Biology subjects

Perez-Granados, C.

Publications and source records attributed to Perez-Granados, C..

7 recordsLinked to original sources

bioRxiv2026

Assessing the impact of spatial and temporal filters on BirdNET performance for monitoring bird communities

Recent advances in automated technologies, such as passive acoustic monitoring, provide a powerful framework for surveying bird communities at broad spatial scales. Among the most widely used artificial intelligence tools for automated bird sound recognition is BirdNET, which can identify over 6,000 species worldwide. However, the effects of key user-defined settings, such as species filtering, remain poorly evaluated. Here, we assess how alternative species-filtering strategies influence BirdNET performance in describing bird communities worldwide. We analysed 5,047 minutes of sound recordings from 72 locations worldwide, comprising 1,192 bird species identified by expert ornithologists. We compared three common species-filtering approaches applied in BirdNET workflows to post-process its output: no filtering, spatial filtering (species present all-year at a given location), and spatio-temporal filtering (species present at a given location and week). The unfiltered approach maximised BirdNET species detection (recall) but suffered very low precision (had many misidentifications) and poor overall performance. In contrast, the other two filtering strategies greatly improved precision and overall performance, despite moderate reductions in recall. Among them, spatio-temporal filtering consistently achieved the best performance across most datasets and regions globally. Within this optimal filtering approach, we also evaluated the role of another parameter: occurrence probability thresholds. Intermediate values of this threshold (around 0.05) maximized BirdNET performance in community-level analyses. Our results demonstrate that species filtering is a key but often underappreciated component of BirdNET workflows. We hope our findings may guide future studies in selecting optimal species filters, while emphasising that filtering selection should be guided by study objectives and data context.

ecology↗

bioRxiv2026

Overcoming software bottlenecks for scalable passive acoustic monitoring: insights from a global expert assessment

1.Passive acoustic monitoring (PAM) enables non-invasive sampling of wildlife across broad spatial, temporal and taxonomic scales. Its ongoing and widespread use has generated unprecedented volumes of acoustic data, shifting the primary bottleneck from data collection to the storage, processing, integration, and interpretation of PAM outputs. Although many software tools exist to address these challenges, differences in their design, scope, and usability often create fragmented and complex analytical workflows. To identify the key barriers and opportunities shaping the implementation of PAM surveys, we conducted a structured expert solicitation involving 30 international practitioners working across terrestrial and aquatic ecosystems. Experts identified and ranked their most critical pain points in current PAM workflows, spanning data storage, processing, and interpretation. The top challenge identified related to accurate species identification using deep learning and artificial intelligence (AI) models, especially in noisy soundscapes or for underrepresented taxa. Eight additional priority challenges included workflow fragmentation, limited availability of user-friendly analytical and visualisation tools, uneven access to software, manual validation bottlenecks, computational constraints, and difficulties in data handling, standardisation, and sharing. Participants also proposed practical mitigation strategies for these priority challenges, supported by step-by-step guidance to help overcome key barriers. Together, these insights provide a roadmap toward more scalable, open-access, and collaborative software systems, which are increasingly essential to realise the full potential of PAM in global biodiversity monitoring.

ecology↗

bioRxiv2025

Unique rhythmic signatures in arrhythmic birdsong

Animal rhythms are gaining increasing attention in the studies of behaviour and musicology. Recently, it has been shown that rhythm itself can be used as an information coding channel. Now we ask: does this hold true for arrhythmic sequences? To answer that, we analysed songs of the tawny pipits (Anthus campestris), migratory songbirds known for their simple songs. Using focal recordings of 384 individuals from six populations collected across their European breeding range, we calculated an extensive set of rhythmic and temporal indices to describe each song. First, the pattern of these songs was inspected and shown to be arrhythmic. Second, songs belonging to specific individuals and populations were compared using permuted discriminant function analysis and supervised uniform manifold approximation and projection. To describe the level of individuality of the rhythmic structure alone, we calculated Beechers statistic for all songs, as well as the potential of identity coding for each parameter separately. We show that tawny pipit males sing using individual rhythmic patterns in their arrhythmic songs, and that modern rhythmic indices, such as beat precision and integer ratios, are among some of the most individually distinct parameters of their songs. Furthermore, contrary to previous investigations based on the spectral shape and basic frequency and temporal characteristics of these songs, we show that the species displays population-specific temporal patterns, with significant differences throughout its European range. This study is the first to demonstrate geographic scale differences in birdsong rhythm, and to show that rhythmic analysis can provide useful descriptions of arrhythmic sequences.

animal behavior and cognition↗

bioRxiv2024

DNA metabarcoding revealed how time and space do matter -sex does not- in the dietary variation of the endangered Duponts Lark

A species diet is highly dependent on the availability of food resources in space and time, as well as on intrinsic factors such as sex or age. Accurate assessments of variations in the diet composition of bird populations across spatial scales, seasons and demographic groups are essential not only for understanding the basic ecology of species, but also for the conservation of endangered ones. However, our current knowledge about how birds diet change according to spatio-temporal variations or intrinsic factors is very limited. Here, we used a multi-marker metabarcoding approach to characterize the diet of a declining shrub-steppe passerine, the Duponts Lark (Chersophilus duponti), throughout a large part of its global distribution range. We also investigated spatial, phenological and sexual variations in its diet. Using markers from two genomic regions (18S and COI), we analyzed fecal samples from 303 adult Duponts larks from Morocco and Spain during the breeding and non-breeding seasons. Overall, arthropods from the orders Coleoptera, Lepidoptera, Julida and Orthoptera were the main prey consumed by Duponts Larks. We found that Duponts Lark diet varied spatially, as well as temporally, reflecting dietary plasticity in response to changes in prey availability across landscapes and the species phenological periods. High dietary overlap and no differences between sexes were observed, suggesting similar foraging behavior and nutritional requirements in both sexes. This is the first study providing detailed information on Duponts Lark food ecology over much of its distribution, which is fundamental for the management and conservation of this declining steppe species.

ecology↗

bioRxiv2022

European scenarios for future biological invasions

O_LIInvasive alien species are one of the major threats to global biodiversity, ecosystem integrity, natures contribution to people and human health. While scenarios about potential future developments have been available for other global change drivers for quite some time, we largely lack an understanding of how biological invasions might unfold in the future across spatial scales. C_LIO_LIBased on previous work on global invasion scenarios, we developed a workflow to downscale global scenarios to a regional and policy-relevant context. We applied this workflow at the European scale to create four European scenarios of biological invasions until 2050 that consider different environmental, socio-economic and socio-cultural trajectories, namely the European Alien Species Narratives (Eur-ASNs). C_LIO_LIWe compared the Eur-ASNs with their previously published global counterparts (Global-ASNs), assessing changes in 26 scenario variables. This assessment showed a high consistency between global and European scenarios in the logic and assumptions of the scenario variables. However, several discrepancies in scenario variable trends were detected that could be attributed to scale differences. This suggests that the workflow is able to capture scale-dependent differences across scenarios. C_LIO_LIWe also compared the Global- and Eur-ASNs with the widely used Global and European Shared Socioeconomic Pathways (SSPs), a set of scenarios developed in the context of climate change to capture different future socio-economic trends. Our comparison showed considerable divergences in the scenario space occupied by the different scenarios, with overall larger differences between the ASNs and SSPs than across scales (global vs. European) within the scenario initiatives. C_LIO_LIGiven the differences between the ASNs and SSPs, it seems that the SSPs do not adequately capture the scenario space relevant to understanding the complex future of biological invasions. This underlines the importance of developing independent, but complementary, scenarios focused on biological invasions. The downscaling workflow we presented and implemented here provides a tool to develop such scenarios across different regions and contexts. This is a major step towards an improved understanding of all major drivers of global change including biological invasions. C_LI

ecology↗

bioRxiv2022

A scenario-guided strategy for the future management of biological invasions

Future dynamics of biological invasions are highly uncertain because they depend on multiple environmental, societal and socio-economic drivers. We adopted a qualitative scenario approach to explore the future of invasive alien species (IAS) in Europe and created an overall strategy for their management that considers different plausible future developments. The scenarios and strategy were developed during two online workshops with a multidisciplinary team of experts. First, we downscaled four global scenarios of biological invasions to the European level. Second, we developed a management strategy structured into 19 goals that cover a broad array of IAS-related topics (i.e. policy, research, public awareness and biosecurity), and provided solutions for achieving these goals considering the European scenarios. Third, we identified four interrelated recommendations around which any long-term strategy for managing IAS in Europe can be structured: (i) a European biosecurity regime, (ii) a dedicated communication strategy, (iii) data standardization and management tools, and (iv) a monitoring and assessment system. Finally, we identified the feasibility of the IAS management strategy, finding strong differences among the four scenarios. High levels of technological development, public environmental awareness, and effectiveness of IAS policies facilitated the implementation of the overall management strategy. Together, our results indicate that it is time for a new management of biological invasions in Europe based on a more integrative perspective across sectors and countries to be better prepared for future challenges.

ecology↗

bioRxiv2021

Capacity of countries to reduce biological invasions

The extent and impacts of biological invasions on biodiversity are largely shaped by an array of socio-ecological predictors, which exhibit high variation among countries. Yet a global synthetic perspective of how these factors vary across countries is currently lacking. Here, we investigate how a set of five socio-ecological predictors (Governance, Trade, Environmental Performance, Lifestyle and Education, Innovation) explain i) country-level established alien species (EAS) richness of eight taxonomic groups, and ii) country capacity to prevent and manage biological invasions and their impacts. Trade and Governance together best predicted the average EAS richness, increasing variance explained by up to 54% compared to models based on climatic and spatial variables only. Country-level EAS richness increased strongly with Trade, whereas high level of Governance resulted in lower EAS richness. Historical (1996) levels of Governance and Trade better explained response variables than current (2015) levels. Thus, our results reveal a historical legacy of these two predictors with profound implications for the future of biological invasions. We therefore used Governance and Trade to define a two-dimensional socio-economic space in which the position of a country captures its capacity to address issues of biological invasions. Our results provide novel insights into the complex relationship between socio-ecological predictors and biological invasions. Further, we highlight the need for designing better policies and management measures for alien species, and for integrating biological invasions in global environmental scenarios.

ecology↗