Assessing the effect of roads on impala (Aepyceros melampus) stress levels using faecal glucocorticoid metabolites

In Tanzania, a proposed road through the Serengeti National Park has caused international debate as to whether it will cause irreversible damage to the ecosystem. We assessed the effect of current roads and traffic in the Serengeti ecosystem on a model ungulate species, the impala antelope (Aepyceros melampus). We measured how faecal glucocorticoid metabolites (FGM), an indicator of physiological stress levels, were affected by different levels of traffic while accounting for other stress‐related variables such as distance to roads, vegetation type and group size. A total of 196 faecal samples were collected. FGM were measured using an enzyme immunoassay (EIA) validated for several ruminants. FGM levels were significantly elevated near major roads with higher traffic levels compared to roads with less traffic. Predators and illegal hunting might also affect FGM levels in the impala, but the potential effect of these variables was inconsistent with the recorded FGM levels and cannot explain the observed variation. These results show for the first time that an African mammal exhibits significant physiological stress in relation to roads and traffic.     

道路生态学中的景观生态问题

道路具有重要的景观生态影响,是道路生态学研究的热点问题之一。本文综述了道路生态学的研究历程和概况,从基础理论研究、道路对生物和理化环境的影响、道路与景观格局以及道路与土地利用/覆盖变化4个方面论述了目前道路生态学中景观生态问题的主要研究内容,并根据现有的研究成果概括了该领域的主要研究方法,即生物调查、道路缓冲区/影响区分析、叠图分析和综合分析。提出中国道路生态学中景观生态问题研究存在的主要问题,并对该领域未来的研究热点进行了展望。     

Genetic diversity, but not hatching success, is jointly affected by postglacial colonization and isolation in the threatened frog, Rana latastei

Both postglacial colonization and habitat fragmentation can reduce the genetic diversity of populations, which in turn can affect fitness. However, since these processes occur at different spatial and temporal scales, the consequences of either process may differ. To disentangle the relative role of isolation and postglacial colonization in determining genetic diversity and fitness, we studied microsatellite diversity of 295 individuals from 10 populations and measured the hatch rate of 218 clutches from eight populations of a threatened frog, R. latastei. The populations that were affected by fragmentation to a greater extent suffered higher embryo mortality and reduced hatch rate, while no effects of distance from glacial refugium on hatch rate were detected. Altogether, distance from glacial refugium and isolation explained > 90% of variation in genetic diversity. We found that the genetic diversity was lowest in populations both isolated and far from the glacial refugium, and that distance from refugium seems to have the primary role in determining genetic diversity. The relationship between genetic diversity and hatch rate was not significant. However, the proportion of genetic diversity lost through recent isolation had a significant, negative effect on fitness. It is possible that selection at least partially purged the negative effects of the ancestral loss of genetic diversity.     

基于层次分析法的厦门环岛路区域植物景观彩化提升评价

运用层次分析法,从生态价值、景观价值、主观感知、经济适用性和功能性5个方面出发,采用物种丰富度、植被类型多样性、植物单体观赏特性、平面构图、色彩构成、意境美、文化内涵、植物健康度等22个指标构建厦门-环岛路区域金砖会议期间植物景观彩化提升评价模型。使用评价标准对77个景观单元进行评价分级,其中,16个Ⅰ级景观单元可作为今后景观提升的参考。最后,综合此次评价结果对厦门市植物景观彩化提升项目提出几点改良建议。     

基于产汇流模拟分析的城市居住小区道路系统布局优化策略研究

道路是城市硬质化下垫面的重要组成部分,它既是居住小区雨水径流的主要来源,也是雨水排放的重要通道,因此居住小区中道路系统与雨水产汇流过程关系的探究对于居住小区雨洪韧性的提升具有重要意义。以天津居住小区为例,借助ArcGIS和SWMM,探讨不同降雨强度下分别具有网格型、尽端型以及环网型、环尽型道路布局模式特点的居住小区产汇流规律,并以此为依据提出以雨洪韧性导向为目标的居住小区道路系统布局优化策略。     

Road avoidance and its energetic consequences for reptiles

Roads are one of the most widespread human‐caused habitat modifications that can increase wildlife mortality rates and alter behavior. Roads can act as barriers with variable permeability to movement and can increase distances wildlife travel to access habitats. Movement is energetically costly, and avoidance of roads could therefore impact an animal's energy budget. We tested whether reptiles avoid roads or road crossings and explored whether the energetic consequences of road avoidance decreased individual fitness. Using telemetry data from Blanding's turtles (Emydoidea blandingii; 11,658 locations of 286 turtles from 15 sites) and eastern massasaugas (Sistrurus catenatus; 1,868 locations of 49 snakes from 3 sites), we compared frequency of observed road crossings and use of road‐adjacent habitat by reptiles to expected frequencies based on simulated correlated random walks. Turtles and snakes did not avoid habitats near roads, but both species avoided road crossings. Compared with simulations, turtles made fewer crossings of paved roads with low speed limits and more crossings of paved roads with high speed limits. Snakes made fewer crossings of all road types than expected based on simulated paths. Turtles traveled longer daily distances when their home range contained roads, but the predicted energetic cost was negligible: substantially less than the cost of producing one egg. Snakes with roads in their home range did not travel further per day than snakes without roads in their home range. We found that turtles and snakes avoided crossing roads, but road avoidance is unlikely to impact fitness through energetic expenditures. Therefore, mortality from vehicle strikes remains the most significant impact of roads on reptile populations.     

Seasonal fluctuations in butterflies and nectar resources in a semi-natural grassland near Mt. Fuji, central Japan

We investigated seasonal fluctuation patterns in species and individuals of adult butterflies and flowering plants providing nectar in a semi-natural grassland in central Japan. We considered their interrelationships and implications for conservation. The semi-natural grassland included different vegetation structures and management regimes, including: (1) firebreaks where the grass was mowed and removed, (2) plantation areas that were mowed, (3) unpaved roads with mowed banks, (4) abandoned grassland, (5) scattered scrub forest, and (6) the surrounding forest. The sites with management (e.g., firebreaks), plantations and banks of the unpaved road sustained a larger number of butterflies and flowers than sites without management, such as the abandoned grassland, scrub forest and surrounding forest. The number of butterflies increased in the firebreak in June and at all sites in August and September. The firebreak sustained flowers in the spring, and the plantation area and banks of the unpaved road sustained flowers primarily in August and September, which was correlated with the distribution of butterflies. The different treatments such as mowing or mowing with removal of grass induced different numbers of flowers of each species affecting the habitat of adult butterflies through a season. On the other hand, the shrub tree species composing the scrub forest were host plants for the larvae of certain butterfly species. Our results suggest that heterogeneous environments with different human management or different vegetation structure or both could support habitat for various butterfly species, depending on the season and the seral stage.     

Impacts of grazing,selective logging and hyper‐aggressors on diurnal bird fauna in intact forest landscapes of the Brigalow Belt,Queensland

The impact of forest management on diurnal bird assemblages and abundance was investigated in contiguous tracts of eucalypt forest in the Brigalow Belt Bioregion, south central Queensland. Sites were located across three levels of livestock grazing intensity and three levels of selective logging intensity within the most extensive habitat type, Corymbia citriodora‐dominant forest. We recorded a high rate of incidence and large numbers of the hyper‐aggressive noisy miner Manorina melanocephala (Passeriformes: Meliphagidae) at the majority of our survey sites, a phenomenon rarely reported in non‐cleared landscapes. As shown by numerous studies in fragmented landscapes, the distribution of this species in our study had a substantial negative effect upon the distribution of small passerine species. Noisy miners exerted the strongest influence upon small passerine abundance, and masked any forest management effects. However, key habitat features important for small passerines were identified, including a relatively high density of large trees and stems in the midstorey. Selective logging appeared to exert a minimal effect upon noisy miner abundance, whereas grazing intensity had a profound, positive influence. Noisy miners were most abundant in intensively grazed forest with minimal midstorey and a low volume of coarse woody debris. Higher road density in the forest landscape also corresponded with increased numbers of noisy miners. Reduction in grazing pressure in Brigalow Belt forests has the potential to benefit small passerine assemblages across large areas through moderating noisy miner abundance. The strong relationship between noisy miners and small passerines suggests that noisy miner abundance could act as an easily measured indicator of forest condition, potentially contributing to monitoring of forest management outcomes.     

Comparison of Source Identification of Metals in Road-Dust and Soil

Source identification of toxic metals is very critical for pollution prevention and human health protection. Many studies only use either road dust metal data or soil metal data to evaluate metal contamination and identify pollution sources, and this may lead to the exclusion of some important information. In this study, the differences of metal spatial distribution and source identification between road dust and associated soil in an industrial area were investigated.

Results indicate the metal concentrations in road dust were generally higher than those in soil. Based on the average concentrations, the order for dust metal concentrations was Fe>>Zn>>Pb>Cu>Cr>Ni. The order for soil metal concentrations was slightly different, namely Fe>>Zn>>Cu～Pb>Ni>Cr. The spatial distributions of metals in the road dust were very different from those in the soil, except for Fe. The GIS results indicate that elevated levels of Fe, Zn, and Pb were present in road dust near a steel plant. High concentrations of Cu, Cr, and Ni appeared at a road intersection. Elevated metal concentrations of Fe, Zn, Pb, Cu, and Cr were present in soil around the steel plant. A coal-fired power plant did not seem to be a significant metal source in this study. Significant correlations for dust metals imply that these were well mixed in the study area. The metal sources identified by PCA with soil metal data were obviously different from those identified with road dust metal data. When road dust metal data were used, the changes of PCA analyzed areas slightly influenced the source identification. The PCA results were obviously influenced by changes of analyzed areas when soil metal data were used.     

Focus Group Evaluation of Night Nurse Shiftwork Difficulties and Coping Strategies

Focus group interviews were performed on 45 intensive care nurses who worked 12-h shifts in a large metropolitan hospital. The purpose of this study was to identify nurses' perceptions of difficulties associated with shiftwork and coping strategies used to combat them. Overall, the findings were not different than those currently discussed in the literature. For example, nurses frequently utilized white noise, telephone answering machines, and light-darkening shades to improve the quality and quantity of day sleep. They also used exercise and increased early shift caffeine consumption to improve night work performance. However, the major incentive for performing night work for these nurses was a high shift differential that equaled approximately 20% of their hourly salary. Most nurses also felt that group educational interventions regarding shiftwork difficulties and coping strategies would be preferred to individual counseling. The most significant finding of this study was the discovery of an extremely high incidence (95%) of automobile-related injuries and near-accidents that occurred while driving to and from the workplace, potentially posing a significant public health risk. (Chronobiology International, 13(6), 457-463, 1996)