Avian communities and ecoacoustics in a tropical human-modified landscape

Large areas of the tropics have been cleared of forest and converted to agriculture. The consequent human-modified landscapes (HMLs) comprise a heterogenous mix of habitats; forest fragments and riparian strips are embedded in a matrix of cattle pasture, non-native timber plantations, and urban centres. These habitat changes can have dramatic consequences for wildlife, leading to range shifts and extirpations. In turn, this can influence the integrity of ecosystem services such as frugivory and seed dispersal. Understanding how habitat conversion affects natural ecosystems is critical to inform conservation interventions, but requires long-term biodiversity monitoring and detailed knowledge of species-level responses to HMLs. The research presented in this thesis was conducted in the Emparador HML, in central Republic of Panama. In Chapter 2, we show that the regional avian community is shaped by extent of forest cover across the landscape, and to a lesser degree, extent of forest fragmentation and distance to core forest. Effects of forest cover and fragmentation were examined at local (10 ha) and landscape (500 ha) scales. Species-level responses to these factors varied widely; while abundance of many species increased with greater local-scale forest cover, greater landscape-scale forest cover was often associated with declines. Generalist species that readily persist in HMLs still responded positively to local-scale forest cover, suggesting that even smaller forest fragments in these landscapes are important for maintaining diverse avian assemblages. Critically, we found that species’ responses were not associated with particular traits such as dietary composition or forest dependence, highlighting that species may often exhibit idiosyncratic responses to landscape structure. Chapters 3 and 4 address the wider issue of long-term monitoring, and the potential for data collection over large spatiotemporal scales using remote audio recorders. Ecoacoustics, the study of environmental sound is a relatively new discipline, and as such there is still considerable uncertainty surrounding best-practice for collecting and processing recordings. One of the most straightforward means of utilising audio recordings for environmental monitoring is via acoustic indices. These are objective measures of sound based on features such as pitch and amplitude. To date, attempts to use these indices have been hindered by inconsistent or inappropriate methodologies. In Chapter 3, we determine how many recordings are required to comprehensively capture a soundscape, the acoustic energy of a location. Furthermore, we demonstrate that there are habitat-specific patterns in acoustic indices values, suggesting that these indices reflect differences in vegetation structure and wildlife. We develop this further in Chapter 4, where we show that avian species richness and abundance are clearly linked to patterns in acoustic indices values. Critically, these patterns were coherent among habitat types emphasising their potential for monitoring. Acoustic indices sensitive to the frequencies occupied by bird song have the greatest potential for monitoring an avian community. The results from these two chapters suggest that acoustic indices can be effective tools for monitoring biodiversity, with values reflecting consistent differences across habitats, and among avian assemblages. Audio recordings are a source of permanent, verifiable evidence that can be collected at much greater spatiotemporal scales than traditional biodiversity monitoring data. As the use of audio recorders grows, it is important to compare their efficacy with standard methods of data collection. In Chapter 5, we contrast data derived from audio recordings with that gathered using standard point count methods, and consider whether recorders are a feasible means of surveying antbirds (Thamnophilidae), a disturbance-sensitive avian taxon. Both approaches revealed species’ responses to landscape structure, with qualitatively similar patterns in response to forest cover and vegetation quality. We show that common species can be readily monitored using audio recorders, with greater levels of detectability compared with point counts. However, rarer species were more likely to be detected using point counts. The work presented in this thesis helps to explain the patterns seen in avian responses to Neotropical HMLs. In particular we emphasise the importance of forest cover for maintaining bird assemblages in these landscapes. We demonstrate the utility of audio recorders for data collection, and highlight their potential for future biodiversity monitoring. In the face of human population growth, and ongoing habitat disturbance and agricultural intensification, conservation efforts are essential to avoid widespread species extinctions and ecosystem collapse. Interventions must take place in HMLs, to bolster ecosystem services, provide buffer zones for protected areas, and improve connectivity in the wider landscape

Using acoustic indices in ecology : guidance on study design, analyses and interpretation

TBL was supported by Leverhulme Trust, research grant number RPG-2020-160; the Lorentz Centre, Leiden, The Netherlands; and UKAN+. AE and OM were supported by UKAN+.The rise of passive acoustic monitoring and the rapid growth in large audio datasets is driving the development of analysis methods that allow ecological inferences to be drawn from acoustic data. Acoustic indices are currently one of the most widely applied tools in ecoacoustics. These numerical summaries of the sound energy contained in digital audio recordings are relatively straightforward and fast to calculate but can be challenging to interpret. Misapplication and misinterpretation have produced conflicting results and led some to question their value. To encourage better use of acoustic indices, we provide nine points of guidance to support good study design, analysis and interpretation. We offer practical recommendations for the use of acoustic indices in the study of both whole soundscapes and individual taxa and species, and point to emerging trends in ecoacoustic analysis. In particular, we highlight the critical importance of understanding the links between soundscape patterns and acoustic indices. Acoustic indices can offer insights into the state of organisms, populations, and ecosystems, complementing other ecological research techniques. Judicious selection, appropriate application and thorough interpretation of existing indices is vital to bolster robust developments in ecoacoustics for biodiversity monitoring, conservation and future research.Publisher PDFPeer reviewe

The potential contribution of terrestrial nature-based solutions to a national ‘net zero’ climate target

1. Many national governments have incorporated nature-based solutions (NbS) in their plans to reduce net greenhouse gas emissions. However, uncertainties persist regarding both feasibility and consequences of major NbS deployment. Using the United Kingdom as a national-level case study, we examined the potential contribution of three terrestrial NbS: peatland restoration, saltmarsh creation and woodland creation. 2. While there is substantial political and societal interest in these three NbS, they also have strong potential for competition with other land uses, which will be a critical barrier to substantial deployment. We conducted a national mapping exercise to assess the potential area available for woodland creation. We then assessed the combined climate change mitigation potential to 2100 for the three NbS options under a range of ambition levels. 3. In line with the most ambitious targets examined, 2 Mha of land is potentially available for new woodland. However, climate change mitigation benefits of woodland are strongly dependent on management choices. By 2100, scenarios with a greater proportion of broadleaved woodlands outsequester non-native conifer plantations, which are limited by regular timber harvesting. 4. Peatland restoration offers the greatest mitigation per unit area, whilst the contribution from saltmarsh creation is limited by the small areas involved. Overall, the contribution of these NbS to the United Kingdom’s net zero emissions target is relatively modest. Even with the most ambitious targets considered here, by 2100, the total cumulative mitigation from the three NbS is equivalent to only 3 years' worth of UK emissions at current levels. 5. Policy implications. Major deployment of nature-based solutions (NbS) is possible in the United Kingdom but reaching ‘net zero’ primarily requires substantial and sustained reductions in fossil fuel use. However, facilitating these NbS at the national scale could offer many additional benefits for people and biodiversity. This demands that policy-makers commit to a UK-wide strategic approach that prioritises the ‘nature’ aspect of NbS. In the push to reach ‘net zero’, climate change mitigation should not be used to justify land management practices that threaten biodiversity ambitions

Spatially targeted nature-based solutions can mitigate climate change and nature loss but require a systems approach

Funding Information: This study was funded by the Royal Society for the Protection of Birds (RSPB) and Natural England (project code ECM 58632). The Breeding Bird Survey is a Partnership between the BTO, RSPB, and Joint Nature Conservation Committee (on behalf of Natural Resources Wales, Natural England, Council for Nature Conservation and Countryside, and NatureScot) and relies on volunteer surveyors. Simon Gillings provided tetrad-level predictions of relative abundance for wading birds. We are grateful to members of the RSPB steering group, who contributed to the development of our scenarios, and Profs. Tim Benton and Andrew Balmford who commented on an earlier version of this manuscript. Conceptualization, T.F. R.B.B. T.B.-L. G.M.B. W.J.P. and R.H.F.; methodology, T.F. T.B.-L. J.P.C. D.M. P.S. and R.H.F.; software, T.F.; formal analysis, T.F.; resources, D.M.; data curation, T.F.; writing – original draft, T.F.; writing – review & editing, R.B.B. T.B.-L. G.M.B. J.P.C. D.M. P.S. W.J.P. and R.H.F.; visualization, T.F.; supervision, W.J.P. The authors declare no competing interests. Publisher Copyright: © 2023 The AuthorsPeer reviewedPublisher PD

Modelling the potential non-breeding distribution of Spoon-billed Sandpiper Calidris pygmaea

SummaryThe Spoon-billed Sandpiper Calidris pygmaea is a ‘Critically Endangered’ migratory shorebird. The species faces an array of threats in its non-breeding range, making conservation intervention essential. However, conservation efforts are reliant on identifying the species’ key stopover and wintering sites. Using Maximum Entropy models, we predicted Spoon-billed Sandpiper distribution across the non-breeding range, using data from recent field surveys and satellite tracking. Model outputs suggest only a limited number of stopover sites are suitable for migrating birds, with sites in the Yellow Sea and on the Jiangsu coast in China highlighted as particularly important. All the previously known core wintering sites were identified by the model including the Ganges-Brahmaputra Delta, Nan Thar Island and the Gulf of Mottama. In addition, the model highlighted sites subsequently found to be occupied, and pinpointed potential new sites meriting investigation, notably on Borneo and Sulawesi, and in parts of India and the Philippines. A comparison between the areas identified as most likely to be occupied and protected areas showed that very few locations are covered by conservation designations. Known sites must be managed for conservation as a priority, and potential new sites should be surveyed as soon as is feasible to assess occupancy status. Site protection should take place in concert with conservation interventions including habitat management, discouraging hunting, and fostering alternative livelihoods.Field surveys in Russian non-breeding grounds were supported by RSPB, MHS and NABU. Field surveys in Gulf of Mottama partly supported by BBC Wildlife Fund. Satellite tagging data collection partly supported by The Biodiversity Investigation, Observation and Assessment Program (2019 - 2023) of the Ministry of Ecology and Environment of China, RSPB and a private donor. Bangladesh Spoon-billed Sandpiper Conservation Project’s fieldwork in Meghna Estuary (2015 - 2016) supported by RSPB. Data collection by EL partly supported by Basic research program (budgetary funds), projects number АААА-А19-119022190168-8 and АААА-А19-119021990093-8). PT supported by Moscow State University Grant for Leading Scientific Schools "Depository of the Living Systems" in the MSU Development Program framework. TBL was funded by the Natural Environment Research Council UK, and the IAPETUS Doctoral Training Partnership

Listening to tropical forest soils

Acoustic monitoring has proven to be an effective tool for monitoring biotic soundscapes in the marine, terrestrial, and aquatic realms. Recently it has been suggested that it could also be an effective method for monitoring soil soundscapes, but has been used in very few studies, primarily in temperate and polar regions. We present the first study of soil soundscapes using passive acoustic monitoring in tropical forests, using a novel analytical pipeline allowing for the use of in-situ recording of soundscapes with minimal soil disturbance. We found significant differences in acoustic index values between burnt and unburnt forests and the first indications of a diel cycle in soil soundscapes. These promising results and methodological advances highlight the potential of passive acoustic monitoring for large-scale and long-term monitoring of soil biodiversity. We use the results to discuss research priorities, including relating soil biophony to community structure and ecosystem function, and the use of appropriate hardware and analytical techniques

Characterising soundscapes across diverse ecosystems using a universal acoustic feature set

Natural habitats are being impacted by human pressures at an alarming rate. Monitoring these ecosystem-level changes often requires labor-intensive surveys that are unable to detect rapid or unanticipated environmental changes. Here we have developed a generalizable, data-driven solution to this challenge using eco-acoustic data. We exploited a convolutional neural network to embed soundscapes from a variety of ecosystems into a common acoustic space. In both supervised and unsupervised modes, this allowed us to accurately quantify variation in habitat quality across space and in biodiversity through time. On the scale of seconds, we learned a typical soundscape model that allowed automatic identification of anomalous sounds in playback experiments, providing a potential route for real-time automated detection of irregular environmental behavior including illegal logging and hunting. Our highly generalizable approach, and the common set of features, will enable scientists to unlock previously hidden insights from acoustic data and offers promise as a backbone technology for global collaborative autonomous ecosystem monitoring efforts

Measuring the intensity of conflicts in conservation

Conflicts between the interests of biodiversity conservation and other human activities pose a major threat to natural ecosystems and human well‐being, yet few methods exist to quantify their intensity and model their dynamics. We develop a categorization of conflict intensity based on the curve of conflict, a model originally used to track the escalation and deescalation of armed conflicts. Our categorization assigns six intensity levels reflecting the discourse and actions of stakeholders involved in a given conflict, from coexistence or collaboration to physical violence. Using a range of case studies, we demonstrate the value of our approach in quantifying conflict trends, estimating transition probabilities between conflict stages, and modeling conflict intensity as a function of relevant covariates. By taking an evidence‐based approach to quantifying stakeholder behavior, the proposed framework allows for a better understanding of the drivers of conservation conflict development across a diverse range of socioecological scenarios

The Acoustic Index User’s Guide: A practical manual for defining, generating and understanding current and future acoustic indices

1. Ecoacoustics, the study of environmental sound, is a rapidly growing discipline offering ecological insights at scales ranging from individual organisms to whole ecosystems. Substantial methodological developments over the last 15 years have streamlined extraction of ecological information from audio recordings. One widely used set of methods are acoustic indices, which offer numerical summaries of the spectral, temporal and amplitude patterns in audio recordings. 2. Currently, the specifics of each index’s background, methodology, and the soundscape patterns they are designed to summarise, are spread across multiple sources. Critically, details of index calculation are sometimes scarce, making it challenging for users to understand how index values are generated. Discrepancies in understanding can lead to misuse of acoustic indices or reporting of spurious results. This hinders ecological inference, replicability, and discourages adoption of these tools for conservation and ecosystem monitoring, where they might otherwise provide useful insight.  3. Here we present the Acoustic Index User’s Guide - an interactive RShiny web app that defines and deconstructs eight of the most commonly used acoustic indices to facilitate consistent application across the discipline. We break the acoustic indices calculations down into easy-to-follow steps to better enable practical application and critical interpretation of acoustic indices. We demonstrate typical soundscape patterns using a suite of 91 example audio recordings: 66 real-world soundscapes from terrestrial, aquatic, and subterranean systems around the world, and 25 synthetic files demonstrating archetypal soundscape patterns. Our interpretation figures signpost specific soundscape patterns likely to be reflected in acoustic indices’ values. 4. This RShiny app is a living resource; additional acoustic indices will be added in the future through collaboration with authors of pre-existing and new indices. The app also serves as a best-practice template for the information required when publishing new acoustic indices, so that authors can facilitate the widest possible understanding and uptake of their indices. In turn, improved understanding of acoustic indices will aid effective hypothesis generation, application, and interpretation in ecological research, ecosystem monitoring, and conservation management.Additional authors: Magnus Janson, Thomas Luypaert, Oliver C. Metcalf, Anna E. Nousek-McGregor, Frederica Poznansky, Samuel R. P.-J. Ross, Sarab Sethi, Siobhan Smyt

Modeling the potential distribution of the threatened Grey-necked Picathartes Picathartes oreas across its entire range

Understanding the distribution and extent of suitable habitats is critical for the conservation of endangered and endemic taxa. Such knowledge is limited for many Central African species, including the rare and globally threatened Grey-necked Picathartes Picathartes oreas, one of only two species in the family Picathartidae endemic to the forests of Central Africa. Despite growing concerns about land-use change resulting in fragmentation and loss of forest cover in the region, neither the extent of suitable habitat nor the potential species’ distribution is well known. We combine 339 (new and historical) occurrence records of Grey-necked Picathartes with environmental variables to model the potential global distribution. We used a Maximum Entropy modelling approach that accounted for sampling bias. Our model suggests that Grey-necked Picathartes distribution is strongly associated with steeper slopes and high levels of forest cover, while bioclimatic, vegetation health, and habitat condition variables were all excluded from the final model. We predicted 17,327 km2 of suitable habitat for the species, of which only 2,490 km2 (14.4%) are within protected areas where conservation designations are strictly enforced. These findings show a smaller global distribution of predicted suitable habitat forthe Grey-necked Picathartes than previously thought. This work provides evidence to inform a revision of the International Union for Conservation of Nature (IUCN) Red List status, and may warrant upgrading the status of the species from “Near Threatened” to “Vulnerable”