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)。     

高原鼠兔在不同植被覆盖的立地占据、局部灭绝和建群率研究

青藏高原的草地生态系统被野生动物和家畜广泛地利用。大型有蹄类动物的放牧和小型哺乳类动物的挖掘行为,会改变其栖息地的植物群落。基于拉萨市墨竹工卡县日多镇年村牦牛(Bos grunniens)放牧的实践,我们发现高原鼠兔(Ochotona curzoniae)立地占域率、建群和区域灭绝率与栖息地变量之间存在一定的格局关系。为了了解高原鼠兔立地占域率、建群和区域灭绝率与栖息地之间的关系,我们采用多季节性立地占据模型,利用Presence软件对相关数据进行分析。结果表明,高原鼠兔局部灭绝率与植被覆盖度之间存在正相关性,而与建群率之间则呈负相关性。     

取食生境对白鹤越冬行为的影响

为探究人工生境与自然生境下白鹤Grus leucogeranus的行为差异及其可能对白鹤造成的影响,2021年1—2月,采用焦点动物取样法对鄱阳湖2个人工生境（藕塘、稻田）和1个自然生境（常湖池）的越冬白鹤行为进行了观察。结果表明,越冬期白鹤在不同生境下均以觅食行为为主,在稻田中比例最高（94.6%）,觅食频次显著高于藕塘（P<0.001）;稻田中的警戒行为频次显著高于藕塘和常湖池（P<0.001;P=0.002）,而藕塘和常湖池中的警戒行为频次无显著差异。白鹤在不同生境下食物的种类、营养成分、觅食方式均会影响白鹤越冬期行为及时间分配。本研究为加强越冬白鹤人工生境的保护与管理提供指导和依据。     

我国越冬白头鹤觅食行为和食物资源研究

食物资源和人为干扰影响越冬候鸟的觅食行为。本研究通过对白头鹤Grus monacha觅食行为和食物资源的研究和分析,探讨其在我国越冬期的觅食生境利用方式。结果显示,白头鹤优先选择在人工生境取食稻谷和蚕豆;同时也会取食自然生境中下江委陵菜Potentilla limprichtii和蓼子草Polygonum criopolitanum的根。白头鹤在人工生境的行为主要为觅食,其行为时间比例极显著高于自然生境(P0.01);在自然生境中警戒行为的时间比例显著高于人工生境中(P0.05);但在人工生境中警戒频次显著高于自然生境(Z=-4.772,P0.01),因更易受到干扰。相对于自然生境的食物,稻谷和蚕豆能提供更高的能量,且容易获取。人为干扰限制了白头鹤最优觅食理论的验证。     

不同种群密度下高原鼠兔的行为模式

在2003年高原鼠兔(Ochotonacurzoniae)的繁殖初期、繁殖盛期、繁殖中期和繁殖末期,采用目标动物取样法对其不同种群密度条件下的行为模式进行研究,探讨高原鼠兔的行为变化和种群密度的相互关系。结果表明:在繁殖盛期和繁殖中期,低密度种群内雌性高原鼠兔的观望时间均显著高于高密度种群内,而在其它两个时期内无明显不同;雄性高原鼠兔的观望时间在不同密度间比较均无显著差异;同一密度条件下,雄性高原鼠兔的观望行为持续时间和发生频次均表现显著的季节性变化,而雌性高原鼠兔无明显差异。高原鼠兔的地面活动时间在不同种群密度间比较无显著差异。低密度种群内,雄性高原鼠兔的地面移动距离和频次均呈显著的季节性差异,而雌性高原鼠兔的差异不显著;高密度种群内,雌、雄个体的地面移动距离和频次都具有显著的季节性差异。在高原鼠兔的社会行为中,亲昵行为和攻击行为强度在不同种群密度间比较均无显著差异;在同一密度条件下,亲昵行为和攻击行为强度也没有表现出明显的季节性变化。以上结果说明高原鼠兔的行为变化与其繁殖期和性别有明显的关系,而在密度间无明显的差异,其主要原因是在不同的繁殖期,动物的繁殖投入不同,导致行为模式产生差异     

捕食风险对高原鼠兔行为的影响

我们在野外条件下利用赤狐的粪尿增加高原鼠兔的捕食风险 ,采用目标动物抽样法对高原鼠兔的 5种行为进行观察 ,分析天敌动物气味增加与天敌动物数量增加对高原鼠兔行为影响的差异 ,探讨高原鼠兔对捕食风险的权衡能力及面对不同风险的行为决策。 2 0 0 1年 ,在捕食风险处理样方中观察雄性成体 1 8只 ,雌性成体2 5只 ,雄性幼体 35只和雌性幼体 4 2只 ,在对照样方中观察雄性成体 1 4只 ,雌性成体 1 5只 ,雄性幼体 2 2只和雌性幼体 1 1只 ;2 0 0 2年 ,在捕食风险处理样方中观察雄性成体 7只 ,雌性成体 1 2只 ,在对照样方中观察雄性成体 8只 ,雌性成体 1 5只。研究结果表明 :增加赤狐的气味后 ,高原鼠兔通过改变行为策略以适应捕食风险的增加。当气味源刚放入后 ,与对照样方比较 ,高原鼠兔明显增加了观察和鸣叫的频次 ,相应减少了取食的频次 ,且随着时间的推移 ,高原鼠兔并未对气味产生适应性。当天敌动物的数量增加后 ,赤狐气味的增加对高原鼠兔行为的影响较小 ,在捕食风险超出高原鼠兔的耐受范围时 ,高原鼠兔扩散。同时 ,高原鼠兔的行为在雌雄之间、成体与幼体之间没有明显的不同 ,雌雄个体、成幼体均采用相同的行为策略减小捕食风险。以上结果表明 :捕食风险明显影响高原鼠兔的行为 ,高原鼠兔能够权衡捕食     

高原鼠兔洞穴数量与其栖息地植被分布格局的GIS分析

高原鼠兔(Ochotona curzoniae)是青藏高原高寒草甸生态系统的关键种,其生境利用特征对高寒草甸植被保护的影响一直是重要的研究内容.我们于2008年9月在四川省石渠县云波沟面积为44 km2的研究区域内进行了高原鼠兔有效洞穴数量样线调查.该地区一直以来放牧压力较小,2006年起执行国家西部退牧还草政策后.放牧完全停止.调查期间共完成样线7条,总长度19 km,获得取样单元2,423个.根据中巴资源2号卫星2008年9月18日拍摄的遥感图像计算并提取研究区域归一化植被指数(normalized difference vegetation index,NDVI)数据.利用石渠县地形数字地图建立数字高程模型计算坡度.用Bonferroni z检验比较取样单元内鼠兔洞穴数量与NDVI以及洞穴数量与坡度间的相互关系发现:NDVI值较低区间(0.1-0.3)内鼠兔洞穴数量显著低于理论预期值,中等NDVI值区间(0.3-0.4)内鼠兔洞穴的数量与理论值没有显著差异,而NDVI值较高区间(0.4-0.6)内,鼠兔洞穴的数量显著高于理论预期.回归分析结果表明:NDVI与洞穴数有显著正相关的线性回归关系y=16.50x+0.87(R2=0.78,P<0.001);鼠兔有效洞穴数量和坡度没有显著的线性关系(R2=0.04,P=0.441).因此,我们认为在无家畜竞争的自然环境中,栖息地植被的质量是影响高原鼠兔空间分布的重要因素.高原鼠兔有选择地利用植被较好的生境而避免使用植被过度退化的生境,这种利用方式在客观上防止了栖息地植被的过度破坏.     

鄱阳湖区稻田生境中灰鹤越冬行为的时间分配与觅食行为

2013年11月—2014年2月,采用瞬时扫描和焦点动物法研究了鄱阳湖区稻田生境中灰鹤越冬行为的时间分配、活动节律与觅食行为。结果显示,觅食(64.09%)行为所占比例最大,其次为警戒(15.97%)、飞行(8.67%)和修整(7.37%)行为。4种主要行为中,觅食行为时间分配随越冬前期(11月)、中期(12月—翌年1月)、后期(2月)逐渐增加,其余行为时间均逐渐减少。各环境因子对主要行为的影响存在显著交互效应,修整行为随各环境因子变化最为明显,日最低温度升高、日最高温度降低、日照长度增加及湿度降低都会使修整行为增加;日照长度增加和湿度降低时,觅食行为增加;日照长度增加时,警戒行为减少。环境因子对成鹤影响效果与总体相同。环境因子仅对幼鹤的觅食行为影响显著,即日照长度增加和湿度降低,幼鹤觅食行为增加。环境因子对行为的影响为非线性关系,致使其影响趋势在不同范围内有所变化。行为节律上,灰鹤昼间各时段觅食行为保持较高水平,觅食高峰出现在11:00—11:59和17:00—17:30。灰鹤觅食生境与其夜宿地分离,致其上午觅食高峰有所推后。幼鹤昼间各时段行为节律与成鹤有较大差异,且各时段觅食行为比例均高于成鹤。灰鹤越冬期在稻田生境的平均啄食频率为(32.06±0.47)次/min,平均步行频率为(6.55±0.35)步/min。啄食频率与步行频率呈极显著负相关。时段和集群类型对啄食频率的影响存在显著交互效应。稻田中食物资源的可利用性逐渐下降,灰鹤的啄食频率随时间逐渐降低,为保证越冬期间获取足够的能量供应,灰鹤采取逐渐增加步行频率和觅食时间的策略。有觅食间隔的抽样单元中,平均警戒次数为(1.37±0.04)次/单元,平均警戒持续时间为(6.02±0.37)s/单元。成鹤花费在警戒的时间多于幼鹤,家庭群中的个体警戒持续时间多于聚集群中的个体。     

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。     

高寒草甸地区小哺乳动物群落多样性的初步研究

高寒苹甸地区的人工草场、半人工草场、次生杂类草草场和撩荒地中共有4个小哺乳类群落;根田鼠+高原鼢鼠群落;根田鼠+甘肃鼠兔群落;高原鼠兔+高原鼢鼠群落;长尾仓鼠+高原鼠兔群落。小哺乳类群落种的多样性与植物群落种的多样性无显著相关关系,而与植被的高度、盖度呈显著负相关关系。高原鼢鼠是各生境中的广布种。根田鼠与甘肃鼠兔在植被郁闭度高的环境中为群落的主要组成者;植被郁闭度低的环境中,高原鼠兔和长尾仓鼠是群落的主要成员。它们的空间格局主要反映空间环境条件的差异。     

高原鼠兔对垂穗披碱草及豆科植物生长特性的影响

高原鼠兔通过取食对高寒草甸产生广泛的影响,从而影响高寒草甸植物的个体生长特征。2012年在青海省果洛州矮嵩草草甸,以高原鼠兔喜食植物(豆科和垂穗披碱草)为研究对象,通过小区控制研究高原鼠兔取食（对照组、低密度处理组、中密度处理组、高密度处理组）对植物个体生长特征的影响。研究显示：在实验前期（5月和6月）,喜食植物个体特征基本上无明显规律;在实验后期（7月和8月）,随着高原鼠兔取食强度增大,高原鼠兔喜食植物的地上生物量、平均高度、分蘖枝数、分蘖枝长度、丛幅均呈下降趋势;叶片长度和叶片数均呈先上升后下降态势。2.高原鼠兔喜食植物个体特征的增长率对照组显著高于高密度处理组（P<0.05）。以上结果表明(1)高寒草甸豆类植物在其生长后期与高原鼠兔的取食强度呈一定的负相关关系;高原鼠兔取食强度在阈值（中、低密度）内有利于垂穗披碱草的生长,但超过其阈值的取食强度不利于其生长。(2)高原鼠兔高强度的取食对其喜食植物个体的生长率有明显的抑制作用。     

Keystone status of plateau pikas (Ochotona curzoniae): effect of control on biodiversity of native birds

The plateau pika (Ochotona curzoniae) of the Qinghai–Xizang (Tibetan) plateau, People's Republic of China, has been considered a pest because it putatively competes with native livestock for forage and contributes to rangeland degradation. As a result the plateau pika has been poisoned across vast areas of the high alpine meadows of the plateau. The plateau pika has also been considered a keystone species for biodiversity on the plateau. As one test of the keystone species hypothesis, we investigated the effects of poisoning plateau pikas on avian species richness and abundance. We conducted standardized censuses of birds on a number of sites across the alpine grassland of Qinghai province on which pikas either had or had not been poisoned. Avian species richness and abundance were higher on non-poisoned sites, in particular for species that nest in pika burrows such as Hume's groundpecker (Pseudopodoces humilis) and six species of snowfinch (Montifringilla spp., Pyrgilauda spp.), and species that prey on pikas (upland buzzard, Buteo hemilasius; black-eared kite, Milvus lineatus). The plateau pika thus appears to be both an allogenic engineer and a keystone species. Poisoning pikas reduces biodiversity of native species on the Qinghai–Xizang plateau, therefore management decisions concerning plateau pikas should reflect caution and careful assessment.     

Pastoralist Decision-Making on the Tibetan Plateau

Despite a growing body of research about rangeland degradation and the effects of policies implemented to address it on the Tibetan Plateau, little in-depth research has been conducted on how pastoralists make decisions. Based on qualitative research in Gouli Township, Qinghai province, China, we analyze the context in which Tibetan herders make decisions, and their decisions about livestock and pastures. We refute three fundamental assumptions upon which current policy is premised: that pastoralists aim to increase livestock numbers without limit; that, blindly following tradition, they do not actively manage livestock and rangelands; and that they lack environmental knowledge. We demonstrate that pastoralists carefully assess limits to livestock holdings based on land and labor availability; that they increasingly manage their livestock and rangelands through contracting; and that herding knowledge is a form of embodied practical skill. We further discuss points of convergence and contradiction between herders’ observations and results of a vegetation analysis.     

The more the merrier? Multi-species grazing of small herbivores mediates plant community impacts

Small herbivores play keystone functional roles in grassland ecosystems. Recognising the combined effects where herbivores co-exist is important for guiding grassland restoration and biodiversity conservation. On the Tibetan Plateau, both plateau pikas and Himalayan marmots are regarded as pests by Tibetan people and local government, but little is known about their combined effects. We conducted a field study to determine the combined effects of pikas and marmots on plant biodiversity and vegetation structure. Plateau pikas alone consistently reduced the plant height and diversity and increased the vegetation cover of physically unpalatable plants. However, the co-existence of marmots with pikas decreased the vegetation cover of physically unpalatable plants, while increasing the cover of palatable plants and plant diversity, ultimately changing the impact of pikas alone and modulating aspects of the plant community. These results illustrate that increasing the abundance and richness of small herbivores in grassland ecosystems may promote plant diversity and benefit vegetation restoration rather than aggravate the degradation of grasslands.     

Five-year population dynamics of plateau pikas (<Emphasis Type="Italic">Ochotona curzoniae</Emphasis>) on the east of Tibetan Plateau

Small mammals mediate trajectories of vegetation change where both their density and the growing season are moderated by temperature and precipitation. On the Tibetan Plateau, the cold and arid climate particularly restricts the plant growing season, but the role of mammals’ density and climate in moderating small mammal populations remains unknown. We conducted a 5-year mark-recapture study of plateau pikas (Ochotona curzoniae) to test the relative importance of density-dependent and climatic factors on survival and reproduction. Plateau pikas had seasonal fluctuations in density and survival. During the warm summer season (May–August), monthly survival was density-independent, ranging from 74.7 to 90.4%, but varied with sex and age, increased with precipitation and NDVI, and decreased with temperature. During the cold season (September–April), monthly survival was around 98%. Density and precipitation had negative effects on reproductive success for the first and second litters of the year, and temperature showed consistently positive effects on reproductive success for both litters of the year. Pika density and climate regulated together the population dynamics of plateau pikas. These data on the relationships between density and climatic factors on survival and reproduction are critical for the management and conservation of plateau pikas on the Tibetan Plateau.     

Tibetan Pastoralists’ Vulnerability to Climate Change: A Political Ecology Analysis of Snowstorm Coping Capacity

Severe snowstorms on the Tibetan Plateau, which lead to large-scale loss of livestock, are projected to increase in intensity and frequency with climate change. At the same time, political-economic and institutional changes from the 1950s to the present have altered pastoralists’ ability to use various coping strategies. We take a political ecology approach to Tibetan pastoralists’ vulnerability to climate change by qualitatively analyzing how the efficacy of strategies of mobility, communal pooling, storage, and covering and sheltering livestock have been transformed over time in Nagchu, Tibet. Recent government projects have focused on emergency aid and providing shelters. However, these are less effective than mobility and less important than the availability of labor power. Mobility and labor power have been reduced by development and environmental policies, as well as by larger political-economic transformations. These transformations have shifted herders’ coping strategies from internal to external, increasing their reliance upon the state.     

青藏高原气候变化与高寒草地

综述了近五十年来青藏高原气候和高寒草地的变化趋势,阐述了气候变化对高寒草地的可能影响。气候变化主要通过水、热过程及其诱导的环境变化对青藏高原高寒草地产生显著的影响。主要过程包括：气候变化对气候带、植被带、植物、植物群落、农业生产以及生态系统固碳潜力等的影响。从目前的观测和研究结果来看,有关青藏高原气候变化及其对高寒草地的可能影响都还很难得出一致的结论。因此,如何科学评价气候变化及其预测和评价对高寒草地结构和功能的潜在影响,以及如何将已经发生的变化纳入到全球变化模型或评价体系中,以便更加精确地评估气候变化的长期影响,将成为必须要回答的关键科学问题。     

Seasonal dynamics of the tick Haemaphysalis tibetensis in the Tibetan Plateau,China

The tick Haemaphysalis tibetensis (Acari: Ixodidae) Hoogstraal is an important arthropod vector widespread in the Qinghai‐Tibet Plateau, and knowledge of its seasonal dynamics is still poor. The current study investigated the seasonal dynamics of the parasitic and non‐parasitic H. tibetensis over a 2‐year period from March 2014 to February 2016 in the Tibetan Plateau, China. During this timeframe, non‐parasitic ticks were collected weekly by flag‐dragging in grassland and shrubland areas, and parasitic ticks were removed weekly from selected sheep. Plateau pikas were captured using traps and examined for immature ticks between May to September 2014. Results suggest that non‐parasitic H. tibetensis were mainly distributed in the grassland, and the parasitic adults and nymphs were found mostly on sheep. Larvae were usually found on Plateau pikas and the prevalence of infestation and mean parasitic intensity were 72.1 and 1.81%, respectively. Adults were observed from March to July with the major peak occurring in mid‐April. Nymphs were found from March to August and reached a peak in late June. Larvae were collected from April to September, and their numbers peaked in late May. In the parasitic and non‐parasitic period, the overall sex ratio of males to females was 1.62 and 1.30, respectively. Results show that H. tibetensis can complete one generation per year, with a population overlap between stages over the spring‐summer months. These findings provide additional information on the biology and ecology of H. tibetensis as well as insights on its control in the environment and on sheep.     

青藏高原植被退化对高原及周边地区大气环流的影响

利用耦合了陆面模式的大气环流模式,结合青藏高原植被退化的范围和程度,通过在模式中修改高原地区(27°—40°N,75°—100°E)的叶面积指数的方法,探讨了植被退化以后对高原及其附近地区上空大气环流的影响。结果表明,该模式对高原地表温度场具有很强的模拟能力,并且能够很好地模拟出青藏高原及附近地区夏季位势高度场的平均特征及南亚高压的位置和强度,但南亚高压中心强度偏大且略微西退。在青藏高原植被出现退化以后,高原整体地表土壤温度和地表2 m空气温度升高,感热通量增加、潜热通量减小,进而改变了高原地区的波文比。地表感热增加导致高原及附近地区500 h Pa高度场降低和200 h Pa高度场升高,并在200 h Pa上存在强大的反气旋性环流异常,导致南亚高压增强和北扩东伸。植被退化造成的青藏高原感热增加导致了高原南部上升运动增强和北部上升运动减弱,同时又引起高原以北地区下沉气流的影响范围扩大,而下沉气流的强度减弱,其结果有助于高原以北的干旱范围扩大,而干旱程度却得到缓解。