Kinetic sodium analyses in the crab Carcinus mediterraneus

Kinetic analyses were made of the stable sodium and radioactive sodium (²²Na) in some tissues of the crab Carcinus mediterraneus CSRN. Fast ²²Na outflux constant is increased in gills, hepatopancreas, hemolymph, digestive tract and muscles. In the reproductive organs the values of the sodium outflux constant are lower. The values of the fast outflux rates (t=20°C) of sodium amount, in the whole animal, to 22.5 M Na/g/h, in the hemolymph, to 69.3 M Na/g/h; the slow outflux rates have much lower values (0.02 to 0.13 M Na/g/h). Moulting crabs show a rate of sodium outflux 6 times greater than that of intermoulting individuals.     

Natural bitumens versus oil pollution in the Vlasina lake peat

Free and associated bitumens were isolated by sequential extraction from Vlasina lake peat (SE Serbia) and were investigated in order to differentiate between oil pollution and natural bitumens. Four peat samples were collected at different depths, on a peat island. Gas chromatographic (GC) and gas chromatography/mass spectrometry (GC/MS) analysis revealed the presence of three markedly different bitumen fractions. Here we show that the free bitumens are representing the native peat bitumens. The two associated bitumens are mainly the products of bacterial rework of organic substance, which were then trapped by two differing mechanisms. The bitumens characteristics and association features exclude a contribution of oil pollution.Selected article from the Regional Symposium on Chemistry and Environment Krusevac, Serbia, June 2003, organised by Dr. Branimir Jovancicevic.     

Nest concealment and parental behaviour interact in affecting nest survival in the blackcap (Sylvia atricapilla): an experimental evaluation of the parental compensation hypothesis

Nest concealment varies strongly within populations of many species. Although some studies have revealed the beneficial effects of concealment in mitigating predation pressure on nests, other studies were unable to find similar effects. One potential reason for the mixed results is that parental behaviour may compensate for the effects of nest cover, and specifically designed experimental studies are needed to reveal this compensation. I studied the effects of concealment on the probability of nest survival in the blackcap (Sylvia atricapilla), by experimentally manipulating the degree of nest-foliage cover. There was a significant effect of the treatment depending on nest type and the phase of nesting. Whereas there was no effect of concealment on nest survival in natural nests, there was a positive effect in real nests baited with plasticine clutches (i.e. without parental activity). Parents probably behaviourally compensated for poor concealment in natural nests (nest guarding, defence). In line with this, there was no effect of concealment on nest survival during incubation, whereas there was probably a positive effect in the nestling phase. Parents spent more time on the nest during incubation (80%) than during the care of nestlings (40%) and, consequently, had more opportunities to compensate for poor cover. In general, we cannot use single measures of behaviours or states (nest concealment) as an indication of predation risk because of the capacity for compensation in other behaviours.Communicated by C. Brown     

Integrated shoreline management and tourism development on the cross-border World Heritage Site: A case study from the Curonian spit (Lithuania/Russia)

The varied and very dynamic landscape with a high biological diversity is a distinctive feature of the Curonian spit at the regional scale. Throughout the 20th century the main morphodynamic trend in the littoral of the Curonian spit was shoreline grading on the lagoon side, whereas on the marine side the increasing erosion at the foot of the spit, and increasing accretion at the head of the spit prevailed. The results of a discriminant analysis (Wilkes’ λ = 0.001626 and F = 29.267 when p < 0.001) show that sites with prevailing erosion, accretion and sediment input from the drifting dunes form regular inter-related spatial structures in the littoral with distinctive resulting discontinuities of the sediment drift along the lagoon coast. Dune littoral cells are characterized by Aeolian sediment input and distribution ‘down-drift’, (usually northwards) from the source. The most likely changes in the current development trends of the lagoon shore zone of the Curonian spit are related to expected climate changes and further slowing down of the dune drift. The probability of storms and ice-drift events, and their impact on coasts is expected to increase as a result of climate change. The dune advance will gradually slow down, and with it, the sand input to the coastal zone will decline. In this paper, we define integrated shoreline management as a system of long-term shoreline management measures, which is based on a littoral cell approach and aimed at harmonizing human activity in the coastal zone with the natural development of the shoreline. We propose an integrated management program for the lagoon shoreline of the Curonian spit, which is site-specific for each littoral cell as a coastal management unit. Drifting dunes and seaside beaches are the natural amenities, which are best known and best appreciated on the Curonian spit by 49% of the respondents representing the total Lithuanian population. A responsible tourism development should be considered as the key means for proper appreciation of the drifting dunes and natural coasts by society, which means to acknowledge and cherish the aesthetic and conservation values of dune and coastal landscapes of the Curonian spit as a World Heritage Site. There are at least two pre-conditions for this: (1) to provide visitors with sufficient information about diverse values and functions of the Curonian dunes and coasts within a broader regional and global heritage conservation context; (2) to enable tourists to enjoy the most impressive dune and coastal landscapes at close range. In this paper we propose to encourage active dune tourism, to reintroduce grazing into the Curonian dune areas, to restore and to preserve the most impressive landscapes of the highest white drifting dunes by bringing the blown out sand from the leeward foot of the dunes back to the crest artificially.     

湖南种子植物重要科属地理分布研究(二)——五味子科

湖南五味子科植物有2属11种2变种,分布于31个县,多生长在海拔600—1200m的山地灌丛或林中。本文依据湖南五味子科植物的地理分布,结合系统分类,植物区系和土壤资料,经分析和推论得知:1.湖南五味子科植物种质资源丰富,以中国特有种为主,它们与毗邻省区的关系密切。2.湖南五味子科植物区系表现为多种区系成分的过渡与汇集,即华南、华东、华中和滇黔桂4个区系成分的交汇、混杂和过渡。3.湖南五味子科植物的多数种类是从湖南以西地区迁移扩散而来,有的种类是从本省西北或西南以外地区而来,极少数植物在本省西南地区及其周边省区分化形成。4.湘西北至湘西南地区是湖南五味子科植物的现代分布中心,现代分化中心是湘西南地区。