布氏田鼠对主要贮草种类的选储嗜好

布氏田鼠 (Ｍｉｃｒｏｔｕｓｂｒａｎｄｔｉ)为内蒙古典型草原区的主要害鼠 ,其危害主要表现在与牲畜争夺牧草资源[1,3 ,5,6,9] 。该鼠属不冬眠种类 ,冬季主要以洞群贮草仓库中的贮草为食 ,因此 ,研究其秋季集群的贮草习性 ,对于分析和了解该鼠的越冬生态特征具有一定的意义。有关布氏田鼠的贮草习性 ,已有一些报道[4 ,7] 。研究表明 ,在羊草 冷蒿 隐子草草场 ,布氏田鼠的越冬贮草以蒿属 (Ａｒｔｅｍｉｓｉａ)植物为主 ,其中冷蒿 (Ａ .ｆｒｉｇｉｄａ)与黄蒿 (Ａ .ｓｃｏｐａｒｉａ)占贮草比例超过 90 % [2 ] ,但上述研究均未涉及布氏田鼠…     

布氏田鼠洞群贮草面积与栖息地植被条件的关系

布氏田鼠 (Ｍｉｃｒｏｔｕｓｂｒａｎｄｔｉ)为内蒙古典型草原区的主要害鼠 ,其危害主要表现在与牛羊争夺牧草资源 ,破坏草场、引起草场沙化退化 ,以及传播疾病等三个方面[3,5,8] 。该鼠为不冬眠种类 ,冬季以储存于地下仓库中的牧草为食[9,10 ] 。因此 ,研究其秋季洞群的贮草面积与草场植被条件的关系 ,对于分析该鼠的越冬适应策略 ,并进一步提出草场鼠害的优化管理方案 ,具有重要意义。有关该鼠秋季贮草习性 ,已有一些文献报道[1,4 ,6 ,7] ,但涉及该鼠秋季洞群贮草面积与草场植被条件的关系的研究较少。为此 ,在内蒙古典型草原区开展了此项…     

储草期增加食物对布氏田鼠越冬存活率的影响北大核心CSCD

布氏田鼠(Lasiopodomys brandtii)是内蒙古典型草原区主要鼠种之一。该鼠种在秋季将食物储存在储草仓内,以此来度过植被贫瘠的冬季。为探究储草期增加食物对布氏田鼠越冬存活率的影响,2004年10月,于内蒙古阿巴嘎旗白音图噶苏木的布氏田鼠鼠害草场随机选取两块100 m×200 m的样地,分别设为增食样地和对照样地。增食样地内给每个布氏田鼠洞群补充食物,每天补充500 g小麦,连续补充2 d共计1000 g。对照样地内则不做任何处理。2004年10月,采用标志重捕法调查两块样地内布氏田鼠种群数量,调查显示,增食样地和对照样地内,布氏田鼠数量分别为310只和318只,以该结果作为计算其越冬存活率的基数。2005年5月,返回样地再次进行标志重捕,分别计算两样地布氏田鼠的越冬存活率。卡方检验显示,储草期增加食物能显著提高布氏田鼠越冬存活率。增食样地布氏田鼠越冬存活率为41.3%,显著高于对照样地布氏田鼠越冬存活率(24.2%,P<0.01)。增食样地雌性和雄性布氏田鼠越冬存活率分别为45.4%和37.3%,均显著高于对照样地雌性和雄性布氏田鼠越冬存活率(25.8%和22.6%,P<0.01)。但样地内雌性和雄性越冬存活率均无明显差异(P>0.05)。本研究结果表明,补充食物可大幅度提升布氏田鼠冬季存活率,增加布氏田鼠越冬存活基数,对来年种群增长起重要作用。     

大鵟对不同数量布氏田鼠越冬洞群的选择偏好

布氏田鼠(Lasiopodomys brandtii)在冬季会形成数量不同的越冬集群,不同大小的集群会面临着不同的捕食风险。2004年秋季在内蒙古锡林郭勒盟典型鼠害草场,采用鼠洞口数量多少作为布氏田鼠秋季集群大小的指标,分析了大鵟(Buteo hemilasius)对不同大小集群的布氏田鼠集群的捕食选择偏好。结果表明：大鵟优先选择集群数量高的布氏田鼠集群,这表明数量高的布氏田鼠集群更容易吸引猛禽类天敌的捕食,该结果可以解释布氏田鼠在秋季出现的分群行为。由于捕食风险的存在,布氏田鼠借助秋季的分群行为以降低冬季集群大小和被捕食风险,从而避免成为捕食性天敌首要攻击的目标,该结果验证了最优集群理论。     

贮草期布氏田鼠采食距离及集群数量对采食量的影响

在内蒙古典型草原区锡林郭勒盟研究了贮草期布氏田鼠(Lasiopodomys brandtii)采食距离及集群数量对采食量的影响。通过人为设置布氏田鼠洞群家族成员数量和采食距离,采用小麦(Triticum aestivum)为采食材料,测定了秋季自由生活状态下,采食距离为5~30 m范围内、每个洞群布氏田鼠数为3~11只范围内,布氏田鼠单次采食量的变化。结果表明,采食距离和家族成员数量对布氏田鼠单次采食量没有明显影响,采食距离和家族成员数量之间也不存在交互作用。布氏田鼠单次搬运麦粒数量平均为8.0粒/次,这可能与田鼠的搬运能力有关。     

群居性啮齿动物集群重组率的估算

提出了一种定量估算群居性啮齿动物的集群重组率的方法。此法以特定时期集群中动物个体之间的异源概率（即来源于不同家族的概率）作为衡量群居性啮齿动物的“混合”程度（即重组率）的定量指标,并与平均重组率（即重组期望）进行比较,进而判断动物在集群过程中的选择倾向。按照这种方法估算了内蒙古典型草原区布氏田鼠越冬集群的重组率。结果表明,该鼠的越冬集群重组率很低,仅在0.1左右,集群个体多数来源于相同的家族。此外,该鼠的集群重组率远低于其重组期望值,表明该鼠在秋季集群中,有强烈的选择同源个体的倾向。     

集群数量和采食距离对储草期布氏田鼠警戒频次的影响

警戒行为是动物对环境中潜在危险做出的反应。为探究影响警戒行为的因素,作者在内蒙古锡林郭勒典型草原区进行了集群数量和采食距离对储草期自由生活状态下布氏田鼠(Lasiopodomys brandtii)警戒频次影响的实验。通过标志重捕法和人工去除法设定3个集群数量梯度(11只、6只和3只),利用人工食物站设置4个采食距离梯度(5 m、10 m、20 m、30 m),共12个梯度组合,每个组合分别观察60次采食过程,共计观察720次,并记录采食过程中的警戒频次。对数据进行双因素方差分析,集群规模和采食距离对布氏田鼠警戒行为频次均有极显著影响(P0.01)。随着集群数量减小,布氏田鼠单次采食的警戒频次显著增加;采食距离越远,单次采食的警戒频次越高;集群数量和采食距离之间还存在极显著的交互作用(P0.01)。集群数量增大意味着采食距离的增加,为保证储草效率,布氏田鼠种群会在增加集群数量和减小采食距离之间权衡,最终集群数量维持在中等水平,支持了最优集群理论。     

大■对不同数量布氏田鼠越冬洞群的选择偏好

2004年10月2~7日在内蒙古东乌珠穆沁旗额和宝力格苏木鼠害草场采用鼠洞口数量作为布氏田鼠(Lasiopodomys brandtii)秋季集群大小的指标,分析了大■(Buteo hemilasius)对不同大小布氏田鼠集群的捕食选择偏好。统计了实验样地内可以观察到的大■蹲守布氏田鼠洞群鼠洞口数量,以及样地内大■没有蹲守的布氏田鼠洞群的鼠洞口数量。运用非参数Mann-Whitney U检验进行分析,大■没有蹲守的布氏田鼠洞群的洞口数量秩和统计量为1 753.5,而大■蹲守的布氏田鼠洞群的洞口数量总秩和为1 406.5,统计量U值为213.5,校正之后的Z值为﹣4.764 26,这表明,两组差异达到极显著水平(P=0.000 002),大■蹲守次数(B)与田鼠洞群洞口数量(N)呈显著的正相关关系,相关式为B=﹣0.733 2+0.044 36 N(r=0.592 65,P0.05)。结果表明,大■优先选择集群数量高的布氏田鼠集群,该结果可以解释布氏田鼠在秋季出现的分群行为。由于捕食风险的存在,布氏田鼠借助秋季的分群行为以降低冬季集群大小和被捕食风险,从而避免成为捕食性天敌首要攻击的目标,该结果从捕食风险角度支持了鼠类最优集群理论。     

围栏育草措施对布氏田鼠种群的生态效应

布氏田鼠(Microtus brandti)是内蒙古典型草原地带的主要害鼠,其高密度种群的形成和扩展(害情发生)与草场植被的过牧退化有密切关系。近年围栏育草(通称草库仑)作     

布氏田鼠G带染色体研究

布氏田鼠(Microtus brandti Radde)是田鼠亚科中的一种小型野鼠,分布在我国内蒙古东部地区,对牧草和农田危害甚大,同时又是鼠疫的贮存宿主。有关布氏田鼠的染色体研究国内外未见报道。作者得到内蒙古锡盟鼠防     

Factors affecting group size and territory size of the Brown hyaena, Hyaena brunnea in the southern Kalahari

The paper describes how the dispersion pattern of food affects group size and territory size in the brown hyaena in different ways. Territory size is affected by the distribution of the food, group size by the quality of the food in the territory.     

Memory for the location of stored food in marsh tits

Marsh tits store several hundred food items per day, in separate locations within their territory, and recover most items within 24 h. Experiments in the laboratory determined that marsh tits return accurately to the sites of stored sunflower seeds 3 h and 24 h after storage. The proportion of returns exceeded chance encounter and initial preferences for those sites. The lack of interocular transfer in birds for some visual tasks provided a test for the hypothesis that memory is used to relocate stored food. After storing food with one eye covered, marsh tits did not return to storage sites when using only the ‘naive’ eye, but did so when using only the eye uncovered during storage. It seems likely that recovery of stored food by marsh tits and other birds occurs by memory of storage sites, not by chance encounter during foraging.     

Why some tits store food and others do not: evaluation of ecological factors

Paridae are among the bird families benefiting from food storing. However, not all its members hoard food. Our objective was to clarify the role of ecological factors in occurrence of food storing. We reviewed the data on major ecological characteristics of the Paridae species and analysed their association with the presence/absence of food storing. Our statistical model revealed that geography (distribution in North America) and taxonomy (genus Poecile) are better predictors of food storing than any of the studied ecological traits. Nevertheless, food-storing Poecile species inhabit mixed or coniferous woodlands with seasonal richness of food, while non-storing species tend to prefer edge and open habitats, where alternative food sources are available. Sociality and territoriality outside breeding season coincides with food storing. The analysis performed within the Baeolophus–Lophophanes–Periparus–Poecile clade with ancestral food storing revealed no factor except continental climate that would explain the persistence of food storing. The phylogenetic analysis of ancestral states of the studied characters allowed us to propose a possible scenario for the emergence of food storing in Paridae. (1) Food storing is not ancestral in Paridae and appeared only once in the common ancestor of the Baeolophus–Lophophanes–Periparus–Poecile group. (2) According to estimation of molecular clock in Paridae, food storing appeared before their radiation in North America.     

Responses in spatial organization to manipulations of the food resource in polygynandrous alpine accentors

The alpine accentorPrunella collaris is a territorial and polygynandrous mating species. The breeding unit is a group consisting of about seven members who share a group territory which contains all the resources necessary for living. Each female holds a small territory around her own nest within the larger group territory. Supplemental food in the form of millet seed was provided for a total of 23 group territories to test the hypothesis that the abundance and distribution of food influences the size of a female's territory and her dispersion pattern which, in turn, determine the mating system. Both males and females had regular access to the feeders, but females and groups provided with feeders did not have smaller territories than those without feeders. No groups were divided into two by offering extra food. Provision of extra food resulted in an increase of group size but did not alter the sex ratio. All members, including new settlers, were sexually active and the sexual relationships among the members of a group were still multiple matings. Food addition did not prompt the fed females to choose nest sites nearer the feeder. Nest sites were restricted to particular rocky slopes and non-vegetated areas which were invariably free from snow each year due to the effects of strong winds and the topography. Females showed a nest-site fidelity for successive years. The reason why supplemental food had no effect on the territory size or dispersion of female alpine accentors is discussed.     

The sociality of solitary foragers: a model based on resource dispersion

Under versions of what may broadly be called the Resource Dispersion Hypothesis (RDH) several authors have concluded that territory size and group size are limited respectively, and independently, by the dispersion and richness of patches of food. This paper presents a model that shows how the frequency distribution of resources available per unit time within a territory may permit the formation of groups even in the absence of any functional advantage to any individual from the presence of another. In this model, animals (called primary occupants) occupy territories containing sufficient resources to meet or exceed their requirements for a critical proportion of feeding periods. The availability of these resources is described in terms of their mean richness and their heterogeneity, and plots of these parameters indicate the circumstances within which individuals may share the minimum territory with the primary occupants. The model shows how, under plausible conditions of resource dispersion, a territory that provides almost total food security for two occupants could also provide, at no cost to the original occupants, substantial food security for an additional group member, even if it never used the same food patches as the originals. It is not therefore, as is sometimes supposed, a necessary condition for the RDH that members of a group often forage simultaneously in the same patch. Thus the model describes ecological circumstances whereby groups could evolve amongst species whose members neither forage communally, nor even meet frequently.     

Importance of communal foraging grounds outside the reed marsh for breeding great reed warblers

Foraging habitat selection of breeding great reed warblers was studied at a shore of Lake Biwa. The foraging grounds of parent warblers during the nesting period were not restricted to the breeding territory of the reed marsh, their nestling habitat. The paddy field outside the reed marsh was used communally by them throughout the breeding season. Females with early stage nestlings did not visit the paddy field whereas when nestlings were older than 3 days, more than half of their total food was collected there. Females with nests adjacent to the paddy field tended to exploit the paddy field more often than those with nests distant from it. Monogamously mated females tended to exploit the paddy field more often than polygynously mated females. Food collected in the paddy field was larger than that in the reed marsh and parent birds were prepared to travel longer distances to exploit the rich source of food in the paddy field. The importance of the communal foraging ground outside the reed marsh as a background of the polygynous mating system of this species is discussed.     

Intruder Pressure Affects Territory Size and Foraging Success in Asymmetric Contests in the Water Strider Gerris lacustris

The theory of evolutionarily stable strategies (ESS) in asymmetric contests predicts that the propensity of an individual to expose itself to risk during contests depends on the individual's resource-holding-potential (RHP) and on the value of the disputed resource (V) for the individual compared with that for an opponent. If encounters of a territory owner with individuals of high RHP and high food demands (V) increase in frequency, one should expect a decrease in total aggressiveness of the territory owner, and in consequence a decrease of its territory size. Such a decrease should result in a lower amount of food consumed by the territory owner. Using natural variability in RHP and V in Gerris lacustris, I experimentally tested these predictions. The average prey item has higher value (V) for reproductive female water striders (which probably transform most of their food into eggs), than for nonreproductive females and for males. Because males are smaller, they have lower RHP than females, as RHP depends on size. Thus the reproductive females are the class of individuals of high RHP and high food demands (high V). Most nonreproductive females defend food-based territories. I observed two groups of water striders in a seminatural laboratory setting. As predicted, there was a negative correlation between the rate of encounter with reproductive females and size of the territory, and a positive correlation between territory size and number of Drosophila flies consumed by the owner. Territories were smaller in the group with high rates of encounter between territory owners and reproductive females. Territory owners caught the same number of Drosophila flies as non-territorial individuals in this group. In contrast, in the group with fewer encounters between territory owners and reproductive females, territories were larger, and territory owners gained more food than non territorial water striders.     

Territory and group living in the polygynandrous Alpine Accentor Prunella collaris

The spacing system of Alpine Accentors Prunella collaris was studied on the summit of Mt. Norikura in central Japan for five breeding seasons. This species lived in groups (mean 7.2 individuals), sharing large areas of their individual home ranges within which all activities occurred. Membership of a group was closed and stable within a breeding season. The group home ranges overlapped little with each other, and antagonistic behaviour, including communal defence, was observed at the boundaries. Each female established an exclusive area around her own nest which she defended against other females (but not males) within the shared home range, but her activities (feeding, singing and mating) were observed over the whole of the group home range. Members of the same group moved around and fed together within the home range during the prebreeding season, but individual birds tended to become more solitary as the breeding season progressed. These results suggest that the primary breeding unit of Alpine Accentors is a group consisting of five to ten members who share a group territory which contains all the resources necessary for living and breeding, but this species is not a typical social one in which all members move around together within their group territory.     

Determinants of territory size in the pomacentrid reef fish,Parma victoriae

Summary Factors governing the size of territories defended by the pomacentrid reef fish, Parma victoriae, were investigated, prompted by contradictory predictions in the literature concerning the effects of food supply and competitors. Observations were carried out over the non-breeding period (March–October) on a medium density population in which territories were partially contiguous. The territory size of adult fish varied between 3 and 26 m², and was inversely correlated with local densities of conspecifics. The same range in territory size was found for both males and females, which did not differ in the time they spent on territory defence and foraging activities. No correlation existed between territory size and the abundance of algal food, body size, age or time spent on territory defence. Also, there was little variation in territory size over time, despite seasonal changes in the abundance of food algae.Experimental reduction of food supplies on isolated territories of males and females had no effect on territory size. In a higher density habitat an experiment was carried out in which population density and food abundance were simultaneously manipulated. This showed that territory size was primarily determined by intraspecific interactions, as territories exhibited considerable increases in size upon removal of neighbours. No changes in the size of defended areas resulted from either artificial increases or decreases of food levels. There were also no changes in the time spent on defence of territories, foraging time or feeding rates associated with food manipulations or territory expansion, which suggested that food was not a limited resource. This conflicted with current theories proposed to explain territory defence and expansion. It is hypothesized that intraspecific interactions constrain territory size well below the optimum in terms of the abundance of preferred food algal species.