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1.
贺兰山马鹿冬季取食和卧息生境选择   总被引:4,自引:1,他引:3  
2007年12月至2008年1月,在贺兰山地区,利用痕迹检验法和直接观察法对马鹿阿拉善亚种的冬季取食和卧息生境选择进行研究.通过在选定的15条沟段里进行调查,共测定了72个取食利用样方,59个卧息利用样方和131个对照样方的18种生态因子.结果表明,马鹿在冬季偏好的取食地为平滑起伏坡,以酸枣、柳为优势乔木、混合型树林或空地,乔木高大稀疏、间距较远,灌木密度大,草本盖度较高,位于<15°的半阴半阳坡的下坡位,距裸岩远,隐蔽度高;偏好的卧息地在山地疏林草原带的平滑起伏坡上,以酸枣、柳为优势乔木、混合型树林或空地,乔木高大稀疏,灌木矮小、稀疏且距离较远,草本盖度较高,位于<15°阳坡的下坡位,远离裸岩,隐蔽程度高.马鹿冬季的取食和卧息生境在草本盖度和隐蔽度上差异极显著.相对于卧息生境, 马鹿冬季的取食生境对草本盖度和隐蔽度要求更低一些.马鹿冬季取食地的资源选择函数为1.155-0.149×乔木高度-0.066×草本盖度+0.190×坡度,模型的正确判别率为86.8%;马鹿冬季卧息地的资源选择函数为 -30.936+0.494×乔木高度+0.257×坡度-0.002×海拔高度+0.387×隐蔽度,模型的正确判别率为95.8%.食物、隐蔽条件以及贺兰山的独特地形特征是影响马鹿冬季取食和卧息生境选择的主要因素.  相似文献   

2.
采用样线法及直接观察法研究天山中部古仁郭楞地区盘羊天山亚种(Ovis ammon karelini)冬季采食地和卧息地的生境分离。2009年12月—2010年1月累计调查5条沟系的12条样线,测量盘羊采食地和卧息地样方分别为120个和114个。记录了样方所在地的海拔、植物种数、植被盖度、植被高度及距道路距离等13项生态因子。结果表明,天山盘羊冬季采食地与卧息地在植被高度、植被盖度、隐蔽级等生态因子差异不显著(P0.05);在海拔、坡度、坡位、距道路距离、距居民点距离、植物种数和雪深等生态因子差异极显著(P0.01),雪盖、坡向和地貌类型生态因子差异显著(P0.05)。逐步判别分析表明,由5个生态因子变量构成的方程能够区分盘羊冬季采食地与卧息地生境,正确率达到95.1%,按照其贡献值的大小排序依次为:雪深、距道路距离、海拔、坡度和植被高度。研究结果支持盘羊冬季采食地和卧息地之间存在明显的生境分离。  相似文献   

3.
生境是野生动物的栖息基底,卧息地是野生动物重要的功能性生境。为深入了解野生马麝(Moschus chrysogaster)冬季卧息地生境的特征及选择利用,于2021年12月至2022年1月对甘肃兴隆山国家级自然保护区的野生马麝的功能性生境开展了基于生境取样的研究。通过样线调查法获取马麝卧息痕迹位点,采用主成分分析和资源选择函数法进行其卧息生境选择的研究。结果表明,野生马麝冬季卧息地生境的海拔较低[(2 488.5±26.6)m]、灌木较高[(1.3±0.3)m]、灌木盖度(31.08%±3.14%)和地表植被盖度(38.36%±3.27%)较大、倒木较多[(0.5±0.1)个]且积雪较浅[(1.0±0.3)cm];马麝冬季卧息地多选择位于南坡的下坡位灌丛生境,而且距水源较近、隐蔽度较好。主成分分析表明,乔木因子、食物因子、安全因子和地形因子的累计贡献率达67%;马麝的卧息生境资源选择函数为:Logit(x)=﹣4.967+0.001×海拔﹣0.02×坡度+0.03×乔木郁闭度+0.104×乔木高度+0.17×灌木盖度﹣0.466×雪被深度﹣1.015×坡向,模型预测正确率为91.1%。...  相似文献   

4.
研究阿尔金山国家级自然保护区高山草甸和高山荒漠区高原兔Lepus oiostolus夏季生境卧息地利用的主要影响因子,为高原兔的科学管理提供依据。2011—2013年夏季,累计调查高原兔卧息地5 m×5 m样方32个,另外在附近相同生境类型中设置对照样方33个。记录样方所在地的植物种数、植被盖度、植被高度、土壤硬度以及距道路的距离等指标。结果表明,卧息地和对照样方在植物种数、土壤硬度等方面差异有统计学意义(P<0.05),而在隐蔽级、植被高度、植被密度等方面差异有高度统计学意义(P<0.01)。Vanderloeg和Scavia选择指数Ei、选择系数Wi分析显示高原兔卧栖地偏好选择高度在30 cm以上、植被盖度大于30%且密度小于80株/m2,隐蔽级在10 cm以上,土质较软(6~9 kg/cm2)的小生境。主成分分析表明影响高原兔卧息地利用的主要因子依次是:植被密度(-0.898),植被盖度(-0.812)和隐蔽级(0.764)。高原兔偏爱植被高度更高、植物密度更低、隐蔽级更高、土壤较软的小生境。我们的结果为高原兔的科学管理提供了重要依据。  相似文献   

5.
2011年和2012年的冬季在桃红岭国家级自然保护区采用随机样方法,调查了森林采伐对梅花鹿冬季生境选择的影响。调查结果表明:梅花鹿冬季在采伐迹地和非采伐区生境选择存在显著性差异。在采伐迹地,梅花鹿多在植被密度适中或稠密、覆盖度适中或较高、海拔200 m以上的生境活动;在非采伐区,梅花鹿多在植被高度低于1 m、植被密度适中、海拔400 m以上的生境活动。森林采伐后第3年梅花鹿的活动利用强度最大。  相似文献   

6.
李叶  余玉群  史军  时磊 《生态学报》2013,33(24):7644-7650
2010年7-8月采用样线调查法及直接观察法对天山中部古仁郭楞高山区的盘羊天山亚种采食地和卧息地生境进行了研究。共调查5条沟系的12条样线,测量天山盘羊147个采食地和136个卧息地样方,分析了13类生态因子对天山盘羊采食地和卧息地选择的影响。研究结果表明,天山盘羊夏季采食地与卧息地在坡位、坡向、地貌类型、海拔高度、距最近家畜距离、距道路距离和距居民点距离差异极显著(P < 0.01),植被高度差异显著(P < 0.05),而其它生态因子差异性不显著(P > 0.05);相对卧息地的选择而言,夏季盘羊采食地的选择更偏爱海拔较低,植被高度低,距离道路、居民点和最近家畜距离近的半阴半阳坡,山体中下位的高山草甸缓坡生境。逐步判别分析表明,距道路距离、距居民点距离、植被高度、距家畜距离4个生态因子可以用于判别夏季天山盘羊采食地与卧息地生境,正确区分率达到90.6%。  相似文献   

7.
贺兰山马鹿冬春季生境的选择   总被引:6,自引:2,他引:4  
2007年12月~2008年1月和2008年4~5月,在贺兰山利用痕迹检验法和直接观察法对马鹿阿拉善亚种冬春季生境选择进行研究.通过在选定的15条沟段里进行调查,冬春季各测定了131个和181个样方的18种生态因子.结果表明,冬春季贺兰山马鹿在植被类型、优势乔木、灌木密度、灌木高度、灌木距离、坡向、坡位、海拔高度、距裸岩距离和隐蔽级10种生态因子上差异极显著(P < 0.001),其余生态因子无显著差异(P < 0.05),相对于冬季生境而言,马鹿春季更偏爱选择以油松和青海云杉为优势乔木的山地针叶林带,灌木密度大、高度高、距离近,半阴半阳坡的中坡位,海拔较高,距裸岩较近,隐蔽程度高的生境.典则判别系数显示冬春季马鹿在生境选择上存在一定程度的重叠,但春季马鹿的分布范围要比冬季更广一些,Wilk's λ值显示冬春季马鹿的生境选择具有较高的差异性(Wilk's λ = 0.683,x2 = 116.995,df = 13,P < 0.001).逐步判别分析表明在区分冬春季马鹿生境方面有一系列生态因子发挥作用,依照贡献值的大小依次为:乔木密度、灌木距离、坡度、海拔高度、距水源距离、距裸岩距离和隐蔽级,由这7个变量构成的方程对冬春季马鹿生境的正确区分率达到79.9%,其中对春季的误判率为22.1%,对冬季的误判率为20.6%.  相似文献   

8.
刘艳华  牛莹莹  周绍春  张子栋  梁卓  杨娇  鞠丹 《生态学报》2021,41(17):6913-6923
在动物生境研究中,移动生境和卧息生境是生境研究的焦点。开展移动生境和卧息生境选择,并在此基础上进行生境评价,有利于深入了解动物对移动和卧息生境条件的需求,制定科学合理的栖息地保护计划。以东北虎(Panthera tigris altaica)的主要猎物物种之一-狍(Capreolus pygargus)为研究对象,于2017-2019年冬季积雪覆盖期在老爷岭南部通过随机布设28个大样方和84条用于足迹链跟踪的样线收集狍的移动点和卧息点信息,再结合近年来收集的东北虎出现点,利用广义可加模型(GAM)和最大熵模型(MaxEnt)进行狍移动、卧息生境选择及评价研究。移动生境选择研究表明,狍在移动的过程中偏好选择坡度小、距农田距离>500 m、远离道路、居民点和低海拔或较高海拔的区域;移动生境评价分析表明,移动适宜和次适宜生境面积之和为1318.16 km2,占研究区域面积的51.28%,当加入虎活动点影响因子后,狍移动适宜和次适宜生境面积之和为901.52 km2,适宜和次适宜生境面积之和减少了31.61%。狍卧息生境选择研究表明,水源、农田、道路和雪深是影响狍卧息的关键因素,其中雪深对狍卧息生境选择的贡献率达到70.13%;卧息生境评价表明,卧息适宜和次适宜生境面积之和为1243.77 km2,占研究区域面积的48.39%,当加入虎出现点因子后,适宜生境和次适宜生境面积之和减少了61.00%,仅为485.02 km2。研究认为,虎的出现对狍移动和卧息生境选择均产生影响,虎的活动及捕食行为可能会减少狍的活动范围和频次,狍远离虎活动区域卧息休息,压缩了狍适宜卧息的空间。  相似文献   

9.
2009年12月到2010年1月,在黄泥河自然保护区采用样线法对狍冬季卧息地选择进行研究.在研究中共设置了47条样线,调查了72个狍利用样方和109个对照样方,评价了15类生态因子对狍冬季卧息地选择的影响.研究结果表明:在黄泥河自然保护区冬季,狍在卧息时喜欢选择平均海拔在591 m,位于阳坡中坡位上雪被较浅、食物丰富度、灌丛盖度、郁闭度和隐蔽水平都较高的针阔混交林生境,尤其喜欢在针阔混交林中的针叶树下卧息,避开选择阴坡、针叶林和裸岩.逻辑斯蒂回归分析结果表明:食物丰富度、针叶树、雪深、裸岩和海拔是影响黄泥河自然保护区冬季狍卧息地选择的主导因子,林型、坡向和隐蔽水平是次要因子.由这7个变量组成的回归模型为:Z=32.628+11.675×坡向(1) +9.741×坡向(2)-5.486×林型(1)-7.933×林型(2)-7.496×裸岩(1)-9.906×针叶树(1)-0.043×海拔+0.170×隐蔽水平+0.220×食物丰富度-0.429×雪深.模型选择利用概率为P(z)=ez/1+ez,整体正确预测率为96.1%.  相似文献   

10.
贺兰山岩羊(Pseudois nayaur)夏季取食和卧息生境选择   总被引:3,自引:1,他引:2  
采用直接观察法和痕迹检验法对贺兰山岩羊夏季取食和卧息生境选择进行研究.结果表明,夏季岩羊偏好的取食地位于海拔高度1 600~2 000 m的山地疏林草原带,地形为平滑起伏的坡、明显断裂的坡和悬崖,以灰榆和山杨为优势乔木或无树,乔木矮小稀疏且距离远,接近低矮但密度较大的灌木,食物较多,位于<30°和>35°半阴半阳坡的下坡位,接近水源,人为干扰距离500~1 000 m,距裸岩2~5 m,隐蔽级25%~75%;夏季岩羊偏好的卧息地具有位于海拔高度1 600~2 000 m和>3 000 m的山地疏林草原带及亚高山灌丛和草甸带,地形为明显断裂的坡和悬崖,以灰榆和山杨为优势乔木或无树,乔木和灌木均矮小稀疏且距离较远,食物较少,位于>35°阴坡的上坡位,接近水源,人为干扰距离远,接近裸岩,隐蔽程度低.岩羊的取食和卧息生境在乔木高度和距水源距离上差异不显著(P > 0.05),而其余生态因子均有显著差异(P < 0.05).与取食生境相比,岩羊选择的卧息生境具有乔木稀疏且距离较远、灌木较少、低矮且距离较远、食物丰富度低、坡度大、远离人为干扰、接近裸岩和隐蔽程度低的特征.逐步判别分析表明,食物丰富度、灌木高度、距水源距离、隐蔽级、灌木密度、灌木距离、乔木高度和乔木距离8个生态因子可以区分取食样方与任意样方,正确判别率为85.8%;而区分卧息样方与任意样方时,距水源距离、灌木高度、距裸岩距离、人为干扰距离、食物丰富度、灌木密度和灌木距离共7个生态因子发挥作用,正确判别率为89.1%.  相似文献   

11.
Few studies have assessed how the dynamics of wetland bird movements relate to changing resource availability, particularly at more than one spatial scale. Within western Oregon's Williamette Valley, we examined winter resident Dunlin Calidris alpina movements in relation to a decrease in availability of preferred shorebird foraging habitat from early to late winter of 1999–2000. By tracking movements of 15 (early winter) and 12 (late winter) radiomarked individuals, we calculated home ranges and characterized presence/absence of a preference for shorebird foraging habitat during each winter period. Between periods, we compared: (1) percentage of shorebird habitat in home ranges to its availability in the landscape (regional preference), (2) percentage of radio locations in shorebird habitat to its availability within home ranges (local preference) and (3) relative use of roost sites. Concurrent with a 75% decrease in available shorebird habitat from early to late winter, average home range sizes increased by a factor of 3.8. At a regional scale, home ranges in early winter included a significantly greater percentage of shorebird foraging habitat than was available in the wider landscape. However, by late winter, the percent of shorebird habitat in home ranges did not match availability in the landscape. At the local scale, for both winter periods Dunlin were located in shorebird foraging habitat more often than expected given availability of habitat within home ranges [Correction added after online pub-lication 23 May 2008: sentence amended]. An increase in the number of roosts used from early to late winter implies possible reliance on additional sites in late winter for foraging opportunities. Results suggest that wet, unvegetated habitat is sought by Dunlin throughout winter, but individuals could not select home ranges in late winter that fully compensated for seasonal loss of habitat.  相似文献   

12.
Acoustic telemetry was used to monitor the movements and landscape scale habitat use of age 2–3 year juvenile Atlantic cod Gadus morhua in Newman Sound, a coastal fjord of Newfoundland, during late autumn and early winter (24 October 1999 to 22 January 2000). Substratum, bathymetric relief and depth use were studied to determine if it differed from the pattern expected given an absence of selectivity (habitat use proportional to habitat availability). Prior to winter migrations, most Atlantic cod maintained small home ranges (0·5–33·4 ha, median = 2·1 ha) although a few individuals moved more widely. No relationship between total length (LT) and home range size was detected. In Inner Newman Sound, Atlantic cod occupied depths of 10–29 m more than expected given availability, while depths of 0–9 and 40–59 m were underutilized. No significant relationship between depth and LT was detected. Areas of medium (5–10%) or high (>10%) bathymetric relief and boulder or kelp habitats were used significantly more than expected given the availability of these habitats. Sand and eelgrass substrata were underutilized given availability, although many Atlantic cod used sandy‐bottomed areas to some degree. Flexibility in habitat use by the individuals that were studied suggested reduced predation risk relative to younger conspecifics. Winter migrations to deeper water beyond Newman Sound began in mid‐November, coinciding with the disappearance of the thermocline, and continued until 27 December. Approximately 30% of monitored individuals did not migrate and maintained their home ranges into the winter season. No significant differences in LT between migrating and resident groups were detected, however, the condition of migrating fish was significantly higher than in resident fish. This finding supports the theory that feeding history plays a role in the decision to undertake migration.  相似文献   

13.
开展野生动物种群分布数量和生境适宜性评价研究是制定物种科学保护决策的基础和关键。以东北马鹿(Cervus canadensis xanthopygus)为研究对象,于2015—2020年在黑龙江省老爷岭南部穆棱林区,采用大样方调查方法收集马鹿在雪地留下的足迹信息分析马鹿种群数量;通过相机监测、足迹链跟踪和大样方调查3种方法综合收集马鹿活动点信息,利用最大熵(MaxEnt)建模分析马鹿生境适宜性。马鹿种群分布数量研究结果表明,穆棱林区马鹿种群密度为(0.0645±0.009)只/km~2,种群数量为47—61只,主要分布在研究地区南部的和平、龙爪沟和共和林场。生境分析结果表明:人为干扰因子中,居民区对MaxEnt模型的贡献率为44%,马鹿主要在距居民区距离约5 km和10—15 km的区域活动,在偏僻的林间小道和乡村道路马鹿生境适宜性较高,其对模型贡献率分别为16.8%和10.2%;植被因子中,在距常绿针叶林和针阔混交林距离4 km范围内,随距离增加马鹿生境适宜性逐渐降低。生境适宜性分析结果表明,研究地区马鹿适宜生境和次适宜生境面积为87.09 km~2,仅占研究区域的10.39%,主要...  相似文献   

14.
Abstract: Identifying and managing Sitka black-tailed deer (Odocoileus hemionus sitkensis) habitat has been an important wildlife issue for many years on the Tongass National Forest of southeastern Alaska, USA. We evaluated habitat selection of Sitka black-tailed deer in the central portion of the region during a winter with snowfall 43% above average using telemetry relocations from 30 individuals that survived the winter. Ivlev indices for habitat selection within home ranges indicated that deer used less than expected, based on availability, north, east, and west aspects, areas >244-m elevation, noncommercial forests, and the low-timber volume stratum while selecting south aspects, areas <153-m elevation, and areas within 305 m of saltwater. Deer used less than expected moderately coarse-canopied forests in the medium- and high-timber volume strata typically found on north slopes while selecting moderately fine-canopied forest in the high-timber volume stratum on south slopes. The lower than expected use of higher volume gap-phase old growth was likely because these were on north aspects where snow accumulated and persisted due to protection from maritime storms. Point relocations suggested less use than expected in clearcuts <41 years of age, while data from 7.2-ha error polygons showed deer were neutral to clearcuts. This suggests that if deer do avoid clearcuts they remain close to the forest-clearcut edge. Of 4 habitat-mapping methods evaluated, the method that incorporated timber volume strata and a wind disturbance-related aspect had greatest utility in identifying areas selected for or used disproportionately little by deer during the deep snow winter. We found that deer exhibited marked changes in habitat use during deep snow conditions compared to a low snow winter, and we agree with previous researchers that providing habitats selected by deer during deep snowfall is an important consideration in Sitka black-tailed deer habitat management.  相似文献   

15.
Most studies of habitat selection by large herbivores focus on the resource availability and interactions with other species, but neglect the importance of an animal being familiar with an area due to past use. Yet, studies of the establishment and retention of territories, home ranges, birth sites, and feeding site choices in experimental settings have shown the importance of spatial familiarity at these scales. We used GPS locations of translocated wapiti Cervus elaphus , resource selection functions (RSF), and time-to-return to examine whether previous site use was important for selection of sites by wapiti in west-central Alberta. To construct RSFs, we used logistic regression that included spatial familiarity (presence of a previous GPS location within a 50-m radius) as well as estimates of herbaceous and shrub biomass, elevation, aspect, slope, and predation risk to wapiti from wolf predation, as dependent variables. We found that previous use had a strong positive relationship with subsequent site use, indicating that wapiti were not avoiding previously visited locations, as would be expected if memory of forage depletion (which we did not measure) determined response to familiar locations. Revisited sites were of higher quality, i.e. had more moderate terrain, higher forage, and lower predation risk, than sites that were not revisited, indicating that the selection of familiar locations was likely not the result of avoidance of unfamiliar locations. Finally, animals demonstrated preference for familiar locations that it had visited most recently, indicating that memory (which would decline with time) of higher site quality, rather than high quality alone, influenced selection for familiar locations. We conclude that spatial familiarity is important not only for large scale processes such as selection of home range and territory, but for smaller scale habitat selection and foraging as well.  相似文献   

16.
Abstract: The fecal pellet-plot method has been used extensively for snowshoe hare (Lepus americanus) population studies across the species' range, but potential biases associated with the technique have not been addressed adequately. We studied hare pellet-plots in northern Idaho to quantify pellet decomposition rates across environmental gradients, and conducted feeding trials on captive hares to assess the role of diet on pellet production rates. We found that across our study area pellet numbers tended to be higher on plots with high vegetative cover, which likely was a reflection of hare habitat choice rather than lesser pellet decomposition in such habitat. A pellet decomposition experiment indicated that pellet persistence was negatively related to moisture level, and that pellets produced by hares during summer decomposed more quickly than those from winter. We found that only 19% of fecal pellets collected from plots located across northern Idaho were produced by hares during winter. There was a correlation between pellet numbers from plots that were pre-cleared 1 year earlier and estimated numbers of hares on 6 study areas. A similar correlation was lacking for pellet counts from uncleared plots, implying that hare population estimation via pellet-plot counts should involve plot pre-clearing. In captive studies, juvenile hares produced slightly fewer pellets per day per gram of food ingested than adults, but pellet production was similar across diets comprised of 10 different browse species. We conclude that for our study area the fecal pellet-plot method may be subject to notable pellet decomposition bias, and therefore recommend that use of the method elsewhere across the species' range be preceded by assessment of both the pellet-hare density relationship and pellet decomposition rates across habitats.  相似文献   

17.
The effect of habitat fragmentation on spatial foraging behaviour in the root vole Microtus oeconomus was investigated in seven experimental populations. Four of the populations were established in large, continuous blocks (30 × 95 m) of meadow habitat (treatment plots), whereas the three remaining populations had six small rectangular habitat fragments (30 × 7.5 m) with variable inter-fragment distances (control plots). Both the small habitat fragments and the large continuous habitat were embedded in a non-habitat matrix area which was regularly mowed. Half-way through the study period, the continuous habitat in treatment plots was destroyed by mowing to give a configuration identical to the control plots. Dyed bait placed at the edges and in the interior of habitat fragments as well as in the matrix area was used to reveal differential use of these areas for foraging. Animals in the small-fragment plots fed more than expected along the edges, while edges were used according to availability in the large blocks of continuous habitat. In the fragmented plots, the frequency of foraging in the matrix decreased with increasing distance to the fragment border and with increasing inter-fragment distances. Furthermore, the frequency of use of more than one habitat fragment in individual foraging ranges decreased with increasing inter-fragment distances. Reproductively inactive animals of both sexes fed more often along habitat edges than reproductively active animals. Reproductively active females fed exclusively in one habitat fragment, whereas inactive animals and especially reproductively active males frequently included more than one fragment in their foraging ranges. The only effect of habitat destruction was less foraging in the matrix habitat in the post-destruction treatment plots compared to the permanently fragmented control plots. This was probably an effect of different matrix quality. Root voles in these experimental populations forage in edge and matrix habitat with great risk of becoming victims to predation, and the results are interpreted in this context. Received: 19 August 1998 / Accepted: 30 June 1999  相似文献   

18.
贺兰山牦牛冬春季的生境选择   总被引:1,自引:0,他引:1  
在2009年12月-2010年1月和2010年4-5月,采用样线法结合直接观察法对贺兰山牦牛的冬春季生境选择进行了研究。结果表明,牦牛冬季对11种生境因子有选择性,偏爱山地针叶林带,海拔小于2 000 m,优势乔木为灰榆,坡度小于10,下坡位,距水源距离大于1 200 m,人为干扰距离2 000-4 000 m,隐蔽级大于70 %;春季牦牛对13种利用生境生态因子有选择性,偏爱于亚高山灌丛和草甸带,海拔大于3 000 m,乔木密度小于1株,乔木高度小于3 m,乔木距离大于3 m,灌木密度大于4 0株,灌木距离小于1 m,植被盖度大于7 0 %,上坡位,距水源的距离小于8 00 m,人为干扰距离大于4 000 m,隐蔽级大于7 0 %。冬春季牦牛在海拔、植被类型、地形特征、优势乔木、灌木种类、坡位、坡向、人为干扰距离、距水源距离上存在显著差异。主成分分析表明冬季第一主成分的贡献率21.100 %,其中绝对值较大的相关系数是乔木距离、优势乔木、乔木高度和乔木密度;春季第一主成分的贡献率是31.247 %,其中绝对值较大的相关系数是植被类型、海拔高度、地形特征和灌木密度。与其他分布地区的牦牛相比,贺兰山地区的牦牛能适应当地的地理特征和气候环境。  相似文献   

19.
栖木是重要的生境因子,对于鸟类生境选择和利用具有重要意义。2003年9月-2004年3月,采用固定样地对照观测的方法,分析研究栖木在越冬红隼(Falco tinnunculus)的栖息地选择与捕食方式选择中的作用。研究结果表明,增加了栖木的试验区(下称试验区),红隼的出现频率远大于未增加栖木的对照区(下称对照区);试验区红隼个体平均停留时间显著长于对照区;在试验区红隼栖停捕食占捕食次数的77.24%,而在对照区红隼只进行飞行捕食,红隼捕食方式和样地中是否增加栖木具有极显著相关性;试验区,红隼栖停行为时间占51.8%,大于对照区(30.1%),对照区中,红隼在空中的行为如飞行、翱翔、悬停等行为时间所占比例为34.8%,远高于试验区(12.1%)。这些结果表明,栖木在越冬红隼的栖息地选择和捕食方式选择中具有重要的作用,栖木的存在是栖停捕食的先决条件,冬季红隼偏好于具有较好栖木条件的栖息地,并且偏向于采取低消耗低收益的栖停捕食。  相似文献   

20.
Xiong L H  Lu J J  Tong C F  He W S 《农业工程》2007,27(6):2160-2166
In winter, Common Kestrel minimizes energy expenditure by using the low-cost, low-profit technique of perch hunting. Existence of the perch sites is the precondition of perch hunting. Therefore, one can predict that the kestrels would prefer a habitat with more perch sites, and perch sites should have an important role in the kestrels' hunting technique use, habitat selection and habitat use in winter. To test this prediction, the authors manipulated two areas in a grassland. They increased the potential perch sites in one area with bamboo poles (hereafter test area) and kept another as control (hereafter control area). They observed and compared the kestrels' use and their behaviors in these two areas. Far more kestrels appearing in the test area with increasing perch sites than in the control area were recorded. The kestrels stayed in the test area with more perch sites significantly longer than in the control area. And in the test area with more perch sites, kestrels hunted 77.24% of the total hunting with the technique of perch hunting. In the control area, kestrels hunted only with the technique of flight-hunting. There was a significant correlation between the technique used by kestrels and the areas with or without perch sites. In the test area with increasing perch sites kestrels spent 51.8% of their time in perching and 12.1% in air, which were 30.1% and 34.8%, respectively, in the control area. There was no significant difference in hunting profit between areas. The results suggest that perch sites play an important role in the selection of hunting technique and foraging habitat for kestrels in winter, and kestrels appear to prefer the habitat with suitable perch sites in winter.  相似文献   

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