Alpha声学指数效应的meta分析

通过声学指数量化声音的特征反映生物的组成和生境信息,是一种高效率、低干扰的监测方式。该研究领域在近十多年来得到了快速的发展,不断有新的声学指数被提出,同时也有大量的实证研究。声学指数可分为反映录音内信息的alpha声学指数和比较不同录音之间差异的beta声学指数,其中alpha声学指数的实证研究较多。本文在汇总已有研究数据的基础上进行meta分析,关注alpha声学指数与动物多样性、生境质量、动物活跃性之间关联的方向和程度。基于文献调研,本文对8个常用的声学指数进行了总结分析:声学复杂度指数(acoustic complexity index,ACI)、声学熵指数(acoustic entropy index,H)、生物声学指数(bioacoustic index,BI)、标准化声景差异指数(normalized difference soundscape index,NDSI)、声学多样性指数(acoustic diversity index,ADI)、声学均匀度指数(acoustic evenness index,AEI)、声学丰富度指数(acoustic richness ind...     

现代生物声学的学科发展趋势及中国机遇

随着数字录音技术、电子学和微电子学、人工智能、信息科学等跨学科领域的技术革新,现代生物声学逐渐与生物学、生态学等学科及关联学科之间形成了广泛的交叉前沿领域。现阶段,现代生物声学主要以生物学、生态学等基础学科的理论方法为指导,着重于揭示环境中各类声音在生物之间以及生物与人类、环境之间的相互作用及相关科学规律,为人类认识、保护和利用生物声学资源提供理论基础和解决方案。本文重点阐述了现代生物声学的学科内涵和学科特征,介绍了动物生物声学、生态声学、水下生物声学、环境生物声学、保护生物声学、计算生物声学以及现代生物声学研究的技术框架等前沿热点和发展趋势,评估了中国生物声学研究的学科现状与发展机遇,并对未来学科建设进行了展望。     

东北虎豹国家公园森林声景的昼夜和季节变化

被动声学监测技术和声学指数通过对音频数据的时频域特征进行定量分析,可以反映声景的复杂度、多样性和健康程度等,已经成为评估生物多样性变化的重要手段。本研究从2020年6月至2021年6月在东北虎豹国家公园采集了52个点的声学数据,计算了春、夏、秋、冬4个季节和黎明、白天、黄昏、夜晚4个昼夜时间段的声音复杂度指数(acoustic complexity index,ACI)、声音多样性指数(acoustic diversity index,ADI)、声音均匀度指数(acoustic evenness index,AEI)、生物声学指数(bioacoustic index,BIO)、标准化声景差异指数(normalized difference soundscape index,NDSI)、声音熵指数(acoustic entropy index,H)和1–21k Hz共20个频段的功率谱密度(power spectral density,PSD)等声学指数,评价了声景构成和多样性的昼夜和季节性差异。结果表明,东北虎豹国家公园的声景随季节变化具有显著的昼夜节律差异,尤其是夜晚的声景和声学成分...     

城市公园春季声景观与植被结构的关系

城市公园是城市生态系统的重要组成部分和城市生物多样性热点地区，具有丰富的声景观资源。由于声景观及声学方法具有信息量大，成本低，低侵入的特点，因此其研究和应用对生态系统健康及监测具有较高价值。声景观研究通过总结生物声的活动或多样性来衡量生物多样性。记录了北京20个城市公园的春季声景观，使用定量方法描述了声景观特征与变化；测试三种了已被证明与生物多样性相关并被广泛使用的声学指数（BIO、ADI、NDSI）与植被群落关系，完成了城市环境中声景观与环境关系的初步探究。研究结果表明：（1）声学指数能够有效表征城市公园声景观信息，具有显著的时间动态特性，能准确反映鸟类黎明合唱等重要生物生态活动；（2）声学强度指数也具有显著的时间动态变化和沿频率梯度的变化，不同的频率区间反映了不同声学群落的活动信息；（3）植被结构尤其是垂直结构对声景观起着重要作用，垂直异质性越大，声学多样性越高。发现支持声景观作为公园植被状况的度量，强调了其作为生物多样性和生态系统健康状况监测方法，用于城市管理和可持续发展的巨大潜力。     

Beta多样性研究进展

Beta多样性度量时空尺度上物种组成的变化, 是生物多样性的重要组成部分, 与许多生态学和进化生物学问题密切相关, 并且其信息可用于保护区选址和布局规划, 因此在最近10年间成为生物多样性研究的热点问题之一。多年来, 学者们利用各种度量方式和分析方法, 在不同地理区域, 对许多生物类群beta多样性的时空格局和形成机制进行了大量研究。本文主要从beta多样性的度量方法、时空格局、形成机制及其在生物多样性保护中的应用等几个方面, 总结了最近10多年来相关研究的进展。Whittaker(1960)最初提出beta多样性概念时就缺乏严格的定义, 随着概念的不断演化, 度量方法也同样呈现出多样化, 而度量手段的多样化非常不利于不同研究之间的比较。目前应用最普遍的度量方法是采用相似性指数, 如Jaccard和Sørensen指数。最近几年, 新的度量方法还在不断出现, 其中一些方法非常值得注意。Beta多样性具有时空尺度和分类尺度依赖性, 一般随分析粒度(grain)的增加而降低。虽然有些研究表明beta多样性随纬度增加而降低, 但学者们并没有达成共识。山区和生物地理区的交界处beta多样性都比较高, 因而需要在这些地区增加保护区的面积或者数量以囊括物种变化梯度。对时间尺度上beta多样性的研究表明, 气候变化确实导致了物种组成在时间上的变化, 并且物种在不同大陆和地区间的迁移导致了生物同质化。扩散过程和生态位过程共同决定了beta多样性, 只是这两个过程的相对重要性依尺度、地理区域和物种类群的不同而有所差异。综上所述, 我们认为未来beta多样性研究的热点问题是：(1)不同生物类群的进化历史和生物学特征对beta多样性的影响; (2)不同的时空尺度对beta多样性及其维持机制的影响; (3)人类活动对beta多样性的影响。     

被动声学监测技术在陆生哺乳动物研究中的应用、进展和展望

被动声学监测(passive acoustic monitoring,PAM)技术指将自动录音机安装在自然环境中收集野生动物及其所在环境的声音信号的监测方法。20世纪90年代以来,PAM技术陆续被应用于翼手目和灵长目等陆生哺乳动物的监测和研究,探究了陆生哺乳动物行为学、生态学和保护生物学等方面的科学问题。然而,当前缺乏对这些研究的系统性总结和展望。本文从活动规律和时间分配、栖息地利用、物种分布、种群大小与密度、生物多样性、人为干扰的影响等领域综述了PAM技术在陆生哺乳动物中的研究进展,并列举了相关应用实例。总体上,PAM技术涉及到生物学、生态学、声学、计算机科学等多学科的交叉融合,其应用受限于声学数据的储存和管理、物种或个体自动化识别以及声学指数评估的普适性,设备价格也相对昂贵,这些可能是导致该技术在我国陆生哺乳动物监测和研究方面的应用还相对滞后于其他国家的原因。最后,本文对未来研究方向进行了展望,并建议尽快建立和完善我国陆生哺乳动物PAM网络和数据共享平台、组织开展面对面访问调查或生物多样性保护相关的知识竞赛等公民科学项目、向更多科研机构或保护区推广PAM技术的应用,使该技术成为陆生...     

声学指数在城市森林鸟类多样性评估中的应用

鸣声是鸟类之间进行沟通和传递信息的重要方式,这为通过声学监测评估鸟类多样性提供了独特的机会。利用声学指数快速评估生物多样性是一种新兴的调查方法,但城市森林中的复杂声环境可能会导致声学指数的指示结果出现偏差。为了解声学指数在城市森林中应用的可行性,本研究在北京市东郊森林公园设置了50个矩阵式调查样点,于2021年4–6月每月进行1次鸟类传统观测和同步鸣声采集,通过比较两种方法的结果来探究声学监测的有效性。采用Spearman相关分析和广义线性混合模型评估6个常用声学指数与鸟类丰富度和多度的关系,并衡量了每个指数的性能。结果表明:(1)本研究共记录到鸟类10目23科35种,通过声学监听识别的总物种数与传统鸟类观测相等,但具体鸟种存在差异;(2)不同月份间声学指数与鸟类丰富度和多度的相关性有明显差别,声学复杂度指数(ACI)和标准化声景差异指数(NDSI)优于其他指数,是评估鸟类多样性的关键变量;(3)声学指数对鸟类多度的预测能力(R²m=0.32,R2c=0.80)要高于丰富度(R²m=0.12,R2c=0.18)。声学指数为快速评估生物多样性提...     

开封市城市水系微生境特征对两栖动物多样性的影响

两栖类生物生活史独特对环境变化极其敏感,是环境变化的重要指示物种。开封城市水系的建设直接影响两栖类生物栖息地与两栖类生物多样性。本研究通过设置样线,采用目视遇测法对开封市水系中的两栖类生物进行调查,并采集相应的生境因子变量。采用Shannon多样性指数、Pielou均匀度指数、Simpson优势度指数研究了不同生境类型下两栖类生物多样性特征,运用聚类分析与冗余分析探究了无尾两栖类对微生境因子的响应特征。结果表明: 在开封水系中,自然驳岸两栖类生物的多样性、均匀度以及优势度均大于两种人工硬化驳岸,表明两栖动物种群在自然生境中稳定性较好,自然驳岸两栖类生物的优势度指数大于两种人工硬化驳岸,两栖类生物生境选择偏向于自然生境;黑斑侧褶蛙与中华蟾蜍的丰富度和夜间光照强度呈显著正相关,金线侧褶蛙与总磷呈显著正相关,泽陆蛙与水体pH值呈显著正相关。开封城市水系建设考虑两栖类生物保护,河渠建设中增加自然驳岸,对提升开封市两栖类生物多样性具有重要意义。     

坝上地区农田和恢复生境地表甲虫多样性

研究采用陷阱法对河北坝上崇礼县农田、禁牧草地及再造林地3种常见生境中地表甲虫进行了取样调查,分别从鞘翅目分科、步甲分种两个分类水平比较分析了不同生境中的生物多样性状况以评估生境恢复状况及其对生物多样性的影响,并探索在以生物多样性为指标评估生境恢复状况过程中,研究结论是否受分类水平的影响。结果显示,草地和林地具有较为相似鞘翅目和步甲的结构组成,但均显著不同于农田。农田较再造林地和禁牧草地具有更多的鞘翅目科数及步甲物种数,且均显著高于林地;农田中步甲群落的Fisher's α多样性指数也显著地高于林地,但鞘翅目分科水平上的Fisher's α多样性指数在各生境中没有差异。结果说明:(1)再造林和草地禁牧的生境修复活动在当前状态下对生物多样性恢复的作用尚不明显,仅是表现出促进了景观尺度上较高的Beta和Gamma多样性,而农田则在维持当地较高的生物多样性中扮演重要角色;(2)在鞘翅目分科和步甲科分种研究数据所反映的不同生境条件下的多样性和组成状况基本相同,因此在需要快速评估生境恢复状况且物种水平鉴定存在困难的时候,可以采用鞘翅目分科的数据替代指示生境恢复的状况并反映生境恢复对生物多样性影响的趋势,从而减少分类的难度并提高工作效率。但是物种水平的多样性状况更能显著反映生境间的差异。     

生物声音监测研究在生物多样性领域的应用

声音是生物之间交流的重要手段,对生物声音的监测与分析是描述和评估生物多样性的新兴方法。这种方法不侵入和破坏自然环境,通过声音记录生态信息,并有效反映生物多样性的相关特征,是一种重要的生态工具。从声音角度探讨生物多样性的变化拓宽了多学科交叉的新思路,因此近年来被越来越多地应用于生态学研究中。本文阐述了利用声音监测评估生物多样性的主要理论基础和研究方法,从发声动物的生物多样性、声景的时空多样性两个方面介绍了相关领域的研究进展,列举了声音监测在评估土地利用变化、气候变化和城市化对生物多样性影响的应用实例。最后,对未来研究方向进行了展望,希望能进一步挖掘声音调查的发展潜力,为生物多样性的监测评估提供有效的借鉴和参考。     

声景生态学研究进展和展望

声景生态学以景观中的声音为研究对象, 探讨其在不同时空维度上的分布和变化模式, 从而揭示自然环境、野生动物和人类活动的相互作用关系。本文通过系统检索声景生态学研究的相关文献, 回顾了该学科的研究框架和研究方法, 总结了目前常用的声学指标, 重点归纳了声景生态学的研究内容, 包括声景组成和各组分间的相互作用, 声景的时空格局, 以及声景生态学在生物多样性监测中的应用。目前, 声景监测中存在的问题主要包括监测的生态系统类型和物种类群有限、声学指标效力有待提高等。建议未来着重推进建立系统性的声景监测网络和数据管理平台, 开发和完善音频数据采集、分析方法和评估指标, 并重视声景数据的采集, 将声景视作一种资源进行研究和保护。     

Do acoustic indices correlate with bird diversity? Insights from two biodiverse regions in Yunnan Province,south China

Human activities are affecting biodiversity to a greater extent than ever. Consequently, tools that can efficiently monitor changes in communities are becoming increasingly important. In the case of birds and other vocalizing animals, it has been suggested that passive acoustic methods can be used for this purpose. Multiple acoustic indices have been developed recently, to be used as proxies for species diversity. Preliminary results have been promising. Yet, before the indices can be applied widely, it is necessary to understand better how well they reflect the communities to be monitored, and how they perform under diverse environmental conditions. Here, we tested seven of the available indices, on sound recordings made in two biodiverse regions in Yunnan Province, south China. We assessed each index’s performance by measuring its correlation to bird species richness and diversity, estimated using point-count surveys. Each survey was conducted by an expert observer, at the same time each recording was made, and for the same duration. We also tested whether the performance of the indices was affected by levels of environmental dissimilarity between the sites sampled. We found that although no index showed a very strong correlation with species richness or diversity, three indices (the acoustic entropy, acoustic diversity and acoustic evenness indices) performed consistently better that the other four, showing moderate correlations. The levels of environmental dissimilarity among the sites did not seem to affect the performance of any of the indices tested, suggesting consistency − an important property for the indices to have. We conclude that although the acoustic indices have the potential to be used for passive acoustic monitoring, perhaps they need to be refined further before they can be applied widely. Meanwhile, they should be tested in more environments to reveal fully their potential and limitations.     

Acoustic detection and acoustic habitat characterisation of the critically endangered white-bellied heron (Ardea insignis) in Bhutan

1. Growing developmental activities, such as hydropower construction, farm roads, and other human activities, are affecting the critically endangered white-bellied heron (WBH). Out of a known global population of 60, 28 individuals inhabit the river basin area and freshwater lakes and ponds of Bhutan. Several constraints impede continuous monitoring of endangered species, such as the isolated and cryptic nature of the species and the remoteness of its habitat; to date, there are no long-term reference data or techniques implemented for continuous monitoring of this species.
2. In this study, we designed acoustic detection and habitat characterisation methods using long-duration recordings from three habitat areas in Bhutan. Acoustic indices were extracted and used to implement a species-specific call detector and to generate habitat soundscape representations. Using WBH calls annotated in month-long recordings from a known site, a novel indices-based detector was implemented and tested. A total of 960 hr of continuous audio recordings from three habitats in Bhutan were analysed.
3. We found that a species call detector implemented using a combination of acoustic indices (that includes measures of spectral and temporal entropy and different angles of spectral ridges) has a correct detection rate of 81%. Additionally, visual inspection of the species’ acoustic habitat using long-duration false-colour spectrograms enabled qualitative assessment of acoustic habitat structure and other dominant acoustic events.
4. This study proposes a combined approach of species acoustic detection and habitat soundscape analysis for holistic acoustic monitoring of endangered species. As a direct outcome of this work, we documented acoustic reference data on the critically endangered WBH from multiple habitat areas and have analysed its temporal vocalisation patterns across sites.

     

Time-series forecasting offers novel quantitative measure to assess loud sound event in an urban park with restored prairie

Soundscape ecology and ecoacoustics study the spatiotemporal dynamics of a soundscape and how the dynamics reflect and influence ecological processes in the environment. Soundscape analysis methods employ acoustic recording units (ARUs) that collect acoustic data in study areas over time. Analyzing these data includes computation of several acoustic diversity indices developed to quantify species abundance, richness, or habitat condition through digital audio processing and algorithm adaptations for within-group populations. However, the success of specific indices is often dependent on habitat type and biota richness present and analyzing these data can be challenging due to temporal pseudo-replication. Time-series analytical methods address the inherent problems of temporal autocorrelation for soundscape analyses challenges. Animal population dynamics fluctuate in a variety of ways due to changes in habitat or natural patterns of a landscape and chronic noise exposure, with soundscape phenology patterns evident in terrestrial and aquatic environments. Historical phenological soundscape patterns have been used to predict expected soundscape patterns in long-term studies but limited work has explored how forecasting can quantify changes in short-term studies. We evaluate how forecasting from an acoustic index can be used to quantify change in an acoustic community response to a loud, acute noise. We found that the acoustic community of a Midwestern restored prairie had decreased acoustic community activity after a loud sound event (LSE), a Civil War Reenactment, mainly driven by observed changes in the bird community and quantified using two methods: an automated acoustic index and species richness. Time-series forecasting maybe considered an underutilized tool in analyzing acoustic data whose experimental design can be flawed with temporal autocorrelation. Forecasting using auto ARIMA with acoustic indices could benefit decision makers who consider ecological questions at different time scales.     

Acoustic communities in an environmental gradient from native to urban areas in Central Brazil

As urban areas expand due to increasing human populations, natural habitats are diminishing in quantity and quality. We conducted a study to examine the response of diurnal acoustic communities along a gradient of environments, ranging from native to dense urban areas. We hypothesized that acoustic indices would decline with urbanization, transitioning from natural and rural areas to urban environments. We conducted the research in and around Brasília, Central Brazil. We deployed 24 digital recorders in native, rural, low-density and high-density urban areas. We employed five commonly used acoustic indices (ADI, ACI, NDSI, H and BI) to characterize the acoustic communities and represent the existing biodiversity numerically. We initially compared the index values across different land use types using a non-parametric rank sum test. Subsequently, we selected eight landscape metrics and performed a principal component analysis to summarize the surrounding matrix at each sampling point. We then employed generalized linear models to determine if the acoustic indices exhibited the anticipated variations. The results indicated significant variations in all indices among the different land use types, indicating their responsiveness to distinct acoustic communities and environmental characteristics. ADI, H and NDSI exhibited declining values from native to urban areas, while ACI and BI displayed the opposite trend. These findings underscore the influence of landscape structure on acoustic indices. Consequently, we concluded that adopting appropriate landscape planning, mainly through integrating natural and urban areas, could help preserve biodiversity in tropical urban regions.     

Connecting soundscape to landscape: Which acoustic index best describes landscape configuration?

Soundscape assessment has been proposed as a remote ecological monitoring tool for measuring biodiversity, but few studies have examined how soundscape patterns vary with landscape configuration and condition. The goal of our study was to examine a suite of published acoustic indices to determine whether they provide comparable results relative to varying levels of landscape fragmentation and ecological condition in nineteen forest sites in eastern Australia. Our comparison of six acoustic indices according to time of day revealed that two indices, the acoustic complexity and the bioacoustic index, presented a similar pattern that was linked to avian song intensity, but was not related to landscape and biodiversity attributes. The diversity indices, acoustic entropy and acoustic diversity, and the normalized difference soundscape index revealed high nighttime sound, as well as a dawn and dusk chorus. These indices appear to be sensitive to nocturnal biodiversity which is abundant at night in warm, subtropical environments. We argue that there is need to better understand temporal partitioning of the soundscape by specific taxonomic groups, and this should involve integrated research on amphibians, insects and birds during a 24 h cycle. The three indices that best connected the soundscape with landscape characteristics, ecological condition and bird species richness were acoustic entropy, acoustic evenness and the normalized difference soundscape index. This study has demonstrated that remote soundscape assessment can be implemented as an ecological monitoring tool in fragmented Australian forest landscapes. However, further investigation should be dedicated to refining and/or combining existing acoustic indices and also to determine if these indices are appropriate in other landscapes and for other survey purposes.     

Assessing marine ecosystem acoustic diversity across ocean basins

Concurrent with the elevation of the concern over the state of sound in the ocean, advances in terrestrial acoustic monitoring techniques have produced concepts and tools that may be applicable to the underwater world. Several index values that convey information related to acoustic diversity with a single numeric measurement made from acoustic recordings have been proposed for rapidly assessing community biodiversity. Here we apply the acoustic biodiversity index method to low frequency recordings made from three different ocean basins to assess its appropriateness for characterizing species richness in the marine environment. Initial results indicated that raw acoustic entropy (H) values did not correspond to biological patterns identified from individual signal detections and classification. Noise from seismic airgun activity masked the weaker biological signals and confounded the entropy calculation. A simple background removal technique that subtracted an average complex spectrum characteristic of seismic exploration signals from the average spectra of each analysis period that contained seismic signals was applied to compensate for salient seismic airgun signals present in all locations. The noise compensated (H_N) entropy index was more reflective of biological patterns and holds promise for the use of rapid acoustic biodiversity in the marine environment as an indicator of habitat biodiversity and health.