Endemic type of animal trypanosomiasis is not associated with lower genotype variability of Trypanosoma congolense isolates circulating in livestock

In order to verify whether the low impact on livestock production in endemic areas is related to a low number of trypanosome strains circulating in livestock, 37 Trypanosoma congolense isolates collected from cattle in 11 sites in an endemic trypanosomiasis area in Eastern Zambia were characterised for genotype variability using a modified amplified fragment length polymorphism technique (AFLP). Isolates were further cloned to evaluate the occurrence of mixed infections in individuals. The results obtained revealed a high genotype diversity (94.6%) among these isolates. Apart from one site, all isolates gave different AFLP profiles in each of the sites. When clones were compared, three (8%) of the 37 isolates had mixed infections. These results indicate the circulation of a high number of strains in this trypanosomiasis endemic area despite the low impact the disease has on livestock production.     

Regional population viability of grassland songbirds: Effects of agricultural management

Although population declines of grassland songbirds in North America and Europe are well-documented, the effect of local processes on regional population persistence is unclear. To assess population viability of grassland songbirds at a regional scale (∼150,000 ha), we quantified Savannah Sparrow Passerculus sandwichensis and Bobolink Dolichonyx oryzivorus annual productivity, adult apparent survival, habitat selection, and density in the four most (regionally) common grassland treatments. We applied these data to a female-based, stochastic, pre-breeding population model to examine whether current grassland management practices can sustain viable populations of breeding songbirds. Additionally, we evaluated six conservation strategies to determine which would most effectively increase population trends. Given baseline conditions, over 10 years, simulations showed a slightly declining or stable Savannah Sparrow population (mean bootstrap λ = 0.99; 95% CI = 1.00-0.989) and severely declining Bobolink population (mean bootstrap λ = 0.75; 95% CI = 0.753-0.747). Savannah Sparrow populations were sensitive to increases in all demographic parameters, particularly adult survival. However for Bobolinks, increasing adult apparent survival, juvenile apparent survival, or preference by changing habitat selection cues for late-hayed fields (highest quality) only slightly decreased the rate of decline. For both species, increasing the amount of high-quality habitat (late- and middle-hayed) marginally slowed population declines; increasing the amount of low-quality habitat (early-hayed and grazed) marginally increased population declines. Both species were most sensitive to low productivity and survival on early-hayed fields, despite the fact that this habitat comprised only 18% of the landscape. Management plans for all agricultural regions should increase quality on both low- and high-quality fields by balancing habitat needs, nesting phenology, and species’ response to management.     

Eucalyptus urophylla root growth, stem sprouting and nutrient supply from the roots and soil

Lack of information concerning root growth of trees limits our knowledge of plant development and fertilizer response. The objective of this work was to study root growth dynamics of an E. urophylla forest after harvesting and the supply of nutrients from the roots and the soil to the new sprouts originating from the stumps. About 7-year-old eucalypt trees were felled and the sprouts and roots were sampled at 0, 60, 120, 180, 240, 330 days after harvesting. The roots were separated into fine roots (<1 mm), medium roots (1–3 mm), coarse roots (>3 mm), and taproot. Nutrient supply to sprouts from the old roots and the soil was calculated based on the change in nutrient content of the roots with time and accumulation of nutrients in the sprouts. Fine, medium and coarse root biomass increased with time after harvesting. However, the increase was more pronounced with fine roots. Between harvesting and day 60 of the new growth, all nutrients allocated to the sprouts, excluding potassium, were supplied by the soil. K was the nutrient most dependent on root reserves for the initial growth of sprouts. The contribution of the old roots to N, P, Ca, and Mg accumulation in the sprouts increased between day 60 and 120. At 330 days after harvesting, about 9.2, 23.9, and 12.6% of the N, K, and Mg, respectively, that had accumulated in the sprouts were supplied by the roots, while all P and Ca were supplied by the soil.     

The Development of Chinese Royal Gardens

This study discussed the development and evolution of Chinese royal gardens from the initial generation period (Zhou,Qin and Han dynasties) to the late mature period (middle Qing Dynasty to the late Qing Dynasty).Through the specific analysis of the typical royal gardens in different periods,the development and changes of the gardening skills and overall layout of the royal gardens in each period were obtained,and the development characteristics of the whole historical period of the Chinese royal gardens were summarized.     

Seasonal,sex and live weight variations in feed and water consumptions of adult captive African Giant rats (Cricetomys gambianus,Waterhouse – 1840) kept individually in cages

Adult African Giant rats (Cricetomys gambianus, Waterhouse) (AGRs) (n = 231) of both sexes (117 bucks, 114 does) were live‐trapped in the wild in Zaria, Nigeria. Live weight (LW), daily feed consumption (FC) and water consumption (WC) of the AGRs were measured during the cold‐dry (CDS), hot‐dry (HDS) and rainy (RS) seasons for 2 years with the aim of determining seasonal, sex and LW variations. Feed consumption was significantly different (p < 0.001) between all the seasons, with the lowest mean value recorded during the HDS, while the highest was obtained during the RS. Water consumption was also lowest (p < 0.001) during the HDS but did not differ significantly (p > 0.05) between the CDS and RS. Both feed and water consumptions were higher (p < 0.01) in the males (bucks) than the females (does) during the CDS and HDS, but the sex difference was not significant (p > 0.05) during the RS. Feed consumption correlated positively (p < 0.0001) with WC and relative humidity, but negatively (p < 0.0001) with LW, ambient temperature and heat index. In conclusion, both feed and water consumptions in AGRs decrease with increased seasonal heat and adult LW and are lower in does than in bucks during the dry seasons (CDS and HDS). Intervention may be indicated during the HDS to improve feed and water consumptions for optimal performance of the AGRs.     

The Costa Rican Association for the Study of Native Forestry Species (CANS)

SUMMARY

In the Gran Sabana of Venezuela and the North Rupununi Savannah of Guyana, protected areas have been established primarily for purposes of conservation. However, both Canaima National Park in Venezuela and the Iwokrama International Centre for Rainforest Conservation and Development in Guyana are multiple use areas where a variety of resource use occurs and/or is planned. Shifting cultivation by the indigenous population is currently both the most common use of the forest and the use of longest duration in both areas. Surveys were conducted of paired primary and secondary forests in order to test the hypothesis that traditional, dispersed shifting cultivation with long fallows and no post-cultivation disturbance is sustainable, resulting in the eventual re-establishment of diverse secondary forests. Interviews and observations of agricultural practices and surveys of agricultural fields were conducted to determine the contemporary forest use practices and the extent to which traditional practices have changed. Results indicate that even dispersed, long fallow shifting cultivation requires careful management and several disturbance-free decades before diversity levels in secondary forests approach those in old growth. Further, that the process of integration and cultural “development” has destabilized this traditionally sustainable system in some areas. A central assumption of the paper is that with an understanding of the impacts of shifting cultivation and of the conditions under which it is sustainable, informed decisions about protected area management can be made. The data provide valuable and hitherto missing information on the levels of forest disturbance that can be sustained in the two protected areas while still meeting conservation goals.     

用多重PCR方法检测奶牛场麻雀中分枝杆菌感染情况

目的：利用可以鉴别分支杆菌属中结核分枝杆菌、牛分支杆菌、非结核分枝杆菌多重PCR方法,检测奶牛场麻雀组织中分支杆菌感染情况。方法根据结核分枝杆菌种特异基因目的片段MTP40、分枝杆菌属特异基因32kD、结核分枝杆菌复合群特异基因IS6110插入序列,设计合成三对特异性引物,扩增对32kD的506bp、MTP40的396bp和IS6110的984bp片段,以此方法检测奶牛场麻雀肺组织中分支杆菌感染情况,并对阳性结果的目的片段进行克隆测序。结果在分析的21份麻雀肺组织中,检测出2例非结核分枝杆菌阳性病料,阳性率9.52%。2例阳性样本PCR扩增得到的片段与GenBank收录的32kD基因同源性分别为95.8%和97.2%。结论麻雀肺组织中存在分支杆菌感染阳性病例提示该牛场中生物体内存在分支杆菌潜伏感染,并可能导致奶牛的潜伏感染以及干扰结核检疫。     

不同禽鸟类传染性法氏囊病病毒分离物核酸及结构蛋白的比较

将从鸡、鸭和麻雀体内分离到的ＩＢＤＶ用ＳＰＦ鸡胚增殖,采用氯仿抽提、聚乙二醇沉淀和蔗糖密度梯度离心的方法纯化病毒,鉴定结果表明,这种方法可有效地将病毒与杂蛋白分开。用异硫氰酸胍－酚－氯仿－抽提一步法提取病毒ＲＮＡ,电泳分析表明,三种ＩＢＤＶ均由双节段ＲＮＡ组成,大、小基因片段的电泳迁移率毒株间无差异。ＳＤＳ－ＰＡＧＥ分析表明,各ＩＢＤＶ的结构蛋白带谱相同,但各蛋白带的相对百分含量有差异,表明这些不同ＩＢＤＶ分离株的同源性和变异。本文还对ＩＢＤＶ的纯化和变异进行了讨论。     

The effects of habitat resolution on models of avian diversity and distributions: a comparison of two land-cover classifications

Quantifying patterns is a key element of landscape analysis. One aspect of this quantification of particular importance to landscape ecologists is the classification of continuous variables to produce categorical variables such as land-cover type or elevation stratum. Although landscape ecologists are fully aware of the importance of spatial resolution in ecological investigations, the potential importance of the resolution of classifications has received little attention. Here we demonstrate the effects of using two different land-cover classifications to predict avian species richness and the occurrences of six individual species across the conterminous United States. We compared models built with a data set based on 14 coarsely resolved land-cover variables to models built with a data set based on 160 finely resolved land-cover variables. In general, comparable models built with the two data sets fit the data to similar degrees, but often produced strikingly different predictions in various parts of the country. By comparing the predictions made by pairs of models, we determined in which regions of the US predictions were most sensitive to differences in land-cover classification. In general, these sensitive areas were different for four of the individual species and for predictions of species richness, indicating that alternate classifications will have different effects in the analyses of different ecological phenomena and that these effects will likely vary geographically. Our results lead us to emphasize the importance of the resolution to which continuous variables are classified in the design of ecological studies.This revised version was published online in May 2005 with corrections to the Cover Date.     

Response of grain sorghum to fertilisation with human urine

Human urine is rich in valuable plant nutrients, and, when separately collected, it can substitute for fertilisers. A high valorisation of urine in crop production requires that each nutrient be balanced to match the actual demand. The objective of the present study was to evaluate the effectiveness of phosphorus- (P) and potassium- (K) balanced urine as a nutrient source for the cultivation of sorghum (Sorghum bicolor (L.) Moench). For this purpose, human urine, mineral fertiliser and compost plus urine were compared in field experiments. Triple super phosphate and potassium chloride were added to the urine fertiliser and potassium chloride to the compost-urine fertiliser to supply similar amounts of nitrogen (N), P and K (100, 44, 83 kg ha⁻¹ in 2006; 50, 22, 42 kg ha⁻¹ in 2007 and 2009) as NPK mineral fertiliser. The mineral fertiliser treatment was repeated with the addition of water at the same volume as contained in urine to one variant.No distinct changes in the chemical soil properties were detected, but a consistent decrease in pH and cation content was observed for mineral fertiliser, while these parameters increased in the urine and compost treatments. The plants responded to all fertilisers with faster development and significant increases in the number of green leaves, size and total area. One hectare produced 520 kg grains in non-fertilised control soil while grain yields per hectare were 1657 kg in urine fertilised, 1244 kg in mineral fertilised and 1363 kg in mineral fertilised and water added and 2127 kg in compost fertilised plots.Our results demonstrate that for the cultivation of sorghum, the N requirement can be fully met and the P and K requirements can be partially met by urine and substitute mineral fertilisers. Where feasible, the combined application of compost and urine is recommended. The long-term impact of fertilisation with human urine requires further investigation with respect to N efficiency, the effect of sulphur and soil salinisation.