洞庭湖区东方田鼠的发生与防治措施探讨

对1982～2005年洞庭湖区东方田鼠的发生与危害进行了系统调查，结果表明：东方田鼠的发生量与冬季降水量密切相关；其越冬基数的大小与上年洞庭湖洪水水位呈负相关，洪水水位高且维持时间长，洲滩裸露时间短，不利于东方田鼠的发生；当洪水淹没洲滩后，东方田鼠被迫向垸内转移，其转移时期取决于洞庭湖水位上涨的迟早；转移数量受发生量的大小和高峰水位维持时间长短的影响。在防治上以设置防鼠墙，切断转入通道为主要防治措施，对转移迁入垸内的东方田鼠实施农业防治、人工捕杀与化学毒饵诱杀相结合的防治方法，全面控制东方田鼠的为害。     

Using presence signs to discriminate between similar species

The Lusitanian and the Mediterranean pine voles (Microtus lusitanicus Gerbe, 1879 and Microtus duodecimcostatus de Selys‐Longchamps, 1839) are fossorial sister species and have an allopatric pattern of distribution in Portugal, which includes a potential sympatry area in the centre of the country. The present study aimed to determine the validity of using presence signs in the field for discrimination of the two species in an area of sympatry (Northern Alentejo) and the characteristics that achieve the best classification accuracy. A total of 175 trapping plots were sampled across the study area. Prior to the set up of traps, ten presence signs were randomly selected for measurements of four variables: proportion of soil mounds, mean diameter of mounds, proportion of burrow openings and mean diameter of burrow openings. On the basis of a classification tree analysis, results showed that presence signs can be used to discriminate plots inhabited by one or the other species in the studied sympatry area. The characteristic that most accurately enables species identification is the proportion of burrow openings: for every ten presence signs found in a plot, if more than eight have an opening, then it is inhabited by M. lusitanicus (i.e. mostly burrow openings with few or no mounds present); if eight or fewer have an opening, M. duodecimcostatus is present (i.e. mostly mounds with few or no burrow openings).     

Effects of corridor width and presence on the population dynamics of the meadow vole (Microtus pennsylvanicus)

We tested the effects of increased landscape corridor width and corridor presence on the population dynamics and home range use of the meadow vole (Microtus pennsylvanicus) within a small-scale fragmented landscape. Our objective was to observe how populations behaved in patchy landscapes where the animals home range exceeded or equaled patch size. We used a small-scale replicated experiment consisting of three sets of two patches each, unconnected or interconnected by 1-m or 5-m wide-corridors, established in an old-field community (S.W. Ohio). Control (0-m) treatments supported significantly lower vole densities than either corridor treatment. Females were the dominant resident sex establishing smaller home ranges (<150m²) than males (>450m²). Significantly more male voles dispersed between patches with corridors than between patches without corridors. However, no difference was observed regarding the number of male voles dispersing between patches connected by corridors when compared to the number dispersing across treatments. Dispersal between connected patches was restricted to corridors based on tracking tube data. Corridor presence was more important than corridor width regarding the movement of male voles within their home range.     

Are hedgerows the route to increased farmland small mammal density? Use of hedgerows in British pastoral habitats

Linear habitats are becoming increasingly common as a consequence of habitat fragmentation, and may provide the sole habitat for some species. Hedgerows are linear features that can vary substantially in structure and quality. Having surveyed 180 hedgerows, in four locations, and sampled their small mammal communities we examined the effect of physical hedgerow attributes on the abundance of small mammal species. Using three elements of landscape structure, we explored whether variation was best explained by the Random Sample Hypothesis (that small islands represent a random sample of those species populating larger areas), or by the Fragmentation Hypothesis (that species abundance will decrease with a loss of habitat area). We tested the relationship between the relative abundance of small mammals and 1. hedgerow connectivity; 2. total habitat availability and 3. local habitat complexity. We then explored the predictive power of combinations of these habitat variables. Connectivity was a positive predictor of wood mice Apodemus sylvaticus, and hedgerow gappiness was a negative predictor of bank voles Clethrionomys glareolus. The total amount of habitat available (hedgerow width, height and length) was a positive indicator of total small mammal biomass. These results support the Fragmentation Hypothesis that species abundance and distribution decrease with a loss of habitat area. The preservation of linear and associated habitats may therefore be important in maintaining metapopulations of the species we studied.     

布氏田鼠社群亲缘关系的研究

采用野外标志流放法和实验室观察研究了洞群内布氏田鼠群体亲缘关系及其对鼠群的作用。保持一定的亲缘关系对鼠群结构稳定起着重要作用。其中以亲体和同代的比例为高。观察表明陌生鼠间组合有3种反应形式,（1）接受,（2）容忍,（3）拒绝。繁殖期♂＋♀、♀＋♀均为接受,♂＋♂为容忍。非繁殖期♂＋♀为容忍,♀＋♀、♂＋♂均为拒绝。采用不同集群方式结果在20天内与母鼠共同集群有利于幼鼠发育,而此后进入陌生群有可能加快其发育。     

洞庭湖区东方田鼠2007年暴发成灾的原因剖析

2007年东方田鼠种群暴发是其种群数量自然波动到达高峰期的体现。洞庭湖湖泊泥沙淤积导致的沼泽化是其成灾的主要基础;而围湖造田、围湖灭螺和滥捕天敌乃是湖区东方田鼠上世纪70年代开始形成严重危害的直接原因;近期三峡工程和退田还湖工程又进一步加强了东方田鼠的暴发危害。因此必须高度关注东方田鼠种群的未来发展趋势。     

东方田鼠胚胎体内外生长发育

采用外阴观察法及阴道涂片法,观察到东方田鼠的发情周期为7d左右;PMSG—HCG的剂量及间隔时间对东方田鼠的超数排卵无显著影响;采用PMSG5～25U注射后即合笼,可使东方田鼠达到或接近正常排卵;东方田鼠的胚胎体外用HTF溶液培养,能正常发育至二细胞胚胎或囊胚期胚胎,比例分别为73%、30%、60%、83%和100%。     

Spatial population structure of the Cabrera vole in Mediterranean farmland: The relative role of patch and matrix effects

There is mounting evidence that both patch networks and the intervening matrix influence species persistence in fragmented landscapes, though the relative importance of each of these factors in determining spatial population structure remains poorly understood. This study examined this issue using a three-year data set on the distribution of Cabrera voles (Microtus cabrerae) in Mediterranean farmland. The spatial pattern appeared consistent with a metapopulation structure, as voles occupied discrete tall herb patches scattered across the agricultural landscape, where local extinctions and colonizations induced temporal changes in occupancy patterns. Patch dynamics determined deviations from classical metapopulation assumptions, with over half the extinctions resulting from agricultural disturbance or vegetation succession, and recolonizations often occurring after the recovery of suitable habitat conditions sometime after disturbance. Occupancy in undisturbed patches was more stable, with vole occurrence in one year strongly reflecting that in the previous year. Overall, occupancy increased with both patch size and connectivity, but the unique contribution of patch variables to explain variation in vole occurrence was far smaller than that of matrix attributes. Voles occurred more often in patches surrounded by natural pastures, while prevalence declined with increasing cover by shrubland, pine plantations, improved pastures and grazed cropland. It is hypothesised that unfavourable land uses may increase the effective isolation of habitat patches through increased predation risk of dispersing voles. Conservation of the Cabrera vole in Mediterranean farmland should thus strive to maintain lightly grazed fields surrounding well-connected networks of suitable habitat patches.     

黄土高原棕色田鼠综合防治技术研究

棕色田鼠是一种高繁殖力种群,在豫西黄土高原,4月份麦田密度可达540～705只/hm~2,严重地破坏农业和果树的生产。1992～1995年连续4年在河南灵宝市程村乡和寺河乡开展棕色田鼠综合防治试验。以自制的复方田鼠灵杀灭棕色田鼠效果达94.95％,辅以调整作物结构、轮作倒茬、伏翻冬翻地、优化果园管理、挖防鼠沟及强化越冬地果园灭鼠等措施,使过去连年灭鼠变为隔年灭鼠,节省了大量人力、物力,减少了对环境污染。几年来通过对棕色田鼠的综合防治,取得了显著的经济、社会和生态效益。     

实验室条件下黑龙江几种主要农业害鼠昼夜活动节律的研究

采用自动记录装置测试了黑龙江地区6种主要农业害鼠的昼夜活动节律和活动强度。结果表明,达乌尔黄鼠为昼行性鼠种,中午时段出现明显的活动间歇期以避开强烈的日晒;莫氏田鼠为昼夜活动型鼠种,日夜活动强度差异不显著,与其生活于草滩底部营食草根的生活方式相适应。大仓鼠、小家鼠、褐家鼠和黑线姬鼠都为夜行性鼠种,其中以小家鼠和黑线姬鼠最为典型,而大仓鼠和褐家鼠在日间都具有相当强度的活动,褐家鼠则是供试鼠种中唯一在各个时段都有活动的夜行鼠种。6种供试鼠种的主要活动特征与前人研究的结果基本相符,但其活动节律与其他研究结果存在活动高峰时间、活动强度等差异,表现出这些鼠种与黑龙江地区特定气候条件的适应。