入侵物种紫茎泽兰研究进展

紫茎泽兰是一种世界公认的恶性有毒杂草。紫茎泽兰的入侵不仅会对我国的生态环境、农林业及畜牧业等造成相当严重的破坏,还会导致巨大的经济损失。就紫茎泽兰的特征特性、化学成分、入侵机理、危害、防除措施、活性及饲料生产中的应用进行了综述。     

Impacts of Fire and Invasive Species on Desert Soil Ecology

A review of literature shows that both fire and invasive species may cause changes in biological, chemical, and physical properties of desert soils. Although soil may recover from the impacts of fire during succession, these changes are permanent under persistent invasive species. The most severe effects of fire occur under high temperatures with high fuel buildup and soil moisture that conducts heat downward. Deserts typically have low fuel mass and low soil moisture, both conditions that would contribute to lower impacts of fire than in mesic soils. Soil is a good insulator, so soil microorganisms will survive a few centimeters deep even in hot surface fires. Immediately postfire there is often an increase in mineral nitrogen (N) and a decrease in soil carbon (C) and organic N, but these changes are often minimal in desert soils, except under fertile shrub islands that have higher fuel loads and fire temperature. Both hot and cold deserts have experienced slow recovery of native shrubs and increased growth of invasive grasses following fire. Invasive species may either increase or decrease soil N and C depending on fire temperature and site and species characteristics. Mineralization and fixation of N are often high enough after fire that subsequent productivity balances N losses. The elimination of islands of fertility coupled with postfire erosion may be a major impact after fire in grass-invaded shrub lands. In the long term, the interaction of fire and invasive species may result in more frequent fires that eliminate fertile islands and reduce the productivity of deserts. Managers may use fire as a tool to control desert invasives without the concern that N will be irrevocably lost, but this must be done judiciously to avoid eliminating shrubs and further increasing invasive species.     

草原火烧及温度处理对五种草原植物种子发芽率的影响

羊草草原火烧后，大针茅等五种植物当年生种子的千粒重平均增加11．7％，发芽率平均增加113．6％。实验室温度处理对种子的发芽有刺激作用，对采自未烧地种子的刺激作用更明显。随着处理温度的升高，种子的发芽率亦随之升高，以50℃、4分钟处理的发芽率最高，但随着处理温度的再升高，发芽率逐步降低。不同草种的种子对温度处理反应的敏感程度各异，灰绿藜受干热刺激最敏感，斜茎黄蓍等硬实种子对干热温度的刺激则反应迟钝。     

Impact of Cultivation Legacies on Rehabilitation Seedings and Native Species Re-Establishment in Great Basin Shrublands

Little is known about how cultivation legacies affect the outcome of rehabilitation seedings in the Great Basin, even though both frequently co-occur on the same lands. Similarly, there is little known about how these legacies affect native species re-establishment into these seedings. We examined these legacy effects by comparing areas historically cultivated and seeded to adjacent areas that were seeded but never cultivated, for density of seeded crested wheatgrass (Agropyron cristatum [L.] Gaertn.) and native perennial grasses, vegetation cover, and ground cover. At half of the sites, historically cultivated areas had lower crested wheatgrass density (P < 0.05), and only one site had a higher density of crested wheatgrass (P < 0.05). Likewise, the native shrub Wyoming big sagebrush (Artemisia tridentata Nutt. subsp. wyomingensis Beetle & Young) had lower cover (P < 0.05) in historically cultivated areas at half the sites. Sandberg bluegrass (Poa secunda J. Presl.) density was consistently lower in historically cultivated areas relative to those seeded-only. At sites where black greasewood (Sarcobatus vermiculatus [Hook.] Torr.) and bottlebrush squirreltail (Elymus elymoides [Raf.] Swezey) were encountered, there was either no difference or a higher density and cover within historically cultivated areas (P < 0.05). Likewise, cover of exotic forbs, especially halogeton (Halogeton glomeratus [M. Bieb.] C. A. Mey.), was either not different or higher in historically cultivated areas (P < 0.05). Bare ground was greater in historically cultivated areas at three sites (P < 0.05). These results suggest that cultivation legacies can affect seeding success and re-establishment of native vegetation, and therefore should not be overlooked when selecting research sites or planning land treatments that include seeding and or management to achieve greater native species diversity.     

两种片形吸虫感染家兔的试验比较

用大片形吸虫和肝片形吸虫感染家兔以便选择大片形吸虫对动物的最佳感染量,及明确肝片形吸虫和大片形吸虫的生物学和对动物宿主的致病力的差别。结果显示肝片形吸虫虫体在兔体内发育成熟的时间早于大片形吸虫,感染成活率更高,对动物的病理损害明显比感染大片形吸虫兔的病变要轻。本试验证实这两种片形吸虫除了形态学的差异外,在对动物致病力、病理损害等方面确实存在差别。     

Potential Spread of Cheatgrass and Other Invasive Species by Feral Horses in Western Colorado

The invasive grass cheatgrass (Bromus tectorum L.) presents major challenges for land management and habitat conservation in the western United States. Feral horses (Equus ferus caballus) have become overabundant in some areas of the West and can impact fragile semiarid ecosystems. Amid ongoing efforts to control cheatgrass in the Great Basin, we conducted a study to determine if feral horses contribute to the spread of cheatgrass through distribution via their feces. We collected feral horse fecal samples from Little Book Cliffs Herd Management Area in western Colorado in 2014. Fecal samples were dried, and 20 from each of 3 collection sessions were cultivated to examine germination success. Six species germinated from 18 samples (30%; mostly one plant per sample where germination occurred), including cheatgrass from 8% of samples. In a separate study we examined the diet of this same horse population using fecal plant DNA barcoding. Plant species that germinated were rare in the diet and germinated from fewer samples than expected relative to their detection in the diet. Our results suggest that feral horses could be contributing to cheatgrass propagation. Native ungulates and domestic cattle also have this potential. Although management of all large ungulates is necessary to mitigate cheatgrass spread, control of feral horse numbers is particularly necessary.     

蛇岛外来物种入侵现状及生态影响调查

蛇岛是我国唯一一个以蛇岛蝮蛇（Agkistrodon shedaoensis）为主要保护对象的国家级自然保护区,具有重要的科研和生态保护价值,但外来物种入侵已经对该岛生态环境及生物多样性造成严重威胁。本文对蛇岛外来物种的入侵现状进行了野外实地调查,并对其入侵途径、危害特点进行了详细分析。同时,为有效保护蛇岛蝮蛇及蛇岛的生物多样性,提出了控制外来物种入侵的具体建议和对策。     

入侵植物美洲商陆与3种牧草的竞争效应研究

以美洲商陆（Phytolacca americana）和紫花苜蓿‘吉利’（Medicago sativa ‘Ghillie’）、拉巴豆‘润高’（Dolichos lablab ‘Rongai’）、甜高粱‘大力士’（Sorghum dochna ‘Hunnigreen’）为试验材料,采用复合De Wit取代试验方法,探讨入侵植物与牧草间的竞争效应。结果表明：美洲商陆与3种牧草低密度混种下,其株高与生物量均显著低于单种的美洲商陆;在高密度混种下,美洲商陆与拉巴豆混种时的差异最显著,其株高比单种降低53.52%~81.95%,生物量比单种降低90.22%~98.67%;在美洲商陆与拉巴豆两者的竞争关系中,美洲商陆相对产量（relative yield,RY）值均极显著小于1.0,拉巴豆RY值在中、高密度下均大于1.0,且拉巴豆对美洲商陆的攻击力系数（aggressivity,A）显著大于0,表明两者混种时,拉巴豆的攻击力大于美洲商陆,混种阻碍了美洲商陆的生长,拉巴豆对美洲商陆具有较强的控制潜力。     

实验条件下四种啮齿动物的日能量收支

1997年在内蒙古鄂尔多斯沙地对小毛足鼠、三趾跳鼠、子午沙鼠和黑线仓鼠日能量收支进行研究。结果表明,4种鼠日能量收支均表现为夏季低,春秋两季高。单位体重日能量收支与其体重呈极显著的负次幂相关,其关系式为:日能量收支(Jg^-1d^-1)=2432.3×体重(g)^－0446。以平均日代谢率为基础的日能量收支实测值与Grodzinski等(1975)经验模型的期望值接近,而与Nagy(1994)经验模型的期望值相差较大。     

升金湖越冬白头鹤集群变化及领域行为

白头鹤是长江中下游的大型越冬水鸟,安徽升金湖是其在国内主要的越冬地之一。近年来,由于生境退化,越冬种群的数量在萎缩,种群的越冬生态研究十分必要。2007年10月～2008年4月,我们在升金湖对白头鹤的主要分布地点进行了调查,并对集群情况进行了观察。升金湖白头鹤觅食地主要分布于湖区外围的稻田,夜栖于上湖核心区内。整个越冬期,白头鹤大部分以5只以上的群类型觅食,以家庭集群活动仅占越冬集群数的29.14%。随着越冬期的变化,集群大小发生改变：越冬前期,越冬鹤以家族群活动频率最高,占集群的35.64%,30～49只集群频率最低,仅为6.38%;越冬中期,家庭集群及5～9只集群频率相对于越冬前期减少,10只以上集群频率增加;越冬后期,以≥50只以上集群频率最高,占28.77%。此外,我们还观察到1对成年鹤占有一定面积的稻田并积极保护,表现领域行为。     

软件学院双师型教师队伍建设的研究与实践

软件学院要培养面向实际应用、实践能力强的高素质应用型复合人才,建设一支具有高水平教学技能、职业技能和职业素养的双师型教师队伍是非常重要的。本文分析了双师型教师标准和培养机制。实践证明,双师型教师能更有效地培养出符合社会需要的、实践创新能力强的大学生。     

淮安地区奶牛子宫内膜炎发病规律和相关原因的调查分析

奶牛子宫内膜炎是最常见的奶牛产科病之一。为了查清淮安地区奶牛子宫内膜炎的发病规律及相关原因,以便有目的进行综合防治。在淮安市的6个县区,每个月每个地区抽样30头,12个月共抽样2160头2～8岁的分娩奶牛进行调查,结果发现,淮安市分娩奶牛的子宫内膜炎平均发病率为34.1%,发病和季节、地区、饲养方式、奶牛年龄、胎衣滞留等因素相关。     

海南及粤西热带地区外来入侵植物假臭草的群落及生境调查

通过调查海南岛及粤西热带地区8个样区3种生境(荒地、林缘、林中)的假臭草(Eupatorium catarium)群落物种、群落特征、环境条件,研究了不同样区及不同生境类型下假臭草群落的组成、群落特征及与环境条件的关系。结果表明:假臭草群落中共有50科117属132种植物,以禾本科、菊科居多;其中外来入侵植物有27种,占总物种数的20.45%,以菊科最多达到9种。不同样区假臭草的重要值均为最大,大多数样区之间盖度没有差异,仅儋州显著大于鹤山,高度差异显著。不同生境之间的假臭草重要值大小为:荒地 >林中 >林缘,盖度为:荒地 >(林中、林缘),高度为:荒地 >林缘 >林中。同一样区不同生境之间的比较中,假臭草盖度除阳江、徐闻、琼海无差异外,其余样区均差异显著;高度除海口、琼中、三亚无差异外,其余样区均差异显著。不同样区中假臭草的高度与土壤温度呈显著正相关,重要值与年降雨量呈显著负相关;不同生境下,荒地和林缘生境下的假臭草高度均与土壤温度呈显著正相关,荒地生境下盖度与土壤水分呈极显著正相关,林中生境下其盖度与土壤NaCl含量呈负相关,重要值与光照强度呈显著正相关。因此假臭草容易入侵气温以及降雨量适宜的样区和强光照及水分充足的生境。     

淮安地区奶牛子宫内膜炎的发病规律和相关原因的调查分析

奶牛子宫内膜炎是最常见的奶牛产科病之一。为了查清淮安地区奶牛子宫内膜炎的发病规律及相关原因,以便有目的地进行综合防治。在淮安市的6个县区,每个月每个地区抽样30头、12个月共抽样2160头2～8岁的成年母牛进行调查,结果发现,淮安市成年母牛的子宫内膜炎平均发病率为34.1%,奶牛子宫内膜炎发病和季节、地区、饲养方式、奶牛年龄及胎衣滞留等因素相关。     

A Simple Aerosol Chamber for Experimental Reproduction of Respiratory Disease in Pigs and Other Species

The design of a simple aerosol chamber for experimental challenge of pigs and other species with respiratory pathogens is described.     

Crested Wheatgrass Defoliation Intensity and Season on Medusahead Invasion

The objective of this study was to determine the effects of crested wheatgrass (Agropyron cristatum [L.] Gaertn.) defoliation intensity and timing on medusahead density and biomass. We hypothesized that crested wheatgrass defoliation greater than 60% during the spring would provide maximum medusahead (Taeniatherum caput-medsae [L.] Nevski subsp. asperum [Simk.] Melderis; taxonomy from US Department of Agriculture) density and biomass. Eighteen treatments (six defoliation levels, three seasons of defoliation) were applied to 2-m² plots in a randomized complete block design on two sites with varying clay content. Blocks were replicated five times at each site. Plants were clipped in 2004 and 2005. Crested wheatgrass was hand clipped to defoliation levels of 0%, 20%, 40%, 60%, 80%, and 100% in the spring, summer, or fall. Density of crested wheatgrass and medusahead was sampled in June 2005 and 2006, but their biomass was harvested only in 2006. Data were analyzed with least square means analysis of variance. Over the two seasons, site had much more of an impact on medusahead invasion than either defoliation intensity or timing of defoliation. The results support previous suggestions that clayey soils favor medusahead and that perennial grasses with high biomass can resist this invasive species. On the clayey site where medusahead did persist, fall defoliation of crested wheatgrass reduced the density of this invasive species by 50% or more compared to spring defoliation. Given the developmental pattern of medusahead, the goal of any management program should be to maximize resource use by the desirable species during April to late July.