Cultural Evolution In Natural Populations: A Quantitative Bioacoustic Analysis

Bird song is a powerful model system in behavioral biology, especially for learning and cultural evolution. Understanding the origins and maintenance of vocal diversity in nature is fundamentally important to acoustic biology. Here, we propose a large-scale, integrative population analysis of nearly 2000 songs of the house finch (Haemorhous mexicanus) (190 individuals) collected in western Long Island of New York during an interval of 37 years (between 1975 and 2012) to explore cultural change of bird songs. Generally, I have three aims in this study. In the chapter 1, to facilitate acoustic analysis for field recordings with ambient noise, of large sample sizes and with continuous variation, I introduce an algorithm (FinchCatcher), which extract signals from the background noise, summarizes songs as a series of spectral shapes and performs dynamic classification that optionally combine the advantages of hierarchical clustering and partitioning. I further test the algorithm on a geographical comparison of 240 songs of the house finch from eight localities, using previously published observations as ground truth for estimating transitions of song (or song element) sharing during the spread of the house finch in North America. In Chapter 2, I quantify spatial variation in the songs of the house finch in western Long Island in 2012. Previous studies have suggested large morphological and behavioural differences between house finches in the east and west coast, which may have profound impact on song evolution of eastern house finch. The result shows great acoustic variation across the sampling range, rather than finding discrete areas within which song and syllable repertoires are highly similar between individuals. Nevertheless, spatial differentiation was neither simply clinal change with geographic distance, nor discrete dialects. To further explore the mechanisms underlying cultural change in this study region, in Chapter 3 I perform a temporal comparative analysis of house finch songs spanning nearly four decades. Substantial cultural change is observed in terms of local song and syllable sharing, song complexity and song type consistency. In addition, not a single song type persists over time and half of syllable types defined in the past data are not present in the recent songs. These results illustrate the potential interplay between multiple drivers of spatial and temporal variation. This body of research has provided a framework for understanding the spatiotemporal variation in house finch song in Western Long Island, incorporating partial migration, population growth, relaxed selection by females on male song, and developmental stress playing interacting roles

Acoustic sequences in non-human animals: a tutorial review and prospectus.

Animal acoustic communication often takes the form of complex sequences, made up of multiple distinct acoustic units. Apart from the well-known example of birdsong, other animals such as insects, amphibians, and mammals (including bats, rodents, primates, and cetaceans) also generate complex acoustic sequences. Occasionally, such as with birdsong, the adaptive role of these sequences seems clear (e.g. mate attraction and territorial defence). More often however, researchers have only begun to characterise - let alone understand - the significance and meaning of acoustic sequences. Hypotheses abound, but there is little agreement as to how sequences should be defined and analysed. Our review aims to outline suitable methods for testing these hypotheses, and to describe the major limitations to our current and near-future knowledge on questions of acoustic sequences. This review and prospectus is the result of a collaborative effort between 43 scientists from the fields of animal behaviour, ecology and evolution, signal processing, machine learning, quantitative linguistics, and information theory, who gathered for a 2013 workshop entitled, 'Analysing vocal sequences in animals'. Our goal is to present not just a review of the state of the art, but to propose a methodological framework that summarises what we suggest are the best practices for research in this field, across taxa and across disciplines. We also provide a tutorial-style introduction to some of the most promising algorithmic approaches for analysing sequences. We divide our review into three sections: identifying the distinct units of an acoustic sequence, describing the different ways that information can be contained within a sequence, and analysing the structure of that sequence. Each of these sections is further subdivided to address the key questions and approaches in that area. We propose a uniform, systematic, and comprehensive approach to studying sequences, with the goal of clarifying research terms used in different fields, and facilitating collaboration and comparative studies. Allowing greater interdisciplinary collaboration will facilitate the investigation of many important questions in the evolution of communication and sociality.This review was developed at an investigative workshop, “Analyzing Animal Vocal Communication Sequences” that took place on October 21–23 2013 in Knoxville, Tennessee, sponsored by the National Institute for Mathematical and Biological Synthesis (NIMBioS). NIMBioS is an Institute sponsored by the National Science Foundation, the U.S. Department of Homeland Security, and the U.S. Department of Agriculture through NSF Awards #EF-0832858 and #DBI-1300426, with additional support from The University of Tennessee, Knoxville. In addition to the authors, Vincent Janik participated in the workshop. D.T.B.’s research is currently supported by NSF DEB-1119660. M.A.B.’s research is currently supported by NSF IOS-0842759 and NIH R01DC009582. M.A.R.’s research is supported by ONR N0001411IP20086 and NOPP (ONR/BOEM) N00014-11-1-0697. S.L.DeR.’s research is supported by the U.S. Office of Naval Research. R.F.-i-C.’s research was supported by the grant BASMATI (TIN2011-27479-C04-03) from the Spanish Ministry of Science and Innovation. E.C.G.’s research is currently supported by a National Research Council postdoctoral fellowship. E.E.V.’s research is supported by CONACYT, Mexico, award number I010/214/2012.This is the accepted manuscript. The final version is available at http://dx.doi.org/10.1111/brv.1216

Data from: Four decades of cultural evolution in House Finch songs

Bird song is the primary animal model system for cultural evolution. Longitudinal studies of bird song across many generations can provide insights into patterns and mechanisms of change in socially transmitted traits. In this study, we conducted a comparative analysis of songs of the House Finch (Haemorhous mexicanus) across an interval of 37 years (in 1975 and in 2012). Recordings from both years were collected in western Long Island, New York, which is thought to be the initial site of introduction of the House Finch around 1940 from the West Coast. Song types experienced a complete turnover during this period, although half of the syllable types were represented in both samples. Song length, frequency bandwidth and several other spectrographic features were the same in both years, and no structural features predicted recurrence of individual syllables. Consistent with the fact that our study population expanded substantially following a cultural founder effect, song and syllable sharing and similarity between individuals were lower in 2012 than in 1975, reflecting an increase in song diversity at the population level. However, in the more recent sample individual songs had fewer syllables, and were sung with less sequence stereotypy across renditions than in the earlier sample. Syllable prevalence in 2012 was associated both with complexity (as gauged by frequency excursion) and increased minimum frequency. Thus, over nearly 4 decades, Eastern House Finch songs remained structurally similar at the whole-song level, diversified between individuals, but became simpler and less consistent within an individual

Long‐term, amplified responses of soil organic carbon to nitrogen addition worldwide

Soil organic carbon (SOC) is the largest carbon sink in terrestrial ecosystems and plays a critical role in mitigating climate change. Increasing reactive nitrogen (N) in ecosystems caused by anthropogenic N input substantially affects SOC dynamics. However, uncertainties remain concerning the effects of N addition on SOC in both organic and mineral soil layers over time at the global scale. Here, we analyzed a large empirical data set spanning 60 years across 369 sites worldwide to explore the temporal dynamics of SOC to N addition. We found that N addition significantly increased SOC across the globe by 4.2% (2.7–5.8%). SOC increases were amplified from short- to long-term N addition durations in both organic and mineral soil layers. The positive effects of N addition on SOC were independent of ecosystem types, mean annual temperature and precipitation. Our findings suggest that SOC increases largely resulted from the enhanced plant C input to soils coupled with reduced C loss from decomposition and amplification was associated with reduced microbial biomass and respiration under long-term N addition. Our study suggests that N addition will enhance SOC sequestration over time and contribute to future climate change mitigation.This is the peer reviewed version of the following article: Xu, Chonghua, Xia Xu, Chenghui Ju, Han YH Chen, Brian J. Wilsey, Yiqi Luo, and Wei Fan. "Long‐term, amplified responses of soil organic carbon to nitrogen addition worldwide." Global Change Biology (2020), which has been published in final form at doi:10.1111/gcb.15489. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Use of Self-Archived Versions.</p

CEPC Conceptual Design Report: Volume 2 - Physics & Detector

The Circular Electron Positron Collider (CEPC) is a large international scientific facility proposed by the Chinese particle physics community to explore the Higgs boson and provide critical tests of the underlying fundamental physics principles of the Standard Model that might reveal new physics. The CEPC, to be hosted in China in a circular underground tunnel of approximately 100 km in circumference, is designed to operate as a Higgs factory producing electron-positron collisions with a center-of-mass energy of 240 GeV. The collider will also operate at around 91.2 GeV, as a Z factory, and at the WW production threshold (around 160 GeV). The CEPC will produce close to one trillion Z bosons, 100 million W bosons and over one million Higgs bosons. The vast amount of bottom quarks, charm quarks and tau-leptons produced in the decays of the Z bosons also makes the CEPC an effective B-factory and tau-charm factory. The CEPC will have two interaction points where two large detectors will be located. This document is the second volume of the CEPC Conceptual Design Report (CDR). It presents the physics case for the CEPC, describes conceptual designs of possible detectors and their technological options, highlights the expected detector and physics performance, and discusses future plans for detector R&D and physics investigations. The final CEPC detectors will be proposed and built by international collaborations but they are likely to be composed of the detector technologies included in the conceptual designs described in this document. A separate volume, Volume I, recently released, describes the design of the CEPC accelerator complex, its associated civil engineering, and strategic alternative scenarios