在物种水平上生物对气候和紫外线B辐射预期变化的响应

控制实验表明,不同物种对每个环境因子变化变量产生的响应也存在着差异.植物往往对营养元素的变化反应最为强烈,尤其是氮素的增加.夏季增温实验表明,木本植物对温度的升高表现出了积极的响应,而地衣、苔藓类植物的丰富度却因增温而降低.物种对增温的响应主要受水分有效性和雪覆盖程度控制.在气候保持湿润的情况下,伴随着夏季温度的升高,许多无脊椎动物种群的数量都有所增加.实验表明,CO2浓度和紫外线B(UV-B)辐射的增加对植物和动物影响较小,但是,一些微生物和真菌却对紫外线B辐射的增加非常敏感,甚至可能会因此产生一些诱导突变而引起流行传染病的爆发.苔原土壤的加温、CO2浓度的升高以及矿物质营养的改善一般都会增加微生物的活动.在温带气候中,藻类往往比蓝藻细菌更占优势.冬季结冰-解冻过程的增加会导致冻壳的形成,从而会大大降低许多陆生动物的冬季存活率,改变这些动物群体的动态过程.厚的积雪会使驯鹿等植食性动物很难采食到雪下的草类植物,同时也不利于其逃避食肉动物的追捕.而无雪期的提前到来则可能会加速植物的生长.物种对气候变化的响应最初可能出现在亚种这一水平上一个具有很高遗传/群系多样性的北极植物或动物物种,演化历史已经使其具有一种适应不同环境条件的能力,这将使它们能够很快适应未来的环境变化.本土知识(IK)、航空照片和卫星图像表明一些物种的分布已经发生了变化北极植被更加趋向灌木化,而且生长也更加旺盛；北极驯鹿的分布范围最近也发生了变化；一些原来在树线以南区域活动的害虫和鸟类也在北极被发现.与此相对应,大多数在北极地区进行繁殖鸟类的数量却都在下降.根据一些模型的预测,随着气候的变暖,苔原带鸟类的数量将会大幅度地下降.据物种-气候响应模型预测,由于受到气候变暖的影响,北极地区现有物种在未来的潜在分布范围都将大大缩小和向北退缩,而一些无脊椎动物和微生物则很可能会迅速向北扩展到北极地区.     

Fetal ductus venosus flow velocity waveforms and maternal serum afp before and after first-trimester transabdominal chorionic villus sampling

Doppler flow velocity waveform recording in the fetal ductus venosus and umbilical artery as well as maternal blood sampling for serum alpha-fetoprotein (MSAFP) was performed before and after transabdominal chorion villus sampling (TACVS) in 36 women of advanced maternal age (≥ 36 years). Gestational age ranged between 11 and 13 weeks. No chromosomal anomaly was detected. No statistically significant difference was observed in ductus venosus velocity parameters or in the umbilical artery pulsatility index (PI) before and after CVS in 35 women with a normal pregnancy outcome. One case resulted in fetal loss. Post-CVS median MSAFP levels at 12 weeks (25 kIU/1) and 13 weeks (35 kIU/1) were significantly higher than pre-CVS levels. In three cases, post-CVS MSAFP levels were higher than 600 kIU/1, correlating with feto-maternal transfusions of approximately 1.0–1.4 ml, i.e., of around 40 per cent of feto-placental blood volume. One of these cases displayed absence of fetal peripheral blood flow velocities and fetal bradycardia following TACVS, resulting in fetal loss 1 week later. The remaining two cases had a normal pregnancy outcome, but showed a more than 50 per cent reduction in ductus venosus velocity after TACVS, whereas umbilical artery PI remained unchanged. However, similar velocity changes were associated with only small feto-maternal transfusions. Umbilical artery PI values remained unchanged.     

Long-distance island hopping without dispersal stages: transportation across major zoogeographic barriers in a Southern Ocean isopod

Species integrity is maintained only if recurrent allelic exchange between subpopulations occurs by means of migrating specimens. Predictions of this gene flow on the basis of observed or assumed mobility of marine species have proven to be error-prone. Using one mitochondrial gene and seven microsatellite markers, we studied the genetic structure and gene flow in Septemserolis septemcarinata, a strictly benthic species lacking pelagic larvae and the ability to swim. Suitable shallow-water habitats around three remote islands (South Georgia, Bouvet, and Marion Island) are geographically disjunct, isolated by more than 2,000 km of uninhabitable deep sea (east–west) and also separated by the Polar Front (north–south), which serves as a strong demarcation line in many marine taxa. Although we did find genetic differentiation among the three island populations, our results also revealed that a scenario with recent gene flow explains our data best. A model assuming no gene flow after initial colonization of the islands performs significantly worse. The tests also favor an asymmetric gene flow pattern (west to east ≫ east to west) thus mirroring the directionality of major oceanographic currents in the area. We conclude that rare long-distance dispersal rather than vicariance or human-mediated transport must be responsible for the observed patterns. As a mechanism, we propose passive rafting on floating substrata in the Antarctic Circumpolar Current. The results demonstrate that the effectiveness of a physical barrier is not solely a function of its physical parameters but strongly depends on how organisms interact with their environment.     

Allometric shape change of the lower pharyngeal jaw correlates with a dietary shift to piscivory in a cichlid fish

The morphological versatility of the pharyngeal jaw of cichlid fishes is assumed to represent a key factor facilitating their unparalleled trophic diversification and explosive radiation. It is generally believed that the functional design of an organism relates to its ecology, and thus, specializations to different diets are typically associated with distinct morphological designs, especially manifested in the cichlids’ pharyngeal jaw apparatus. Thereby, the lower pharyngeal jaw (LPJ) incorporates some of the most predictive features for distinct diet-related morphotypes. Thus, considering that piscivorous cichlids experience an ontogenetic dietary shift from typically various kinds of invertebrates to fish, concomitant morphological changes in the LPJ are expected. Using Lepidiolamprologus elongatus, a top predator in the shallow rocky habitat of Lake Tanganyika, as model, and applying geometric and traditional morphometric techniques, we demonstrate an allometric change in ontogenetic LPJ shape development coinciding with the completion of the dietary shift toward piscivory. The piscivorous LPJ morphotype is initiated in juvenile fish by increasing elongation and narrowing of the LPJ and—when the fish reach a size of 80–90 mm standard length—further refined by the elongation of the posterior muscular processes, which serve as insertion for the fourth musculus levator externus. The enlarged muscular processes of the fully mature piscivorous morphotype provide for the construction of a powerful lever system, which allows the large individuals to process large prey fish and rely on exclusive piscivory.     

Bewertungskriterien des Umweltbundesamtes: Auswirkungen von Pflanzenschutzmitteln auf terrestrische Arthropoden

The fundamental data requirements for the authorization of plant protection products and the inclusion of active ingredients in Annex I of Council Directive 91/414/EEC are described in the Annexes II and III of the Directive. Definite guidelines concerning investigations with arthropods are partially deficient. The uniform principles for the registration of plant protection products in the Member States described in Annex VI of the directive were primarily developed to assess the effects on the beneficial capacity of arthropods in agriculture. However, the risk for arthopods as an essential part of the environment need to be assessed, too. Hence, the German Federal Environmental Agency has developed a tiered approach to assess the effects of plant protection products on arthopods based on the data requirements of Annex II and III of the Directive 91/414/EEC. The risk is assessed using the effect-concentration evaluated in ecotoxicological tests and the environmental concentration predicted by validated exposure models. To protect non-target species in terrestrial ecosystems assessment factors need to be considered.     

Large Mammalian Herbivores and the Conservation of Arid Acacia Stands in the Middle East

Abstract: High mortality and poor recruitment in Acacia tree populations in many parts of the Middle East may result in loss of biodiversity. Human activities in recent decades have caused drastic changes in the water regime and the abundance of wild and domestic ungulates, which may negatively affect these trees. We studied the effects of large mammalian herbivores on the establishment of young Acacia raddiana and A. tortilis in the Arava Valley between the Red Sea and the Dead Sea, Israel. Seed accumulation under trees was high when large herbivores were excluded, and direct observations confirmed that ungulates were the main seed dispersers of these Acacia species. Insect seed predators (bruchid beetles) damaged more than 95% of seeds not consumed by ungulates. Seed germination was facilitated by gut passage through ungulates. Seedling survival was determined largely by water availability and was independent of herbivore density. Under present conditions, several years of high rainfall are necessary for successful establishment of young trees. Under severe browsing pressure by ungulates, growth in juvenile trees was delayed and smaller sizes were overrepresented. There was no evidence, however, of effects on the long-term demography of Acacia trees, perhaps because ungulates increased seedling densities by enhancing the viability and germination of seeds. We conclude that large mammalian herbivores are essential components of arid Acacia savannas and that wild and domestic ungulates must be included in future conservation plans.     

Wassergefährdungspotenzial nativer Öle und Fette: Berücksichtigung physikalischer Effekte

Aim and Background

Varying interpretations of the hazard potential of native oils and fats for aquatic ecosystems have led to conflicting international and national regulations. Background is the different consideration of physical effects. This study aimed at compiling published data on behaviour and effects of native oils and fats in water, hereby providing a basis for discussion on adequate classification of these substances.

Results

According to scientific data, physical effects may significantly contribute to the hazard potential of native oils and fats. This is especially important in risk assessment of spills, e.g. in the case of accidents. Basically, these effects are the same in marine and freshwater environments; the latter may even be regarded as worst-case situations with respect to physical effects.

Recommendations

Based on these facts, the German classification of native oils and their derivates as ‘not hazardous to waters’ according e.g. to § 19g of the Water Resources Act and § 4 of the Ordinance of Hazardous Substances should be revised. New criteria need to be incorporated into the evaluation procedure to allow an adequate assessment of these substances regarding physical effects.