1,721,012 research outputs found
Improved timber harvest techniques maintain biodiversity in tropical forests
Full text linkTropical forests are selectively logged at 20 times the rate at which they are cleared, and at least a fifth have already been disturbed in this way. In a recent pan-tropical assessment, Burivalova et al. demonstrate the importance of logging intensity as a driver of biodiversity decline in timber estates. Their analyses reveal that species richness of some taxa could decline by 50% at harvest intensities of 38 m3 ha-1. However, they did not consider the extraction techniques that lead to these intensities. Here, we conduct a complementary meta-analysis of assemblage responses to differing logging practices: conventional logging and reduced-impact logging. We show that biodiversity impacts are markedly less severe in forests that utilise reduced-impact logging, compared to those using conventional methods. While supporting the initial findings of Burivalova et al., we go on to demonstrate that best practice forestry techniques curtail the effects of timber extraction regardless of intensity. Therefore, harvest intensities are not always indicative of actual disturbance levels resulting from logging. Accordingly, forest managers and conservationists should advocate practices that offer reduced collateral damage through best practice extraction methods, such as those used in reduced-impact logging. Large-scale implementation of this approach would lead to improved conservation values in the 4 million km2 of tropical forests that are earmarked for timber extraction
Impact, evaluation, and mitigation of linear infrastructure development on primates in Diani, Kenya
Full text linkRoads and electrical infrastructure are essential for achieving the United Nations Sustainable Development Goals. Twenty-five million kilometres of new roads are expected to be built globally by 2050, and governments are targeting universal access to electricity. However, linear infrastructure is known to have devasting impacts on wildlife including a wide range of non-human primates. Yet, the effects and the complex interactions between these various impacts are often overlooked, particularly in urban environments. This thesis examines the effects of roads and power lines on six primate species in Diani, a town in southeastern Kenya where development is interspersed with forest patches of a Global Biodiversity Hotspot. The research draws on 25 years of data on primate populations and cases of injury and death, collected by Colobus Conservation, a local conservation organisation. The data show that colobus monkeys suffer significant losses, with approximately 8% of the population affected annually due to vehicle collisions and electrocutions. Sykes' monkeys, vervets, and baboons experience sustainable losses (3.3%, 2.0%, and 1.8%, respectively), but these still represent over 1,000 individuals reported injured or killed since the organisation's inception in 1997. The impact on two species of galagos remains uncertain. This study highlights key ecological factors that influence species' vulnerability to roads and power lines, with arboreal species at higher risk on roads than more terrestrial species and larger individuals of arboreal species are at higher risk on power lines. The efficacy of canopy bridges in mitigating the road barrier effect and primate-vehicle collisions was assessed and shown to be successful and cost-effective overall. In addition, this research highlights that a commonly used approach to quantify the number of wildlife-vehicle collisions and electrocutions-carcass surveys-underestimate the true scale, because injured individuals who survive the initial impact make up a significant proportion of total collisions. This thesis found that correction factors of 1.5 for vehicle collisions and 2.15 for electrocutions are needed to improve carcass survey estimates. Regarding power lines, Diani's growth has not led to an increase in electrocution cases, indicating that the mitigation strategies of trimming vegetation near power lines and insulating cables are effective. Overall, this thesis calls for the protection of wildlife to be explicitly considered in road and electricity infrastructure planning by using the findings of this and previous research
The benefits of biodiversity: Human-wildlife interactions in urban Guyana
Full text linkWorldwide, human populations are growing, the climate is changing, and natural habitat is being converted to alternative land-uses. In particular, urbanisation has both positive and negative implications for society and biodiversity conservation. Within cities, there is increasing evidence that green (e.g. parks, gardens) and blue spaces (e.g. rivers, coast) can benefit human subjective wellbeing by restoring attentional fatigue and reducing stress, while also providing resources to support biodiversity. However, it remains unclear how biodiversity, and other specific features of urban green and blue spaces, enhance or detract from wellbeing. These details are crucial to informing land-use management and policy decisions in towns and cities. Much of the existing evidence originates from the global North, despite biodiversity loss, population growth, and urbanisation rates accelerating in the global South. Drawing on theories and methods from multiple disciplines, this thesis empirically explores relationships between green and blue spaces and human wellbeing in Georgetown, the capital city of Guyana. This biodiversity-rich country in northern South America has the highest rate of suicide worldwide and is poised to transform due to the discovery of vast quantities of off-shore oil. First, I expose a dose-response relationship between patterns of visitor use to urban green and blue spaces and experiential wellbeing, finding that age, safety concerns, and nature-relatedness dictate patterns of use. Second, I show that green and coastal blue spaces are important for bird diversity and human wellbeing respectively, although the two do not relate. Third, I assess how human perceptions of bird diversity, naturalness, sounds, and safety affect wellbeing, influenced by how restorative these spaces are perceived to be. Finally, I use participatory video to triangulate earlier findings, discovering that biodiversity provides a multisensory experience, with place attachment, personal insecurity, and cultural beliefs contributing to wellbeing in green and coastal blue space. This interdisciplinary thesis makes important empirical contributions to the field of biodiversity-wellbeing research, representing the first evidence gathered from neotropical South America. Overall, my results provide a valuable evidence-base to inform the development of interventions (e.g. targeted public health and educational campaigns) in biodiversity-rich cities like Georgetown. From a wider perspective, these findings could be harnessed by policy-makers striving to meet international targets on sustainability while maximising human quality of life at a national scale
The use of acoustics for monitoring tropical bats in Southeast Asia
Full text linkHalting the loss of biodiversity is one of our century's greatest challenges. In Southeast Asia, the biodiversity crisis is driven by unprecedented rates of forest clearance and degradation. Here, conservation efforts face the inherent complexity of trying to protect species in landscapes that also support human livelihoods. Most of our understanding of how bats are affected by land-use change in the tropics is limited to those species which can be monitored using live-trapping techniques. However, acoustic monitoring is an important survey method for monitoring the whole bat community in other regions of the world. In this thesis, advanced technological and statistical approaches are used to investigate how tropical bats respond to land-use change in Borneo. Specifically, the thesis explores the application of acoustic monitoring for bats in this region.
In the first chapter, I outline how conservation zoning can be effective at protecting tropical bat diversity. To do so, I use a combination of live-trapping and acoustic monitoring to assess bat diversity and activity within The Crocker Range Biosphere Reserve compared to the surrounding agriculture. This includes demonstrating how acoustic data can be used to analyse differences in bat activity between habitats, even if it is not possible to classify calls to sonotype/species. Namely, this research highlights the importance of strict protective zones for conserving forest specialist species.
Next, I refine the bat call classification process by using acoustic data manually classified sonotype/species to assess the value of conservation set-asides. These data were combined with forest structural metrics measured using airborne LiDAR to assess the effectiveness of riparian reserves (areas of native forest along waterways) for conserving bats in oil-palm landscapes. Using Bayesian occupancy modelling, I demonstrate how - unlike other components of tropical biodiversity - forest quality is more important than riparian reserve width for maintaining suitable habitat for bats. This provides important evidence for designing effective conservation policies for tropical mammals. The lack of reference call libraries and automated classification tools in Southeast Asia impedes ongoing acoustic monitoring for bats in this region. Acoustic monitoring generates large datasets - often approaching the scale of big data - which requires time and expertise to manually process. These costs limit the application of bioacoustics as a feasible method for monitoring bats in tropical regions, not least in Southeast Asia - thus, limiting our understanding of how bat communities persist in human-modified landscapes. Therefore, for the third data chapter, I focus on developing a semi-automated framework for classifying bat calls in Southeast Asia when reference libraries may be limited. As proof of concept, this viii framework is then used to develop a classifier for the bats of Borneo using reference calls for 52% of all 81 known echolocating species on the island. This classifier was developed using free software to ensure the same framework could be applied to other regions of Southeast Asia.
Last, I apply the newly-developed classifier to examine patterns of bat activity in response to habitat disturbance at the Stability of Altered Forest Ecosystems Project in Sabah. The data used in this assessment represented a seven-fold increase in the number of recording hours compared to the combined effort of the previous studies. This acoustic dataset is combined with forest structural metrics measured using airborne LiDAR to assess responses across a gradient of habitat disturbance - comprising old-growth forest, logged forest, and monoculture tree plantations. In this chapter, I demonstrate how logged forests can provide important habitat for bats in human-modified landscapes, maintaining acoustic diversity and activity of many common species, particularly when compared to tree plantations. However, I also demonstrate how old-growth forest remains important for conserving forest specialist species.
Collectively, in this thesis, I document how bats can benefit from conservation initiatives that protect landscape features within human-modified landscapes. Crucially however, I also demonstrate that as disturbance intensity increases, less resilient species are lost from humanmodified landscapes. Whilst I provide important empirical contributions for understanding bat responses to disturbance, there remain substantial questions about how best to conserve these species and promote sustainable land use. The pipeline and classifier provided in this thesis will help improve accessibility for future acoustic studies to address these questions in Borneo and other areas of Southeast Asia. Therefore, the findings and resources presented here are an important step towards evidence-based land management for conserving Southeast Asian bats in human-modified landscapes
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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