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1.
BearisveryvaIuableeconomicanimal.BearresourcereducedsharplywithMan'sexploitingandutilizingonnatufe,wbrseningofecologicalenvirorunent.Itisveryvaluabletoaccumulatebasicbiologicaldataofbcarre-searchinordertostudybcarpopulationecol-ogyindetail,providescientificbasisforbearresourcemanagement,thcnccdofarchacologr'andthestUdy'onthedataofnatUraldeathinfield.Toothisthemostdifficultdecomposedpall,sotheywillprovidcalotofinformationduringtheproccssofstudyonarchaeologyandnatllfaldeathindividual.Itisavery…  相似文献   

2.
The geographical distribution and the abundance of Moose(Alces alces)popula-tion were studied in Northeastern China between 1985 and 1987,309 trails on the snow crossingthe 2,446km sampling lines were counted.The Moose range had been shrunked to northwest for100-200 km since 1976,and at present they covered an area about 190,000 km~2.The densitiesvaried from 0.0187 Mooses/km~2 to 0.1226 Mooses/km~2 and the average was 0.0519Mooses/km~2.The Moose population size was 9,955±397 Mooses(α=0.2,P=84.5%),about7000 of them was distributed in Daxinganling Mountains and the others were in XiaoxinganlingMountains.The present population had decreased to 53.4%in 1976,and the annual decreaserate was 6.27%.At present,Moose population is likely rare in China and should be strictly pro-tected.  相似文献   

3.
Many biotic factors impact forest health and productivity and an important damage agent in many forests in North America is the black bear (Ursus americanus). Black bears use trees for feeding and marking purposes, both resulting in cambial damage, which reduces growth rates and can increase mortality rates. Black bear behavior is strongly impacted by human activities including forest management and supplemental feeding. During the 2010 permanent sample plot census and tree health survey in Fundy National Park, New Brunswick, Canada we measured high rates of bear damage; roughly 10% of the sampled population experienced damage in a non-uniform way within the Park. The goal of the present research was to examine the spatial distribution of bear damage, determine underlying causes of spatially non-homogeoneous bear damage and quantify the impact of this damage on forest dynamics.Bear damage was more frequent around the periphery of the Park and using spatial scan statistics, we identified two clusters of bear damage, both at the Park’s inland borders and adjacent to areas of high bear hunting baiting station density. Species differed in the extent of damage, with hardwood species incurring proportionally greater damage. Using multiple regression we modeled bear damage as a function of stand type (%hardwood), stem density, proximity to and density of bait stations and distance to the nearest major edge. Models containing stand type and bait station metrics garnered the greatest support based on minimum AIC analysis. Bear damage was greater in hardwood stands and in sites closer to or in areas of higher density of bait stations. Bear damage had a significant negative impact on forest dynamics; 2005-2010 diameter growth showed significant reductions in response to bear damage.Our findings implicate bear bait stations used by hunters in aggregating black bears at the Park periphery where they cause greater damage to the trees, which results in reduced growth rates in these areas. Effectively, high bait station densities surrounding the Park are contributing to two related edge effects: (1) increased activity in and use of forests at the Park edges by bears; and (2) increased damage and decreased growth in peripheral stands where bear activity is high. Continued heavy bear damage could pose a threat to forest integrity along the boundaries of the Park. Thus, despite the high protection afforded this National Park, its function and long-term integrity is impacted by adjacent land uses as demonstrated by the present study, an increasingly widespread problem facing protected areas.  相似文献   

4.
基于红外相机监测的汪清自然保护区东北豹种群动态   总被引:1,自引:0,他引:1  
【目的】东北豹是分布最北、种群数量最小的豹亚种,濒危等级为“极危”。分析采用相机监测技术得到的汪清保护区内东北豹种群数量和分布情况的长期动态,为这一濒危物种的保护提供科学依据。【方法】 2013年秋-2017年秋,在汪清保护区内东北豹主要分布区以每3km×3km网格1对的密度布设相机。采用相对丰富度指数(relative abundance indices,RAI)计算东北豹相对丰富度,以99%核密度等值线定义东北豹分布区,在Extract Compare软件中进行个体识别。在CAPTURE软件中对有效监测期的数据进行闭合种群检验、适宜模型评估和种群数量估计。以8 km为半径,在相机布设处向周边外延绘制缓冲区作为有效监测面积,评估东北豹种群密度。【结果】在9个监测季,东北豹RAI指数波动在0.34~2.12之间。2013年秋季东北豹分布区为201km^2, 2017年秋季分布区为992 km 2。共识别东北豹个体9只,其中成年雌性和雄性各3只、幼崽2只、性别不明个体1只。在种群数量低的情况下,CAPTURE闭合种群检验效力并不强,检验结果总体偏低。Mh模型(假设拍摄率有个体差异)选择标准得分在2015春、2015秋、2016秋、2017春4个监测季最高,在其他5个监测季得分仅次于M 0(假设拍摄率一致)。卡方拟合优度检验显示,Mb(假设捕获前后拍摄率有差异)、Mt(假设不同时段拍摄率有差异)模型评估捕获率与M0模型无显著差异。研究期间东北豹种群密度波动在0.12~0.88只·(100 km 2)^-1 ,种群总捕获率整体较高,但2017年春季拍摄个体仅占种群评估数量的0.43。【结论】受地理因素和猎物丰富度变化影响,东北豹时空分布具有异质性。CAPTURE闭合种群检验对小样本检验效力不强。M h假设是进行东北豹种群数量评估的适宜模型,“拍摄羞怯反应”会导致种群密度评估结果偏高。  相似文献   

5.
PREFACETibetansnowcock(Tetragallustibetanus)isakindofplateaubird,whichlivesinhighestlandamongseveralpheas-antsintheworld.ThesnowcockismainlydistributinginTibetanditshabitatstretchesfromeastinQinlingMountainstowestinPamirPlateau.Tibetisavastexpanseofplateauterritorywithe1evationofmorethan4,OOom.TherearemanysnowmountainsinTibet,especial1yinwesternparts.Theriversand1akesspreadovera1lplaces.BecauseofhightopographyfeaturesandtheHimalayasmountainsys-temacrossfromeasttowest,thechimateisveryco…  相似文献   

6.
清凉峰自然保护区华南梅花鹿种群数量与分布研究   总被引:3,自引:0,他引:3  
于2006年1—3月,采用雪地足迹计数法和样带法对清凉峰国家级自然保护区内野生华南梅花鹿种群与分布进行调查研究,结果表明,在38条样带中有13条样带发现有华南梅花鹿,这13条样带构成一个狭长地带;清凉峰自然保护区内野生梅花鹿种群最低密度为0.90头/km^2,最高密度为2.79头/km^2,平均密度为1.84头/km^2,种群数量为104(51~156)头。研究揭示,华南梅花鹿主要在海拔800-1200m的范围内活动,栖息地植被类型以草甸和灌丛为主。  相似文献   

7.
采用样线法对新疆西昆仑地区野生有蹄类的种群分布和数量进行了调查,并运用Distance软件对调查数据进行了分析。结果显示:该地区的岩羊(Pseudois nayaur)种群密度为3.075头/km2,北山羊(Capraibex)的种群密度为1.27头/km2。在设定的3个调查区域:矿区、公路区、低干扰区内,岩羊的种群密度依次为:2.55头/km2、3.17头/km2和4.38头/km2;北山羊在3个调查区域的种群密度依次为:0头/km2、2.28头/km2、0.16头/km2。对动物群的行为进行了观察和分析,结果表明:公路的对动物行为有一定程度的影响,而矿点分布对动物的分布和行为未表现出显著的相关性。  相似文献   

8.
IntroductionBrownbearisanen~redspecies.ThereisverylowwiahonOfbroWnbearsinthefie1d.Theanificialbredngincaghvitybecon1esaveryimPOrtantaPProachtoiareasethenumberofbearsandtorecoverwildbearresources.ThempseofthisstUdyistoProvidebasicbouSeAninfOnnationfOrthesu…  相似文献   

9.
Greenhouse gases in the atmosphere, mainly carbon dioxide (CO2), can be mitigated by the planting of trees and shrubs. Appropriate agroforestry practices in Saskatchewan include field and farmyard shelterbelts, wildlife plantations, poplar plantations and managed woodlots. A study was conducted to determine the amount of carbon held in prairie shelterbelts. The effect of the soil type and tree species on biomass and carbon content was measured in shelterbelts in the brown, dark brown and black soil zones of Saskatchewan. For some of the main shelterbelt species, the mean aboveground carbon content was 79 kg/tree (32 t/km) for green ash, 263 kg/tree (105 t/km) for poplar, 144 kg/tree (41 t/km) for white spruce and 26 t/km for caragana. In the brown and the dark brown soils, which are more arid than the black soil zone, trees had 60.6% and 65.5%, respectively, of the biomass and carbon content of trees and shrubs in the black soil zone. Improved, fast-growing poplar clones had the greatest biomass at maturity and fixed the greatest amount of carbon. Simple equations were developed to calculate the carbon contents of prairie shelterbelts, based on easily measured tree or shrub parameters. This paper will discuss the results of this particular study and the broader implications of this work. This revised version was published online in June 2006 with corrections to the Cover Date.  相似文献   

10.
Xu Li  Li Li  Yang Xiujuan 《林业研究》1997,8(2):115-116
From 1991 to 1992, we observed behavior of 7 brown bears (5 females, 2 males) in mating season. Results showed that the oestrus of brown bears was mainly from May to July. The oestrus of most individuals occurred at the end of May and the beginning of June. There were some differences in the oestrus among individuals. Average duration of the oestrus was 30.8 days (16–50 days). The mating behavior was mainly observed during 8.00–9.00 a.m., and 15.00–16.00 p.m., Rest and sleep were the next behavior after mating for most bears, especially for male bears. All bears had poor appetite. The pattern and process of a successful mating was that a male bear approached a female, smelled the pudendum of the female, climbed on female hip, mated, parted and rested. Oestrus females approached males sometimes. (Responsible Editor: Sun Yueqi)  相似文献   

11.
刺槐尺蠖防治指标的研究   总被引:2,自引:0,他引:2  
经过对刺槐的蓄叶量、叶面积、刺槐尺蠖食叶量、人工模拟摘叶对刺槐生长量影响等因子的调查分析,得出胸径D与刺槐蓄叶量M之间的关系式为M=135265.73 + 13949.41D(相关系数r=0.976),刺槐叶面积与鲜重(长宽平均值)的关系:S=0.096W - 0.086(r=0.986),S=1.99L - 0.68(r=0.988),刺槐尺蠖幼虫期平均每头损叶量为295.45cm^2,根据CT=M*H/Q(1-R)关系式,计算出不同径阶刺槐树的刺槐尺蠖的防治指标。  相似文献   

12.
Today's growing demand for timber is increasing road development in once roadless forest ecosystems. Roads create both local changes in plant communities and landscape-level changes in forest connectivity. Roads also increase human access, which can be detrimental to species such as grizzly bears. Because most grizzly bear mortalities occur near roads, we examined grizzly bear attractants near roads, which could increase bear use of roadsides and consequently increase human/grizzly bear interactions. We measured the prevalence of 16 grizzly bear foods near roads and examined patterns in road placement to better understand use of roaded habitats by grizzly bears in west-central Alberta. We found that roadsides had a higher frequency of ants, Equisetum spp., Taraxicum officinale, Trifolium spp., graminoids, and sedges; whereas, interior forest stands had a higher frequency of Shepherdia canadensis, Vaccinium myrtilloides, V. vitis-idaea, and ungulate pellets, an indicator of ungulate presence. In addition, roads near water had a greater occurrence of Arctostaphylos uva-ursi and Equisetum spp. than roads not near water, indicating that road placement influenced bear food diversity. Patterns in road placement varied between the upper and lower foothills, although models for the lower foothills predicted road placement in both regions. In the lower foothills, roads were constructed at low elevation, low soil moisture, high sun exposure, and intermediate terrain ruggedness, possibly similar to sites selected by bears. Reducing grizzly bear foods near roads should involve decreasing the width of roadside ditches, banning the planting of clover (Trifolium spp.), and reevaluating road placement in areas with high grizzly bear density.  相似文献   

13.
卡拉麦里山有蹄类自然保护区蒙古野驴的数量与分布   总被引:2,自引:0,他引:2  
2005年9—10月在新疆北部卡拉麦里山有蹄类自然保护区调查了蒙古野驴的数量和分布。调查过程共设置样线8条,总长640.90km,共发现野驴53群1 039头,平均群体大小为(11.90±7.84)头/群,最大群为189只,2~10头的小群遇见率最高,占总群体数的43.40%。采用实体观测垂距法计算,蒙古野驴的平均密度为(1.231±0.196)头/km~2。结合有效分布面积,可计算得出保护区内约有野驴(5 234±834)头。调查显示蒙古野驴主要分布于保护区北部和中部食物和水源条件较好的区域。  相似文献   

14.
本文通过收集托里桉的实地栽培点地理数据,运用最大熵软件(Maxent)和地理信息系统技术(ArcGIS),结合12个气候因子数据,预测划定了托里桉在我国南部的潜在地理适生分布区。结果表明:Maxent模拟托里桉的潜在地理分布准确性较高,模型预测训练子集和验证子集AUC值均大于0.87。托里桉最适宜分布区集中在广东和海南沿海、广西沿海和中部及福建南部沿海,面积依次为广东(8.63×10~4 km~2)、海南(2.65×10~4 km~2)、广西(2.22×10~4 km~2)、福建(1.18×10~4 km~2);适宜区集中在广西中南部、广东中北部、福建南部、江西中南部,面积依次为广西(10.17×10~4 km~2)、广东(6.15×10~4 km~2)、福建(2.52×10~4 km~2)、江西(1.43×10~4 km~2)。Maxent刀切法(Jackknife)分析结果表明:影响托里桉适生区分布的主导气候因子为年平均气温、≥10℃积温、极端低温、最冷月最低温、最冷月均温、≥10℃的天数。  相似文献   

15.
基于WEB数据库和Maxent模型的白头叶猴潜在生境评价研究   总被引:3,自引:0,他引:3  
白头叶猴是中国广西特有分布种,属我国一级保护动物,其空间分布及其生态环境因子知识,是制定白头叶猴保护和发展规划前提。以2007—2008年中国广西白头叶猴93个痕迹点数据和开放式生态环境WEB数据库的63个环境变量为主要信息源,采用最大熵法(Maxent)生态位模型,进行白头叶猴潜在生境预测。在此基础上,采用专家经验法对预测结果进行重分类,并与植被斑块信息、距离道路及居民点距离、历史分布资料进行叠加分析。研究结果表明:太阳辐射、最湿季节降水量、月平均昼夜温差、距离水源距离、最冷月最低温和土壤酸碱度是影响白头叶猴空间分布的主要生态环境因子;白头叶猴最适宜区、适宜区、不宜区面积分别为112.60km2,78.92km2,17 056.13 km2;白头叶猴的分布面积(最适宜区、适宜区)分别比20世纪60年代、80年代、90年代下降了65%,50%,9.5%。为保护白头叶猴免于灭绝,应当加强动物保护的宣传教育、加强对白头叶猴的科学研究和保护、实施生态移民和建立生态园。  相似文献   

16.
为了了解近年来石家庄土地利用变化趋势,基于Landsat TM/OLI影像数据,运用ENVI空间分析与土地利用动态度模型对石家庄1987-2015年的土地利用时空变化特征进行了分析。结果表明,高密度建筑用地面积从1987年的24.51km~2扩张到2015年的168.44km~2,低密度建筑用地面积从92.22km~2减少到86.93km~2,绿地面积从250.78km~2下降到111.29km~2;各土地类型变化差异显著,石家庄单一土地利用动态度在-4%~14%之间,各时间段综合土地利用动态度分别为0.16%、0.32%和0.38%;人口增加、经济增长和人民生活水平提高是导致石家庄土地利用变化的主要原因。  相似文献   

17.
基于MaxEnt模型对大花序桉 在我国南方的适生区预测   总被引:1,自引:0,他引:1  
大花序桉材性优良是我国重要的实木利用树种,本文对大花序桉在我国南方十省(区)的潜在分布区进行预测,并对其适生区进行划定和分析.通过收集大花序桉的地理信息数据,利用最大熵模型(MaxEnt)和ArcGIS空间分析技术,综合相关气候因子,预测划定大花序桉在我国南方十省(区)的潜在地理分布区.结果表明:采用MaxEnt模拟大花序桉潜在地理分布的准确性较高,模型预测准确性的衡量指标训练子集和验证子集AUC值均大于0.88.大花序桉在我国南方的发展空间较大,其中最适宜分布区主要集中在广东、广西、海南、福建沿海,面积依次为广东(11.25×104 km2),广西(9.19×104 km2),海南(2.00×104 km2),福建(1.91×104 km2);适宜区集中在广西、广东、重庆、福建省中部,面积依次为广西(5.87×104 km2)、广东(4.51×104 km2)、重庆(3.64×104 km2)、福建(3.02×104 km2).刀切法(Jackknife)分析结果显示,影响大花序桉潜在适生区分布的主导气候因子为年平均气温、≥10℃积温、最冷月最低温、最冷月均温和极端低温.结合最大熵模型(MaxEnt)和ArcGIS技术,预测和分析了大花序桉在我国南方十省(区)的潜在适生区,阐明了影响其分布的主导气候因子,为该树种在我国的有序推广种植提供科学依据.  相似文献   

18.
通过对2010—2012年小兴安岭北坡森林土壤有机碳密度、碳储量的调查、测算、分析,对小兴安岭北坡森林土壤有机碳储量时空分布格局进行了研究,结果表明:各类型土壤有机碳密度大小顺序为沼泽土〉暗棕壤〉黑土〉草甸土〉白浆土,各土壤类型有机碳密度与年均降水量之间除暗棕壤(P=-0.900,0.01〈ɑ〈0.05)外,均无显著相关性,说明降水量对土壤有机碳密度影响不大;处于寒温带的爱辉区和孙吴县与处于温带季风气候区的4个地区之间土壤有机碳密度未发现普遍规律;土壤碳储量分布规律为暗棕壤〉白浆土〉沼泽土〉草甸土〉黑土。2010—2012年,小兴安岭北坡森林土壤有机碳储量整体呈先减后增趋势,这主要与森林经营导致的森林面积改变有关。  相似文献   

19.
In a view of natural conditions of establishing nature reserve,an index system was prepared for quantitative assessment on status of endangered species,and thus degree of endangered species in Tibet was evaluated.Taking a sub-ecozone as basic unit,top 5 animals and 1 plant with high E as well as the number of species in each unit were enumerated;and the degree of land utilization was figured out.Afterward,we selected 6 coefficients,assigned weight,and framed formula to reckon proportion of nature reserve,thus an area of nature reserve in each sub-ecozone was obtained.In 5 schemes of weight assignment,a scheme with medium area of nature reserve was selected.All sub-ecozones were classified into 4 grades prior conservation,1 was in grade A,2 in grade B,2 in grade C,and 11 in grade D.Total planned area was approximately 365 135 km2,about 48 834 km2 smaller than the actual area of 413 969 km2,ratio of nature reserve in Tibet diminishes from 34.4% to 30.38%.Based on 3 factors of human disturbance,ratio of buffer-experimental zone in proposed nature reserve was calculated.It was demonstrated that existing size of nature reserves is excessive on the whole,and their distribution is not reasonable entirely.The size of nature reserves in 3 sub-ecozones of northern Changtang should decrease,and decrement of area is apportioned among other 13 sub-ecozones which should increase nature reserve.Heterogeneity of regional distribution of rare species in Tibet is quite obvious,so proposed area distribution of nature reserves is more scattered than the existing.  相似文献   

20.
小飞蓬(Conyza canadensis(L.)Cronquist)是我国分布最广的入侵植物之一。根据文献搜集和生物信息数据库,获得有效数据共325个,结合ArcGIS与SPSS相关性分析筛选获得8个气象因子,基于最大熵模型(MaxEnt)预测了小飞蓬的潜在适生区。结果表明:基于MaxEnt模型预测小飞蓬在中国的潜在适生区ROC曲线,AUC平均值为0.971,预测结果极好;通过刀切法(jackknife method)分析表明,最热季度的降水量(BIO_18)、温度季节性变化标准差(BIO_4)、年平均气温(BIO_1)、最冷季度的降水量(BIO_19)4个气象因子对小飞蓬的分布影响最大;小飞蓬在中国的潜在适生区分布广泛,秦岭淮河以南的各个省份以及秦岭淮河以北至辽宁省南部均为小飞蓬高适生区范围。随着气候变化,2050年小飞蓬潜在适生区面积与当前相比增加了559 016.09km2,2070年小飞蓬潜在适生区面积与当前相比增加了68 423.65km2。本研究结果实现对小飞蓬入侵动态预警,为进一步防范工作提供了一定的理论基础。  相似文献   

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