Separating the effects of habitat amount and fragmentation on invertebrate abundance using a multi-scale framework

Context

Herbicide treatments in viticulture can generate highly contrasting mosaics of vegetated and bare vineyards, of which vegetated fields often provide better conditions for biodiversity. In southern Switzerland, where herbicides are applied at large scales, vegetated vineyards are limited in extent and isolated from one another, potentially limiting the distribution and dispersal ability of organisms.

Objectives

We tested the separate and interactive effects of habitat amount and fragmentation on invertebrate abundance using a multi-scale framework, along with additional environmental factors. We identified which variables at which scales were most important in predicting patterns of invertebrate abundance.

Methods

We used a factorial design to sample across a gradient of habitat amount (area of vegetated vineyards, measured as percentage of landscape PLAND) and fragmentation (number of vegetated patches, measured as patch density PD). Using 10 different spatial scales, we identified the factors and scales that most strongly predicted invertebrate abundance and tested potential interactions between habitat amount and fragmentation.

Results

Habitat amount (PLAND index) was most important in predicting invertebrate numbers at a field scale (50 m radius). In contrast, we found a negative effect of fragmentation (PD) at a broad scale of 450 m radius, but no interactive effect between the two.

Conclusions

The spatial scales at which habitat amount and fragmentation affect invertebrates differ, underpinning the importance of spatially explicit study designs in disentangling the effects between habitat amount and configuration. We showed that the amount of vegetated vineyards has more influence on invertebrate abundance, but that fragmentation also contributed substantially. This suggests that efforts for augmenting the area of vegetated vineyards is more beneficial for invertebrate numbers than attempts to connect them.

     

北方农牧过渡带农户农业生产系统模式评价与优化研究

以内蒙古赤峰市为例,采用切诺斯评价法对北方农牧过渡带典型地区的偏牧区、偏农区和半农半牧区3种类型区常见的6种家庭农业生产系统模式进行了社会经济效益、生态效益和资源利用效率的系统评价与优选,结果表明草地畜牧业和养猪模式、种植业和育肥牛模式、农牧结合模式效益较好,并针对3种模式存在的问题提出优化改良方案,改良后的优化模式分别比原模式户均收入提高26．8％、81．0％和46．9％,投资效益提高4．7％、7．1％和4．2％;产出总能分别提高27．0％、77．0％和70．5％;光能利用率分别提高14．6％、23．8％和47．6％。     

入侵植物薇甘菊和三叶鬼针草对土壤细菌群落的影响

【研究目的】通过比较外来植物薇甘菊和三叶鬼针草对入侵地土壤细菌群落的影响,以期揭示外来植物入侵的土壤微生物学机制。【方法】基于16S rDNA的PCR-DGGE图谱分析,结合条带割胶回收DNA进行序列分析的方法,对入侵植物薇甘菊和三叶鬼针草在广州不同入侵程度的土壤中细菌群落的多样性及优势类群进行比较分析。【结果】DGGE图谱分析结果表明：薇甘菊重度入侵与轻度入侵、重度入侵与未入侵样品中的细菌群落结构的相似性分别为59.6%和54.2%;三叶鬼针草重度入侵与轻度入侵、重度入侵与未入侵样品中的细菌群落结构的相似性分别为60.0%和58.6%。DGGE图谱中特异性条带序列分析表明：薇甘菊和三叶鬼针草入侵引起变化的优势菌群为与α、β、γ变形菌纲和芽孢杆菌有很近亲缘关系的不可培养细菌。【结论】2种入侵植物在不同入侵程度土壤中改变了土壤细菌群落的组成和种类,有可能形成有利于自身生长的微环境,以便于进一步扩张。     

Effect of probiotic supplementation on growth performance,intestinal morphology,barrier integrity,and inflammatory response in broilers subjected to cyclic heat stress

This study investigated the protective effects of probiotic on heat stress‐induced intestinal injury and inflammatory response in broilers. A total of 180 male broilers were randomly allocated to three treatments with four replicates each from 22 to 42 days of age. The broilers were either raised under thermoneutral (TN) conditions (23 ± 1°C) or subjected to cyclic heat stress (28–35–28°C for 12 hr daily). The broilers kept at TN conditions were fed a basal diet, and those exposed to heat stress were fed basal diets supplemented with or without probiotic at a dose of 1.5 × 10⁸ cfu/kg. Compared with the TN group, heat stress decreased (p < .05) the growth performance, reduced (p < .05) villus height and villus height: crypt depth ratio in intestinal mucosa, increased (p < .05) serum levels of D‐lactic acid on day 28 and endotoxin, TNF‐α and IL‐6 on day 42, and decreased (p < .05) serum IL‐10 content on day 42. Dietary supplementation of probiotic reversed (p < .05) all these changes except for the growth performance in heat‐stressed broilers. In conclusion, dietary inclusion of probiotic could improve intestinal morphology and barrier function, alleviate inflammatory response, but exert no ameliorative effect on growth performance of broilers under cyclic heat stress.     

杭椒采收期内辣椒素类物质和维生素C的动态变化

  目的  研究杭椒Capsicum annuum ‘Hangzhou Jizhua’בJilin Zaojiao’果实辣椒素、维生素C等物质在采收期的动态变化,以确定最佳采收期。  方法  选取4个常见杭椒品种,采用高效液相色谱法分别测定开花后14、21、28、35、42、49、56 d采收的果实中辣椒素、二氢辣椒素和维生素C以及干物质质量分数。  结果  采收期内4个杭椒品种果实辣椒素类物质质量分数不同,品种间差异显著(P＜0.05);维生素C质量分数和干物质相对含量随果实成熟度增加而升高。  结论  花后49 d是杭椒果实最佳采收期,此时果实成熟度好,辣椒素类物质、维生素C质量分数和干物质相对含量均较高。采收期内不同品种辣椒素类物质质量变化差异大,具体采收计划应综合种植品种、市场需求和供求关系等多方面因素考虑。图4表3参27     

竹产品设计理论分析

通过揭示和阐述竹产品设计、产品特征、形成规律等现象和实质，推导论证单体元素功能、设计构成法则和“重构”设计运用等竹产品设计固有成份和特点，剖析规范竹单体、基本型和集合连接方式等在设计中的位置和作用，从而加深了对竹产品属性的认识，丰富产品设计理论内容，为电脑辅助设计提供初步的专业术语和创作途径。     

Metabolic clearance rate of cortisol in pigs: relationship to adrenal responsiveness

Experiments were conducted on 12 prepuberal (18- to 20-week-old) Landrace cross Large White gilts to establish if differences in adrenal responsiveness between individuals could be explained by differences in the metabolic clearance rate (MCR) of cortisol. Pigs with the highest (n = 6) and lowest (n = 6) cortisol concentration 60 minutes after challenge with ACTH were selected from a pool of 36 commercial pigs. Tritium-labelled cortisol was infused (17 to 27 ml h-1) continuously for 120 minutes to establish 'steady state' conditions. Blood samples (10 ml) were collected at 90, 100, 110 and 120 minutes. Replicate experiments were performed on some pigs. Classification of individual pigs as high or low adrenal responders to ACTH challenge was confirmed at the end of the clearance rate experiments. The MCR of cortisol in the group classed as low adrenal responders was 59.7 +/- 7.8 litres h-1 or 1.01 litres h-1 kg-1 (n = 7) which was not significantly different from the average MCR in the group classed as high adrenal responders 60.2 +/- 5.9 litres h-1 or 1.19 litres h-1 kg-1 (n = 10). These results suggest that the repeatable differences in adrenal responsiveness to ACTH that exist between individuals within a particular strain of pig depend on differences in the rate of synthesis of cortisol in response to ACTH stimulation, rather than on differences in its rate of metabolism.     

外源DNA导入水稻的初步研究

设计了不同药剂和接种方法处理的胚培法将玉米DNA导入水稻的试验,对导入后代进行单株产量的分析结果表明:a.水稻采用一般胚培法(MS+DNA+胚)导入玉米DNA,未能产生主要经济性状(单侏产量)的有利变异;b.胚经不同药剂(丙酮、氯化钙和十二烷基硫酸钠)处理后,能促进外源DNA的导入;c.采用4%丙酮浸胚12h后。再接种到培养基(MS+DNA)上的方法,导入效果较好。     

谈Windows中汉字输入方法的挂接

本文介绍了在Windows下如何增加、挂接新的汉字输入法的方法、步骤及其注意事项,简单、实用。     

珍龙13和窄叶青8号抗稻瘟病遗传分析

 用稻瘟病(Pyricularia oryzae)的菌株75-49和0206-1(分别代表ZB和ZC群小种)接种抗病品种窄叶青8号、珍龙13与感病品种朝六早、朝阳一号的杂交组合,根据F₁、F₂、F₃和B₁F₁分析结果,窄叶青8号对菌株75-49和0206-1的抗性由两对抗性基因控制,而珍龙13对菌株0206-1的抗性由单显性抗性基因控制。