人熊冲突缓解措施研究进展——以三江源国家公园为例

人与熊科动物之间的冲突已成为亚洲、欧洲和美洲地区的一个普遍问题,科学有效的人熊冲突管控措施有助于人熊共存机制的建立。目前,全球范围内肇事熊科动物涉及7种,分别为棕熊、亚洲黑熊、美洲黑熊、北极熊、马来熊、懒熊和眼镜熊。肇事类型主要包括伤人、捕食牲畜、入侵房屋、损害庄稼、袭击蜂箱以及翻食垃圾。引发人熊冲突的原因与人类活动范围扩大、熊科动物种群数量上升、熊科动物生境质量下降、熊科动物自然食源周期性短缺、人类食物来源易获得性以及公众对肇事熊的容忍度下降有关。国际上已有的人熊冲突缓解措施包括物理措施、生物措施、化学措施以及政策导向性措施,然而,多数措施的制定仅停留在措施本身的技术层面上,缺乏对地方实际情况和冲突驱动因素的分析。西藏棕熊属于棕熊的一种稀有亚种,生活在靠近人类的中亚高海拔地区。在中国三江源国家公园地区,人类与西藏棕熊的冲突引起了人们的关注,为协助制订有效的保育目标、解决区内人熊冲突问题,提出以下缓解建议:(1)缓解措施的制定需因地而异,综合考虑地方实际情况,如地理环境、法律法规、民俗文化以及宗教信仰等;(2)冲突类型多样,防熊措施需持续更新与完善;(3)加强人类社会发展与熊科动物生存之间的关系研究,探索人们生产生活方式的改变与熊科动物行为变化之间的关系;(4)加强棕熊生态学方面的研究,从棕熊生境质量、种群动态、自然食源以及生态系统完整性等方面去深入挖掘人熊冲突的驱动因素,进而从根本上制定缓解措施,促进三江源国家公园地区人熊共存。     

亚洲树轮平均敏感度分布特征及其影响因素

树轮敏感度是指示树轮对气候变化敏感程度的重要统计参数,研究大尺度树木敏感度的分布特征及其影响因素有助于理解树木生长和气候的相互关系.本文使用来自国际树轮库(ITRDB)的573条树轮宽度记录,研究亚洲树轮敏感度的分布特征及可能的影响因素.结果表明: 在干旱地区和温度较低的区域,树木的平均敏感度更高,降水对敏感度的影响强于温度.平均敏感度随海拔的上升表现出下降-上升-下降的波动变化.这种波动与降水随着海拔表现的上升-下降-上升的变化相吻合,说明海拔变化导致的降水改变可能是导致平均敏感度变化的重要因素之一.不同树种生理性状的差异导致其敏感度差异较大,祁连圆柏、西藏白皮松等阳生树种由于耐旱性而具有更高的敏感度,而阴生树种如云杉属和冷杉属则敏感度较低;老龄树可能具有更高的敏感度.     

贡嘎山国家级自然保护区兔狲的活动节律与适宜栖息地预测

2016年6月-2017年5月,采用红外相机陷阱法研究了四川贡嘎山国家级自然保护区兔狲Otocolobus manul的活动节律,以样线法和红外相机调查得到的兔狲分布点为数据源,采用最大熵(MaxEnt)模型预测了兔狲的适宜栖息地分布。结果显示:(1)兔狲分布在海拔3 780~4 956 m的灌丛、草甸和流石滩生境,其中87.2%的分布点位于海拔4 500 m以上;(2)日活动差异指数为0.071 2,昼行性指数为0.34,兔狲的活动高峰为05∶00-07∶00和20∶00-22∶00;(3)增强型植被指数2年最大值均值、海拔、平均日较差和气温年较差是影响兔狲栖息地选择的主要环境因子,兔狲偏好在海拔4 000 m以上、温差较大的高山流石滩生境活动,保护区兔狲的适宜栖息地面积为187 km^2,占保护区总面积的4.56%。本研究充实了兔狲的生物学、生态学资料,也为该物种的保护管理提供了参考资料。     

光呼吸研究进展

光呼吸是指植物绿色组织依赖光能吸收O₂并释放CO₂的过程,它被认为是一个浪费能量的过程。正常生长的C₃植物光呼吸可损耗光合产物的25%~30%,在干旱、高温、高光等逆境胁迫下,该损耗可高达50%,因此,显著提高C₃植物的生产力可通过减少光呼吸通量来实现。尽管光呼吸对植物生产力的负面影响明显,但它对植物一些必要生理活动可能起着重要作用,其中包括参与光保护、H₂O₂信号发生、氮代谢、光氧化和抗逆反应等。该文对光呼吸的改造优化需要把握好平衡点与适配度。基于Rubisco改造、CO₂浓缩机制(CCM)和光呼吸支路创建的光呼吸改造研究进展进行了综述。通过了解调控光呼吸提高植物光能转化效率方面的最新进展, 可望为光呼吸代谢的分子调控及改良研究提供指导。     

Isolation and functional analysis of a Brassica juncea gene encoding a com-ponent of auxin efflux carrier

Polar auxin transport plays a divergent role in plant growth and developmental processes including root and embryo development, vascular pattern formation and cell elongation. Recently isolated Arabidopsis pin gene family was believed to encode a component of auxin efflux carrier (G(?)lweiler et al, 1998). Based on the Arabidopsis pin1 sequence we have isolated a Brassica juncea cDNA (designated Bjpin1), which encoded a 70-kDa putative auxin efflux carrier. Deduced BjPIN1 shared 65% identities at protein level with AtPINl and was highly homologous to other putative PIN proteins of Arabidopsis (with highest homology to AtPIN3). Hydrophobic analysis showed similar structures between BjPINl and AtPIN proteins. Presence of 6 exons (varying in size between 65 bp and 1229 bp) and 5 introns (sizes between 89 bp and 463 bp) in the genomic fragment was revealed by comparing the genomic and cDNA sequences. Northern blot analysis indicated that Bjpin1 was expressed in most of the tissues tested, with a relatively h     

Sambunigrin and cyanogenic variability in populations of Sambucus canadensis L. (Caprifoliaceae)

The presence or absence of cyanogenic glycosides was determined for individuals from nine populations of Sambucus canadensis L. (elderberry) of east-central Illinois. In most of the populations tested, all or most of the individuals did not produce these compounds, in one, all were cyanogenic, whereas in another population this trait was highly variable. Addition of the enzyme emulsin to negative tests did not result in any further release of cyanide. The glycoside responsible is (S)-sambunigrin.     

The use of basis functions in modelling joint articular surfaces: application to the knee joint

This article introduces a new method to represent bone surface geometry for simulations of joint contact. The method uses the inner product of two basis functions to provide a mathematical representation of the joint surfaces. This method guarantees a continuous transition in the direction of the surface normals, an important property for computation of joint contact. Our formulation handles experimental data that are not evenly distributed, a common characteristic of digitized data of musculoskeletal morphologies. The method makes it possible to represent highly curved surfaces, which are encountered in many anatomical structures. The accuracy of this method is demonstrated by modeling the human knee joint. The mean relative percentage error in the representation of the patellar track surface was 0.25% (range 0-1.56%) which corresponded to an absolute error of 0.17mm (range 0-0.16mm).     

The synthesis of mycosporine-like amino acids (MAAs) by cultured, symbiotic dinoflagellates

We tested the hypothesis that there is a relation between phylotypes (phylogenetic types, as determined by restriction fragment length polymorphism (RFLP) and partial sequence analysis of the small subunit ribosomal RNA gene (SSUrDNA)) and the synthesis of mycosporine-like amino acids (MAAs) by symbiotic dinoflagellates under the influence of ultraviolet radiation (UV-B/A) and photosynthetically active radiation (PAR). We exposed 27 isolates of symbiotic dinoflagellates simultaneously to UV-B/A and PAR, and subsequently determined the MAAs present in cell extracts and in the media. The algae used included 24 isolates of Symbiodinium spp. originating from jellyfishes, sea anemones, zoanthids, scleractinians, octocorals, and bivalves, and three others in the genera Gymnodinium, Gloeodinium and Amphidinium from a jellyfish, an hydrocoral and a flatworm, respectively. In this study, all of the phylotype A Symbiodinium spp. synthesized up to three identified MAAs. None of the 11 cultured phylotypes B and C Symbiodinium spp. synthesized MAAs. The three non-Symbiodinium symbionts also synthesized up to three MAAs. The results support a conclusion that phylotype A Symbiodinium spp. have a high predilection for the synthesis of MAAs, while phylotypes B and C do not. Synthesis of MAAs by symbiotic dinoflagellates in culture does not appear to relate directly to depths or to the UV exposure regimes from which the consortia were collected.