第二届东亚熊类学术讨论会介绍

第二届东亚熊类学术讨论会由日本熊类研究会和中国兽类学会熊类专家组联合发起,东北林业大学主办,于1991年8月4—8日在哈尔滨市举行。参加这次学术讨论会的国家除中国外,还有日本、美国、南朝鲜以及世界野生动物基金会(WWF)的代表,共86人。会议收到研究论文116篇,其中,保护和生态44篇,生化和形态15篇,驯养和利用31篇,疾病防治12篇,另外,有关大熊猫的研究报告14篇。较全面地反映了目前熊类研究、保护和开发利用的现状。     

中国熊类资源数量估计及保护对策

我国熊类资源丰富,是多熊的国家之一．历史上,我国对熊类资源的猎捕利用,一直维持着较高的水平．然而,近百年来,特别是近５０年来,由于人口增多,森林采伐,熊类的栖息条件发生了很大的变化,资源数量显著减少,分布区亦大大缩小,许多原来有熊地区现在已经无熊了,尤其是近１０年来活熊取胆汁技术试验成功之后,城乡各地养熊取胆事业一时曾出现高潮,亦给野生种群带来很大的压力,因而,尽快查明熊类资源数量的现状已是急待解决的问题．依据近年的调查及若干重点产区的实地踏查,估计我国棕熊约有５９００～７２００只,黑熊１７５００～１９５００只,马来熊１４０只左右,本文讨论了数量分布特点、栖息地变化及保护对策     

第一届亚洲熊类会议简讯

第一届亚洲熊类会议于1985年8月6-8日在日本枥木县宇都宫市博物馆召开,参加这次会议(或递交论文)的有中国、日本、印度及印度尼西亚4个国家的66位代表。代表们就亚洲熊类的研究及管理现状进行了学术交流及讨论。     

解开大熊猫起源之谜

大熊猫是我国的国宝,栖息于西藏高原边缘地带的高山竹林里,过着游牧般生活。大熊猫眼点很大,耳朵小巧,加上天性贪玩、朝气蓬勃,因此,深受世界各国人民的喜爱。从分类学方面来看,大熊猫又是最迷惑科学家们的动物之一。关于大熊猫的祖先是谁,一直存在着三种不同的见解:一种认为大熊猫起源于熊科动物,另一种认为是从浣熊科动物进化而来的;还有一种观点主张大熊猫应该单列一科。这三种观点争论了一个多世纪,直到最近才见分晓。大熊猫看起来像熊,但有许多地方与熊不同,而与浣熊相似。例如,熊类为食肉动物,而大熊猫主要以吃竹子为生;熊类每只脚有五个趾头,拇趾的运动方向与其余四趾相同,但大熊猫可有第六趾,拇趾的运动方向与其余五趾相反,可灵活剥竹叶;熊类不能坐立,而大     

土地利用生态安全格局研究进展

土地生态安全格局研究不仅可以为有效解决水土流失、土壤退化等区域生态安全问题提供新的思路,而且对提高区域土地生态系统的安全性和可持续性具有重要的现实意义。从土地利用生态安全评价、面向生态的土地利用格局和土地生态安全格局构建方法3个方面,综述了土地利用生态安全格局的研究现状和最新进展,并对今后的研究方向进行了展望,以促进土地生态安全格局研究的继续深入开展。提出近期的研究重点主要包括：（1）面向生态安全格局设计的生态安全评价方法与模型;（2）不同类型生态脆弱地区的土地生态安全格局;（3）土地生态安全格局的空间显示模型;（4）区域土地生态安全格局情景模拟。     

第九届国际熊类学术讨论会简介

第九届国际熊类学术讨论会,分两期分别在两个地区召开。新大陆部分,于1992年2月23—28日在美国蒙大拿的密苏里召开,会期6天。旧大陆部分,于1992年10月9—22日在法国格勒诺布尔市召开,会期4天。会议均分为6个专题进行研讨。新大陆部分专题为:1.熊类管理生物学的主要任务;2.公众姿态:熊类与人;3.国际熊类保护;4.种群数量:计量和管理;5.生态学:熊的生活环     

黑龙江省熊类资源现状及其保护对策

黑龙江省现分布有 2种熊 ,棕熊 (Ursusarctoslasiotus)和黑熊 (Selenarctosthibetanusussuricus)。棕熊广泛分布于全省各个林区 ;黑熊在大兴安岭无分布 ,仅分布于小兴安岭和东部山地的张广才岭、老爷岭和完达山林区 ,其分布北界为北纬 48～ 49°,东经 1 2 8～ 1 2 9°附近。 2种熊的总分布区虽无明显变化 ,但集中分布区明显向大兴安岭、小兴安岭、东部山地的腹地退缩。 1 996～ 2 0 0 0年全省棕熊的分布数量为 (63 1±1 43 )头 (n =463 9) ,种群密度为 (0 0 0 2 2± 0 0 0 0 5 )头 km2 ;黑熊的分布数量为 (1 1 1 0± 2 93 )头 (n =463 9) ,种群密度为 (0 0 0 65± 0 0 0 1 7)头 km2 。全省森工国有林区熊类分布数量 (1 1 71± 2 98)头 (n =61 2 ) ,与1 992年该林区熊类调查结果 (3 0 5 7± 73 0头 ;n =2 1 3 6)相比较 ,全林区 6年间熊类数量减少了 1 886头 ,减少率达 61 7% ,年递减率为 1 6%。熊类资源呈锐减趋势。其主要原因为 :(1 )森林长期超量采伐引起熊类栖息生境总体质量下降 ;(2 )人类活动导致熊类栖息地片断化日趋严重 ;(3 )人为捕杀是造成熊类数量减少的直接原因。最后 ,提出了今后全省熊类保护管理的 5点建议。     

记甘肃广河晚中新世祖熊头骨化石（英文）

记述了一件与下颌咬合在一起的完整的祖熊头骨化石。化石发现于甘肃临夏州广河县槐沟村柳树组地层中上部,其层位与时代为新近纪灞河阶/期的晚期,距今约8 Ma。对比研究表明,该头骨与目前所有已知熊类祖先类型都不同,应为一新种,定名为Ursavus tedfordi(戴氏祖熊)。采用TNT软件包对11种祖先熊类和37个特征组成的数据进行不同条件(non-additive,additive等)下全搜索(Implicit Enumeration),并采用自引导法(bootstrapping)进行可信度评价。我们从基于部分特征加积(partially additive)条件下所得出8个最简约树中选取树5作为最可信简约树。该树表明,熊科从渐新世-早中新世的豺熊类(hemicyonids)分出后产生了两类基干类型,Ballusia elmensis和B.orientalis。后者稍更进步,可能为一特异支。此后产生了两大次支:一支向印度熊(可能还有郊熊)+大熊猫演化;另一支则由中-晚中新世的祖熊(Ursavus)和此后由某类祖熊所产生的现生熊类(不包括大熊猫)组成。从现有的化石判断,新建戴氏祖熊是与现生熊类在形态上最为接近的祖先类型,但戴氏祖熊具有某些自近裔性状,可能为一早期旁支。     

国际熊类会议简介

熊是现代生存的陆生食肉目动物中体型最大者,由于它们特殊的形态、生态特征和较大的经济利用价值,很早就引起人们的注意。近两千年来,地球上的兽类灭绝了106种和亚种,其中熊科占首位,共17个种和亚种,而且半数以上是本世纪上半期消亡的(Harper,1945)。目前,世界上许多国家已经无熊或正在消亡中,由于人类经济活动对自然界的影响越来越大,熊的某些种和地理种群正处于濒临灭绝的危险之中,因而,对于熊类的研究和保护,不仅受到兽类学家的重视,也为自然保护学者所瞩目。     

熊类头骨的三维几何形态学初步研究

三维激光扫描技术在骨骼形态学研究中得到越来越广泛的应用。运用激光扫描可得到骨骼三维几何形态学的全部信息,用于骨骼形态的定量分析,对于建立客观的分类指标以及形态生态学研究有重要意义。本研究以大熊猫、亚洲黑熊、棕熊和北极熊为研究对象,为亚洲黑熊、棕熊和北极熊的共计28件头骨和对应下颌建立三维模型,提取熊类下颌的9个形态测量的比例指标和头骨的15个形态测量的比例指标,对下颌和头骨进行数学建模。使用Weka的J48算法,构建决策树,成功实现了模式分类。又在上述三维模型的基础上,确定了23个下颌形态标志点和29个头骨形态标志点;以标志点的三维坐标为初始变量,进行主成分分析,比较4种熊类的下颌和头骨形态差异。结果显示大熊猫的下颌和头骨形态与其他3类熊差别显著;棕熊的头骨和下颌形态介于黑熊和北极熊之间。在此基础上,以同样方法将一例大熊猫小种化石头骨与4种现生熊类头骨形态进行比较,结果显示大熊猫小种头骨形态与现生大熊猫相似,而又不在其种内差异的形态区间内。除去大小因素,大熊猫小种在头骨形态上与现生大熊猫仍有一定差异,略倾向于杂食熊类。     

Gene flow between insular, coastal and interior populations of brown bears in Alaska

The brown bears of coastal Alaska have been recently regarded as comprising from one to three distinct genetic groups. We sampled brown bears from each of the regions for which hypotheses of genetic uniqueness have been made, including the bears of the Kodiak Archipelago and the bears of Admiralty, Baranof and Chichagof (ABC) Islands in southeast Alaska. These samples were analysed with a suite of nuclear microsatellite markers. The 'big brown bears' of coastal Alaska were found to be part of the continuous continental distribution of brown bears, and not genetically isolated from the physically smaller 'grizzly bears' of the interior. By contrast, Kodiak brown bears appear to have experienced little or no genetic exchange with continental populations in recent generations. The bears of the ABC Islands, which have previously been shown to undergo little or no female-mediated gene flow with mainland populations, were found not to be genetically isolated from mainland bears. The data from the four insular populations indicate that female and male dispersal can be reduced or eliminated by water barriers of 2–4 km and 7km in width, respectively.     

Efficacy of Bear Deterrent Spray in Alaska

Abstract: We present a comprehensive look at a sample of bear spray incidents that occurred in Alaska, USA, from 1985 to 2006. We analyzed 83 bear spray incidents involving brown bears (Ursus arctos; 61 cases, 74%), black bears (Ursus americanus; 20 cases, 24%), and polar bears (Ursus maritimus; 2 cases, 2%). Of the 72 cases where persons sprayed bears to defend themselves, 50 (69%) involved brown bears, 20 (28%) black bears, and 2 (3%) polar bears. Red pepper spray stopped bears' undesirable behavior 92% of the time when used on brown bears, 90% for black bears, and 100% for polar bears. Of all persons carrying sprays, 98% were uninjured by bears in close-range encounters. All bear—inflicted injuries (n = 3) associated with defensive spraying involved brown bears and were relatively minor (i.e., no hospitalization required). In 7% (5 of 71) of bear spray incidents, wind was reported to have interfered with spray accuracy, although it reached the bear in all cases. In 14% (10 of 71) of bear spray incidents, users reported the spray having had negative side effects upon themselves, ranging from minor irritation (11%, 8 of 71) to near incapacitation (3%, 2 of 71). Bear spray represents an effective alternative to lethal force and should be considered as an option for personal safety for those recreating and working in bear country. (JOURNAL OF WILDLIFE MANAGEMENT 72(3):640–645; 2008)     

Fatal attacks by American black bear on people: 1900–2009

At least 63 people were killed in 59 incidents by non-captive black bear (Ursus americanus) during 1900–2009. Fatal black bear attacks occurred in Canada and Alaska (n = 49) and in the lower 48 states (n = 14). There were 3.5 times as many fatal attacks in Canada and Alaska but only 1.75 times as many black bears, and much less human contact for black bears in Canada and Alaska. There was a weak positive correlation (r_s = 0.56, P ≤ 0.000) between the estimated size of a bear population within a given jurisdiction and the number of fatal black bear attacks. Some jurisdictions had no fatal black bear attacks but had large estimated black bear populations. Of fatal attacks, 86% (54 of 63, 1.08/yr) occurred between 1960 and 2009. There was positive linear relationship between the number of fatal black bear attacks per decade and human population size in the United States and Canada per decade (r² = 0.92, β = 0.000, P ≤ 0.001). Of fatal attacks, 91% (49 of 54) occurred on parties of 1 or 2 persons. In 38% (15 of 40) of incidents, peoples' food or garbage probably influenced the bear being in the attack location. We judged that the bear involved acted as a predator in 88% (49 of 56) of fatal incidents. Adult (n = 23) or subadult (n = 10) male bears were involved in 92% (33 of 36) of fatal predatory incidents, reflecting biological and behavioral differences between male and female bears. That most fatal black bear attacks were predatory and were carried out by 1 bear shows that females with young are not the most dangerous black bears. As a result of our research agencies managing black bear can more accurately understand the risk of being killed by a black bear, and can communicate this to the public. With training, people can learn to recognize the behaviors of a bear considering them as prey and can act to deter predation. © 2011 The Wildlife Society.     

Distinguishing Asiatic Black Bears and Sun Bears by Claw Marks on Climbed Trees

Abstract: Asiatic black bears (Ursus thibetanus) and sun bears (Helarctos malayanus) are sympatric in mainland Southeast Asia and face similar threats of habitat loss and commercial poaching. They are rarely seen but leave distinct signs, especially claw marks on climbed trees. These markings, which are potentially valuable indicators of presence, population status, and behavior of black bears and sun bears, have limited usefulness if the 2 species cannot be differentiated. We measured 121 claw mark imprints on climbed trees from 43 known (mainly captive) individual black bears and sun bears of both sexes in Thailand and Cambodia. The span across the markings made by 3, 4, or 5 claws from the hind foot was significantly greater for black bears than sun bears. We developed discriminant function models with these variables and arranged them in a 3-step process that distinguished claw marks as either sun bear, black bear, or indeterminate. This procedure correctly classified 95% of claw marks from the experimental animals. Tested on wild bears (at sites where only one species occurred), the procedure correctly classified 91% of claw marks of black bears in China (n = 94) and 100% of claw marks of sun bears in Indonesia (n = 32). The main limitation of the method was in distinguishing young, small black bears (cubs and yearlings) from sun bears. Nevertheless, application of these findings will be valuable in bear research and monitoring programs throughout Southeast Asia, where sign surveys have, until now, been hampered by the inability to differentiate these 2 ecologically and behaviorally similar species. (JOURNAL OF WILDLIFE MANAGEMENT 72(3):814–821; 2008)     

Genomic evidence of geographically widespread effect of gene flow from polar bears into brown bears

Polar bears are an arctic, marine adapted species that is closely related to brown bears. Genome analyses have shown that polar bears are distinct and genetically homogeneous in comparison to brown bears. However, these analyses have also revealed a remarkable episode of polar bear gene flow into the population of brown bears that colonized the Admiralty, Baranof and Chichagof islands (ABC islands) of Alaska. Here, we present an analysis of data from a large panel of polar bear and brown bear genomes that includes brown bears from the ABC islands, the Alaskan mainland and Europe. Our results provide clear evidence that gene flow between the two species had a geographically wide impact, with polar bear DNA found within the genomes of brown bears living both on the ABC islands and in the Alaskan mainland. Intriguingly, while brown bear genomes contain up to 8.8% polar bear ancestry, polar bear genomes appear to be devoid of brown bear ancestry, suggesting the presence of a barrier to gene flow in that direction.     

West Nile Virus Exposure in Black Bears of Northeastern Wisconsin

ABSTRACT Knowledge of the distribution and pathology of West Nile virus (WNV) in black bears is a necessary tool that allows wildlife managers to implement a management plan, set harvest quotas, and relocate nuisance bears. We studied the presence and significance of WNV titers in free-roaming black bears (Ursus americanus) in northeastern Wisconsin between February 2003 and March 2005. Serum neutralizing antibodies to WNV, with confirmation by plaque-reduction neutralization test to both WNV and Saint Louis encephalitis, identified exposure in 13 of 74 (17.6%) bears. This compares with a 6% infection rate in black bears in Virginia and 22% in European brown bears (Ursus arctos). Pathologic effects from exposure to WNV were not seen in any of the black bears studied.     

The tensile strength of black bear (Ursus americanus) cortical bone is not compromised with aging despite annual periods of hibernation

Black bears (Ursus americanus) may not develop disuse osteoporosis during long periods of disuse (i.e. hibernation) because they may be able to maintain bone formation. Previously, we found that cortical bone bending strength was not compromised with age in black bears' tibias, despite annual periods of disuse. Here we showed that cortical bone tensile strength (166-198MPa) also does not decrease with age (2-14 years) in black bear tibias. There were also no significant age-related changes in cortical bone porosity in black bear tibias. It is likely that the ability of black bears to maintain bone formation during hibernation keeps bone porosity low (2.3-8.6%) with aging, notwithstanding annual periods of disuse. This low porosity likely preserves ultimate stress with aging. Female bears give birth and nurse during hibernation; however, we found no significant differences between male and female tensile material properties, mineral content, or porosity. Our findings support the idea that black bears, which hibernate 5-7 months annually, have evolved biological mechanisms to mitigate the adverse effects of disuse on bone porosity and strength.     

It's all relative: allometry and variation in the baculum (os penis) of the harp seal, Pagophilus groenlandicus (Carnivora: Phocidae)

We compared allometry and variation in the baculum (os penis), mandible, and humerus of the harp seal, Pagophilus groenlandicus. This species is presumed to have a promiscuous mating system in which choice of mate by females during intromission with different males is likely. The baculum is large and grows throughout life so may be an honest indicator of males' quality (size) or viability (age). We predicted that bacular size would exhibit stronger allometry relative to body size than mandibles or humeri. The baculum is less functionally (mechanically) constrained than mandibles or humeri so we also predicted it would be more variable, though less variable than sexually selected traits which do not function as honest indicators. Our sample (N=67 seals) represented broad ranges of size and age (0–35 yr) so we compared variation using residuals from allometric regressions of skeletal measurements on body length. Bacular size was isometric to body length until ∼ 137 cm (when some seals enter puberty) in body length then was highly positively allometric; mandibular and humeral size were negatively allometric to body length throughout growth. Bacula were more variable than mandibles or humeri. Bacular size in large specimens (>137 cm in body length) was related strongly to body length and weakly to age. We interpret bacular size to be an uncheatable honest indicator of male quality and viability. High bacular variation conforms with theoretical predictions of females' asymmetrical choice of mate and choice of extremes, and may reflect corresponding anatomical variation among females. Some bacular variation may also result incidentally from positive allometry coupled with lifelong bacular growth, which can amplify early differences between reproductive and somatic growth, enabled by weak selection on bacular form in relation to function.     

Prevalence of Trichinella spp. in black bears, grizzly bears, and wolves in the Dehcho Region, Northwest Territories, Canada, including the first report of T. nativa in a grizzly bear from Canada

Samples of muscle from 120 black bears (Ursus americanus), 11 grizzly bears (Ursus arctos), and 27 wolves (Canis lupus) collected in the Dehcho Region of the Northwest Territories from 2001 to 2010 were examined for the presence of Trichinella spp. larvae using a pepsin-HCl digestion assay. Trichinella spp. larvae were found in eight of 11 (73%) grizzly bears, 14 of 27 (52%) wolves, and seven of 120 (5.8%) black bears. The average age of positive grizzly bears, black bears, and wolves was 13.5, 9.9, and approximately 4 yr, respectively. Larvae from 11 wolves, six black bears, and seven grizzly bears were genotyped. Six wolves were infected with T. nativa and five with Trichinella T6, four black bears were infected with T. nativa and two with Trichinella T6, and all seven grizzly bears were infected with Trichinella T6 and one of them had a coinfection with T. nativa. This is the first report of T. nativa in a grizzly bear from Canada. Bears have been linked to trichinellosis outbreaks in humans in Canada, and black bears are a subsistence food source for residents of the Dehcho region. In order to assess food safety risk it is important to monitor the prevalence of Trichinella spp. in both species of bear and their cohabiting mammalian food sources.     

Efficacy of firearms for bear deterrence in Alaska

We compiled, summarized, and reviewed 269 incidents of bear–human conflict involving firearms that occurred in Alaska during 1883–2009. Encounters involving brown bears (Ursus arctos; 218 incidents, 81%), black bears (Ursus americanus; 30 incidents, 11%), polar bears (Ursus maritimus; 6 incidents, 2%), and 15 (6%) unidentified species provided insight into firearms success and failure. A total of 444 people and at least 367 bears were involved in these incidents. We found no significant difference in success rates (i.e., success being when the bear was stopped in its aggressive behavior) associated with long guns (76%) and handguns (84%). Moreover, firearm bearers suffered the same injury rates in close encounters with bears whether they used their firearms or not. Bears were killed in 61% (n = 162) of bear–firearms incidents. Additionally, we identified multiple reasons for firearms failing to stop an aggressive bear. Using logistic regression, the best model for predicting a successful outcome for firearm users included species and cohort of bear, human activity at time of encounter, whether or not the bear charged, and if fish or game meat was present. Firearm variables (e.g., type of gun, number of shots) were not useful in predicting outcomes in bear–firearms incidents. Although firearms have failed to protect some users, they are the only deterrent that can lethally stop an aggressive bear. Where firearms have failed to protect people, we identified contributing causes. Our findings suggest that only those proficient in firearms use should rely on them for protection in bear country. © 2012 The Wildlife Society.