The significance of the gastrointestinal parasites of Asian buffalo in Sri Lanka

Buffalo aged 3–15 months on institutional farms and in the villages of an irrigation project were monitored for gastrointestinal nematodes by faecal egg counts over two years. Apart from treatment for Toxocara vitulorum at 10–16 days of age, no anthelmintics were used. Half of the strongylid egg counts were zero and 90% were less than 500 epg of faeces on the institutional farms, and 67% were zero and 97% less than 500 epg in the villages. No problems arose during four years without anthelmintics on the institutional farms and during two years in the villages. Autopsies demonstrated that the eggs which were present were produced by mixed infections of small numbers of Haemonchus spp., Mecistocirrus digitatus, Trichostrongylus spp., Bunostomum phlebotomum and Cooperia spp. High egg counts of Strongyloides papillosus occurred in calves up to six months old, but were not pathogenic.     

The extraparasitic life cycle of Toxocara vitulorum in the village environment of Sri Lanka

The extraparasitic life cycle of Toxocara vitulorum of buffalo in the villages of Sri Lanka is related to observations on buffalo behaviour, experimental studies on the development and persistence of the eggs in soil and in wallows and the presence of eggs in village locations. Calf faeces on soil were rapidly incorporated by insect activity and the eggs developed only slightly slower than in the laboratory. Some infective eggs persisted 3–4 cm deep for 17 months, finally dying during a prolonged hot, dry period. Eggs in a wallow developed intermittently over 16 months as it was flushed with rain water, and eventually died when the wallow dried out. When infected faeces were placed in water, decomposition caused some material to rise to the surface and eggs developed. In villages, eggs are ubiquitous where young calves are kept but survive best where there is moisture and shade around animal pens and wallows. Cows and calves acquire infection from infective eggs in wallow water, soil and pasture, while calves may also be infected from contamination on the udder and teats of the cow. The larvae resulting from this infection do not mature until the infection is passed to the calf through the milk of the cow. At least 72% of village calves have patent infections and current treatment procedures do not reduce the prevalence.The possibility that T. vitulorum is a cause of human visceral larva migrans is discussed.     

山西关帝山亚高山灌丛、草甸物种多样性的研究

运用12个多样性指数对12个灌丛群落样地和21个草甸群落样地进行了数量分析,结果如下,1)关帝山亚高山灌丛、草甸群落的物种多样性与海拔有较密切的关系,随着海拔的升高,其丰富度指数明显下降;均匀度指数表现为升高趋势;综合多样性指数也呈下降趋势;2)关帝山亚高山灌丛、草甸群落的物种多样性与坡度有较密切的关系,随着坡度的下降,灌丛、草甸的丰富度呈现平缓下降的趋势;均匀度和综合多样性呈现明显上升的趋势;3)在各多样性指数的变化幅度上,灌丛群落较草甸群落明显.     

小兴安岭3种阔叶红松林土壤微生物多样性

采用BIOLOG微平板法对小兴安岭3种阔叶红松林土壤微生物多样性进行了研究。结果表明,平均吸光值(AWCD)在春季表现为,蒙古栎(Quercus mongolica)红松林椴树(Tilia amurensis)红松林白桦(Betula platyphylla)人工林;夏季,蒙古栎红松林椴树红松林白桦人工林;秋季,椴树红松林蒙古栎红松林白桦人工林;冬季,椴树红松林蒙古栎红松林白桦人工林。微生物多样性指数随土层深度变化表现为:物种丰富度指数(SW)、物种优势度指数(SP)和群落物种均匀度指数(McIntosh)均以蒙古栎红松林最高,且显著高于白桦人工林。由此可见,原始阔叶红松林较人工林土壤相比具有更丰富的微生物多样性。     

山西省亚高山草甸群落组成及其多样性研究

[目的]以山西省从南到北分布的6个亚高山草甸为研究对象,探讨亚高山草甸的群落物种多样性和空间分布格局.[方法]采用有限样方内生物多样性的测定方法,测定了从南到北分布的6个亚高山草甸的物种组成和多样性指数,并比较了各草甸之间的群落相似性.[结果]6个亚高山草甸上共有172种植物,菊科、禾本科、蔷薇科、豆科分布较为广泛.各草甸物种多样性指数存在显著差异(P<0.05),其中大同市灵丘县亚高山草甸的群落物种多样性和丰富度指数最高,太原市娄烦县亚高山草甸的均匀度最高.从物种组成的群落相似性结果来看,吕梁市离石区亚高山草甸与大同市灵丘县亚高山草甸的物种组成相似性最高,忻州市宁武县亚高山草甸和大同市广灵县亚高山草甸的物种组成相似度最低.[结论]随着海拔的升高,亚高山草甸的多样性指数呈现随之降低的趋势.     

云雾山本氏针茅草地群落恢复演替过程中的物种多样性变化动态

采用样方法对云雾山干草原区本氏针茅草地群落进行长期定位监测,对未封育样地和封育5,10,15,20和25年样地群落的平均高度、盖度、多度和地上生物量以及植物多样性进行实地调查分析,以研究围栏封育对草地植物群落特征动态变化的影响.结果表明,围封10年样地群落的高度、多度以及地上生物量最大,而群落的盖度则随封育年限的增加呈显著增加趋势,在封育25年达到最大;围栏封育的不同年限也显著影响了群落的物种多样性,在围封10年样地群落具有最高的多样性指数,围封15年样地具有最高的丰富度指数,而均匀度指数则是在未封育群落中表现为最高值,最低值是在物种丰富度最高时出现.由此可见,围栏封育在一定时间范围内可以显著改善群落的特征,增加群落的生产力,对于本研究地本氏针茅群落的最佳封育期限为10～15年,但围封时间过长在草地退化方面有一定程度的影响.     

东洞庭湖冬、夏两季湿地鸟类多样性比较分析

2007年8月—2009年1月对东洞庭湖湿地鸟类资源进行调查,从物种丰富度指数、多样性指数、均匀性指数、G-F指数等方面对比分析了冬夏两季鸟类的群落多样性。将物种数、多样性指数、均匀性指数作为基数,运用欧氏和最短距离法进行了聚类分析,结果表明:夏季树林灌丛和居民区生境鸟类群落结构十分相似,而水域和沼泽生境鸟类群落结构相似,冬季树林灌丛和芦苇、草滩沼泽生境鸟类群落结构十分相似,而水域和居民区生境鸟类群落结构相似。     

大花金鸡菊入侵对植物多样性的影响

采用样方法研究了青岛市5个不同生境下大花金鸡菊（Coreopsis grandiflora）入侵地植物的种类和数量,分析了其物种丰富度、多样性指数和均匀度指数,并计算出每种植物的重要值。5个样地共采集本地植物92种,隶属16科,以菊科和禾本科最多,其中出现频率较高或植株数量较多的植物共33种。大花金鸡菊入侵地物种丰富度、Simpson指数、Shannon Wiener指数和Pielou指数较对照均有下降,最大下降幅度分别为34.75%、60.53%、58.22%和41.98%。大花金鸡菊的平均重要值高达56.92%,远大于群落中其他植物的重要值,并且和群落的物种丰富度有显著相关性(R2=0.907),当大花金鸡菊重要值高于20.25%时,样方内物种丰富度随着重要值的增加而减少,对入侵地的植物多样性产生不利的影响。     

不同草种混播组合在公路边坡的建植效果研究

在青海省高速公路边坡进行不同牧草与灌木混播试验,结果表明,出苗最快的为苜蓿+扁穗冰草,盖度增加也最快,到2005年9月盖度已达70%,赖草+柠条组合盖度变化较大,从2005年的5%增加到次年的90%,且生物多样性最大,群落稳定性最强。地上植物量(干重)增加最快的组合为扁穗冰草+星星草+沙棘,从2005年9月的40 g/m2增加到2006年10月的1200 g/m2。在短期内,适宜当地阴坡种植的优良组合为扁穗冰草+星星草+沙棘,阳坡为苜蓿+扁穗冰草,不同混播组合的建植效果排序如下:扁穗冰草+星星草+沙棘>苜蓿+扁穗冰草>柠条+赖草>其他。     

小兴安岭原始红松林的植被多样性

以小兴安岭凉水自然保护区为研究对象,采用生态群落学调查方法研究了红皮云杉（Picea koraiensis）红松林及落叶松（Larix gmelini）林地表植被群落结构特征及群落物种多样性。结果表明,红松林共有维管束植物36种,隶属22科32属,落叶松林共有维管束植物31种,隶属22科27属,二者均属稳定型植被群落。两种林型的物种丰富度指数（S）与物种多样性指数（SP）均表现为乔木层＜灌木层＜草本层,且红松林各层之间差异显著;物种多样性指数（SW）在落叶松林各层中差异不明显,但在红松林各层中存在显著差异,以草本层最高;物种均匀度指数（Jsw）在红松林中表现为乔木层＞灌木层＞草本层,在落叶松林中以灌木层Jsw指数最高,且明显高于红松林中各层指数。