使用罗斯比中心海洋模型检测波罗的海次盆地的周转时间

尤其在判断气候变化可能带来的影响时,事实证明有必要对受到显著的外部影响的有限海域的水更新速度进行评估.随SWECLIM项目一起,上述工作已在波罗的海的两个生态敏感的次盆地(即里加湾和格但斯克湾)中开展.为此目的,我们已分别以质量平衡收支和拉格朗日轨迹线为基础,采用了两种方法上不同的做法.与采用拉格朗日技术获取的结果相比,事实证明,在作为一个在形态上受到极大约束的盆地的里加湾中,使用这种箱状模型方法非常合适,而在将它用于以更加开阔的地形条件为特点的格但斯克湾时却表现出一些不足.     

Social organization in the bat Pipistrellus pipistrellus

Summary The social organization of the pipistrelle bat (Pipistrellus pipistrellus) was studied by means of bat boxes in southern Sweden. The males set up territories around a roosting site in the beginning of the summer at the same time as the females formed nursing colonies. After breeding, the females joined the single males in their day roosts establishing transient mating harems. Subsequently, immatures arrived at the mating grounds. The immature females, which probably attained sexual maturity during their first autumn, were admitted to the day roosts of the harem males, in contrast to the immature males. The size of the harem was dependent on the total number of females present on the mating grounds. The size, however, was also restricted by some factor, presumably the quantity of food resources in the surroundings of the specific roost site, or the capability of the harem male for mating. The mating system in the pipistrelle bat is best characterized as a resource defence polygyny. Available data on other related temperate species indicate a similar social organization in Pipistrellus nathusii and Nyctalus noctula.     

The value of small size: loss of forest patches and ecological thresholds in southern Madagascar.

Many services generated by forest ecosystems provide essential support for human well-being. However, the vulnerability of these services to environmental change such as forest fragmentation are still poorly understood. We present spatial modeling of the generation of ecosystem services in a human-dominated landscape where forest habitat patches, protected by local taboos, are located in a matrix of cultivated land in southern Madagascar. Two ecosystem services dependent on the forest habitats were addressed: (1) crop pollination services by wild and semidomesticated bees (Apoidea), essential for local crop production of, for example, beans, and (2) seed dispersal services based on the presence of ring-tailed lemurs (Lemur catta). We studied the vulnerability of these ecosystem services to a plausible scenario of successive destruction of the smallest habitat patches. Our results indicate that, in spite of the fragmented nature of the landscape, the fraction of the landscape presently covered by both crop pollination and seed dispersal services is surprisingly high. It seems that the taboo system, though indirectly and unintentionally, contributes to upholding the generation of these services by protecting the forest patches. Both services are, however, predicted to be very vulnerable to the successive removal of small patches. For crop pollination, the rate of decrease in cover was significant even when only the smallest habitat patches were removed. The capacity for seed dispersal across the landscape displayed several thresholds with habitat patch removal. Our results suggest that, in order to maintain capacity for seed dispersal across the landscape and crop pollination cover in southern Androy, the geographical location of the remaining forest patches is more crucial than their size. We argue that in heavily fragmented production landscapes, small forest patches should increasingly be viewed as essential for maintaining ecosystem services, such as agricultural production, and also should be considered in the ongoing process of tripling the area of protected habitats in Madagascar.     

The consequences of avoiding conflict: lessons from conservation planning for Europe's last wild reindeer

This paper seeks to contribute to debates on the potential for conservation planning to engage actively with conflict. Current research in conservation planning generally approaches conflict by concentrating on the challenges of securing agreement and consensus. Recent planning literature advocates approaches that are more open to conflict. In the analysis of a Norwegian regional planning process for wild reindeer conservation, we examine how planning authorities handled conflict, and in particular how planning documents portrayed conflicts expressed during the planning process. Findings show that the aim of reaching regional consensus limited the scope of planning, and led to the exclusion of difficult issues and opposing views. Instead of engaging actively with conflict, the planning authority framed opposing positions as unplannable, and failed to recognise them as legitimate. This contributed to weakening of the legitimacy of the regional plan when put to the test.     

Ecological Feasibility Studies in Restoration Decision Making

The restoration of degraded systems is essential for maintaining the provision of valuable ecosystem services, including the maintenance of aesthetic values. However, restoration projects often fail to reach desired goals for a variety of ecologic, financial, and social reasons. Feasibility studies that evaluate whether a restoration effort should even be attempted can enhance restoration success by highlighting potential pitfalls and gaps in knowledge before the design phase of a restoration. Feasibility studies also can bring stakeholders together before a restoration project is designed to discuss potential disagreements. For these reasons, a feasibility study was conducted to evaluate the efficacy of restoring a tidal freshwater marsh in the Potomac River near Alexandria, Virginia. The study focused on science rather than engineering questions, and thus differed in approach from other feasibility studies that are mostly engineering driven. The authors report the framework they used to conduct a feasibility study to inform other potential restoration projects with similar goals. The seven steps of the framework encompass (1) initiation of a feasibility study, (2) compilation of existing data, (3) collection of current site information, (4) examination of case studies, (5) synthesis of information in a handbook, (6) meeting with selected stakeholders, and (7) evaluation of meeting outcomes. By conducting a feasibility study using the seven-step framework, the authors set the stage for conducting future compliance studies and enhancing the chance of a successful restoration.     

Independent effects of food and predator-mediated processes on annual fecundity in a songbird

We investigated the relative importance and interaction of ecological processes affecting annual fecundity in birds by simultaneously manipulating food availability and nest predation risk in a small songbird, the Wrentit (Chamaea fasciata). From 2000 to 2002 we provided supplemental food to individual Wrentit territories, and during 2002 we altered nest predation risk by providing supplemental food to their principal predators, Western Scrub-Jays (Aphelocoma californica). These experiments were conducted during a period of high interannual variation in rainfall, with 2002 being one of the driest years on record. Food-supplemented Wrentits in a normal predation environment produced an average of 0.54 more fledglings per year than control pairs over the three breeding seasons. During the feeding plus predation manipulation experiment, Wrentit food supplementation and lowered nest predation risk each independently increased the probability that a Wrentit pair would fledge young; however, the interaction between food supplementation and altered nest predation risk was not significant. Thus, even in an extreme drought year, both food and nest predation had equal but independent effects on reproductive success and annual fecundity. Combining supplemental food with reduced nest predation did not result in a synergistic increase in annual fecundity, primarily because Wrentits did not produce multiple broods. Our results suggest that whether food and predation have additive or synergistic effects on reproductive success depends on the life history of the species and the environment in which they live.     

A new method for monitoring long-term transport variability in the Baltic

Direct measurements of the potential induced by motion of electrically conducting seawater through the earth's magnetic field may be used to estimate ocean transports. For the purpose of evaluating the feasibility of monitoring the Baltic climate, a number of temporary observational systems based on this principle have been established around the Swedish coast. Some results from these investigations are presented, and the study is concluded by an outlook towards the prospects for future work along these lines.     

Photoperiodic activity pattern in the brittle star<Emphasis Type="Italic"> Amphiura filiformis</Emphasis>

Diurnal activity pattern of suspension-feeding arms of the infaunal brittle star Amphiura filiformis was recorded in situ by time-lapse photography at 30 m water depth in the Gullmarsfjord, west Sweden. Activity was clearly related to the photoperiod with high activity at night and low or no activity during daytime. In laboratory experiments, the activity of the arms of A. filiformis changed in relation to new manipulated photoperiods, demonstrating exogenous circadian rhythms. The time difference for the greatest change in activity of the arms between control and treatment was correlated with the photoperiodicity. The recently found microlenses and associated neural photoreceptors in ophiuroids may apply also to A. filiformis. The trade-off between efficient feeding and predator avoidance is discussed.Communicated by M. Kühl, Helsingør     

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.