Application of bovine microsatellite markers for genetic diversity analysis of European bison (Bison bonasus)

In this study, the cross‐amplification of a commercial multiplex set of 11 cattle (Bos taurus) microsatellites was tested on a panel of 35 European bison (Bison bonasus) individuals. After polymerase chain reaction optimization, all loci cross‐amplified successfully in investigated bisons. Number of alleles and observed and expected heterozygosity per locus are in the range of 2–4, 0.086–0.629 and 0.288–0.621 respectively. The availability of a heterologous set of multiplexed microsatellite markers derived from cattle opens an avenue for collecting profound genetic data for efficient conservation management strategies of the European bison.     

The socioeconomics and management of Santiago de Chile''s public urban forests

Santiago, Chile's semi-arid climate and urbanized environment poses a severe limitation for the establishment and maintenance of urban forests. Municipalities, or comunas, are the main stakeholders in the management of Santiago's public urban forests. A tenable hypothesis would be that as the socioeconomic level of a comuna increases, the better the condition of a comuna's urban forest. Unfortunately, there is little comprehensive information on management, public expenditure, and structure of Santiago's public and private urban forests. To examine this hypothesis, Santiago was divided into socioeconomic strata, then using air photo interpretation and stratified field sampling, urban forest structures were quantified by socioeconomic strata. In addition, interview surveys were used to determine municipal urban forest management and expenditures for different public urban forests based on socioeconomic strata. Urban forests in the high socioeconomic strata had fewer public trees, greater tree cover, tree and leaf area density, and leaf area index than lower socioeconomic strata. The percentage of total municipal budget allocated to public urban forest management was consistent among strata, but the total public urban forest budgets were greater in the high socioeconomic strata. Public urban forest structure is related to the socioeconomic strata of Santiago's different comunas.     

氮源对番茄灰霉病菌菌丝生长的影响

选用15种常见氮源,应用固体和液体培养方法,筛选适宜番茄灰霉病菌生长的氮源营养物质.结果表明:在固体培养中,病菌对氮源的利用以蛋白胨为最好,其次为酵母膏.在液体培养中,病菌对氮源的利用以酵母膏为最好,其次为(NH4)2SO4.     

Cytochrome P-based resistance mechanism and pyrethroid resistance in the field Anopheles albimanus resistance management trial

The relative rates of cytochrome P⁴⁵⁰ selection in southern Mexican Anopheles albimanus populations were investigated during a 3 years indoor residual house spraying intervention with a pyrethroid (PYR) or DDT, a mosaic of organophosphate (OP)-PYR, and the annual rotation of OP-PYR-carbamate (CARB). This insecticide resistance mechanism, initially evenly spread in the mosquito population, correlated with PYR resistance during the second treated year, when cytochrome P⁴⁵⁰ contents increased in most villages of the PYR, rotation and mosaic schemes. However, by the third year, mean cytochrome P⁴⁵⁰ contents declined to susceptible levels in mosquitoes of the rotation and one mosaic group but not in the PYR-treated villages. In DDT-treated villages, a continuous decrement of cytochrome P⁴⁵⁰ levels occurred since the first treatment year, and susceptible levels were observed at the end of the intervention. Most correlations of cytochrome P⁴⁵⁰ levels and PYR resistance were lost during the third year, indicating that another mechanism evolved in resistant mosquito populations.     

氮素水平与光强互作对‘蓝伞’玉簪生长和光合特性的影响

 以蓝灰类型玉簪‘蓝伞’（Hosta 'Blue Umbrella'）为材料，研究了4种光强（自然光照的100%、50%、30%、10%）和4种氮素水平（盆栽土施尿素量0、0.5、1.5和2.5 g·kg^-1）处理对玉簪生长和光合特性的影响。结果表明：‘蓝伞’玉簪的生长和光合特性受光强、氮素水平以及光氮互作的影响。在同一氮素水平下，随着光照强度的减弱，玉簪的生物量、叶面积、叶片数、光合速率及可溶性蛋白含量均表现先上升后下降的趋势，在30%～50%光强下达到最大值；叶绿素含量则随光强的减弱而增加。在同一光照强度下，随着氮素水平的升高，玉簪的生物量、叶面积、叶片数、光合速率及叶绿素和可溶性蛋白含量均呈先上升后下降的趋势，在0.5 g·kg^-1氮素水平下达到最大值。     

Geospatial methods provide timely and comprehensive urban forest information

Urban forests are unique and highly valued resources. However, trees in urban forests are often under greater stress than those in rural or undeveloped areas due to soil compaction, restricted growing spaces, high temperatures, and exposure to air and water pollution. In addition, conditions change more quickly in urban as opposed to rural and undeveloped settings. Subsequently, proactive management of urban forests can be challenging and requires the availability of current and comprehensive information. Geospatial tools, such as, geographic information systems (GIS), global positioning systems (GPS) and remote sensing, work extremely well together for gathering, analyzing, and reporting information. Many urban forest management questions could be quickly and effectively addressed using geospatial methods and tools. The geospatial tools can provide timely and extensive spatial data from which urban forest attributes can be derived, such as land cover, forest structure, species composition and condition, heat island effects, and carbon storage. Emerging geospatial tools that could be adapted for urban forest applications include data fusion, virtual reality, three-dimensional visualization, Internet delivery, modeling, and emergency response.     

Simulating the cumulative effects of multiple forest management strategies on landscape measures of forest sustainability

While the cumulative effects of the actions of multiple owners have long been recognized as critically relevant to efforts to maintain sustainable forests at the landscape scale, few studies have addressed these effects. We used the HARVEST timber harvest simulator to predict the cumulative effects of four owner groups (two paper companies, a state forest and non-industrial private owners) with different management objectives on landscape pattern in an upper Michigan landscape managed primarily for timber production. We quantified trends in landscape pattern metrics that were linked to Montreal Process indicators of forest sustainability, and used a simple wildlife habitat model to project habitat trends. Our results showed that most trends were considered favorable for forest sustainability, but that some were not. The proportion of all age classes and some forest types moved closer to presettlement conditions. The trend for the size of uneven-aged patches was essentially flat while the average size of patches of the oldest and youngest age classes increased and the size of patches of the remaining age classes decreased. Forest fragmentation generally declined, but edge density of age classes increased. Late seral forest habitat increased while early successional habitat declined. The owners use different management systems that cumulatively produce a diversity of habitats. Our approach provides a tool to evaluate such cumulative effects on other landscapes owned by multiple owners. The approach holds promise for helping landowner groups develop and evaluate cooperative strategies to improve landscape patterns for forest sustainability.     

Linking Land-use, Water Body Type and Water Quality in Southern New Zealand

Land-use and vegetation cover have been linked to the nutrient levels (nitrogen, phosphorus) of surface waters in several countries. However, the links generally relate to streams and rivers, or to specific types of standing water, for example shallow lakes in a geologically defined region. We measured physical variables and nutrient chemistry of 45 water bodies representative of the wide range of lentic wetland environments (swamps, riverine wetlands, estuaries, reservoirs, shallow lakes, deep lakes) in Otago, New Zealand, and related these to catchment variables and land-use in order to assess the potential influence of catchment modification on water quality of these diverse wetlands. Catchment boundaries and land cover were derived from maps using ArcView GIS software. Our predictions that concentrations of nutrients and other components of water quality would correlate positively with the nature and intensity of catchment modification were confirmed in multivariate analyses. Physical and chemical measures were positively related to the extent of modification in the catchment (percentage of the catchment in pasture, planted forest, scrub and urban areas), and negatively related to lack of catchment modification (more of the catchment in bare ground, tussock grassland and indigenous forest). The strong negative correlations between nutrient concentrations, suspended sediment, water colour and the percentage of tussock cover in the catchment imply that increased conversion of the␣native tussock grassland to pastoral farming in␣Otago will increase nutrient concentrations and␣reduce water quality of the diverse lentic ecosystems.     

浑善达克沙地东段风沙源治理模式初步研究——以内蒙古克什克腾旗为例

针对浑善达克沙地东段的自然经济条件和沙漠化危害特点,因地制宜地营建农防林与牧防林相结合,防护林与经济林相结合,沙漠化治理与沙产业开发相结合的综合防护体系6667hm2。防护体系建立后,区域内生态环境明显改善,维护了首都的生态安全。     

Relating plant and pathogen development to optimise fungicide control of phoma stem canker (<Emphasis Type="Italic">Leptosphaeria maculans</Emphasis>) on winter oilseed rape (<Emphasis Type="Italic">Brassica</Emphasis><Emphasis Type="Italic">napus</Emphasis>)

In winter oilseed rape experiments at Rothamsted in 2000/01 to 2002/03 growing seasons, the severity of phoma stem canker epidemics in summer depended on the timing of phoma leaf spot epidemics in the previous autumn, and hence on the timing of Leptosphaeria maculans ascospore release. The first major release of L. maculans ascospores was earlier in 2000 (26 September) and 2001 (18 September) than in 2002 (21 October). Consequently, the autumn phoma leaf spot epidemic was also earlier in 2000 and 2001 than in 2002. The resulting stem canker epidemics were severe by harvest (July) in 2001 and 2002 but not in 2003. No correlation was found between the severity or duration of phoma leaf spotting (lesion days or lesion °C-days) and the subsequent severity of phoma stem canker epidemics. Rates of leaf production and loss were similar in the three growing seasons. Out of ca. 25 leaves produced on plants during each season, leaf numbers 10–14 generally remained on plants for the longest. Treatment with flusilazole + carbendazim in autumn decreased the severity of phoma leaf spotting for several weeks after treatment, decreased the severity of stem canker the following summer and increased yield significantly in 2001 and 2002 but not in 2003. The most effective timings for flusilazole + carbendazim application were when leaves 7–11 were present on most plants and at least 10% of plants were affected by phoma leaf spot. Two half-dose applications of fungicide reduced phoma stem canker and increased yield more than a single full dose application when phoma leaf spot epidemics were early (<800 °C-days after sowing).