瑞典水文变化-气候变化影响模拟

温室效应加剧导致的气候变化将会引起水文系统的变化.随着气候要素的变化,水文变化将会在全球呈现出区域差异性.因此,有必要开展局地和区域尺度上的水文变化影响研究,评价不同区域将会受到怎样的影响.本研究旨在对广泛的瑞典流域上气候变化的水文影响(响应)进行评估.我们采用不同的方法,将气候模型中产生的气候变化信号转换输入到水文模型中.利用瑞典区域气候模拟计划(SWECLIM)生成的区域气候情景,我们进行了几次水文模型模拟研究.得出的基本结论是根据流域的地理位置处于瑞典北部或南部,气候变化对河道水流的分区影响是显著不同的.此外,预测的水文变化不仅与用于确定区域气候模型边界条件的全球气候模型的选择有关,而且与人为气体排放情景的选取有关.     

Individual variation in mate care by alpha males in crested tit winter flocks

Summary Winter flocks of crested tits Parus cristatus, typically consisting of two adults and one or two non-kin 1st-year birds, were observed to split up into subflocks in a way related to ambient temperature. On warm days, when they were foraging in subflocks without 1 st-year birds, alpha males always occupied the most preferred upper foraging sites, as expected from their top dominance rank. On cold days, when foraging in flocks with 1st-year birds, 8 out of 13 alpha males shifted to lower (less preferred) positions below their alpha mates while allowing the latter to forage at the best sites. As enhanced access to preferred microsites on days with high energy stress is believed to increase overwinter survival probability, this shifting behaviour of alpha males can be considered as a form of mate care. Out of 13 alpha males, however, 5 did not shift and always occupied the best foraging sites irrespective of flock composition. As (i) these non-shifting males were in poorer physical condition than shifting males, (ii) they scanned significantly less for predators than either females or shifting males when foraging in the uppermost tree parts, and (iii) four out of five non-shifting males were replaced by immigrants in early spring, absence of mate care during winter may be caused by constraints due to condition. High-quality-territory owners in poor condition at the end of autumn were most vulnerable to replacement by immigrants. Therefore, as four out of five replacements affected high-quality territories, selective intrusion by immigrants is suggested. Correspondence to: L. Lens     

Mimicry: imitative depiction of discharged defensive secretion on carapace of an opilionid

Summary. The opilionid, Parampheres ronae, has a pair of orange markings on its carapace at a location where some other opilionids discharge yellowish, quinone-containing defensive fluid. P. ronae itself produces a defensive secretion, but the fluid is quinone-free and nearly translucent. We suggest that the orange markings in P. ronae are aposematic in the sense that they are imitative of the glandular emissions of quinone-producing opilionids.     

Temporal changes in wetland landscapes of a section of the St. Lawrence River,Canada

Historical aerial photographs (from 1946 through 1983) were used to study and describe the nature and extent of changes in wetland vegetation of a section of the St. Lawrence River and to evaluate the relative importance of water level, fire, and vegetational development as causal factors of these historical changes. Data were encoded and analyzed using a geographical information system, autocorrelation, and Mantel tests. Results show three temporal patterns in wetland dynamics. First, some wetland zones have been reduced by human activities (urbanization, landfilling, canal dredging). The second group consists of wetland areas that remain stable and do not change over time. They are generally protected sites artificially maintained by water-level control. A third situation has occurred in the Lake Saint-François National Wildlife Area, where no significant wetland losses were detected, but where landscape structure has changed greatly. Modeling with Mantel tests suggests that, in the latter case, these changes in wetland landscape are related to the suppression of burning (fires set deliberately by Indians) since the purchase of the territory by the Canadian federal government. This situation has caused rapid replacement of wet meadows byAlnus rugosa scrub and a possible decline in habitat diversity.     

Integrated Assessment of Swiss GHG Mitigation Policies After 2012

The residential sector presents a great potential for greenhouse gases (GHG) mitigation. We perform an integrated assessment of different mitigation policies for Switzerland focusing on the residential sector. We analyze the case of pure incentive taxes and technical regulations. For our analysis, we have coupled a general equilibrium model with a Swiss residential energy model. We find that a progressive GHG tax of more than 200 USD2000/tCO₂ eq is necessary to reach a target of 50% reduction of GHG emissions in 2050. Finally, we also find that efficiency-based technical regulations provide limited additional abatement incentives.     

Organic carbon and environmental quality of riverine and off-shore sediments from the Gulf of Cádiz,Spain

Here we show that heavy metal geoaccumulation is apparent in the Tinto and Odiel estuary and, at a lower magnitude, in off-shore sediments. Values above probable effects level (PEL) are recorded for As, Cu, Hg, Pb and Zn in the Tinto and Odiel estuary, for As and Hg in the associated off-shore sediments and for As in the Guadiana River. Significant correlations were found between total organic carbon (TOC) and Cr, Cu, Ni and Zn in the Tinto and Odiel estuary, and Cr, Cu, Ni, Pb, Hg and As in the Guadiana River. PCA analysis differentiated the three studied locations.