哈尔滨市东南郊菜地土壤重金属环境效应分析

通过分析哈尔滨市东南郊菜地土壤重金属含量及3种蔬菜作物对重金属的累积情况,研究土壤重金属的环境效应。结果表明,哈尔滨市东南郊土壤重金属含量分别为:Cu28.451mg·kg-1、Pb35.258mg·kg-1、Zn57.654mg·kg-1、Ni30.209mg·kg-1、Cr32.660mg·kg-1、Cd0.126mg·kg-1、As3.934mg·kg-1、Hg0.049mg·kg-1。在环境效应方面,作物根、茎、叶、果实重金属含量依次递减,即根部的重金属含量最高。不同蔬菜作物对土壤中重金属的富集能力不同,菜豆比较容易累积Pb、Cr,葱比较容易累积Cd,茄子则比较容易累积As。在食用安全性方面,这3种蔬菜的重金属含量均未超过国家标准。     

幼年梨树品种光合作用的研究

 利用CIRAS-1光合仪, 分别于5月下旬和10上旬田间测定了19个梨品种幼树叶片净光合速率( Pn) , 结果表明, 新梢中部叶片Pn值较高且稳定, 不同品种功能叶片平均Pn值以‘中梨1号’最高,达13.13μmol·m^{- 2} ·s^{- 1} , 秋月最低, 仅8.08μmol·m^{- 2} ·s^{- 1} , 其余大多数品种Pn值介于二者之间。分析影响梨树光合作用因素的结果表明, 叶片Pn值并不与枝条长短有直接关系, 而是与其生长状态有关, 未封顶的长梢叶片Pn明显高于已封顶的中梢和短梢。叶片背面受光时的Pn明显低于正面受光, 叶龄长的春梢叶片(约150 d) Pn明显低于健壮的秋梢叶片(约50 d) , 叶片上午Pn值明显高于下午。利用相关分析计算出梨树叶片光合作用的理论光补偿点为59.40 μmol·m^{- 2} · s^{- 1} , 表观量子效率0.038, 暗呼吸速率2.25μmol·m^{- 2} ·s^{- 1} , 最低叶温为13.77℃, 最适叶温为26.86℃, 最高叶温为39.96℃, 最适大气相对湿度为26.50% , 最高为84.23% , CO₂ 补偿点为42.17μmol·mol^{- 1}。     

Landscape Position, Local Environmental Factors, and the Structure of Molluscan Assemblages of Lakes

Biotic communities are structured by both regional processes (e.g., dispersal) and local environmental conditions (e.g., stress). We examined the relative importance of landscape position (position within the hydrologic flow system and distance from other lakes) and local environmental factors in determining the assemblage structure of lake-dwelling snails and fingernail clams in a boreal landscape. Both landscape position and local environmental factors were highly influential in structuring the molluscan assemblages. In canonical correspondence analysis, 53.6% of snail and 48.2% of fingernail clam assemblage composition were accounted for by both sets of variables. The pure effects of landscape position were higher than those of environmental variables, and a considerable amount of variability was shared by the two sets of variables. In regression analysis, 95.5% of snail and 62.2% of fingernail clam species richness was accounted for by the explanatory variable groups, with most of the variability being related to shared effects, followed by landscape position. The effects of landscape position on species composition suggest that passive dispersal increases the similarity of molluscan assemblages in adjacent lakes. This process does not lead to an overall homogenisation of assemblage composition across the landscape, however, because local conditions set a strong environmental filter, excluding species that arrive at an unsuitable lake. These environmental filters may reflect either extinction probability (area, productivity) or species niche differences (calcium levels, abiotic stress). Landscape position may also be important in maintaining the species richness of lake-dwelling molluscan assemblages. By providing potential colonists, nearby source lakes are likely to be important in countering local extinctions. Our test of the relative importance of landscape position and local drivers of assemblage structure was partly confounded by their co-variation. Nevertheless, studying the relationship between landscape position and local variables is useful because it can tell us about the importance of local and regional processes in shaping lake communities.     

Contrasting changes in freshwater fish assemblages and food webs follow modification of tropical waterways

Fresh waters are increasingly threatened by flow modification. Knowledge about the impacts of flow modification is incomplete, especially in the tropics where ecological studies are only starting to emerge in recent years. Using presence/absence data dated approximately four decades apart (~1966 to ~2010) from 10 tropical rivers, we assessed the changes in freshwater fish assemblage and food web after flow modification. The sites were surveyed with methods best suited to habitat conditions (e.g., tray/push netting for low‐order forest streams, visual surveys for canalised rivers and net casting for impounded rivers). With the presence/absence data, we derived and compared six measures of fish assemblage and food web structure: species richness, proportion of native species, overall functional diversity, native functional diversity, food web complexity and maximum trophic level. We found that changes in community assemblage and food web structure were not generalisable across modification regimes. In canalised sites, species richness and maximum trophic levels were lower in the second time period while the opposite was true for impounded sites. However, proportion of native species was consistently lower in the second time period across modification regimes. Changes in fish assemblages and food webs appear to be driven by species turnover. We recorded 79 cases of site‐specific extirpation and 117 cases of site‐specific establishment. Our data further suggest that turnover in assemblage is again contingent on flow‐modification regime. While the process was stochastic in canalised rivers, benthopelagic species were more likely to be extirpated from impounded rivers where species lost were replaced by predominantly alien fish taxa.     

基于物联网的环境监测系统的研究及实现

基于物联网的环境监测系统是一个小型气候信息的自动化监测控制系统,能更好地帮助用户们管理作物。阐述了该系统的总体设计方案,并介绍了其硬件系统设计和软件系统设计,最后对其应用案例进行了阐述。     

麦田间作大蒜减排温室气体:兼顾经济环境效益

为应对气候变化,实现农业减排,发展生态农业,提高土地资源利用率,于2013-2014年在南京信息工程大学农业气象试验站,进行冬小麦-大蒜间作小区温室气体减排试验,研究冬小麦间作大蒜对麦田CH4排放通量的影响,并对其经济与环境效益进行比较分析。结果表明:对冬小麦生长,冬小麦田间作大蒜能分别提高小麦植株鲜质量、穗质量、千粒质量134.67%、2.20%、3.51%;与对照单作小麦处理相比,间作大蒜处理下单位面积农田投入与产出比从1∶9.8提高到1∶16.7,即在相同投入成本的情况下,产出提高70.41%;对小麦间作大蒜处理下,在小麦抽穗期和灌浆期,比对照处理的土壤CH4排放通量分别减少38.35%、16.59%;在小麦整个生长季内,土壤CH4排放通量累计减少了53.45%。研究显示,大蒜-小麦种植模式,不仅可以提高冬小麦的产出,还同时减少土壤CH4的排放,减缓温室效应,具有节能减排、提高经济环境效益双重功能,是发展可持续生态农业的一个重要途径。     

山水园林诗中的情境类型及其建构对园林营造的启示——以张九龄的山水园林诗为例

古代山水园林诗中蕴藏着丰富的文化意象资源,挖掘诗中对园林空间情境和环境意象的描述,有益于今天的园林意境创造。通过对岭南诗派开山鼻祖张九龄的山水园林诗情境类型进行梳理分类,归纳出包括山水园林环境体验、园林宴集在内的7种常见类型,分析其情境建构中对环境意象的选择和组织,并从物象属性、情态特征和虚拟、暗示意象等方面展开讨论,系统梳理“环境意象-情境”的内在关系,最后总结了它们对今天园林营造的启示,即丰富多彩的环境意象和其在诗歌中建构情境的方式可以作为园林景观塑造和空间组织的直接参考。     

Ecological and genetic evidence of the vulnerability of shallow‐water populations of the stylasterid hydrocoral Errina novaezelandiae in New Zealand's fiords

• 1. Some of the key life history characteristics that make modular marine invertebrates such as corals vulnerable to disturbance and stress are susceptibility to damage, slow growth, longevity, and philopatry. This may be particularly so for marginal populations at the limits of their range and, for instance, that are attractive to scuba divers.
• 2. In this study we examined the population structure and incidence of damage, quantified growth rates and estimated gene flow to assess the effects of divers on the deep‐water emergent populations of the fragile red coral Errina novaezelandiae in the Te Awaatu Marine Reserve in Fiordland, New Zealand.
• 3. We found that population structure in red corals is skewed, with small colonies the most abundant. Damage was up to eight times higher in dived than in non‐dived populations of red coral, and large colonies were more likely to be damaged. Growth in red corals can be high (up to 7 cm ^?1), although net growth is much lower (0.7 cm yr^?1) due to the effects of partial mortality. On the basis of the slow growth rate, we estimate that large corals (>20 cm diameter) will be in excess of 30 yr old. We also found high genetic subdivision among red coral populations and evidence of inbreeding, indicative of limited larval dispersal among neighbouring populations.
• 4. Overall, our results indicate the shallow‐water populations of red coral in Fiordland will be susceptible to impacts from scuba diving, and the development of a management strategy to ensure ecologically sustainable tourism and to minimize the effects of divers will be essential for their conservation.

Copyright © 2003 John Wiley & Sons, Ltd.     

Normalized difference vegetation index (NDVI) as a marker of surrounding greenness in epidemiological studies: The case of Barcelona city

The normalized difference vegetation index (NDVI) is often used as a marker of surrounding greenness in epidemiological studies aiming to evaluate the health effects of green space in urban settings. However, it is not clear the relationship between built environment characteristics, including green space, and NDVI. We aimed to evaluate the relationship between built environment characteristics, based on land-use and land-cover maps, and NDVI as a marker of surrounding greenness in the city of Barcelona. We used data from an already existing cohort of pregnant women in Barcelona (N = 8402). NDVI was derived and averaged within buffers of 100 m and 300 m for each participant, and categories of the built environment (m²) were derived from land-use and land-cover maps of Barcelona. We conducted ANOVA models to calculate the contribution (R²) of each land-use (or land-cover) category. The variability in NDVI in Barcelona was mainly explained by urban green (R² between 0.32 and 0.53) and natural green areas (R² between 0.19 and 0.52), although for the latter less than 4% of the participants were exposed to this. Both land-use and land-cover maps explained NDVI at 300 m better (full models explaining 76% and 78%, respectively) than at 100 m buffers (full models explaining 55% and 54%, respectively). Results of the present study indicate that NDVI can be a useful greenness metric depending on the hypothesis and area of study. However, for certain sizes of study areas (buffers smaller than 100 m), NDVI might have a lower predictive value. Results of the present study should be replicated in studies from other cities with different urban characteristics and climate conditions.     

Feed particle selection and nutrient intake altered by pecking stone consumption and beak length in free-range laying hens

The present study investigated the effects of pecking stones on feeding behaviour of hens from 16 to 46 weeks of age. Eighteen flocks of Hy-Line Brown hens were housed in 2 commercial free-range housing systems. Farm A housed 10 flocks of beak trimmed (infrared beak treatment) hens in fixed sheds. Farm B housed 8 flocks of hens with intact beaks in mobile sheds. On each farm, flocks were equally assigned to control groups (no access to pecking stones) and treatment groups (access to pecking stones). Data were evaluated every 10 weeks. At each time point, 10 hens per flock were housed in individual pens, and each hen was provided with 250 g of mash diet and ad libitum water for 24 h. After 24 h, feed samples were collected and used to determine 24-h feed intake. Nutrient and particle selection was measured by subtracting nutrients and particles present in the leftover feed from the vaules obtained in the offered feed and expressed the change (Δ). In addition, pecking stone consumption was recorded for each flock. Data were analysed separately for each farm using fixed effects of pecking stone availability and hen age. Spearman's rho correlation coefficients and linear regression models were constructed to evaluate the relationship of beak length and pecking stone usage, discrete mean particle size (dMEAN) consumption (Δ dMEAN), and Δ nutrient intake. Hens with access to pecking stones consumed significantly lower quantities of large feed particles (>2.8 mm) on farm A (P = 0.029) and selected significantly more fine particles, on farm B (P = 0.013). Overall, positive relationships (P = 0.001) between beak length and pecking stone consumption, Δ dMEAN, and Δ phosphorus consumption were observed. In conclusion, pecking stone consumption resulted in reduced selection and consumption of feed particles in hens housed on both farms. Further research is warranted to investigate the effect of pecking stones on sensory innervation of the beak.