深圳市重型与轻型屋顶绿化降温增湿效应研究

应用比较研究法评估了重型屋顶花园与轻型屋顶绿化的降温增湿效应。观测结果表明,重型和轻型屋顶绿化在夏季均能有效地降低屋面高温、增加屋面相对湿度,且重型屋顶花园的降温增湿效应明显优于轻型屋顶绿化。为屋顶花园的发展提供参考。     

北美浆果树种在中国西部地区引种效果及应用前景

中国西部地区水资源贫乏，生态环境极其脆弱，适合生长的造林树种十分稀少，为此近10a来引进了许多北美生态经济型灌木类浆果树种，以满足生态环境恢复和建设的需要。引种试验结果表明，多数树种适合在中国西部地区栽培，发展前景十分广阔，应尽快大面积推广。同时也指出了易出现的问题、解决方法及发展建议。     

吉安林化产业发展的现状与对策

吉安林业化工资源丰富，但林化产业发展滞后，通过对该产业存在问题的分析，提出加快该产业发展的对策。     

A generalized nonlinear mixed-effects height–diameter model for Eucalyptus globulus L. in northwestern Spain

A generalized height–diameter model was developed for Eucalyptus globulus Labill. stands in Galicia (northwestern Spain). The study involved a variety of pure stands ranging from even-aged to uneven-aged. Data were obtained from permanent circular sample plots in which trees were sampled within different radii according to their diameter at breast height. A combination of weighted regression, to take into account the unequal selection probabilities of such an inventory design, and mixed model techniques, to accommodate local random fluctuations in the height–diameter relationship, were applied to estimate fixed and random parameters for several models reported in the relevant literature. The models that provided the best results included dominant height and dominant diameter as fixed effects. These models explained more than 83% of the observed variability, with mean errors of less than 2.5 m. Random parameters for particular plots were estimated with different tree selection options. Height–diameter relationships tailored to individual plots can be obtained by calibration of the height measurements of the three smallest trees in a plot. An independent dataset was used to test the performance of the model with data not used in the fitting process, and to demonstrate the advantages of calibrating the mixed-effects model.     

Does afforestation increase bird nest predation risk in surrounding farmland?

Afforestation of agricultural land is increasingly used to deliver environmental benefits, but their effects on biodiversity remain poorly understood. This paper tests the hypothesis that afforestation changes predation processes in surrounding farmland, examining how the characteristics and landscape context of forest plantations affect predator (birds and mammalian carnivores) and key prey (rabbits and hares) abundances, and bird nest predation rates in Iberian cereal-steppes. Lagomorphs and predators were surveyed in fallow fields around 50 forest plantations, where predation rates were estimated using artificial nests set at 0, 100, 200 and 300 m from the forest edge. Recent plantations structurally similar to sparse (oak) or dense (pine) shrublands were associated with the highest hare and rabbit abundances, respectively, whereas both species avoided landscapes with high eucalyptus cover. In contrast, mature eucalyptus plantations showed strong positive effects on typical nest predators such as corvids and carnivores. Open farmland fragmentation favoured the abundance of lagomorphs and carnivores. Despite these effects and the high predation rate on artificial nests (49%), there was neither evidence for increased predation near plantation edges nor higher predation in fields with more lagomorphs and predators. However, predation tended to increase with cover by young oak plantations and overall forest plantation cover, to decrease with eucalyptus cover at both the local and landscape scales, and to peak in landscapes with intermediate edge densities. These results suggest that afforestation may have strong effects on bird nest predation rates by changing landscape composition and configuration, rather than by inducing local increases in predator and prey populations. Nevertheless, increased abundances of generalist predators associated with forest plantations may still be considered of conservation concern, thus supporting the recommendation for strongly restricting afforestation in areas important for open grassland birds. Where this is unavoidable, monitoring should be undertaken to provide early signals for bird population declines associated with predator increases, eventually triggering conservation action such as predator exclusion or removal.     

山西省太谷县不同退耕还林模式生态效应研究

以撂荒地作为对照,通过野外采样、定点观测、室内试验,研究了山西省太谷县不同退耕还林模式的生态效应。结果表明:不同退耕还林模式生态效应是不同的,刺槐+山桃>刺槐>山桃林>撂荒地;刺槐+山桃、刺槐、山桃林负氧离子浓度分别为2019、1893、1738个/cm^3,是撂荒地的1.86倍;负氧离子寿命分别为17.35、16.28、14.94 min,是撂荒地的1.96倍;PM_2.5浓度分别为59.07、65.77、73.36μg/m^3,是撂荒地的0.65倍;土壤容重分别为1.15、1.17、1.19 g/cm^3,是撂荒地的0.80倍;土壤总孔隙度分别为49.60%、48.94%、47.57%,是撂荒地的1.24倍;土壤非毛管孔隙度分别为7.16%、6.77%、6.17%,是撂荒地的1.43倍;土壤有机质分别为2.93%、2.71%、2.53%,是撂荒地的1.42倍,土壤表层日较差分别为11.63、11.77、11.85℃,是撂荒地的0.80倍。     

马来酸二乙酯对藿香精油触杀枸杞蚜毒力增效作用研究

文章以枸杞蚜虫为试虫,采用玻璃管药膜法研究了藿香精油的触杀剂量效应、藿香精油+马来酸二乙酯的触杀剂量效应、马来酸二乙酯对藿香精油的触杀毒力增效作用。结果表明,藿香精油在处理4 h后,精油最高剂量表现出的校正死亡率最高,是最低剂量校正死亡率的19.6倍。藿香精油对枸杞蚜虫的剂量效应为正比例关系。藿香精油+马来酸乙酯触杀枸杞蚜虫的触杀剂量在1 mL·L^-1下,最长处理时间的枸杞蚜虫死亡数是最低处理时间的10.4倍。马来酸二乙酯(增效剂)+藿香精油对枸杞蚜虫的剂量效应为正比例关系。藿香精油对枸杞蚜虫触杀4 h后,枸杞蚜虫的LC50为3.17 mL·L^-1,含有马来酸二乙酯的藿香精油对枸杞蚜虫的LC50为1.09 mL·L^-1。枸杞蚜虫对含有增效剂的藿香精油的触杀处理更敏感。两者的95%置信限覆盖率为0,表明两者对枸杞蚜虫的触杀毒力存在极显著差异。0.02%马来酸二乙酯的增效比为2.90,证明其对藿香精油具有增效作用。     

Crown development in young Picea abies stands

A dynamic model of branch length and weight growth was developed for two contrasting sites, both with young stands of spruce. At one site sample trees were obtained from both unfertilised plots and from plots with increased growth rate maintained by annual fertilisation. At the second site unfertilised trees and trees subject to single applications of fertiliser were modelled. A model of the same structure was developed for each site and tested by application at the alternate site. In view of the close agreement between sites, model parameters were calculated based on all data combined. The model is driven by height increment and branch age. The sample trees were mostly open grown so that only a tentative estimate of the effects of between tree competition is given. The limitations of the model are stressed.     

竹镂舟蛾无公害防治技术研究

为了探索竹镂舟蛾的无公害防治方法和措施,使用森得保粉剂、苦参.烟碱烟剂和高渗苯氧威烟雾剂进行防治试验,防治效果均可达80%以上,可在竹镂舟蛾危害时应用。     

The regulation of mycorrhiza formation— carbohydrate and hormone theories reviewed

Two “classical” theories, both originating in Elias Melin's laboratory in Uppsala, have tried to explain the regulation of ectomycorrhiza formation. The carbohydrate theory, formulated by E. Björkman in 1942, identifies root carbohydrate concentrations as regulatory, while these are in turn considered to be strongly influenced by plant mineral nutrition and light conditions. The hormone theory, expounded by V. Slankis in the 1960s, claims auxin of fungal origin to be the key regulator, influencing root carbohydrate status, while the fungus itself may, to some extent, be affected by mineral nutrition. Both theories have been subject to much discussion and have led to further work, without ever having been conclusively proven experimentally. Recent results in Uppsala and elsewhere have shed new light on several of the key issues. The development of research in this field since 1942 is critically reviewed in light of later data, and a unifying theory is sketched on the basis of E. Hacskaylo's proposal from 1969 to reconcile contradictory results.