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231.
Juvenile and adolescent male chimpanzees sometimes threaten older, apparently stronger individuals such as mature females. I label the behavior harassment. Harassment comprises 25 behaviors, 14 of which are accompanied by the use of objects such as branches: Clubbing, flailing and throwing are the most common. Females respond to harassment with 10 behaviors, including scream, avoid, ignore, and retaliate. Females tend to respond to harassment by juvenile males by ignoring them. However, they are more likely to retaliate, scream or avoid in response to harassment by adolescent males. I propose the rank improvement hypothesis that harassment initiates the process of male domination of females, and compare the predictions derived from it with those of the exploratory aggression hypothesis. Males stopped harassing females significantly earlier when females ignored them versus when they did not ignore them. This is not consistent with the exploratory aggression hypothesis. Males harassed adult females significantly longer when females retaliated than when they did not, which is consistent with the rank improvement hypothesis. Although the observations are congruent with my hypothesis, we need more data to test it. 相似文献
232.
233.
Species composition and structure characteristics of the major montane shrub communities in the west slope of Helan Mountains,Nei Mongol,China北大核心CSCD
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Scrubland is the most important vegetation component in Helan Mountains, Nei Mongol, but remians very poorly studied. In order to understand the distribution and growth status of the scrubland resources in this area, the shrub communities in the National Nature Reserve of Helan Mountains were sampled. Using the community data, the characteristics of the community structure were quantitatively analyzed. The results show that the shrub communities along an altitudinal gradient in the National Nature Reserve of Helan Mountains include the following formations: Form. Cotoneaster soongoricus, Form. Syringa oblata, Form. Potentilla parvifolia, Form. Ostryopsis davidiana, Form. Lonicera microphylla, Form. Potentilla glabra, Form. Salix oritrepha and Form. Caragana jubata. Furthermore, we also provide the data on species composition and structures of these montane shrub communities, which could provide insight for the conservation and management of these valuable communities. © 2018 Editorial Office of Chinese Journal of Plant Ecology. All Rights Reserved. 相似文献
234.
该研究采取路线调查、样方套记录、野外标本采集鉴定以及查阅文献资料等方法,对色季拉山野生药用植物多样性进行了系统普查分析,为该区野生药用植物资源的保护、利用和系统研究提供科学依据。结果显示:(1)色季拉山共有野生药用植物104科350属647种,其中蕨类植物13科15属22种,裸子植物2科3属9种,被子植物89科332属616种。草本野生药用植物478种,占总种数的73.88%;木本植物169种,占总种数的26.12%;全草类、根与根茎类药用植物最多,分别占药用植物总种数的46.21%和30.14%。(2)含1~5种的单种科和寡种科为绝对多数,占色季拉山野生药用植物总科数的72.11%,但仅占药用植物总种数的22.57%;而含种数最多的7科,只占总科数的6.73%,却共含255种之多,占总种数的39.41%,对色季拉山药用植物资源的构建起主导作用。(3)含有1个种的属最多,占总属数的64.00%,色季拉山药用植物没有明显优势的大属,表明属的构成较为复杂多样。(4)清热是色季拉山药用植物的主要功效,共有260种清热药用植物,占药用植物总种数的40.19%。(5)民族药用植物83科249属360种,占色季拉山野生药用植物总种数的55.64%。其中,藏药植物在民族药用植物中所占比例最大,共有63科156属235种,占民族药用植物总种数65.28%。研究表明,色季拉山野生药用植物种类多样性较高,药用植物生活型、部位、药效、民族用药类型丰富,但部分珍稀濒危资源如云南红景天、天麻、西藏八角莲等个体数量极少,建议建立专门的保护区,加强对野生药用植物资源及其原生境的保护,并加强人工繁育研究,针对资源储量制定适度合理的采摘利用量,以期实现野生药用植物资源的可持续利用。 相似文献
235.
地表死可燃物含水率是火险天气和火行为预报中的重要指标.本研究基于时滞平衡含水率法(Nelson和Simard方法)及气象要素回归方法,于2010年9—10月对黑龙江省大兴安岭地区盘古林场不同郁闭度的山杨-白桦混交林、红皮云杉纯林,以及采伐迹地(原1∶1樟子松-白桦混交林)地表死可燃物含水率进行以小时为步长的连续测定,建立其预测模型,得到预测误差,并使用相应的模型对其他林分地表死可燃物含水率进行外推精度分析.结果表明:采用Nelson平衡含水率法构建的地表死可燃物含水率变化模型的平均绝对误差、平均相对误差和均方误差根(0.0154、0.104和0.0226)低于Simard法(0.0185、0.117和0.0256)和气象要素回归法(0.0222、0.150和0.0331).在外推效果方面,气象要素回归法的平均绝对误差、平均相对误差和均方误差根(0.0410、0.0300和0.0740)低于Simard法(0.610、0.492和0.846),但前两者均高于Nelson法(0.034、0.021和0.0660),说明以小时为步长的时滞平衡含水率法,尤其是Nelson法适用于大兴安岭地区所测林分.外推虽不能降低误差,但有助于提高现有模型应用至不同林分条件或大尺度范围内的地表死可燃物含水率预测精度和利用率.模型建模和外推误差与不同树种和郁闭度条件差异有关,研究时应根据不同林分和地点选择合适的平衡含水率模型. 相似文献
236.
Exploring invasibility with species distribution modeling: How does fire promote cheatgrass (Bromus tectorum) invasion within lower montane forests?
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Aim
Cheatgrass (Bromus tectorum) is notorious for creating positive feedbacks that facilitate vegetation type conversion within sagebrush steppe ecosystems in the western United States. Similar dynamics may exist in adjacent lower montane forest. However, fire‐forest‐cheatgrass dynamics have not been examined. We used species distribution modeling to answer three questions about fire and invasibility in lower montane forests: (Q1) Does fire create more suitable habitat for cheatgrass? (Q2) If so, which site attributes are altered to increase site suitability? (Q3) Does fire increase connectivity among suitable habitat and enhance spread?Location
Shoshone National Forest, Wyoming, USA.Methods
We measured cheatgrass presence–absence in 93 plots within Interior Douglas‐fir (Pseudotsuga menziesii var. glauca) forests. Random Forests predicted cheatgrass distribution with and without fire using nine site attributes: elevation, slope, aspect, solar radiation, annual precipitation, maximum temperature in July, minimum temperature in January, forest canopy cover and distance to nearest trail or road. Additionally, invasion pathways and spread were mapped using Circuitscape.Results
Cheatgrass distribution was controlled by topographic and climate variables in the absence of fire. In particular, cheatgrass was most likely to occur at low elevation along dry, south‐ and east‐facing slopes. High‐severity fire increased potential cheatgrass distribution when forest canopy cover was reduced to below 30%. This process created new invasion pathways, which enhanced cheatgrass spread when modelled in Circuitscape.Main conclusions
Our study showed that in the absence of fire, drier south‐ and east‐facing slopes at low elevation are most susceptible to cheatgrass invasion. However, high‐severity fire increased the total area susceptible to invasion—allowing cheatgrass to expand into previously unsuitable sites within lower montane forests in the western United States. These results are important for present day management and reflect that integrating responses to disturbance in species distribution models can be critical for making predictions about dynamically changing systems.237.
The last 50 years of climate‐induced melting of the Maliy Aktru glacier (Altai Mountains,Russia) revealed in a primary ecological succession
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Roberto Cazzolla Gatti Anastasia Dudko Artem Lim Alena I. Velichevskaya Inna V. Lushchaeva Alice V. Pivovarova Stefano Ventura Erica Lumini Andrea Berruti Igor V. Volkov 《Ecology and evolution》2018,8(15):7401-7420
In this article, we report and discuss the results obtained from a survey of plants, microorganisms (bacteria and fungi), and soil elements along a chronosequence in the first 600 m of the Maliy Aktru glacier's forefront (Altai Mountains, Russia). Many glaciers of the world show effects of climate change. Nonetheless, except for some local reports, the ecological effects of deglaciation have been poorly studied and have not been quantitatively assessed in the Altai Mountains. Here, we studied the ecological changes of plants, fungi, bacteria, and soil elements that take the form of a primary ecological succession and that took place over the deglaciated soil of the Maliy Aktru glacier during the last 50 year. According to our measurements, the glacier lost about 12 m per year during the last 50 years. Plant succession shows clear signs of changes along the incremental distance from the glacier forefront. The analysis of the plant α‐ and β‐diversity confirmed an expected increase of them with increasing distance from the glacier forefront. Moreover, the analysis of β‐diversity confirmed the hypothesis of the presence of three main stages of the plant succession: (a) initial (pioneer species) from 30 to 100 m; (b) intermediate (r‐selected species) from 110 to 120–150 m; and (c) final (K‐selected species) from 150 to 550. Our study also shows that saprotrophic communities of fungi are widely distributed in the glacier retreating area with higher relative abundances of saprotroph ascomycetes at early successional stages. The evolution of a primary succession is also evident for bacteria, soil elements, and CO2 emission and respiration. The development of biological communities and the variation in geochemical parameters represent an irrefutable proof that climate change is altering soils that have been long covered by ice. 相似文献
238.
Genetic differentiation of Rubus chamaemorus populations in the Czech Republic and Norway after the last glacial period
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Leona Leišová‐Svobodová Jade Phillips Inger Martinussen Vojtěch Holubec 《Ecology and evolution》2018,8(11):5701-5711
The population structure of cloudberry (Rubus chamaemorus L.), collected from Krkonose Mountains (the Czech Republic), continental Norway and Spitsbergen, was examined using microsatellite analyses (SSR). Among 184 individuals, 162 different genotypes were identified. The overall unbiased gene diversity was high (). A high level of genetic differentiation among populations (FST = 0.45; p < .01) indicated restricted gene flow between populations. Using a Bayesian approach, six clusters were found which represented the genetic structure of the studied cloudberry populations. The value of correlation index between genetic and geographical distances (r = .44) indicates that gene flow, even over a long distance, could exist. An exact test of population differentiation showed that Rubus chamaemorus populations from regions (Krkonose Mountains, continental Norway and Spitsbergen) are differentiated although some individuals within populations share common alleles even among regions. These results were confirmed by AMOVA, where the highest level of diversity was found within populations (70.8%). There was no difference between 87 pairs of populations (18.7%) mostly within cloudberry populations from continental Norway and from Spitsbergen. Based on obtained results, it is possible to conclude that Czech and Norwegian cloudberry populations are undergoing differentiation, which preserves unique allele compositions most likely from original populations during the last glaciation period. This knowledge will be important for the creation and continuation of in situ and ex situ conservation of cloudberry populations within these areas. 相似文献
239.
Hidden in the Arabian Mountains: Multilocus phylogeny reveals cryptic diversity in the endemic Omanosaura lizards
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Joana Mendes Daniele Salvi David James Harris Johannes Els Salvador Carranza 《Journal of Zoological Systematics and Evolutionary Research》2018,56(3):395-407
An increase in studies in the Hajar Mountains from the southeastern Arabian Peninsula has revealed a high richness of endemic evolutionary lineages with many cryptic taxa. Omanosaura is the only lacertid lizard genus endemic to the Hajar Mountains, with two species O. cyanura and O. jayakari distributed throughout this mountain range. The phylogenetic relationships and genetic diversity between and within these species have been poorly studied. In this study, we collected mitochondrial (12S, cytb, and nd4) and nuclear (cmos and mc1r) sequences for 25 specimens of Omanosaura, including 15 individuals of O. jayakari and 10 of O. cyanura. We performed phylogenetic analyses based on network reconstruction, maximum likelihood and Bayesian inference to estimate the relationships and intraspecific genetic diversity of these species. We estimated the time of divergence between the two species in the Miocene, around 8.5 million years ago. Omanosaura jayakari shows little genetic diversity, while O. cyanura presents two differentiated lineages. These are reciprocally monophyletic at mitochondrial and nuclear genes and present a high genetic distance between them. These two lineages are associated with the geographic features of the Hajar Mountains, with one lineage distributed in the northernmost part of the Hajar Mountains and the other in the rest of the western Hajars, the Jebel Akhdar, and the eastern Hajars. This geographic relationship has been recovered previously in other reptile taxa and is generally associated with high levels of local genetic diversity. Our results suggest the existence of cryptic diversity within O. cyanura and support a general biogeographic pattern of high diversity and endemism in the northern Hajar Mountains that certainly deserves additional research in the future. 相似文献
240.
应用模糊聚类分析法和模糊图论分析对太白山针叶林进行了数量分类比较研究。将26个样地分为两大类共7个群落类型。研究结果表明,两种方法在植物群落分类研究中,不但是可行的,而且所分类的实际结果是等价的,与实际观测情况也是吻合的。其中的图论法直接依据模糊相似系数得到树状图,简便易行,显示出更大的适用性。 相似文献