The use of acoustic analyses to evaluate ecological and social impacts of habitat degradation in contemporary conservation biology

Overexploitation of the earth’s resources is causing concern for ecosystem health globally and demands clear strategies for biodiversity conservation. The development of non-invasive and cost-effective tools for ecosystem assessment is an urgent global imperative. In this context, the nascent discipline of ecoacoustics provides a new framework to assess the effects of habitat degradation on human and non-human populations. Sound is considered as a core component and indicator of ecological processes and therefore can be investigated to infer ecological information about populations, communities and landscapes. A subfield of this discipline, soundscape ecology, provides fresh perspectives on understanding coupled natural-human dynamics. Despite the contributions of ecoacoustic methods in biodiversity assessment, landscape ecology and conservation biology some factors are constraining their full potential. This is principally due to challenges in interpreting the acoustic community through current acoustic metrics. Moreover, research gaps in understanding coupled natural-human dynamics through soundscape analysis have been identified, which could make significant further contributions to conservation biology in the near future. This thesis contributes to ecoacoustics from the perspective of conservation biology. The relevance and potential use of acoustic methods for assessing biodiversity and exploring social dimensions within conservation biology are presented throughout. Chapters include both Ecological and Social research components. A systematic review of publications on soundscape and its association with ecological and human wellbeing contextualizes the following empirical work, in chapter 1. Chapter 2 provides an evaluation into how effectively current acoustic metrics (ACI, BI, AE and H) reflect the status of wildlife populations along a gradient of forest disturbance. A novel approach to rapidly assess habitat status using automatic detection of indicator species (IS) is presented in chapter 3. Empirical studies are complemented by an analysis of the cost-effectiveness of acoustic sensors for assessing biodiversity, in chapter 4. Finally, social factors are addressed in chapter 5, which presents a novel approach for evaluating the human and environment relationship through soundscape perception analysis. The acoustic analyses explored show potential in analysis of ecological and social research dimensions in conservation biology. The systematic review shows that soundscape, and its association with wellbeing, evolved from an interest in sounds, and their influence on health, into a multidimensional and integrative concept incorporating multiple domains of wellbeing (Health, Social and Cultural Wellness and Ecological Integrity). Within the Ecological component in chapter 2, although significant differences in acoustic biodiversity metrics along sites were found, relevant qualitative biodiversity values that describe the status of wildlife populations were not reflected through the acoustic indices. To tackle this issue, I observed that the tool for automatic detection of IS was effective for rapid evaluation of habitat status; however, it should only be used for obtaining data of presence/absence of species. The combination of community level (acoustic indices) and individual level (automatic detection of indicator species) acoustic analysis showed a great potential as a tool for rapid evaluation of habitats. Moreover, I found that use of acoustic sensors was effective for registering high number of birds and indicator species; however, it is best applied in conducting multiple surveys or long term monitoring due to expensive equipment costs. Within the Social component I observed that soundscape perception analysis generated insights into human-environment relationships and highlighted the implications of habitat degradation on humans. Sounds of social relevance were also identified, which could be used for determining priority areas for conservation. Great potential for investigating social implications of habitat degradation through acoustic methods was revealed. The acoustic approaches investigated proved to be useful tools in understanding the dynamics of ecosystems, by exploring both ecological and social dimensions, and contribute to knowledge in conservation biology. Further research on the application of acoustic methods in conservation biology is recommended.