Governing climate change in Dutch cities: anchoring local climate strategies in organisation,policy and practical implementation

Although Dutch cities were among the forerunners in local climate policy, a systematic overview on climate mitigation and adaptation policy is still missing. This study aims to fill this gap by analysing 25 Dutch cities using indicators for the level of anchoring in policy, organisation and practical implementation as well as multi-level relations. Since Tilburg, Amsterdam, Den Haag and Rotterdam show a higher performance than other Dutch cities, these four cities are used as reference cities. The findings suggest that structural integration of climate mitigation and adaptation is limited in Dutch cities. The study points at three recent trends in local climate governance in the Netherlands: (i) decentralisation within municipal organisations, (ii) externalisation initiatives that place climate policy outside the municipal organisation and (iii) regionalisation with neighbouring municipalities and the provincial government.     

The functional biology and trophic role of krill (Thysanoessa raschii) in a Greenlandic fjord

Despite being a key zooplankton group, knowledge on krill biology from the Arctic is inadequate. The present study examine the functional biology and evaluate the trophic role of krill in the Godth?bsfjord (64°N, 51°W) SW Greenland, through a combination of fieldwork and laboratory experiments. Krill biomass was highest in the middle fjord and inner fjord, whereas no krill was found offshore. The dominating species Thysanoessa raschii revealed a type III functional response when fed with the diatom Thalassiosira weissflogii. At food saturation, T. raschii exhibited a daily ration of 1% body C d^?1. Furthermore, T. raschii was capable of exploiting plankton cells from 5 to 400???m, covering several trophic levels of the pelagic food web. The calculated grazing impact by T. raschii on the fjord plankton community was negligible. However, the schooling and migratory behaviour of krill will concentrate and elevate the grazing in specific areas of the euphotic zone.     

Determination of total and partially extractable solid-bound element concentrations using collision/reaction cell inductively coupled plasma-mass spectrometry and their significance in environmental studies

Determination of solid-bound element concentrations is an important initial step in environmental studies especially for assessment of contamination level, and of origin, relative mobility, and fate of contaminants. This study revealed that a relatively new collision/reaction cell inductively coupled plasma-mass spectrometry is a potent tool for determining total and partially extractable solid-bound element (V, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, and Pb) concentrations in a complex matrix solution containing HF and/or HCl. Six different extraction methods commonly used for environmental monitoring studies were tested for their bias and variability using estuarine and marine standard reference materials. Microwave-assisted methods based on concentrated [HNO₃] or [HNO₃?+?HF (4:1)] and [HNO₃?+?HF?+?HCl (10:3:2)] were applied for determining pseudo-total and total element concentrations, respectively. Dilute-acids (1 M HNO₃, 1 M HCl, and 0.5 M HCl) were utilized in single-step partial extraction protocols. Except the 0.5 M HCl cold-extraction method which was performed at room temperature, other partial extraction protocols used microwave-digestion. This study demonstrated that the use of microwave-assisted methods in studies aimed at determining the non-residual, non-specific extractable fractions of elements in solid environmental samples may result in overestimation, and thus needs to be re-examined. We believe that the cold extraction method will play a significant role in future environmental monitoring studies. Nevertheless, results of the cold extraction method not accompanied with total element concentrations have limited value, as the amount of extraction may vary significantly with the nature (origin) of the elements, and with the types of the samples. Therefore, we suggest combining microwave-assisted total digestion and 0.5 M HCl cold-extraction methods as a relatively cost- and time-effective, environmentally sound screening procedure for routine environmental monitoring programs involving a large number of samples from diverse geological and anthropogenic settings.     

The toxicity of copper contaminated soil using a gnotobiotic Soil Multi-species Test System (SMS)

A gnotobiotic multi-species study was designed to consist of a food-web of soil-dwelling animals. The food-web was exposed to five concentrations copper (Cu) spiked soil for three exposure durations i.e. 28, 56 and 84 days. Based on multivariate analysis the food-web was significantly affected by Cu exposure at and above 300 mg Cu kg(-1) soil (lowest tested concentration). The number of animals present in the 2500 mg Cu kg(-1) (highest tested concentration) was at all sampling occasions below the starting point level. Based on analysis of the individual species the lowest 10% effect concentration (EC10) observed was 50 mg Cu kg(-1) soil, for Enchytraeus crypticus. Using the EC10 for the individual species the HC5 (Hazard Concentration at the 5% level) was estimated to be between 25 and 36 mg Cu kg(-1) soil, depending on the exposure duration. A similar experiment but using a reduced design was performed employing soil contaminated with Cu in the field more than 80 years ago. The trend in the field-contaminated soil was similar to that observed for the spiked soil.     

Use of carrion fly iDNA metabarcoding to monitor invasive and native mammals

Severely fragmented habitats increase the risk of extirpation of native mammal populations through isolation, increased edge effects, and predation. Therefore, monitoring the movement of mammal populations through anthropogenically altered landscapes can inform conservation. We used metabarcoding of invertebrate-derived DNA (iDNA) from carrion flies (Calliphoridae and Sarcophagidae) to track mammal populations in the wheat belt of southwestern Australia, where widespread clearing for agriculture has removed most of the native perennial vegetation and replaced it with an agricultural system. We investigated whether the localization of the iDNA signal reflected the predicted distribution of 4 native species—echidna (Tachyglossus aculeatus), numbat (Myrmecobius fasciatus), woylie (Bettongia penicillata), and chuditch (Dasyurus geoffroii)—and 2 non-native, invasive mammal species—fox (Vulpes vulpes) and feral cat (Felis catus). We collected bulk iDNA samples (n = 150 samples from 3428 carrion flies) at 3 time points from 3 conservation reserves and 35 road edges between them. We detected 14 of the 40 mammal species known from the region, including our target species. Most detections of target taxa were in conservation reserves. There were a few detections from road edges. We detected foxes and feral cats throughout the study area, including all conservation reserves. There was a significant difference between the diversity (F_3, 98 = 5.91, p < 0.001) and composition (F_3, 43 = 1.72, p < 0.01) of taxa detections on road edges and conservation reserves. Conservation reserves hosted more native biodiversity than road edges. Our results suggest that the signals from iDNA reflect the known distribution of target mammals in this region. The development of iDNA methods shows promise for future noninvasive monitoring of mammals. With further development, iDNA metabarcoding could inform decision-making related to conservation of endangered taxa, invasive species management, and impacts of habitat fragmentation.     

Costs of overlapping reproduction and moult in passerine birds: an experiment with the pied flycatcher

The process of moult in birds requires the investment of substantial amounts of energy and nutrients in feather production and attendant processes. Flight performance may be reduced during the moult of the wing feathers, and moulting birds may suffer from an increased predation risk. These factors may explain why the moult is usually separated in time from other energetically demanding processes, such as reproduction. In this study, we investigated the importance of the temporal separation of moult from breeding activities in the pied flycatcher Ficedula hypoleuca. We induced a moult-breeding overlap by removing the two innermost primaries on both wings, thus imitating the natural loss of these feathers during the initial stage of the moult. The experiment probably did not stimulate feather regrowth, but may have reduced flight performance. Just before fledging of the young, manipulated males and females, as well as the fledglings, had a lower body condition than control birds. The return rate of adult males in the year following the manipulation was significantly lower for males in the manipulated group than for control males. The return rate of females was lower than that of males, but there was no difference between the two female groups. The number of nestlings recruited in the year after the manipulation was significantly lower for the group with an induced moult-breeding overlap than for the control group. The reproductive performance in recruited and returning old females was independent of the manipulation, and in returning adults and recruits the feather quality in terms of number of barbs/mm was independent of the manipulation. These results suggest that a moult-breeding overlap induces fitness costs in terms of reduced recruitment rate and adult survival in a long-distance migrant. Received: 17 September 1997 / Accepted after revision: 23 February 1998     

An enhanced compost temperature sampling framework: Case study of a covered aerated static pile

Spatial and temporal temperature variations exist in a compost pile. This study demonstrates that systematic temperature sampling of a compost pile, as is widely done, tends to underestimate these variations, which in turn may lead to false conclusions about the sanitary condition of the final product. To address these variations, a proper scheme of temperature sampling needs to be used. A comparison of the results from 21 temperature data loggers randomly introduced into a compost pile with those from 20 systematically introduced data loggers showed that the mean, maximum and minimum temperatures in both methods were very similar in their magnitudes. Overall, greater temperature variation was captured using the random method. In addition, 95% of the probes introduced systematically had attained thermophilic sanitation conditions (?55 °C for three consecutive days), as compared to 76% from the group that were randomly introduced. Furthermore, it was found that, from a statistical standpoint, readings from at least 47 randomly introduced temperature loggers are necessary to capture the observed temperature variation. Lastly, the turning of the compost pile was found to increase the chance that any random particle would be exposed to the temperature ?55 °C for three consecutive days. One turning was done during the study, and it increased the probability from 76% to nearly 85%. Using the Markov chain model it was calculated that if five turnings had been implemented on the evaluated technology, the likelihood that every particle would experience the required time–temperature condition would be 98%.     

Baltic sub-basin turnover times examined using the Rossby Centre Ocean model

Not least when judging the possible effects of climate change it proves necessary to estimate the water-renewal rates of limited marine areas subject to pronounced external influences. In connection with the SWECLIM programme this has been undertaken for two ecologically sensitive sub-basins of the Baltic, viz. the Gulf of Riga and Gdansk Bay. For this purpose two methodologically different approaches have been employed, based on mass-balance budgets and analysis of Lagrangian trajectories, respectively. When compared to the results obtained using the Lagrangian technique, the box-model approach proved to be adequate for the Gulf of Riga representing a morphologically highly constrained basin, whereas it demonstrated certain shortcomings when applied to the more open topographic conditions characterizing Gdansk Bay.