Comparison of data from two vegetation monitoring methods in semi-natural grasslands

Two vegetation-monitoring methods were compared: subplot frequency analysis (SF) and visual estimation of percentage cover (VE). Two independent observers collected data from two semi-natural, species-rich grasslands on three different occasions during the growth-season. During the last data collection period, survey times were also recorded. The two different data sets from the two methods were compared using partial Redundancy Analyses. The purpose of the comparison was to identify the method that explains most of the relevant variation in biodiversity-monitoring (inter-and intra-site variation), and the variation irrelevant when evaluating data (systematic inter-observer variation and variation due to phenological changes). Compared with VE data, more variation in SF data could be explained by spatial variables, while less variation depended on the observer and time of year surveyed. SF also found more species per plot but took on average five times longer to complete than VE. In conclusion, the different methods are suitable for different purposes: SF is more suitable for purposes demanding high accuracy and high precision, such as long-term biodiversity-monitoring when the identification of small changes has high priority, while VE might be more suitable for a one-time mapping of a large area.     

Changes Versus Homeostasis in Alpine and Sub-Alpine Vegetation Over Three Decades in the Sub-Arctic

Plant species distributions are expected to shift and diversity is expected to decline as a result of global climate change, particularly in the Arctic where climate warming is amplified. We have recorded the changes in richness and abundance of vascular plants at Abisko, sub-Arctic Sweden, by re-sampling five studies consisting of seven datasets; one in the mountain birch forest and six at open sites. The oldest study was initiated in 1977–1979 and the latest in 1992. Total species number increased at all sites except for the birch forest site where richness decreased. We found no general pattern in how composition of vascular plants has changed over time. Three species, Calamagrostis lapponica, Carex vaginata and Salix reticulata, showed an overall increase in cover/frequency, while two Equisetum taxa decreased. Instead, we showed that the magnitude and direction of changes in species richness and composition differ among sites.     

Polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs) and perfluorinated alkylated substances (PFASs) in traditional seafood items from western Greenland

In this study, contamination levels were determined for polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs) and perfluorinated alkylated substances (PFASs) in traditional Greenland seafood items, such as raw and smoked fish fillet (salmon and halibut), whale and seal meat and narwhal mattak (skin and blubber). The daily intake of PCBs, PBDEs and PFASs through traditional seafood items in Greenland was assessed. Based on the presented levels of contaminants, in combination with earlier food intake studies, suggests that the daily exposure was below the tolerable daily intake threshold for all compounds. BDE-47 was the only PBDE-congener detected in all food items, except in smoked halibut. The levels of BDE-47 varied from < LOD in smoked halibut up to 18 ng/g lw in narwhal mattak and 21 ng/g lw in whale beef. ∑PCB were lowest in smoked halibut (37 ng/g lw) and highest in narwhal mattak with 1,146 ng/g lw. Perfluorooctane sulfonate (PFOS) was the most common of the PFASs. However, ΣPFASs were below detection limits in most fish fillet samples, and varied from 2.9 ng/g ww in whale beef to 13.5 ng/g ww in seal beef. The present study shows that the exclusion from the diet of local food items such as intestines and blubber have a strong positive effect for the reduction of POPs levels in food, without a reducing the health benefits of traditional food intake considerably.     

Habitat preference increases territorial defence in brown trout (Salmo trutta)

The striking ability of territory owners to repel intruders has generated a number of theoretical explanations as well as experimental studies in many animal species. However, effects of individual habitat preferences on territorial defence have rarely been studied. From the territory value hypothesis, we predicted that owners of preferred habitats should invest more resources in defence than owners of non-preferred habitats. We tested this prediction with young territorial brown trout in a two-stage experiment. First, trout were allowed to choose individually between gravel and a uniform bright substrate. As expected, they showed a significant (79%) preference for gravel. However, there was considerable variation between individuals in substrate preference, with a few fish preferring the bright substrate. Half of the tested fish were then transferred to a gravel substrate and the rest to a bright substrate, manipulating habitat type in relation to preference. Territory owners were then staged against size-matched intruders whereupon contest aggression was observed and the winner of each contest determined. Overall, owners won most of the contests. Satisfied owners won 86% and owners of less preferred territories, 74% of the contests. Furthermore, more satisfied owners attacked sooner and were more aggressive relative to the intruders. We conclude that brown trout show individual variation in habitat preference, which appears to be linked with their investment in territorial defence. These results suggest that understanding and modelling of animal contests could benefit from considering how territorial defence is influenced by individual habitat preference and specialisation. Received: 25 February 2000 / Revised: 22 May 2000 / Accepted: 25 June 2000     

Environmental pollutants in the Swedish marine ecosystem, with special emphasis on polybrominated diphenyl ethers (PBDE)

Levels of polybrominated diphenyl ethers (PBDEs), polybrominated biphenyls (PBBs), polychlorinated biphenyls (PCBs), dichlorodiphenyltrichloroethane (DDT) and perfluorinated organic compounds (PFCs) were analysed in whole herring (Clupea harengus) and sprat (Sprattus sprattus), eggs from common eider (Somateria mollissima) and eggs and livers from herring gull (Larus argentatus) from the Swedish west coast. The contaminant values obtained were compared with published values from the Arctic marine ecosystem. Tetra- and penta-brominated PBDEs were detected at low levels in herring, sprat and common eider (ΣPBDE 0.3-2.0 ng g⁻¹ ww), while the levels were higher in the herring gull samples (ΣPBDE 1.3-29.9 ng g⁻¹ ww). Hexa-decaBDEs were also found in samples from herring gulls. Eggs from herring gulls from the sub-Arctic contained four times more PBDE than the Swedish herring gulls eggs. Fish samples from the Arctic had two times higher levels of PBDEs and DDTs than similar samples from Sweden. The higher levels of contaminants in fish and seabirds from the Arctic reflect differences in transport processes, feeding ecology (reflected by trophic levels) and metabolism. PBDEs contributed to <10% of the total contaminant load in all investigated samples. The relative contribution of DDTs was higher in fish and bird samples from the Arctic when compared to Swedish samples, e.g. 65% in glaucous gull livers compared to 10% in herring gull livers. This study shows that even though the Swedish west coast is more urban than the Arctic, higher pollutants levels are found in seabird species from the Arctic.     

Electrochemical reduction of Cr(VI) in the decontamination process ELDECON

One of ABB Atom's methods, ELDECON, is an electrochemical process for decontamination of components used in nuclear power plants. ELDECON removes radioactive species while producing small amounts of waste. However, the waste sludge that is produced in the ELDECON process contains chrornate (Cr(VI)). According to the US Cod of Feguration, 40 CFR 261, if a process in any step creates chromate, the final waste has to be tested in a toxicity characteristic leachate procedure. In order to pass the test, the chromate has to be reduced to chromium (Cr(III)). Electrochemistry has proven to be a valuable tool. When incorporating indirect electrolysis into the ELDECON concept, the chromate ions are reduced. This is done by the use of an electrochemical cell (reactor bed). The method involves ferric nitrate as a reagent which, besides converting the chromate completely, also decreases the reaction time. The reaction time and the amount of solution treated in the cell have a close to linear relationship (i.e. the reaction time is proportional to the amount of solution). This makes the test cell feasible to scale up and use in the industry.     

Purification and characterisation of octopine dehydrogenase from the marine nemertean Cerebratulus lacteus (Anopla: Heteronemerta): comparison with scallop octopine dehydrogenase

Octopine dehydrogenase from the nemertean Cerebratulus lacteus was purified over 1000-fold to almost homogeneity. The enzyme does not bind to arginine Sepharose 4B. It has a monomeric structure with a relative molecular mass of 40000. Two isoenzymes were identified with isoelectric points of 5.6 and 5.4, whereas the purified isoenzymes of Pecten jacobaeus adductor mucles (which bind to arginine Sepharose 4B) had lower IEP's of 4.9 and 4.7. Apparent K_m's of the nemertean ODH for arginine and pyruvate are dependent on the respective co-substrate concentration. This phenomenon may result in activation of ODH and, thus, production of octopine in locomotory highly active individuals while attacking food, especially when this takes place in a hypoxic habitat, such as decaying mud near the high-water mark. The apparent K_m's for octopine (0.22 mM) and NAD⁺ (14 M) are low. Octopine is a substrate inhibitor for the reverse reaction above 2 mM, and a product inhibitor of the forward reaction by 50% at 1.2 mM. Therefore, only small amounts of octopine are likely to accumulate in vivo. Amino acid substrate specificity is limited to guanidino amino acids. We believe that the amino acid substrate specificity is not an evolutionary modification, but rather that it is narrowed to guanidino amino acids (or even specificity to arginine) in those species where ODH has a physiological function in maintaining redox balance during exercise. The specificity for keto acids is dependent on chain length, (-ketobutyrate>-ketocapronate); a second carboxyl group inactivates the enzyme.     

Environmental Information Management in Municipalities

This paper presents results from a study on the present needs for and management of environmental information in three Swedish municipalities. It was found that there are considerable differences between the municipalities studied, regarding needs for environmental information as well as approaches and tools used for providing the information needed—differences that seem closely related to the structures of the municipalities. The paper ends with a discussion on some general requirements for municipal environmental information management. Besides a need for analytical tools, it is argued that municipalities would have to pay more attention to political aspects of the environmental situation in environmental decision making, and thus in environmental information management.     

Environmental Information Management in Municipalities

This paper presents results from a study on the present needs for and management of environmental information in three Swedish municipalities. It was found that there are considerable differences between the municipalities studied, regarding needs for environmental information as well as approaches and tools used for providing the information needed--differences that seem closely related to the structures of the municipalities. The paper ends with a discussion on some general requirements for municipal environmental information management. Besides a need for analytical tools, it is argued that municipalities would have to pay more attention to political aspects of the environmental situation in environmental decision making, and thus in environmental information management.