directive on the Energy Performance of Buildings (9 pp)

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Goal Scope and Background. The European Directive on Energy Performance of Buildings which came into force 16 December 2002 will be implemented in the legislation of Member States by 4 January 2006. In addition to the aim of improving the overall energy efficiency of new buildings, large existing buildings will become a target for improvement, as soon as they undergo significant renovation. The building sector is responsible for about 40% of Europe's total end energy consumption and hence this Directive is an important step for the European Union in order that it should reach the level of saving required by the Kyoto Agreement. In this the EU is committed to reduce CO2 emissions relative to the base year of 1990 by 8 per cent, by 2010. But what will be the impact of the new Directive, how large could be the impacts of extending the obligation for energy efficiency retrofitting towards smaller buildings? Can improvement of the insulation offset or reduce the growing energy consumption from the increasing installation of cooling installations? EURIMA, the European Insulation Manufacturers Association and EuroACE, the European Alliance of Companies for Energy Efficiency in Buildings, asked Ecofys to address these questions.

Methods

The effect of the EPB Directive on the emissions associated with the heating energy consumption of the total EU 15 building stock has been examined in a model calculation, using the Built Environment Analysis Model (BEAM), which was developed by Ecofys to investigate energy saving measures in the building stock. The great complexity of the EU-15 building stock had to be simplified by examining five standard buildings with eight insulation standards, which are assigned to building age and renovation status. Furthermore, three climatic regions (cold, moderate, warm) were distinguished for the calculation of the heating energy demand. This gave a basic 210 building types for which the heating energy demand and CO2 emissions from heating were calculated according to the principles of the European Norm EN 832.

Results and Discussion

The model calculations demonstrates that the main contributor to the total heating related CO2 emissions of 725 Mt/a from the EU building stock in 2002 is the residential sector (77%) while the remaining 23% originates from non-residential buildings. In the residential sector, single-family houses represent the largest group responsible for 60% of the total CO2 emissions equivalent to 435 Mt/a.

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- The technical potential: If all retrofit measures in the scope of the Directive were realised immediately for the complete residential and non-residential building stock the overall CO2 emission savings would add up to 82 Mt/a. An additional saving potential compared to the Directive of 69 Mt/a would be created if the scope of the Directive was extended to cover retrofit measures in multi-family dwellings (200-1000m2) and non-residential buildings smaller than 1000m2 used floor space. In addition including the large group of single-family dwellings would lead to a potential for additional CO2 emission reductions compared to the Directive of 316 Mt/a.

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- Temporal mobilization of the potential: Calculations based on the building stock as it develops over time with average retrofit rates demonstrated that regulations introduced following the EPB Directive result in a CO2 emissions decrease of 34 Mt/a by the year 2010 compared to the business as usual scenario. Extending the scope of the EPB Directive to all residential buildings (including single and multi-family dwellings), the CO2 emission savings potential over the 'business as usual' scenario could be doubled to 69 Mt/a in the year 2010. This creates an additional saving potential compared to the Directive of 36 Mt/a.

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- Cooling demand: The analysis demonstrated that in warm climatic zones the cooling demand can be reduced drastically by a combination of lowering the internal heat loads and by improved insulation. With the reduction of the heat loads to a moderate level the cooling demand, e.g. of a terraced house located in Madrid, can be reduced by an additional 85% if the insulation level is improved appropriately.

Conclusions

This study demonstrates that the European Directive on Energy Performance of Buildings will have a significant impact on the CO2 emissions of the European building stock. The main saving potential lies in insulation of the existing building stock. Beyond this, CO2 emissions could, however, be greatly reduced if the scope of the Directive were to be extended to include retrofit of smaller buildings.

Recommendation and Perspective

The reductions should be seen in relation to the remaining gap of 190 Mt CO2 eq. per annum between the current emission levels of EU-15 and the target under the Kyoto-Protocol for the year 2010. The energy and industrial sector will probably contribute only a fraction of this reduction via the newly established EU emissions trading scheme and connected projects under the flexible mechanism. In addition, the traffic sector is likely to continue its growth path leading to a widening of the gap. Thus, there is likely to be considerable pressure on the EU building sector to contribute to the EU climate targets beyond what will be achieved by means of the current EPB Directive. Legislators on the EU and national level are therefore advised to take accelerated actions to tap the very significant emission reduction potentials available in the EU building stock.     

Occurrence of aminopolycarboxylates in the aquatic environment of Germany

Aminopolycarboxylic acids, such as ethylenediaminetetraacetic acid (EDTA), nitrilotriacetic acid (NTA), diethylenetriaminepentaacetic acid (DTPA), 1,3-propylenediaminetetraacetic acid (1,3-PDTA), beta-alaninediacetic acid (beta-ADA), and methylglycinediacetic acid (MGDA), are used in large quantities in a broad range of industrial applications and domestic products in order to solubilize or inactivate various metal ions by complex formation. Due to the wide field of their application, their high polarity and partly low degradability, these substances reach the aquatic environment at considerable concentrations (in the microg/L-range) and have also been detected in drinking water. This review evaluates and summarizes the results of long-term research projects, monitoring programs, and published papers concerning the pollution of the aquatic environment by aminopolycarboxylates in Germany. Concentrations and loads of aminopolycarboxylates are presented for various types of water including industrial and domestic waste waters, surface waters (rivers and lakes), raw waters, and drinking waters.