高原鼠兔贮草选择及其生物学意义

本文采用观察法和样方法对不同栖息地类型高原鼠兔的贮草选择进行了分析,旨在探讨高原鼠兔在不同栖息地类型中干草堆的放置方式、数量、植物种类组成以及与栖息地类型和冬季食物组成的关系,在此基础上,阐明高原鼠兔建立干草堆的生物学意义。结果表明,高原鼠兔堆集干草堆的方式与其它鼠兔不同,它们将干草堆放置于独一味、甘肃棘豆等植物上,以减少干草堆植物的腐烂;不同栖息地类型干草堆数量有所不同,杂类草草甸中干草堆较多,平均为29.00 ± 17.09 个/ hm² ,其次为垂穗披碱草草甸,干草堆数量平均为16.33 ± 9.50个/hm² ,矮嵩草草甸中干草堆最少,平均为12.67 ± 6.66 个/ hm² 。在矮嵩草草甸中,5 个较大的干草堆由37 种植物组成,其中10 种植物选择水平在3 级以上,而甘肃棘豆和铺散亚菊占有较大的比例,分别为23.6% 和19.% 。不同干草堆间相似性分析结果表明,除第2 个干草堆外,其余干草堆间相似性指数较高,最高为第3 个和第4 个干草堆之间,为0.9070。相关分析结果显示,干草堆主要植物组成与高原鼠兔冬季食物主要组成之间呈显著的正相关(r = 0.7323,df = 6,P <0.05)。扣笼试验结果表明,高原鼠兔冬季未取食扣笼内的干草堆。在综合分析高原鼠兔的贮草行为的基础上,我们认为,高原鼠兔建立干草堆的目的是为了应付冬季食物条件的不可预测性。     

不同土地利用方式和植被特征对高原鼠兔行为的影响

2009年3~7月,在西藏自治区墨竹工卡县日多乡念村(29o46′N,92o19′~92o20′E,海拔4 423~5 015 m),采用目标动物抽样法对高原鼠兔(Ochotona curzoniae)的警戒行为和取食行为进行了观察,利用广义线性模型(GLM)的泊松回归模型分析了不同土地利用、植被覆盖度、植物类别和植被优势种对高原鼠兔行为影响的差异。研究结果表明,雌性高原鼠兔取食行为频率高于雄性(β=﹣0.203,SE=0.096,P0.05),警戒行为频率低于雄性(β=0.199,SE=0.088,P0.05)。高原鼠兔的取食行为(β=﹣0.009,SE=0.004,P0.05)随着栖息地内双子叶植物覆盖比例增高而呈递减趋势,相应地,随着栖息地内单子叶植物覆盖比例的增高呈现递增趋势(β=0.009,SE=0.004,P0.05)。高原鼠兔的警戒行为在放牧地(β=0.273,SE=0.131,P0.05)以及植被覆盖度高的栖息地内(β=0.007,SE=0.003,P0.05)均呈递增趋势。随着薹草属植物覆盖度比例增高,高原鼠兔的取食行为(β=0.023,SE=0.006,P0.001)呈现递增趋势,而警戒行为呈递减趋势(β=﹣0.018,SE=0.007,P0.05)。     

高原鼠兔贮草行为初探

2004年7—10月,在青海省果洛州玛沁县境内的大武镇东南方向25 km处的格多牧委会草场,采用 样带法和样方法对高原鼠兔(Ochotona curzoniae)贮草行为过程中刈割植物的种类和放置方式进行初步研究。 结果表明:高原鼠兔在植物的生长旺盛期具有为冬季贮藏干草堆的行为,贮草行为始于7月,结束于10月初。 高原鼠兔对所刈割植物种类的选择,在一定程度上受栖息地植被物种丰富度的影响,并且将刈割植物放置于具 有宽大叶片的植物上,以防止干草的腐烂。挖洞结果显示,高原鼠兔具有洞内贮藏食物的习性。     

植物生长季节不同栖息地高原鼠兔的食物选择

本文采用胃内容物镜检分析法,对栖息于青藏高原矮嵩草草甸、垂穗披碱草草甸和杂类草草甸中的高原鼠兔的主要食物组成进行了比较分析,旨在探讨栖息地变化对高原鼠兔食物组成的影响,揭示高原鼠兔对栖息地变化的生存对策和适应性.研究结果表明:在矮嵩草草甸,高原鼠兔主要取食垂穗披碱草、早熟禾、蓝花棘豆和甘肃棘豆;在垂穗披碱草草甸,主要选择垂穗披碱草、甘肃棘豆、蓝花棘豆、矮嵩草和二柱头蔗草;在杂类草草甸,喜食植物种类为垂穗披碱草、蓝花棘豆、甘肃棘豆、早熟禾、弱小火绒草、长茎藁本、兰石草和红花岩生忍冬.在整个植物生长季节,高原鼠兔在3种栖息地共取食27种植物,其中垂穗披碱草、甘肃棘豆和蓝花棘豆在不同栖息地中选择指数较高,为高原鼠兔优先选择的食物;在不同栖息地,高原鼠兔取食植物有差别,垂穗披碱草草甸为16种、矮嵩草草甸为22种,杂类草草甸为24种;喜食食物比例也存在着明显差别,在垂穗披碱草草甸,垂穗披碱草比例高达40.5%,在矮嵩草草甸,甘肃棘豆比例也达到23.7%,而在杂类草草甸,选食比例最高的兰石草仅为14.6%,说明在该草甸高原鼠兔食物选择呈现泛化趋势.相似性指数分析结果也表明,杂类草草甸中高原鼠兔主要食物组成与其它两种栖息地有较大的区别.从而说明当栖息地植物群落种类组成发生变化后,高原鼠兔可以通过改变其食物组成而适应新的栖息地.     

高原鼠兔冬季的食物选择

本文采用胃内容物镜检分析法,对高原鼠兔在矮嵩草草甸、垂穗披碱草草甸和杂类草草甸三种类型栖息
地中的主要食物组成进行了比较分析,旨在探讨三类栖息地不同食物资源状况对高原鼠兔食物组成的影响,以
及高原鼠兔在食物匮乏的冬季的觅食对策。研究结果表明:高原鼠兔在冬季主要选食弱小火绒草和铺散亚菊,
甘肃棘豆、垂穗披碱草和长茎藁本也是冬季食物主要组成部分。在冬季食物资源较为匮乏的情况下,高原鼠兔
选食的主要植物种类相对较多,且不同植物比例变化明显,说明高原鼠兔对食物具有一定的选择性。在矮嵩草
草甸中,其食物组成依次为铺散亚菊(16. 2% ) > 弱小火绒草(11. 5% ) > 甘肃棘豆(11. 3% ) > 大籽蒿
(9. 7% ) > 早熟禾(7. 6% ) > 长茎藁本(7. 5% ) > 垂穗披碱草(5. 5% )等7 种,占其食物的69. 3% ;在垂
穗披碱草草甸,其主要食物组成依次为垂穗披碱草(15. 8% ) > 甘肃棘豆(14. 7% ) > 弱小火绒草(14. 5% )
> 铺散亚菊(14. 2% ) > 早熟禾(7. 8% ) > 长茎藁本(6. 9% ) > 锥果葶苈(6. 2% )等7 种,占其食物的
80. 1% ;在杂类草草甸中,其主要食物组成依次为铺散亚菊(20. 8% ) > 长茎藁本(20. 6% ) > 大籽蒿
(9. 9% ) > 弱小火绒草(9. 8% ) > 锥果葶苈(6. 5% ) > 圆齿狗娃花(5. 5% )等6 种,占选食食物的73. 1% 。
不同栖息地之间食物组成比较分析结果表明,在冬季食物资源匮乏的情况下,栖息地类型不同对高原鼠兔食物
组成的影响较小,杂类草构成了它们的主要食物,这可能是由食物质量决定的,而不同栖息地中喜食植物可利
用量是决定鼠兔食物组成的主要因子,进一步验证了食物可利用量和质量决定植食性小哺乳动物食物选择模式
的假设。     

高寒地区植食性小哺乳动物的越冬对策

利用多年工作积累的观察资料 ,讨论几种植食性小哺乳动物的越冬对策。其中 ,高原鼢鼠、甘肃鼠兔和根田鼠均贮存食物 ,以减少寒冷条件下的取食暴露。高原鼢鼠以个体为单位贮存和利用贮存食物 ,相互之间不协作 ;而两种地面活动的种类则可能以家庭为单位贮存和分享越冬食物。喜马拉雅旱獭体型较大 ,不贮存食物 ,它以冬眠方式越冬 ,这是一种对食物依赖最小的方式。高原鼠兔 ,既不贮存食物 ,也不进入冬眠 ,而是主要靠增加身体产热能力来保持体温 ,抵御严寒。作者认为 ,动物自身的生理限制、生活方式、环境条件以及捕食风险等诸多因素的综合作用决定动物的越冬对策。     

地下茎多奉献：薯蓣科简记

薯蓣科属于单子叶植物,但它的叶子却像双子叶植物,尤其是薯蓣属,叶脉３—９,基出,侧脉网状,与一般单子叶植物的平行脉或弧形脉不同,是地道的双子叶植物叶脉类型。这说明,所谓双子植物与单子叶植物叶脉类型的划分,只能相对于大多数植物而言。薯蓣科有１０个属,６...     

高原鼠兔刈割行为与栖息地植物群落的关系

采用观察法和样条法对不同栖息地高原鼠兔刈割植物的行为、相对频次、生物量百分比以及刈割植物与鼠兔冬季食物组成之间的关系进行了分析,并阐述了高原鼠兔刈割植物的生物学意义。结果表明:高原鼠兔刈割植物始于每年的6 月下旬,早于其它草原小型哺乳动物贮草时间。不同栖息地鼠兔对植物的刈割频次和生物量比例并非完全一致。在矮嵩草草甸,鼠兔刈割频次较高的为垂穗披碱草、二柱头藨草、甘肃棘豆、短穗兔耳草、铺散亚菊和鹅绒萎陵菜;这些植物生物量所占比例亦较高,仅短穗兔耳草比例较低;在垂穗披碱草草甸,鼠兔刈割频次较高的为垂穗披碱草和早熟禾;垂穗披碱草生物量较高;而在杂类草草甸,鼠兔主要刈割植物为铺散亚菊、大籽蒿、黄帚橐吾、长茎藁本和圆齿狗娃花,生物量比例较高的主要为铺散亚菊。相似性分析结果表明,不同栖息地间鼠兔刈割植物频次和生物量比例差异较大,相似性系数最大分别为0. 7862 和0. 6100, 最小仅为0.1422 和0. 1035,而同一栖息地间鼠兔刈割植物频次和生物量差异相对较小,相似性系数最高达0. 9203 和0. 8490,最小亦达到0. 6662 和0. 4440,表明栖息地变化对鼠兔刈割植物频次和比例有明显的影响作用。鼠兔刈割主要植物频次和生物量比例与冬季主要食物组成的相关分析结果表明,生物量比例与主要食物组成呈显著的正相关(r =0.8412,df = 6, P <0. 05),而刈割植物频次与主要食物相关不显著。     

运城盐湖十种耐盐植物体内无机及有机溶质含量的比较研究

运城盐湖的 1 0种耐盐植物体内的有机及无机溶质含量差异较大。总无机溶质含量在各种植物间的变化幅度小于总有机溶质 ,其中双子叶植物 (除二色补血草外 )地上部 K+ 含量及 K/Na比均低于单子叶植物 ,而双子叶植物地上部的Na+ 含量明显高于单子叶植物。双子叶植物 (除二色补血草外 )的 Na/Cl>1 ,而单子叶植物的 Na/Cl≈ 1。二色补血草的二价离子 Ca2 +和 Mg2 +含量较高。单子叶植物的可溶性糖及游离氨基酸含量高于双子叶植物 (除枸杞外 ) ,碱莞、盐角草、盐地碱蓬、碱地肤、二色补血草的脯氨酸含量均较低 ( <7μmol/g FW) ,且脯氨酸占游离氨基酸的比例高于其它植物。另外还计算了各种溶质占 COP的百分比 ,并讨论了它们在植物渗透调节过程中的作用。     

高原鼢鼠对高寒草甸植被特征及生产力的影响

本研究结果表明,高原鼢鼠栖息10年的斑块,植物群落的物种数减少,植物物种多样性指数下降,地上、地下总生物量显降低,单子叶和可利用双子叶植物生物量极显减少,但不可利用双子叶植物生物量显增加。高原鼢鼠去除5年后,斑块内植物群落的单子叶植物物种数增加,而双子叶植物下降,植物群落物种多样性指数下降,地上、地下总生物量显增加,单子叶和可利用双子叶植物生物量增加极显,不可利用双子叶植物生物量显降低。高原鼢鼠栖息10年的斑块,净初级生产量较未栖息地区减少68.98%。高原鼢鼠去除5年后,净初级生产量增加,但仅达到未栖息地区的58.69%。     

Effects of temperature and photoperiod on thermogenesis in plateau pikas (Ochotona curzoniae) and root voles (Microtus oeconomus)

We examined the effects of temperature and photoperiod on metabolic thermogenesis and the thermogenic characteristics of brown adipose tissue in plateau pikas (Ochotona curzoniae) and root voles (Microtus oeconomus), the dominant species of small mammals in the alpine meadow ecosystems on the Qinghai-Tibetan Plateau. Pikas and voles were acclimated in the following groups: (1) Long day – warm temperature (16L:8D, 23 °C), (2) Long day – cold temperature (16L:8D, 5 °C), (3) short day – warm temperature (8L:16D, 23 °C), and (4) short day – cold temperature (8L:16D, 5 °C). Both temperature and photoperiod were important environmental cues for changes in thermogenesis for both species. Low temperature and short photoperiod induced increases in metabolic rate, nonshivering thermogenesis (NST), mitochondrial protein contents of brown adipose tissue, and cytochrome C oxidase activity of brown adipose tissue mitochondria in both species. Plateau pikas were more sensitive to cold (79% of the total NST response) than to short photoperiod (21%), while root voles were more sensitive to short photoperiod (60% of the total NST response) than to cold (40%), although cold clearly enhanced thermogenesis. Their thermogenic characteristics correlated with their preferred habitats: plateau pikas are found mainly in more exposed microhabitats in open sunny meadow, while root voles live in more sheltered microhabitats in relatively closed shrub. Our results also showed that temperature and photoperiod combined induce thermogenic adjustments in both species in seasonal acclimatization in their alpine meadow macrohabitat. Accepted: 10 November 1998     

高原鼠兔对高寒草甸土壤有机质及湿度的作用

为探讨高原鼠兔对土壤理化性质的作用, 本研究于2005年8月, 采用灼烧和烘干法, 分别测定了高原鼠兔栖息及被灭杀地区土壤有机质含量及湿度。结果表明： 高原鼠兔栖息地区, 0～5 cm及6～10 cm土壤层有机质含量和湿度均极显著或显著高于被灭杀地区; 11～30 cm 土壤层, 二者无显著的差异;31～50 cm土壤层, 有机质含量差异极显著, 而土壤湿度则无显著差异。说明, 高原鼠兔活动可增加高寒草甸土壤表层有机质含量和湿度, 进而改变土壤理化性质, 促进生态系统物质循环。     

Phenotypic plasticity of reproductive traits in response to food availability and photoperiod in white-footed mice (Peromyscus leucopus)

Changes in photoperiod, ambient temperature and food availability trigger seasonal acclimatization in physiology and behavior of many animals. In the present study, seasonal adjustments in body mass and in several physiological, hormonal, and biochemical markers were examined in wild-captured plateau pikas (Ochotona curzoniae) from the Qinghai-Tibetan plateau. Our results showed that plateau pikas maintained a relatively constant body mass throughout the year and showed no seasonal changes in body fat mass and circulating levels of serum leptin. However, nonshivering thermogenesis, cytochrome c oxidase activity, and mitochondrial uncoupling protein 1 (UCP1) contents in brown adipose tissues were significantly enhanced in winter. Further, serum leptin levels were positively correlated with body mass and body fat mass while negatively correlated with UCP1 contents. Together, these data suggest that plateau pikas mainly depend on increasing thermogenic capacities, rather than decreasing body mass, to cope with cold, and leptin may play a potential role in their thermogenesis and body mass regulation.     

Effects of plateau pika (Ochotona curzoniae) on alpine meadow phytocoenosium and analysis of the strategy it uses to expand habitat

High-density plateau pikas (Ochotona curzoniae) disturbance is one of the main causes of alpine meadow degradation. The response of phytocoenosium to the disturbance of plateau pika may reflect its habitat expanding strategy. We used quadrat sampling method to investigate vegetation height, coverage, and aboveground biomass of non-pika area (NA), transition area (TA), and pika-active area (AA) distributed continuously in alpine meadow located in Guoluo Tibetan Autonomous County of Qinghai Province in 2011 and 2012. The results showed that, from NA to AA (i) vegetation coverage, height, and above-ground biomass decreased (P < 0.01). (ii) While the number of plant species decreased from 41 to 30, and species diversity decreased significantly (P < 0.05), evenness of the alpine meadow showed no significant variations. (iii) Dominant species changed from grasses to weeds. (iv) While plants in TA showed no obvious difference in height between 2011 and 2012, coverage reduced significantly (P < 0.05). These results demonstrate that (i) plateau pikas disturbance on alpine meadow will change plant community structure and composition, directly leading to degeneration of alpine meadow. Additionally, (ii) plateau pikas expand their habitat by altering plant coverage firstly.     

Talus fragmentation mitigates the effects of pikas, Ochotona princeps, on high alpine meadows

North American pikas (Ochotona princeps) are central-place foragers that are restricted to talus slopes in the mountains of western North America. They graze meadows surrounding talus producing a gradient of grazing pressure extending out from the talus edge. We asked: 1) how does the physical structure of the talus slope affect pika foraging behavior? and 2) how do differences in foraging behavior affect the relative abundance of different plant functional groups?
Pikas at three talus-meadow interfaces differed in the distances they traveled for forage, depending upon the structure of the talus slope. Pikas fed preferentially on vegetation within the talus, ventured into the surrounding meadow when intra-talus vegetation was rare, and ranged farther when haying than when grazing. They ventured into the surrounding meadow less when talus fields were more fragmented and intra-talus vegetation was more abundant.
We tested the effects of pikas on meadow vegetation by excluding pikas from small plots located at various distances from talus edges. When habitat structure forced pikas to venture out from the talus to forage, they decreased total vegetative biomass by as much as 80% and increased the relative importance of cushion plants and sedges. These effects were undetectable at distances beyond one meter. These patterns appear to result from a change in the relative performance of different plant functional groups caused by herbivory.     

Disparate determinants of summer and winter diet selection of a generalist herbivore,Ochotona princeps

The North American pika, Ochotona princeps, is a generalist herbivore that simultaneously selects two distinct diets: one consumed immediately (summer diet), the other harvested, transported, and stored for later consumption (winter diet). I investigated factors influencing diet selection at two sites on the West Knoll of Niwot Ridge, Boulder County, Colorado during 1991 and 1992. The composition of summer and winter diets differed significantly from each other as well as from the relative abundance of food items in the environment. Thus, pikas were not foraging randomly for either diet. To explore winter and summer diet selection, I tested two existing hypotheses: (1) that plant morphology restricts the winter diet breadth to plants that are easily harvested and large, and thereby maximizes the amount collected per foraging effort, or (2) to compensate for nutrients lost during storage, pikas bias their winter diet with high-nutrient species. I also tested the hypothesis that plant secondary compounds may be higher in the winter diet either because they function as preservatives or because pikas delay consumption of these species until the toxins degrade. For individual dietary items, I measured energy, nitrogen, water, fiber, total phenolic, condensed tannin, and astringency contents. There was little evidence to suggest that morphology excluded plants from the winter diet. Plant size was not a good predictor of abundance in the winter diet. Even after harvesting costs had been experimentally removed, cushion plants were still not included in the winter diet. There was weak support for an effect of nutrients on winter diet selection; in three of four cases, the winter diet was significantly lower in water and higher in total energy content as predicted by the nutrient compensation hypothesis. However, other nutrients exhibited no consistent pattern. Nutrients were not reliable predictors of the winter diet in multiple regression analyses. There was strong support for the hypothesis of manipulation of secondary compounds. The winter diet was significantly higher in total phenolics and astringency. Total phenolics were consistent predictors of the winter diet in multiple regression analyses. The winter diets of six additional pika populations contained plant species high in secondary compounds. The results suggest that pikas preferentially select plants with high levels of secondary compounds for their winter diet, possibly because the presence of such compounds promotes preservation of the cache. This behavior may also enable the exploitation of an otherwise unusable food resource, i.e., toxic plants.     

SOCIAL BEHAVIOR OF OCHOTONA CANSUS: ADAPTATION TO THE ALPINE ENVIRONMENT

Field observations were carried out on the Gansu pikas, Ochotona cansus Lyon, in its natural habitat from July 1987 to November 1988 at Haibei Alpine Meadow Ecosystem Research Station, Qinghai Province,PRC. Communicative behavior, reproductive behavior, spatial and social organization of the Gansu pika were described, and their adaptive significance discussed. The major communicative methods are acoustical and olfactory.At least four types of call (long call,short call, trill and whine)were distinguished. The peculiar habits of vocalization of species in the genus Ochotona appear to be the result of adaptation to boreal and/or high altitude severe climates. Two types of scent marking patterns were observed, and faeces play an important role in olfactory communication. Mother-infant relationships differ from most small rodents, but resemble those of medium-sized lagomorphs. The suckling time is "scheduled", and the frequency seems positively related to litter-size. This mother-infant relationship is thoug