Application of Uncertainty Factors in the Priority Substances Program and International Harmonization

The Canadian Environmental Protection Act (CEPA) authorizes the Ministers of the Environment and of Health in Canada to investigate a wide variety of substances that may contaminate the environment and cause adverse effects on the environment and/or on human health. Under the Act, assessments have been completed for 44 environmental contaminants on the first Priority Substances List (PSL) and are relatively advanced for 25 compounds on the second PSL. The principles developed for the application of uncertainty factors in assessment of risks to human health for Priority Substances under CEPA are outlined, with emphasis on those aspects which are somewhat unique and/or evolving. The interface of developments in the Priority Substances program with an initiative of the International Programme on Chemical Safety in this area to effect greater harmonization of approaches is also described.     

Lower plasticity exhibited by high- versus mid-elevation species in their phenological responses to manipulated temperature and drought

Background and Aims Recent global changes, particularly warming and drought, have had worldwide repercussions on the timing of flowering events for many plant species. Phenological shifts have also been reported in alpine environments, where short growing seasons and low temperatures make reproduction particularly challenging, requiring fine-tuning to environmental cues. However, it remains unclear if species from such habitats, with their specific adaptations, harbour the same potential for phenological plasticity as species from less demanding habitats.Methods Fourteen congeneric species pairs originating from mid and high elevation were reciprocally transplanted to common gardens at 1050 and 2000 m a.s.l. that mimic prospective climates and natural field conditions. A drought treatment was implemented to assess the combined effects of temperature and precipitation changes on the onset and duration of reproductive phenophases. A phenotypic plasticity index was calculated to evaluate if mid- and high-elevation species harbour the same potential for plasticity in reproductive phenology.Key Results Transplantations resulted in considerable shifts in reproductive phenology, with highly advanced initiation and shortened phenophases at the lower (and warmer) site for both mid- and high-elevation species. Drought stress amplified these responses and induced even further advances and shortening of phenophases, a response consistent with an ‘escape strategy’. The observed phenological shifts were generally smaller in number of days for high-elevation species and resulted in a smaller phenotypic plasticity index, relative to their mid-elevation congeners.Conclusions While mid- and high-elevation species seem to adequately shift their reproductive phenology to track ongoing climate changes, high-elevation species were less capable of doing so and appeared more genetically constrained to their specific adaptations to an extreme environment (i.e. a short, cold growing season).     

塔里木荒漠优势植物——胡杨种内、种间竞争研究

采用逐步扩大范围的方法确定影响对象木的邻体最佳竞争范围,利用Hegyi提出的单木竞争指数模型对塔里木荒漠优势植物———胡杨种内、种间竞争强度进行定量分析。结果表明,在胡杨群落中,对象木的最适竞争距离为6 m,胡杨种内、种间竞争强度随着植株径级的增大而逐渐减小,种内竞争较种间竞争剧烈。竞争强度与对象木胸径服从幂函数关系,从模型预测结果可知当胡杨胸径达30 cm以上时,竞争强度变化很小。因此,应在此前采取适当的人工疏伐措施来促进植株生长和增强生态系统的稳定性。     

Effect of rainfall exclusion on ant assemblages in montane rainforests of Ecuador

Models of global climate change generally predict higher rainfall variability, with more intense rainfall events separated by extended dry periods. We experimentally studied the effects of prolonged droughts on diverse ant assemblages found at three elevations in an Ecuadorian montane rainforest. We hypothesized that most species will be negatively affected directly (physiological stress) or indirectly (less food or suitable nesting resources) by drought. We thus expected a decrease in species richness as well as changes in assemblage composition. As the decrease of moisture content was expected to be more marked above ground than in soil, its impact on ants should differ according to their nesting site (dead wood, leaf litter, soil). After 6-month treatments, dead wood, leaf litter and soil samples were on average 53%, 46% and 4% drier under tents than controls, respectively. The drought did not alter overall species richness in the three nesting situations. However, species composition was significantly modified, mostly in dead wood and in leaf litter. Camponotus in dead wood, Strumigenys in leaf litter and Solenopsis in all three microhabitats were more abundant under tents. In contrast, Pheidole in dead wood, and Pachycondyla in leaf litter, were less abundant than in controls. Similar trends were observed at the three study sites. To conclude, after 6-month droughts dominant ant genera in the assemblages were affected differently. In the longer term, alteration of the rainfall regime is therefore expected to have an important impact on ants, as well as on their ecosystem functions and services, through shifts in species dominance and composition.     

刺萼龙葵种群在中国不同分布地区的表型变异

外来有害植物刺萼龙葵(Solanum rostratum)又名黄花刺茄, 已扩散至中国多省, 各地的种群在表型上存在差异。为揭示刺萼龙葵在中国不同分布区表型变异产生的原因及变异规律, 该文以来自中国9个地区的刺萼龙葵种群的种子为材料, 进行同质生物园种植。通过对营养和生殖器官共10个表型性状进行严格细致的测量, 并采用单因素方差分析(one-way ANOVA)、变异系数分析、主成分分析、聚类分析(UPGMA)和相关性分析等数理方法, 分析了各个种群的表型变异。结果表明: (1)来自不同种群的刺萼龙葵在10个性状上差异均极显著(p < 0.01), 表明种群间的性状差异具有遗传上的稳定性; (2)营养性状平均变异系数(CV = 18.2%)显著高于花部性状(CV = 9%), 结合主成分分析的结果, 可得出冠幅、 花冠直径、节间距以及株高是决定表型变异的主要代表性状; (3)种群间的聚类分析将刺萼龙葵的9个种群划分为3类, 表型性状并没有依地理距离而聚类; (4)地理因子中, 对性状影响最大的是海拔, 其次是经度, 最后是纬度。     

Climate change, conservation and management: an assessment of the peer-reviewed scientific journal literature

Recent reviews of the conservation literature indicate that significant biases exist in the published literature regarding the regions, ecosystems and species that have been examined by researchers. Despite the global threat of climatic change, similar biases may be occurring within the sub-discipline of climate-change ecology. Here we hope to foster critical thought and discussion by considering the directions taken by conservation researchers when addressing climate change. To form a quantitative basis for our perspective, we assessed 248 papers from the climate change literature that considered the conservation management of biodiversity and ecosystems. We found that roughly half of the studies considered climate change in isolation from other threatening processes. We also found that the majority of surveyed scientific publications were conducted in the temperate forests of Europe and North America. Regions such as Latin America that are rich in biodiversity but may have low adaptive capacity to climate change were not well represented. We caution that such biases in research effort may be distracting our attention away from vulnerable regions, ecosystems and species. Specifically we suggest that the under-representation of research from regions low in adaptive capacity and rich in biodiversity requires international collaboration by those experienced in climate-change research, with researchers from less wealthy nations who are familiar with local issues, ecosystems and species. Furthermore, we caution that the propensity of ecologists to work in essentially unmodified ecosystems may fundamentally hamper our ability to make useful recommendations in a world that is experiencing significant global change.     

A review of indicators of climate change for use in Ireland

Impact indicators are systems/organisms, the vitality of which alters in response to changes in environmental condition. The indicators assessed in this review fall within the impact category of the driver-pressure-state-impact-response (DPSIR) framework. Instrumental records have shown unequivocal changes in climatic conditions over the past 30 years at a global level but impact indicators allow these changes to be monitored at a finer resolution. Our main aim was to review sets of indicators of climate change currently used in various countries and to make recommendations for their use in the Irish environment. We review a preliminary set of climate change impact indicators in five sectors: agriculture; plant and animal distribution patterns; phenology; palaeoecology and human health. Currently, the most effective impact indicators of climate change have proved to be phenological observations of tree developmental stages. The strongest factor limiting the use of indicators is the lack of long-term data sets from which a climatic signal can be extracted.     

气候变化对鸟类影响：长期研究的意义

过去一个多世纪全球气候发生了明显变化,地球表面温度正在逐渐变暖。已有大量研究结果表明,鸟类已经在种群动态变化、生活史特性以及地理分布范围等方面对全球气候变化作出了相应的反应。根据全球范围内气候变化对鸟类影响的研究资料,尤其是北美和欧洲的一些长期研究项目的成果,综述了气候变化对鸟类分布范围、物候、繁殖和种群动态变化等方面的可能影响。这些长期研究项目为探讨气候变化在个体和种群的水平上如何长时间地影响鸟类提供了独特的机会,对未来中国鸟类学研究也会有所裨益。