Can urban forests provide acoustic refuges for birds?Investigating the influence of vegetation structure and anthropogenic noise on bird sound diversity

As a crucial component of terrestrial ecosystems,urban forests play a pivotal role in protecting urban biodiversity by providing suitable habitats for acoustic spaces.Previous studies note that vegetation structure is a key factor influencing bird sounds in urban forests;hence,adjusting the frequency composition may be a strategy for birds to avoid anthropogenic noise to mask their songs.However,it is unknown whether the response mechanisms of bird vocalizations to vegetation structure remain consistent despite being impacted by anthropogenic noise.It was hypothesized that anthropogenic noise in urban forests occupies the low-frequency space of bird songs,leading to a possible reshaping of the acoustic niches of forests,and the vegetation structure of urban forests is the critical factor that shapes the acoustic space for bird vocalization.Passive acoustic monitoring in various urban forests was used to monitor natural and anthropogenic noises,and sounds were classified into three acoustic scenes(bird sounds,human sounds,and bird-human sounds)to determine interconnections between bird sounds,anthropogenic noise,and vegetation structure.Anthropogenic noise altered the acoustic niche of urban forests by intruding into the low-frequency space used by birds,and vegetation structures related to volume(trunk volume and branch volume)and density(number of branches and leaf area index)significantly impact the diversity of bird sounds.Our findings indicate that the response to low and high frequency signals to vegetation structure is distinct.By clarifying this relationship,our results contribute to understanding of how vegetation structure influences bird sounds in urban forests impacted by anthropogenic noise.

Relationships between bird communities and vegetation structure in Honghuaerji, northern Inner Mongolia

The survey on bird communities was conducted by the belt-style method in six different sample plots in the Honghua抏rji Forests area in the northern Inner Mongolia in June 2001 and totally 28 bird species were recorded. Vegetation investigation was carried out in five 10 m×10 m quadrats at each plot. The asymptotic regression function formulae were adopted to identify the relationships between the vegetation coverage and the numbers of bird species and individuals. The analytical results showed that the changes of species number and density of bird as well as the formation of bird communities follow the changes of forest type and the total foliage. Both the number of bird species and their density decreased with the de-crease of total foliage. The similarity of bird community was very low at the breeding time. In the same classification of cluster, no similarity was higher than 0.65, which indicated that the composition of species had a great difference between all the bird communities. The bird breeding density was closely related to forest growth stage. From the bare grassland ecosystem to cli-max ecosystem, the density of bird species showed a gradually increasing trend.

Landscape structure and bird's diversity in the rural areas of Taiwan

This study tries to discuss the relationship between landscape structure and organisms in the perspective of landscape architecture. The research hypotheses were then proposed as (1) there are relationships between landscape structure indexes and birds' diversity in the rural areas of Taiwan; (2) the relationships between landscape structure and birds' diversity will be different in different hierarchical levels. In order to increase the bird species, landscape planners could tries to increase the density of water bodies, but decrease the farms and human planted woods. Decrease the density of constructed and human planted grasslands. Increase the area of un-worked acres, natural grasslands, and the area of water bodies and circular the water bodies and natural forest. In order to increase birds' diversity, landscape planners could decrease the concentration of paved areas. Concentrate the human planted trees to increase the core areas of woodlands. Increase the area of natural grassland circular. In order to increase the total number of birds in the planning areas, landscape planners could scattered the paved areas and lengthen the constructed areas. Decreases the core region of the constructed areas. Increase the area of un-worked acres and water bodies. Decrease the disturbance of both the interior area of natural and human planted woodlands and try to increase the density of water bodies.;The analysis results showed that the small grain size indexes are more suitable for the rural areas of Taiwan to capture the influential factors of bird communities. The high fragmentation of land usages in Taiwan lessens the influences of the regional landscape pattern.

Precipitation is the dominant driver for bird species richness,phylogenetic and functional structure in university campuses in northern China

Background:Although urbanization is threatening biodiversity worldwide,the increasing green urban spaces could harbor relatively high biodiversity.Therefore,how to maintain the biodiversity in urban ecosystem is crucial for sustainable urban planning and management,especially in arid and semiarid regions with relatively fragile environment and low biodiversity.Here,for the first time we linked species richness,phylogenetic and functional structure of bird assemblages in university campuses in northern China with plant species richness,glacial-interglacial climate change,contemporary climate,and anthropogenic factors to compare their relative roles in shaping urban bird diversity.Methods:Bird surveys were conducted in 20 university campuses across Inner Mongolia,China.Ordinary least squares models and simultaneous autoregressive models were used to assess the relationships between bird species richness,phylogenetic and functional structure with environmental factors.Structural equation models were used to capture the direct and indirect effects of these factors on the three components of bird diversity.Results:Single-variable simultaneous autoregressive models showed that mean annual precipitation was consistently a significant driver for bird species richness,phylogenetic and functional structure.Meanwhile,mean annual temperature and plant species richness were also significant predictors for bird species richness.Conclusions:This study suggests that campuses with warmer and wetter climate as well as more woody plant species could harbor more bird species.In addition,wetter campuses tended to sustain over-dispersed phylogenetic and functional structure.Our findings emphasize the dominant effect of precipitation on bird diversity distribution in this arid and semiarid region,even in the urban ecosystem.

Identification of habitat requirements of farmland birds based on a hierarchical structured monitoring scheme

Agricultural landscapes are essential for the conservation of biodiversity. Nevertheless, a negative trend continues to be observed in many rural areas for the most prominent indicator species group, the farmland birds. However, clear cause-effect relationships are rarely reported and sometimes difficult to deduce, especially from monitoring data which are based only on the detection of species and counts of the numbers of individuals. Because the identification of habitat preferences is a precondition for farmland bird biodiversity conservation efforts, a monitoring scheme for the simultaneous collection and analysis of bird and land use data was developed and tested. In order to assign the occurrence of bird species to land characteristics at various spatial scales and different land use and crop types, we applied a hierarchical structured sampling design. The spatial scales were ‘agricultural landscape', ‘agricultural landscape types', ‘field crops and other habitats' and ‘vegetation structures'. These scales were integrated with a novel concept, the ‘habitat matrix'(HM). This method was applied to farmland breeding bird abundances on 29 plots, each 1 km2 in size, by the use of the territory mapping method. The same plots were enlarged by a 100 m buffer and the sizes and location of habitats documented. Vegetation height, coverage and density were also recorded for all crop fields in the study area. We propose that this monitoring method facilitates the identification of scale dependent relationships between farmland bird habitat characteristics and bird abundance. This is demonstrated by the farmland bird species Corn Bunting(Emberiza calandra), Skylark(Alauda arvensis), and Whinchat(Saxicola rubetra). The breeding territories of these species reveal large differences within the various spatial scales ‘agricultural landscape', ‘agricultural landscape types' and ‘field crops'. Throughout the breeding season the abundances varied, dependent on the field crop and the development of vegetation structures(height, coverage, and density). HM-analysis led to the identification of specific habitat configurations preferred by individual bird species within the agricultural landscape. These findings indicate that the methodology has the potential to design monitoring schemes for the identification of cause-and-effects of landscape configuration, land use and land use changes on the habitat suitability and abundance of farmland birds.

基于Quick Bird遥感影像的铜仁市城市绿地景观结构特征分析

以2004年9月4日Quick Bird遥感影像,辅以实时动态差分GPS RTK技术高精度定位,运用GIS技术和景观斑块谱分析方法,对铜仁市城市绿地景观结构特征进行分析。结果表明:(1)铜仁市城市绿地斑块面积5 857.96 hm2,斑块数量6 503块,规划区绿地斑块面积和斑块数量均大于中心城区;(2)在各种绿地类型中,其他绿地在斑块面积上占绝对优势,其次为农业用地和生产防护绿地,道路绿地面积最小。在斑块数量上,居住区绿地>农业用地>其他绿地>生产防护绿地>道路绿地>单位附属绿地>公园绿地;(3)按绿地斑块面积统计,大于10 000 m2的大型绿地占绝对优势,占整个绿地面积的92.44%,按斑块数量统计,小于500 m2的小型斑块占优势,占整个绿地斑块的69.72%;(4)小型斑块以居住区绿地最多,其次为农业用地和其他绿地等,公园绿地最少;中型斑块和大中型斑块以农业用地最多,大型斑块在面积上以其他绿地最多,数量上以农业用地最多;公园绿地和居住区绿地在各等级绿地斑块中,面积和斑块数量相对较小。综合分析,铜仁市在今后的城市绿地建设中,中心城区内应加强绿化力度,适当将现有的绿地扩大连片,规划区内应合理调整和规划绿地性质,丰富绿地功能特性,注重绿地结构的合理规划,将小型、中型绿地尽可能有效地连片,增加大中型绿地斑块,特别是在与人居密切相关的居住区、单位和街道等周围,增加大中型绿地、大型绿地,以满足人们生产生活对绿地的需求,同时,保护生物多样性,优化城市生态环境。

珠江三角洲城市群留鸟多样性格局及其驱动机制

鸟类是反映城市生境和生物多样性变化的重要指标,城市鸟类多样性分布格局模拟与预测是当前城市生物多样性保护研究中重点关注的难题。珠江三角洲城市群经历了快速的城市化过程,景观变化显著,给城市生境和生物多样性保护带来了巨大挑战。为解析城市鸟类多样性与城市生境之间的空间关联机制,构建“单物种分布预测-物种多样性聚类-多样性的影响归因”的空间综合途径,开展珠江三角洲城市群留鸟空间格局与形成机制研究。结果表明:1)珠江三角洲城市群的87种留鸟构成的多样性与适宜性具有高度的城-乡梯度分布模式;将留鸟的空间适宜性聚类可分为8类,总体上留鸟的中高适宜区占比小于30%。2)结构方程模型的解析可以发现,人类活动显著地正向影响了鸟类多样性的空间分布格局,影响系数介于0.28~1.94;而植被、气候、地形的正向或负向效应差异明显。研究可为城市生物多样性保护,调控鸟类多样性的生境影响因素,开展城市生态建设与管理提供科学依据。

Effects of vegetation strata and human disturbance on bird diversity in green areas in a city in southern Chile

Background: Urbanisation is a dominant geographical trend and an important component of global change, with unprecedented implications for socio?economic, cultural and environmental characteristics. However, green areas, including original fragments, can help to conserve native diversity, improving the functioning of these artificial systems in the long term. Urban areas can still provide habitats usable by wild birds, however the structural charac?teristics of the habitat formed by different types of green area differ, and therefore dissimilar bird diversities are to be expected. The object of this study was to characterise the α and β diversities of birds in different green areas and to analyse how diversity relates to ten variables that characterise the habitat.Methods: We studied the green areas in the city of Temuco, southern Chile(Park, Square and Median strips of main streets), evaluating the variables:(a) surface area,(b) vegetation,(c) estimated human impact as the proportions of vegetation and bare soil by area, and the vehicle traffic. The bird assemblage structures were characterised by α(intra?environment) diversity and β diversity(between environments) and the statistical analysis identified the environmen?tal variables related with the presence and abundance of birds. A statistical model was constructed to describe the contribution of the variables to bird diversity.Results: We found significant differences between the diversity of bird species in the three types of green area. The β showed medium to high similarity between the different study units. There was a negative correlation with bare soil areas; the correlations with vehicle flow, plant structure and tree and shrub cover were not significant, meaning that these variables did not explain the variation in the richness of bird species between the green areas. However the surface area did explain this variation presenting a positive potential relation. There was also a high correlation with the origin(native) of shrub species.Conclusions: The bird diversity varied significantly according to the type of urban green area. The environmental variables presenting significant correlations with bird diversity were: surface area, native species of shrub stratum, shrub cover, and bare soil area. The best multiple regression model showed that the three most important variables for bird diversity are the surface area of the green area, the cover of the shrub stratum and the presence of native shrub species.

自然保护地与社区协调发展研究进展

自然保护地是建设生态文明的核心载体,在维护国家生态安全中居于首要地位。自然保护地与社区协调发展是实现自然保护地建设和管理目标的关键,因此,正确认识自然保护地建设与社区的关系并开展深入研究具有必要性和紧迫性。借助文献计量软件,对近30年自然保护地与社区协调发展研究领域的重要学术文献进行梳理分析。研究发现:自然保护地与社区关系的研究可划分为萌芽探索阶段(2000年以前)、全面推进阶段(2001—2010年)和深化拓展阶段(2011—2021年)。研究主题集中在自然保护地建设对社区的影响、社区对自然保护地建设的认知与影响、自然保护地建设与社区协调发展措施等3个方面,其中关于自然保护地对社区影响的实证研究较为丰富,协调发展措施的研究从概念研究转向具体模式、实践路径等方面。已有研究主要存在4个方面的不足:缺乏综合性和长期性的自然保护地对社区影响研究,社区对自然保护地建设认知的衡量标准未达成共识,自然保护地与社区协调发展的差异化措施研究薄弱,自然保护地与社区协调发展措施的效益评估研究较少。据此尝试提出未来自然保护地建设与社区协调发展的研究框架,建议加强自然保护地建设对社区居民福祉综合影响的研究,完善社区对自然保护地建设认知的衡量标准,加强自然保护地与社区协调发展措施的差异化研究,深化自然保护地与社区协调发展措施的综合效益评估研究等,以期完善自然保护地与社区协调发展的研究体系。

纤维金属板蜂窝夹芯结构鸟体高速冲击损伤分析

纤维金属板蜂窝夹芯结构作为一种轻质航空结构,研究其抗鸟体高速冲击性能具有重要的现实意义。本文提出一种基于连续介质损伤力学的有限元模型,研究鸟体高速冲击下纤维金属板蜂窝夹芯结构的力学行为及损伤机理。采用光滑粒子流体动力学(Smooth particle hydrodynamics, SPH)法对鸟体类流体力学行为进行建模;采用Johnson-Cook模型模拟金属层冲击力学响应;采用三维Hashin准则,考虑应变率效应,模拟复合材料层板面内损伤演化;采用界面单元模拟层间分层现象。编写用户材料VUMAT子程序,实现基于ABAQUS/Explicit软件平台的数值求解。探讨鸟体速度、蜂窝高度和面板厚度对纤维金属板蜂窝夹芯结构鸟体冲击性能的影响,分析预应力条件下纤维金属板蜂窝夹芯结构鸟体高速冲击损伤特性,为夹芯结构鸟体冲击问题数值分析提供一定的参考。

点阵构型对夹层结构抗鸟撞性能的影响

空心夹层叶片由于同时具备轻量化与吸能特性而被广泛应用于航空发动机设计,研究了四种不同点阵构型对填充式叶片等效模拟件的抗鸟撞能力的影响。通过均匀化方法给出四种点阵构型的等效刚度,然后基于随形自适应点阵填充结构的建模方法建立点阵填充的曲板模型,通过3D打印将单胞填充平板结构制造出来进行鸟撞试验并进行数值仿真。从变形机理和能量吸收的角度分析了四种不同单胞下填充结构的抗鸟撞性能,BCC具有更好的抵抗z方向挠度和面内y方向的褶皱两种变形的表现且相比于其他几种结构的吸能作用更优,所以BCC具有更好的抗鸟撞能力。

仁怀市鸟类群落结构与多样性分析

赤水河流域仁怀段是中国酱香酒核心产区,其健康稳定的生态系统对酿酒工艺具有重要影响。2022年8月至2023年7月,利用样线法对仁怀市鸟类多样性开展调查,并结合红外相机监测数据以及公民科学数据等进行统计分析。调查结果显示,共记录鸟类131种,隶属于15目44科,其中,国家一级保护鸟类1种,国家二级保护鸟类14种。鸟类群落结构较稳定,雀形目是构成鸟类群落的主要组成部分(70.99%),繁殖鸟(留鸟和夏候鸟)物种数较多,以东洋界鸟类为主。春季迁徙期鸟类丰富度最高,秋季迁徙期最低;不同季节之间鸟类群落相似性比较结果显示,春季与冬季相似度最高(0.68),秋季与冬季相似度最低(0.59)。本研究初步探明了仁怀市鸟类本底资源,为中国酱香酒核心产区生态系统的健康稳定运行提供保护和管理的必要基础数据。

以“揽雀尾”为切入点的太极拳技术结构及“舞对合彀”的训练方法

太极拳当前发展存在的一个很严重的问题是因过分突出健身养生而忽视了作为“拳”之本质的技击。为探寻太极拳的技击本体,便于明晰太极拳的技术结构及相应的训练方法,以太极拳的核心技术“揽雀尾”为研究对象,采用文献资料、专家访谈、实修体悟等方法展开研究,得出以下研究结论:(1)揽雀尾包含了从下向上的掤势、左右转动的捋势、向前逼近的挤势、后坐下引的挂按、弓步向前的推按等技术环节,是一个涵盖上下前后左右6个方向的立体综合技术,在太极拳中处于核心地位;(2)以揽雀尾为核心的太极拳技击训练包括单人舞练、双人对打两方面内容,两者是“舞对合彀”的技术结构,即单人舞练的目的是对打实战,舞练内容与实战内容完全一致;(3)单人舞练训练可以按照外部身体结构的完整训练、内部劲力的整透训练、攻防转化的流畅训练、单势拳路的多样化次第训练4个逐步进阶的步骤依次推进;双人对打训练可按照预备对峙、组合套招、拆招变势、融合归一4个逐步进阶的步骤依次推进。并从进攻方法、技法进阶、技击理念与训练等方面归纳了“揽雀尾”一脉相承的武学思想。

江苏大丰沿海地区林鸟的食果网络研究

鸟类对植物果实的取食影响着植物种群更新,对维系生物多样性至关重要。于2022年11月至翌年2月在江苏大丰沿海地区林地生境收集鸟类多样性数据,研究林鸟对植物种子的取食,用以构建鸟类食果网络并分析网络结构与鸟类特征和植物特征的关联性。结果表明,大丰沿海地区秋冬季林鸟共记录7目22科44种;食果网络由15种食果鸟类和7种结果植物组成,连接度和专业性较低;鸟类数量与物种度、物种强度和连接多样性呈显著相关,但鸟类形态特征并不影响网络结构;植株数量和结实量与物种度呈显著相关,植株数量与连接多样性呈显著相关,而株高与专性指数呈显著负相关。研究表明,大丰沿海地区秋冬季鸟类食果网络结构较为简单,鸟类种群大小和植物特征是影响网络结构的关键因素。

Design of aircraft structures against threat of bird strikes

In this paper, a method to design bird-strike-resistant aircraft structures is presented and illustrated through examples. The focus is on bird strike experiments and simulations. The explicit finite element software PAM-CRASH is employed to conduct bird strike simulations, and a coupled Smooth Particles Hydrodynamic（SPH） and Finite Element（FE） method is used to simulate the interaction between a bird and a target structure. The SPH method is explained, and an SPH bird model is established. Constitutive models for various structural materials, such as aluminum alloys, composite materials, honeycomb, and foam materials that are used in aircraft structures,are presented, and model parameters are identified by conducting various material tests. Good agreements between simulation results and experimental data suggest that the numerical model is capable of predicting the dynamic responses of various aircraft structures under a bird strike,and numerical simulation can be used as a tool to design bird-strike-resistant aircraft structures.

A numerical model for bird strike on sidewall structure of an aircraft nose

In order to examine the potential of using the coupled smooth particles hydrodynamic （SPH） and finite element （FE） method to predict the dynamic responses of aircraft structures in bird strike events, bird-strike tests on the sidewall structure of an aircraft nose are carried out and numerically simulated. The bird is modeled with SPH and described by the Murnaghan equation of state, while the structure is modeled with finite elements. A coupled SPH-FE method is developed to simulate the bird-strike tests and a numerical model is established using a commercial software PAM-CRASH. The bird model shows no signs of instability and correctly modeled the break-up of the bird into particles. Finally the dynamic response such as strains in the skin is simulated and compared with test results, and the simulated deformation and fracture process of the sidewall structure is compared with images recorded by a high speed camera. Good agreement between the simulation results and test data indicates that the coupled SPH-FE method can provide a very powerful tool in predicting the dynamic responses of aircraft structures in events of bird strike.

Mass and performance optimization of an airplane wing leading edge structure against bird strike using Taguchi-based grey relational analysis

Collisions between birds and aircraft are one of the most dangerous threats to flight safety. In this study, smoothed particles hydrodynamics(SPH) method is used for simulating the bird strike to an airplane wing leading edge structure. In order to verify the model, first, experiment of bird strike to a flat aluminum plate is simulated, and then bird impact on an airplane wing leading edge structure is investigated. After that, considering dimensions of wing internal structural components like ribs, skin and spar as design variables, we try to minimize structural mass and wing skin deformation simultaneously. To do this, bird strike simulations to 18 different wing structures are made based on Taguchi’s L18 factorial design of experiment. Then grey relational analysis is used to minimize structural mass and wing skin deformation due to the bird strike. The analysis of variance(ANOVA) is also applied and it is concluded that the most significant parameter for the performance of wing structure against impact is the skin thickness. Finally, a validation simulation is conducted under the optimal condition to show the improvement of performance of the wing structure.

基于图像处理技术的太阳神鸟图几何结构分析

为揭示并破译太阳神鸟金箔图案可能存在的历史与文化内涵,利用图像处理技术对图案的几何结构进行定量研究和分析。首先,利用最小二乘法结合等角螺旋的数学表达式对图案内层弧形旋转芒纹进行拟合。其次,在猜想图案几何结构的基础上得到重构图形,利用弦点距离累积技术检测出图案所涉内、外两组角点,通过计算内、外圈角点到中心的径向距离相对于重构图形中两内切圆半径的误差平均值,定量验证相关猜想的合理性。实验结果显示:太阳神鸟图案内层的弧形旋转芒纹对应等角螺旋结构,内、外圈角点到中心的径向距离相对于重构图形中两内切圆半径的误差平均值都在5.3%以内,证明了图案与古代历法的关联性。

上海市城乡梯度上林地鸟类群落结构及多样性研究

利用样线法对上海中心城区、近郊和远郊的10个典型林地生境开展了2019—2020年繁殖季和越冬季林地鸟类多样性调查。共记录到鸟类82种5423只,隶属14目36科。雀形目鸟类种类最多,占总物种丰富度的70%,在上海城市鸟类群落种类组成及数量中占主要地位,其中麻雀和白头鹎为优势种。上海城乡梯度上鸟类组成在种类上表现为近郊>远郊>中心城区,在数量上表现为随城市化程度降低而递增,鸟密度变化表现为随城市化程度降低而降低。

河北昌黎黄金海岸国家级自然保护区七里海潟湖湿地鸟类多样性

【目的】为完善“中国黄(渤)海候鸟栖息地(二期)世界自然遗产申报提名地”七里海潟湖湿地的鸟类基础资料,同时为地方政府及保护区管理部门制定保护管理规划及生态修复提供技术支撑。【方法】2022年1月至12月,根据七里海潟湖周围地貌和生境分布的特点,采用样点法和样线法相结合的方法,共设置3个样点和1条样线,记录调查到的鸟类种类、数量、分布型和区系组成、鸟类居留类型,分析鸟类的优势种、常见种、珍稀濒危状况、多样性和受威胁状况。【结果】调查共记录到鸟类17目42科165种,其中湿地水鸟共计102种、非湿地水鸟63种。鸻形目、雁形目和鹈形目是七里海潟湖湿地鸟类主体,主要分布于潟湖湖面生境,以旅鸟为主,旅鸟和候鸟占总物种数的90%,体现了七里海潟湖是迁徙鸟类重要栖息地的特点。在165种鸟类中,有国家Ⅰ级重点保护鸟类12种、国家Ⅱ级重点保护鸟类30种、世界自然保护联盟(IUCN)红色物种名录濒危及以上级别种类5种。【结论】七里海潟湖湿地鸟类的多样性指数H′和均匀度指数J的平均值分别为3.27和0.66,表明该湿地鸟类群落具有较高的物种多样性和群落结构稳定,保护价值较高,目前面临的主要威胁因素为违规采集底栖生物等人类活动。