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1.
黑长臂猿的群体大小及组成   总被引:13,自引:4,他引:9       下载免费PDF全文
黑长臂猿(Hylobatesconcolor)是长臂猿科中较为原始的类群,对其野外行为生态习性近年来已有所报道,但意见不一。本文根据近两年的野外观察,认为黑长臂猿的群体大小为4.3±1.0只,(范围3—6,n=7),群体组成为1成年雄性,1—2成年雌性,1—3后代个体,群体之大小除与其本身的特点有关外,还与其赖以生存的生境条件好坏有关。  相似文献
2.
可可西里地区藏羚的社群特征   总被引:12,自引:2,他引:10       下载免费PDF全文
藏羚(Pantholopshodgsoni)的集群类型有雌性群、雄性群、母仔群、雌雄混群和独羚5种形式。2002年7月~2003年12月,在可可西里地区沿青藏公路设立试验区,直接观察到936群次,计13795只次藏羚。藏羚的集群类型受到生育周期的影响,季节间差异显著。春季以雌性群(60.49%)和雄性群(30.86%)为主;夏季和秋季主要为雌性群(41.65%,49.66%)和母仔群(49.36%,33.67%);雌雄混群(58.14%)主要出现在冬季。雄性群在1年中很少见,尤其是夏秋两季,冬季较为常见,多由亚成体雄性组成。独羚是一种特殊的集群类型,占11.32%。常见的集群大小为2~20只,占71.90%,其次是21~200只的群,占16.35%;>200只的集群极少,仅占0.43%,且仅出现于夏季产羔往返迁徙途中。藏羚的集群大小受竞争、捕食风险以及迁徙繁殖的共同影响。藏羚的集群极不稳定,交配期雌雄混合群受雄性亚成体的干扰经常改变,而在迁徙季节大群和小群之间的转换也很频繁。大型集群为雌性群或母仔群,其最适集群大小为2~20只。  相似文献
3.
春季和夏初黄羊的集群行为   总被引:9,自引:3,他引:6  
高中信  关东明 《兽类学报》1996,16(3):176-181
本文对春季和夏初在野外观察到的637群黄羊(Procapragutturosa)的集群行为进行了研究。给出了春季和夏初各种类型黄羊群平均大小及其方差,并对黄羊群的平均大小、所占比例及其稳定性也进行了比较分析。结果表明,春季和夏初羊群的平均大小存在着显著差异(F=3.09>F0.05),春季羊群(2~412只)较夏初羊群(2~103只)变动范围要大。春季羊群主要是混合群(63.14%),夏初羊群主要是雌性群(60.73%)。在春季和夏初两个季节,雄性群比例皆最低,分别为7.45%和7.59%。较大的集群往往是混合群,春季平均大小为38.95只,夏初为29.13只。而雄性群和雌性群集群规模皆较小。在春季,雌性群平均大小为11.35只,雄性群平均大小为8.84只。在夏初,雌性群平均大小为4.88只,雄性群平均大小为9.63只。混合群的社群组织最为松散,处于不稳定状态,雄性群最为稳定,羊群波动最小。产仔期、食物丰富度及羊群类型是影响黄羊春季和夏初集群变化的重要因素。  相似文献
4.
贺兰山保护区冬季岩羊集群特征的初步分析   总被引:9,自引:1,他引:8  
Group size and composition of blue sheep (Pseudois nayaur) were studied in the Helan Mountains, Ningxia Autonomous Region from November to December 2003. We scanned mountain slopes with binoculars and observed with 20 - 60 x spotting-scope. A total of 310 herds of blue sheep and 1 336 individuals were observed during the study period. Blue sheep were frequently seen in small herds of 2 to 8 individuals, which represent 94.8% of total herds observed. Herds consisting of 9 individuals or more represented 5.2%. The largest herd we observed numbered 51 individuals. Mean group size was 4.2 individuals. Blue sheep herds can be divided into three types: male herds (composed solely of males), female herds (consisting of females with or without juveniles of both sexes), and mixed herds (including adult males, females, and subadults). Among the 310 herds, female herds were counted 150 times (48.4%}, mixed herds 154 times (49.7%), and male berds 6 times (1.9%) . Of 1 336 blue sheep classified by sex and age, adults, subadults and juveniles composed 64.1%, 20.8%, and 15.1% respectively. The female: male ratio of adults was 1:0.73. The ratio of adult females to juveniles was 1:0.56, which is higher than the ratio recorded in spring ( 1:0.43) or summer ( 1:0.44). The results showed that the Helan Mountains State Nature Reserve has succeed in protecting blue sheep.  相似文献
5.
Neolamprologus pulcher is a cooperatively breeding cichlid fish,in which helpers stay in their natal territory and help withbrood care, territory defense, and maintenance. In this studywe investigated helper effects by an experimental group sizereduction in the field. After this manipulation, focal helpersin reduced groups tended to feed less, and small helpers visitedthe breeding shelter significantly more often than same-sizedhelpers in control groups. No evidence was found that remaininghelpers compensated for the removed helpers by increasing territorydefense and maintenance behavior. Breeders, however, did showa lower defense rate, possibly caused by an increase in broodcare effort. Survival of fry was significantly lower in removalthan control groups, which provides the first experimental proofin a natural population of fish that brood care helpers do effectivelyhelp. The data suggest that in small, generally younger, helpers,kin selection may be an important evolutionary cause of cooperation.Large helpers, however, who are generally older and less relatedto the breeders than small helpers are suggested to pay to beallowed to stay in the territory by helping. All group membersbenefit from group augmentation.  相似文献
6.
Isolation from mammalian predators differentially affects two congeners   总被引:8,自引:2,他引:6  
Evolutionary isolation from predators can profoundly influencethe morphology, physiology, and behavior of prey, but littleis known about how species respond to the loss of only someof their predators. We studied antipredator behavior of tammarwallabies (Macropus eugenii) and western gray kangaroos (Macropusfuliginosus) on Kangaroo Island (KI), South Australia, andat Tutanning Nature Reserve on the mainland of western Australia.Both species on KI have been isolated from native mammalian predators for several thousand years. On KI, wallabies (becauseof their size) are vulnerable to diurnal aerial predators.In contrast, on the mainland both species have been exposedcontinuously to native and introduced mammalian and avian predators.At both locations, wallabies modified the amount of time they allocated to vigilance and foraging in response to group size,whereas kangaroos did so only at the higher risk Tutanningsite. Both species modified overall time budgets (they werewarier at the higher risk site), and both species modifiedspace-use patterns as a function of risk. At the higher risk site, tammars were closer to cover, whereas kangaroos were,on average, farther from cover. We hypothesize that the presenceof a single predator, even if it is active at a different timeof day, may profoundly affect the way a species responds tothe loss of other predators by maintaining certain antipredatorbehaviors. Such an effect of ancestral predators may be expected as long as species encounter some predators.  相似文献
7.
Forcible eviction and prevention of recruitment in the clown anemonefish   总被引:7,自引:1,他引:6  
Buston  Peter 《Behavioral Ecology》2003,14(4):576-582
How big an animal group will be depends on how the group's sizeis regulated and on the costs and benefits of living in thegroup. To determine which individuals regulate group size ofthe clown anemonefish, Amphiprion percula, I investigated thestrategies involved in the formation, maintenance, and dissolutionof its groups. Groups composed of a single breeding pair andof zero to four nonbreeding subordinates occupied individualsea anemones (Heteractis magnifica), which provided the fishwith oviposition sites and protection from predators. Groupsize increased linearly with anemone size. I used the residualsof this relationship as a measure of the degree of saturationof each anemone. Residents evicted low-rank subordinates andprevented the recruitment of additional subordinates at anemoneswith a high degree of saturation, but not at anemones with alow degree of saturation. These strategies indicate that residentscontrol group membership of their subordinates, and suggestthat residents might incur costs from the presence of subordinatesin more saturated anemones. In general, whenever residents cancontrol group membership, the prevention of recruitment andthe eviction of subordinates will set an upper limit on groupsize.  相似文献
8.
作者于2001年4月至2003年1月研究了社群大小的年变化、气候和人类活动对神农架自然保护区千家坪地区一群川金丝猴(Rhinopithecusroxellana)日移动距离的影响。对该群金丝猴进行了8个季节的跟踪研究,每季连续跟踪30d。用社群直线距离法确定猴群的日移动距离,同时调查社群大小,记录人为活动和气象因子。研究结果显示:(1)两年间猴群的个体数增加了14%,但其日移动距离没有明显变化,说明社群大小的年变化对日移动距离没有影响。(2)猴群在人为活动影响下的日移动距离比没有人为活动影响时长。(3)多变量回归分析显示,各个季节中,猴群的日移动距离与一天中晴和有云但无降水所占时间的比例没有相关性;与春季和冬季日降雨或雪所占时间的比例呈负相关,但与夏季和秋季的没有相关性,说明降水缩短了冬春季猴群的日移动距离,这可能与川金丝猴的繁殖有关。人为活动对猴群是不利的;冬春季的长时间降水可能是川金丝猴的灾害性天气。  相似文献
9.
The ecological-constraints model assumes that food items occur in depletable patches and proposes that an increase in group size leads to increased day range due to more rapid patch depletion. Smaller groups become advantageous when an increase in travel costs is not repaid by an increase in energy gained or some other fitness advantage. On the other hand, we also know that group size can be influenced by social factors. Here we contrast the diet and group size of red colobus (Procolobus badius) and black-and-white colobus (Colobus guereza) in Kibale National Park, Uganda to consider how ecological and social factors are affecting their group sizes. Subsequently, we examine whether the insights gained from this detailed comparison can provide an understanding of why the social organization and group size of mantled howlers (Alouatta palliata) and black howlers (A. pigra) differ. Two groups of red colobus and two groups of black-and-white colobus were studied over 10 months. Red colobus groups were larger (48 and 24) than black-and-white colobus groups (9 and 6). The two groups of red colobus overlap home ranges with the two groups of black-and-white colobus; 75% and 95% of their home ranges were within red colobuss home range. There was a great deal of similarity in the plant parts eaten by the two species and both species fed primarily on young leaves (red colobus 70%, black-and-white colobus 76%). In terms of the actual species consumed, again there was a great deal of similarity between species. The average dietary overlap among months for the two neighboring groups of red colobus was 37.3%, while the dietary overlap between the red colobus and the black-and-white colobus group that had its home range almost entirely within the home range of the red colobus groups averaged 43.2% among months. If ecological conditions were responsible for the difference in group size between the two colobine species, one would expect the density of food trees to be lower in the home ranges of the black-and-white colobus monkeys, since they have the smaller group size. We found the opposite to be true. Both black-and-white colobus groups had more food trees and the cumulative size of those trees was greater than those in the red colobuss home ranges. We quantify how these differences parallel differences in mantled and black howlers. The average group size for mantled howlers was 12.9 individuals, and for black howlers it was 5.3 individuals. We explore possible social constraints, such as infanticide, that prevent black-and-white colobus and black howlers from living in large groups.This revised version was published online in April 2005 with corrections to the cover date of the issue.  相似文献
10.
春冬两季贺兰山岩羊集群特征的比较   总被引:7,自引:2,他引:5       下载免费PDF全文
20 0 3年 1 1~ 1 2月和 2 0 0 4年 4~ 6月在贺兰山国家级自然保护区对岩羊 (Pseudoisnayaur)春冬两季集群行为进行了初步研究。春季观察到的 2 1 8群 1 3 70只岩羊样本和冬季观察到的 3 1 0群 1 3 3 6只岩羊样本进行了比较 ,发现春季平均岩羊群大小为 (5. 5 7± 5 .3 8)只 ,冬季平均岩羊群大小为 (4. 2 9± 5 . 48)只 ,春冬两季岩羊集群大小季节性变化不显著 (P >0. 0 5 )。贺兰山岩羊在春冬两季 2~ 8只的群所占比例均居多 (春季 :85 . 3 % ;冬季 94 8% )。春季贺兰山岩羊群以雌性群 (4 0 . 3 % ,n =88)为主 ,冬季以混合群(4 9 7% ,n =1 5 4)和雌性群 (4 8 4% ,n=1 5 0 )为主。春冬两季雌性群平均大小间 (P >0 . 0 5 ) ,雄性群平均大小间 (P >0 . 0 5 )和混合群平均大小间 (P >0 . 0 5 )均无显著性差异。将春季和冬季贺兰山岩羊的雌雄比与雌幼比相比 ,春季观察到的雄性个体偏多 ,冬季观察到的幼体较春季多。  相似文献
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