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1.
野生动物的自然行为受当地家畜影响。作为与家畜共享一个栖息地、并具有挖掘行为的兔形目高原鼠兔,其行为也受当地高原家畜影响。本文采用了Poisson回归分析方法,确定牦牛、不同土地利用对高原鼠兔行为频次的影响。结果显示觅食、移动频次是高原鼠兔的主要行为频次。在冬季牦牛觅食地高原鼠兔觅食行为频次高于警戒行为频次。相反,在夏季,无论是在牦牛觅食地还是在其夜宿地,高原鼠兔警戒行为的频次高于觅食行为频次。高原鼠兔行为也受不同土地利用、植被覆盖度以及季节因素的影响。植被覆盖度与觅食频次成反比,植被覆盖度高的生境高原鼠兔觅食较少,相反,植被覆盖度较低生境觅食行为频繁。另外当前牧民的定居化趋势造成局域放牧过度,加速了土地荒漠化。因此本文也认为,季节性传统游牧模式对于草地可持续发展具有重要意义。  相似文献   

2.
放牧干扰下高原鼢鼠栖息地选择因素   总被引:4,自引:1,他引:3  
以祁连山东段高寒草甸栖息的高原鼢鼠(Myospalax baileyi)为研究对象,探讨放牧干扰下高原鼢鼠适合栖息地选择的影响因素,为合理控制草原鼠害和保护生物多样性提供科学依据。在5个不同放牧强度小区中,连续3年监测高原鼢鼠相对种群密度变化,同时获取植被和土壤的变化数据。分析高原鼢鼠相对种群密度、植被(盖度、高度、频度、植被生物量、植被均匀度、丰富度、多样性和地下根系生物量)和土壤(紧实度、容重、水分)之间的关系。中度放牧干扰下,高原鼢鼠相对种群密度最低,不利于对栖息地的选择,轻度、次轻度放牧区的高原鼢鼠相对种群密度高于重度、次重度放牧区的;轻度放牧干扰的草地有利于高原鼢鼠种群数量的增加。高原鼢鼠相对种群密度与土壤紧实度、容重呈显著负相关(R=﹣0.921、﹣0.883,P0.05);与土壤水分呈显著正相关(R=0.879,P0.05);高原鼢鼠相对种群密度与地下根系生物量呈极显著正相关(R=0.982,P0.01),与植被丰富度呈显著正相关(R=0.921,P0.05),与地上植被总盖度呈显著正相关(R=0.909,P0.05),与地上生物量、均匀度、多样性呈不显著正相关(P0.05)。在草地放牧干扰系统中,非生物因素土壤紧实度、水分可能是高原鼢鼠栖息地选择的首要选择因素,食物资源也许是次要选择因素。  相似文献   

3.
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。  相似文献   

4.
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。  相似文献   

5.
高原鼠兔贮草行为初探   总被引:6,自引:0,他引:6  
张毓  刘伟  王学英 《动物学研究》2005,26(5):479-483
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。  相似文献   

6.
植物生长季节不同栖息地高原鼠兔的食物选择   总被引:4,自引:2,他引:2  
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.  相似文献   

7.
2010 年和2011 年8 月在青海省果洛州矮嵩草草甸,采用样方法测定了不同密度高原鼠兔栖息地内杂草斑和秃斑植物群落特征及地上生物量的变化。结果表明:2010 年与2011 年相比,相同高原鼠兔密度的栖息地内杂草斑和秃斑植物总盖度、平均高度和总地上生物量差异不显著,但同一年份不同密度栖息地间差异显著。高原鼠兔低、中、高密度栖息地植物总盖度、平均高度和总地上生物量显著低于无鼠兔对照组(P < 0.05),不同密度间无明显变化规律。低、中、高密度栖息地的莎草、禾草和豆科植物盖度、平均高度和地上生物量显著低于无鼠兔对照组(P <0.05),秃斑上豆科植物消失;杂类草平均高度在低密度栖息地和无鼠兔对照组显著高于中、高密度栖息地(P < 0. 05),盖度和地上生物量对照组最小,随高原鼠兔密度增加呈增加趋势。2010 年和2011 年,高原鼠兔低、中、高密度栖息地内杂草斑面积分别占样地面积的4. 0% 、4.3% 、13. 3% 和3.8% 、4. 3% 、11. 0% ,秃斑面积分别占样地面积的0 2% 、2 6% 、4 0% 和0 2% 、2 2% 、3 4% ;植物损失地上生物量分别为110.84 kg/ hm2 、203. 18 kg/ hm2 、431.58 kg / hm2 和107.67 kg / hm2 、189. 46 kg / hm2 、365. 72 kg/ hm2 。高原鼠兔
的密度(x)与植物损失地上生物量(y)之间存在对数曲线关系,说明高原鼠兔的活动显著降低了植物总盖度、平均高度和总地上生物量,同时也改变了植物功能群组成。随高原鼠兔密度增加,栖息地内杂草斑、秃斑的面积和植物损失地上生物量呈增加趋势。  相似文献   

8.
甘肃鼠兔贮草越冬及其生物学意义   总被引:3,自引:0,他引:3  
对采自草甸、灌丛和弃耕地3 种类型栖息地共27 个甘肃鼠兔草堆的研究结果表明, 每个草堆干重在23.8~984.2 g 之间, 平均184.2 g , 总计含有26 种双子叶植物和一些禾本科单子叶植物。分析显示, 草堆大小(食物重量) 与栖息地植被类型无关。在贮存干草堆时, 甘肃鼠兔对不同植物成分具有强烈的选择性, 其中, 单子叶植物和双子叶植物分别占总重量的8.06 %和84.61 % , 与它们各自在栖息地中的生物量百分比51.76 %和39.57 %形成鲜明对照。甘肃鼠兔对植物种类的选择性在一定程度上受栖息地植被类型的影响, 但最喜食的几种植物却基本不变, 它们是美丽风毛菊、棘豆、麻花艽、禾草、线叶龙胆。人工去除栖息地中的干草堆后, 甘肃鼠兔种群越冬存活率从对照样地的51.84 %下降到21.33 % , 表明草堆食物对其成功越冬有一定正效应。野外观察证实, 甘肃鼠兔的鸣声不及同域分布的高原鼠兔发达, 但前者具有贮存食物越冬的习性, 而后者却不贮存越冬食物, 此结果不支持“鼠兔类动物建立草堆的行为与鸣声行为平行发育”的观点。  相似文献   

9.
高原鼠兔贮草选择及其生物学意义   总被引:1,自引:0,他引:1  
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。  相似文献   

10.
高原鼠兔洞穴数量与其栖息地植被分布格局的GIS分析   总被引:2,自引:0,他引:2  
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.  相似文献   

11.
植食性小型哺乳动物的觅食行为是对特定生境的适应性产物。食物斑块周边植被对动物视野遮挡是否通过作用于其觅食活动中的警觉而影响摄入率。采用新鲜白三叶叶片构建东方田鼠密集均质食物斑块,以牛皮纸模拟食物斑块周边植被遮挡田鼠视野,测定其在食物斑块上的觅食行为序列过程及行为参数,检验食物斑块周边植被高度对东方田鼠摄入率的影响。结果发现,个体在不同程度视野受阻条件下食物摄入率无显著差异。分析觅食行为参数动态发现,在不同视野受阻条件下,个体能通过调整各采食回合内警觉行为动作的发生频次和持续时间,维持觅食回合内总的觅食中断时间的稳定,进而保证进食时间的稳定。东方田鼠在不同程度的视野遮挡条件下均能通过行为变异和优化使摄入率保持稳定。结果亦充分说明,东方田鼠在警觉强度上的变化不能反映觅食中断所带来的食物收益减损的代价,但觅食活动中各警觉动作的持续时间的变异却能够明确指示个体摄入率的动态变化,因此,以觅食活动中警觉引起的觅食中断时间代价为线索,检验其对摄入率的影响,是评价植食性小型哺乳动物在不同生境觅食适应性策略的有效的方法。  相似文献   

12.
青海可可西里地区的植被   总被引:4,自引:0,他引:4       下载免费PDF全文
郭柯 《植物生态学报》1993,17(2):120-132
青海可可西里地区位于青藏高原腹地,总面积8万多平方公里,平均海拔高度4600—5000m,是青藏高原,也是我国植被科学研究最大的空白地区。 根据1990年夏为期3个月的实地考察,发现本区由东南到西北主要分布着高寒草甸,高寒草原和高山冰缘植被。垫状植被、高寒荒漠和高山河谷灌丛等也有分布。植物区系组成以青藏高原成分为主,其次为中亚高山分布的种。各种植被类型的分布往往与地形部位和基质状况存在着密切的联系。  相似文献   

13.
The combination of the visual obstruction and protection properties of vegetation is considered to be one of the most important factors determining the trade-off between vigilance and foraging in a prey species. In the Negev desert, diurnal fat sand rats construct their burrows in the ephemeral river beds ("wadis"), under dense and tall shrubs of Atriplex halimus, or on the open first fluvial terrace, covered with scattered low shrubs of Anabasis articulata. We tested the hypothesis that properties of the vegetation would affect the time budget of female sand rats. Sand rats spent more time aboveground, rested more, were less vigilant, and moved more slowly under the dense cover in the wadi than at the open terrace. No differences in the total foraging time were revealed, but foraging tactics varied between habitats: individuals in the wadi mainly fed aboveground, whereas those at the terrace mainly hoarded. Our results indicate that sand rats perceive the dense vegetation cover as good protection despite its visual obstructive nature, and that vigilance in Psammomys obesus is performed at the cost of resting rather than at the cost of foraging. Received: January 15, 2001 / Accepted: April 17, 2001  相似文献   

14.
Relationships between vegetation and climate on the Loess Plateau in China   总被引:3,自引:0,他引:3  
The Loess Plateau is one of the most environmentally sensitive regions in China. This study addresses the relationships between vegetation and climate of this area quantitatively at a large-scale, in order to determine the factors that control vegetation distribution. The Loess Plateau, located at 101°01′–155°10′ E and 34°02′–40°40′ N, covers an area of 52 million hectares. Vegetation data were collected from the vegetation map (1:500,000) and the Landsat Thematic Mapper scenes of the Loess Plateau. The Loess Plateau was divided into small districts of 30′ latitude by 30′ longitude on the vegetation map. In each district, areas with different vegetation were measured and used as vegetation data. The climatic data were average values of county meteorological records in each district in the past 25 years. GIS, TWINSPAN and canonical correspondence analysis (CCA) were employed for analysis. 257 small districts were clustered into 7 groups using TWINSPAN, representing 7 vegetation regions or subregions. The first three CCA axes had significant correlations with climate. The first CCA axis represented the variation of vegetation and climate along the latitude gradient, while the second CCA axis the variation along the longitude gradient. The distribution pattern of 171 vegetation formations on the CCA plot is identical to that of vegetation regions (districts). The spatial distribution of vegetation is closely related to climate variables on the Loess Plateau. Water variables and temperature are important in both latitude and longitude gradients, while the sunshine hours, accumulated temperature and wind speed are more important than water variables and temperature in longitude gradients.  相似文献   

15.
Resource heterogeneity across the landscape prompts animals to make behavioral tradeoffs to survive and reproduce. Behavioral thermoregulation can buffer organisms from thermal extremes but may conflict with other essential activities such as predator avoidance or foraging, and necessitate tradeoffs among resource requirements. We evaluated patterns of habitat selection relative to thermal conditions, forage availability, and concealment cover for female eastern wild turkeys (Meleagris gallopavo silvestris) with broods to assess potential tradeoffs among resource requirements. We quantified air temperature (°C), vegetation characteristics (e.g., visual obstruction), and arthropod biomass (g/m2) at locations used by broods across 5 study sites in the southeastern United States during May–July 2019–2020. We used conditional logistic regression to estimate brooding female resource selection at the second (home range) and third (within home range) orders. Specifically, we identified differences in selection between brooding and non-brooding females (second order), and factors influencing selection of sites used by brooding females during the day (when loafing and foraging) and night (roosting; third order). Brooding females selected sites with cooler temperatures (β = −0.22; 95% CI = −0.338–−0.102) and greater ground cover vegetation (β = 0.02; 95% CI = 0.013–0.033) than non-brooding females. Additionally, biomass of large prey (Orthoptera) was positively related to ambient temperature, suggesting that use of thermal refuge by brooding females may limit availability of large prey. Brooding females appeared to balance the tradeoff between thermal refuge and forage availability by altering habitat selection patterns within home ranges. Brooding females selected for herbaceous areas that provided greater biomass of large arthropods during the day, and avoided areas dominated by woody vegetation during both the day and night. We did not observe brooding females using locations where woody cover exceeded 27% of understory vegetation. Thermal refuge is an important component of brood habitat, but within thermally suitable areas brooding females can select sites with greater availability of large prey to meet energetic demands of broods. Evaluation of multiple spatial scales is key when assessing tradeoffs among resource needs and determining the potential of behavioral thermoregulation to buffer an organism's thermal environment and allow persistence in a warming climate.  相似文献   

16.
Whereas there are many studies of the time allocated to antipredator vigilance while animals forage, the vast majority of these studies remain correlative. This is potentially problematic because a variety of factors other than variation in perceived risk might influence putative antipredator behaviors such as time allocated to vigilance and foraging. We conducted an experimental study of yellow‐bellied marmot (Marmota flaviventris) antipredator behavior while marmots foraged at a replicated set of feeding stations established 1, 5, 10, and 20 m from their main burrows. Marmots appeared to perceive a reduced risk of predation when they foraged in the presence of other marmots; they allocated more time to foraging and decreased the time allocated to vigilance. When they foraged farther from their burrows, marmots initiated foraging after a substantially greater amount of time, tended to increase the frequency of their bouts of vigilance, and decreased the duration of each bout. Yearling marmots took less time to begin foraging than adults. Marmot flight initiation distance at our feeding trays was independent of the distance they foraged away from the burrow. Taken together, these experimental results demonstrate that marmots' perceptions of risk increased with distance to the burrow and decreased when other individuals were within 10 m of them while they foraged.  相似文献   

17.
2016年3~6月,在广西西南部龙州县弄岗村(22°26′35.20′′~22°30′46.90′′N,106°57′46.35′′~107°03′32.99′′E),通过野外观察和自动温度记录仪相结合的方法对褐翅鸦鹃(Centropus sinensis)的孵卵行为与节律进行了研究。结果表明,1)褐翅鸦鹃边筑巢边产卵,每2 d产1枚卵,卵长径和短径分别为(36.11±0.42)mm和(28.46±0.38)mm,卵重(16.35±0.51)g(n=44枚)。窝卵数3~5枚,孵卵期为(16.75±1.65)d(n=4巢),孵化率为45.45%(n=44枚)。孵卵期与窝卵数之间无显著相关性(r=0.865,P0.05);2)白天双亲共同参与孵卵,夜晚则由其中1只负责。夜间亲鸟的在巢时间从19时左右持续至翌日晨6时左右;3)亲鸟采取离巢次数少和离巢时间长的孵卵策略。亲鸟日活动时间在700 min以上(n=45 d),日离巢次数为(8.82±0.34)次(n=45 d),平均每次离巢持续时间为(52.91±2.35)min(n=397次),每次离巢持续时间与环境温度呈显著负相关关系(r=﹣0.113,P0.05);4)巢内平均孵卵温度为(31.7±0.3)℃(n=4巢),随孵卵天数增加而增加,并与环境温度(最高温r=0.566,最低温r=0.537,平均温r=0.706,P0.01)和日活动时间正相关(r=0.506,P0.01);5)有延迟孵卵行为。延迟孵卵期间夜晚巢内最低温是22.1℃。在桂西南北热带气候环境中,高的环境温度是保障褐翅鸦鹃孵卵成功的主要因素之一。  相似文献   

18.
Synopsis Recent studies show that fish forage actively when perceived risk is low, but decrease foraging and increase vigilance when perceived risk is high. Isolated juvenile chum salmon,Oncorhynchus keta, were visually exposed to groups of conspecifics engaged in different activities to examine their ability to gain information about foraging opportunity and risk by interpreting conspecific behavior. Isolates ate most when exposed to feeding groups, less when exposed to nonfeedig groups, and least when exposed to alarmed groups. Isolates exposed to alarmed conspecifics also spent more time motionless than did fish exposed to either feeding or nonfeeding conspecifics. These findings indicate that schooling fish gain information by interpreting conspecific behavior, and are consistent with research showing that animals balance the conflicting demands of foraging and vigilance.  相似文献   

19.
During times of high activity by predators and competitors, herbivores may be forced to forage in patches of low‐quality food. However, the relative importance in determining where and what herbivores forage still remains unclear, especially for small‐ and intermediate‐sized herbivores. Our objective was to test the relative importance of predator and competitor activity, and forage quality and quantity on the proportion of time spent in a vegetation type and the proportion of time spent foraging by the intermediate‐sized herbivore European hare (Lepus europaeus). We studied red fox (Vulpes vulpes) as a predator species and European rabbit (Oryctolagus cuniculus) as a competitor. We investigated the time spent at a location and foraging time of hare using GPS with accelerometers. Forage quality and quantity were analyzed based on hand‐plucked samples of a selection of the locally most important plant species in the diet of hare. Predator activity and competitor activity were investigated using a network of camera traps. Hares spent a higher proportion of time in vegetation types that contained a higher percentage of fibers (i.e., NDF). Besides, hares spent a higher proportion of time in vegetation types that contained relatively low food quantity and quality of forage (i.e., high percentage of fibers) during days that foxes (Vulpes vulpes) were more active. Also during days that rabbits (Oryctolagus cuniculus) were more active, hares spent a higher proportion of time foraging in vegetation types that contained a relatively low quality of forage. Although predation risk affected space use and foraging behavior, and competition affected foraging behavior, our study shows that food quality and quantity more strongly affected space use and foraging behavior than predation risk or competition. It seems that we need to reconsider the relative importance of the landscape of food in a world of fear and competition.  相似文献   

20.
Locomotor Ability and Wariness in Yellow-Bellied Marmots   总被引:3,自引:0,他引:3  
Animals employ a variety of behaviors to reduce or manage predation risk. Often, these are studied in isolation, but selection may act on packages of behavior that are referred to as behavioral syndromes. We focused on yellow‐bellied marmots (Marmota flaviventris) and examined three commonly studied antipredator behaviors. We fitted general linear models to explain variation in maximum running speed, time allocated to vigilance and foraging during bouts of foraging, and flight initiation distance (FID). Marmot maximum running speed was influenced by the substrate run across; marmots ran fastest across dirt or low vegetation and slowest across stones or talus. Incline and several other variables shown to affect running speed in other marmot species failed to explain significant variation in yellow‐bellied marmots. From these results we expected marmots to be sensitive to substrate while foraging, but insensitive to incline. However, time allocated to foraging was affected by incline but not by substrate. In bouts of foraging observed in different habitats, and on different inclines, more time was allocated to foraging and less to vigilance on steep slopes and less on level ground. Substrate influenced FID. Marmots in tall vegetation were less tolerant of an approaching person than were those in shorter vegetation. Finally, we found significant correlations between the residuals from the maximum running speed model and the residuals from the time allocated to vigilance and foraging models. We found a tendency for marmots that ran slower than predicted to be less vigilant while foraging. We also found that relatively slow marmots engaged in more active foraging and less vigilance during foraging bouts. This finding suggests a ‘locomotor ability‐wariness while foraging’ syndrome. It also suggests that vulnerable individuals minimize their exposure while foraging.  相似文献   

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