Cristian Pérez Granados

University of Alicante | UA · Ecology

In recent years, several automated and noninvasive methods for wildlife monitoring, such as passive acoustic monitoring (PAM), have emerged. PAM consists of the use of acoustic sensors followed by sound interpretation to obtain ecological information about certain species. One challenge associated with PAM is the generation of a significant amount...

Passive acoustic monitoring (PAM) is a reliable method for studying the behaviour and ecology of vocally active animals, providing insights into species' activity patterns. Here, we utilised a year-long recording programme conducted in six areas of the Afromontane tropical forest of Cameroon to assess the utility of PAM, describe the annual and cir...

Passive acoustic monitoring is a reliable method to study species behaviour and ecology, enabling the discovery of species activity patterns, especially in remote locations. Here, we conducted a year-long recording study to describe annual and circadian patterns in the vocal activity of two African barbet species, the Yellow-rumped Tinkerbird Pogon...

Insects are the most diverse animal taxon on Earth and play a key role in ecosystem functioning. However, they are often neglected by ecological surveys owing to the difficulties involved in monitoring this small and hyper-diverse taxon. With technological advances in biomonitoring and analytical methods, these shortcomings may finally be addressed...

The need for remote, reliable, and scalable monitoring of plummeting biodiversity amidst mounting human pressures on ecosystems and changing climate has sparked enormous interest in Passive Acoustic Monitoring (PAM) over multiple disciplines and ecosystems. Even though PAM could support UN Sustainable Development Goals and the Global Biodiversity I...

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, b...

Future dynamics of biological invasions are highly uncertain because they depend on multiple social–ecological drivers. We used a scenario‐based approach to explore potential management options for invasive species in Europe. During two workshops involving a multidisciplinary team of experts, we developed a management strategy arranged into 19 goal...

Machine learning tools are widely used in support of bioacoustics studies, and there are numerous publications on the applicability of convolutional neural networks (CNNs) to the automated presence-absence detection of species. However, the relation between the merit of acoustic background modelling and the recognition performance needs to be bette...

Biological invasions pose significant threats to biodiversity and ecosystem functioning. Removal of introduced species is most successful when detected early. We evaluate the effectiveness of passive acoustics combined with automated recognition in detecting the invasive American bullfrog (Lithobates catesbeianus). We applied this technique to two...

Territorial defence depends on highly interrelated factors such as food abundance and conspecific density. We used Dupont's Lark Chersophilus duponti as a model species to evaluate the response of a territorial bird to a foreign male playback, examining how conspecific density, habitat quality and male body condition impact responses. The study was...

Invasive alien species are one of the major threats to global biodiversity, ecosystem integrity, nature's contributions 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...

Insects are the most diverse animal taxon on Earth and play a key role in ecosystem functioning. However, they are often neglected from biodiversity surveys due to the difficulties of monitoring this small and hyper-diverse taxon. With technological advancements in biomonitoring and analytical methods, these shortcomings may finally be addressed. H...

The Kunming-Montreal Global Biodiversity Framework (KM-GBF) envisions a world living in harmony with nature by 2050, with 23 intermediate targets to be achieved by 2030. However, aligning international policy and local implementation of effective actions can be challenging. Using steppe birds, one of the most threatened vertebrate groups in Europe,...

Insects are the most diverse animal taxon on Earth and play a key role in ecosystem functioning. However, they are often neglected from biodiversity surveys due to the difficulties of monitoring this small and hyper-diverse taxon. With technological advancements in biomonitoring and analytical methods, these shortcomings may finally be addressed. H...

Food availability plays a key role affecting almost every aspect of bird ecology, including bird population, distribution, reproduction, and behavior. Understanding the functional relationship between prey availability and insectivorous birds' diet is important in the current scenario of habitat loss and declining of insect and bird populations. We...

The Asian hornet (Vespa velutina) has rapidly become a source of stress for the beekeeping sector. Several methods have been developed to control its impact and spread, though some of these impose a high risk for native insects. Among these methods are electric harps, which are physical barriers that electrocute hornets pass through two wires power...

Passive acoustic monitoring usually generates large datasets that require machine learning algorithms to scan sound files, although the complexity of developing machine learning algorithms can be a barrier. We assessed the ability and speed of two user-friendly machine learning tools, Kaleidoscope Pro and BirdNET, for detecting the American toad (A...

Parental food provisioning is crucial for the growth and survival of offspring. Growth rate depends on food quality and food supplied to offspring may differ from what adults use for their own. In the case of steppe passerine birds, detailed characterization on nestling dietary composition, as well as prey choice and resource partitioning among spe...

The efficient analyses of sound recordings obtained through passive acoustic monitoring (PAM) might be challenging owing to the vast amount of data collected using such technique. The development of species-specific acoustic recognizers (e.g., through deep learning) may alleviate the time required for sound recordings but are often difficult to cre...

The Dupont’s lark (Chersophilus duponti) is an endangered passerine typical of Mediterranean shrub-steppes, whose European distribution is restricted to Spain. Here, we update the population size and distribution range of the species at a European scale and evaluate (i) the current status; (ii) the change in population size and distribution range o...

The co-occurrence of morphologically similar species may be enabled by differences in resource use that limit the effects of interspecific competition, allowing coexistence. This study aimed to evaluate differences in nest structure and to characterise nesting microhabitats to test for nesting niche segregation among sympatric steppe passerines. fr...

Bird vocalisations, like any other acoustic signals, attenuate over distance, and therefore their structure degrades progressively. Such degradation may have an impact on the ability of automated signal recognition software, to detect and correctly identify bird vocalisations. BirdNET is a recently launched automated bird song recogniser commonly e...

The frequency and intensity of extreme weather events represent a threat for biological diversity and are expected to increase in many regions over the following decades due to climate change. Our current knowledge about the impact of extreme weather events on the population dynamics of bird species is very limited. Here, we evaluated the impact of...

Automated recognition software is paramount for effective passive acoustic monitoring. BirdNET is a free and recently developed bird sound recognizer. I performed a literature review to evaluate the current applications and performance of BirdNET, which is growing in popularity but has been subject to few assessments, and to provide recommendations...

Passive acoustic monitoring coupled with automated signal recognition software has been widely used in recent years as an effective and affordable tool for wildlife monitoring and to combat illegal activities within protected areas. Here, we evaluate this technique to monitor the patterns of illegal cattle occurrence in the Brazilian Pantanal over...

Monitoring temporal dynamics in genetic diversity is of great importance for conservation, especially for threatened species that are suffering a rapid population decline and increased fragmentation. Here, we investigate temporal variation in genetic diversity, structure, and gene flow in the Dupont’s lark (Chersophilus duponti) across most of its...

Passive acoustic monitoring is a powerful tool for monitoring vocally active taxa. Automated signal recognition software reduces the expert time needed for recording analyses and allows researchers and managers to manage large acoustic datasets. The application of state-of-the-art techniques for automated identification, such as Convolutional Neura...

Passive acoustic monitoring, when coupled with automated signal recognition software, is a useful technique for monitoring vocally active taxa. In this study, we evaluated the utility of automated signal recognition to gain insights into the ecology of little-studied species. For this purpose, we selected an avian family, Caprimulgidae (nightjars),...

Arthropod biomass is a key element in ecosystem functionality and a basic food item for many species. It must be estimated through traditional costly field sampling, normally at just a few sampling points. Arthropod biomass and plant productivity should be narrowly related because a large majority of arthropods are herbivorous, and others depend on...

1. Invasive 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...

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 dev...

In human-wildlife conflicts, it is crucial to develop accurate protocols for the reliable verification of the causative species and its relationship with potential damage claims. One of such conflicts is that occurring between apiarists and bee-eaters. In this work, we aim to assess the utility of passive acoustic monitoring (PAM) as an efficient m...

Abstract Studying seasonal changes in the vocal activity of birds may shed light on the function of avian vocalizations and the phenology of life history events. Our current knowledge about the seasonality of the vocal behaviour of tropical birds in general, and avian brood parasites in particular, is very limited. Here, we employed passive acousti...

Unlabelled: The extent and impacts of biological invasions on biodiversity are largely shaped by an array of socio-economic and environmental factors, which exhibit high variation among countries. Yet, a global analysis of how these factors vary across countries is currently lacking. Here, we investigate how five broad, country-specific socio-econ...

Iberian natural steppes have traditionally been used for extensive sheep grazing, which has been noted to be positively associated with steppe bird abundance and diversity. Sheep numbers in Spain, which harbors the largest European populations of many steppe bird species, decreased by 9.2 million (37.3%) between 1992 and 2020. Steppe birds in Spain...

Stress in birds has been widely studied through the measurement of heterophil-to-lymphocyte ratio (H/L ratio). In this study we aimed to assess for the first time the potential variation of stress, measured as H/L ratio, associated to geography (between-country variation) and seasonality (between seasons and within the breeding season), as well as...

The Asian hornet ( Vespa velutina ) has rapidly become a source of stress for the beekeeping sector. Several methods have been developed to control its impact and spread, though some of these impose a high risk for native insects. Among these methods are electric harps, which are physical barriers that electrocute hornets passing through two wires...

Chaco Chachalaca (Ortalis canicollis) is a declining Neotropical bird, for which our current knowledge about its natural history is very limited. Here, we evaluated for first time the utility of passive acoustic monitoring, coupled with automated signal recognition software, to monitor the Chaco Chachalaca, described the vocal behavior of the speci...

Nighttime studies are underrepresented in ecological research. Even well-known behaviors, such as the loud call of howler monkeys, are rarely studied at night. Our goal was to help fill this knowledge gap by studying the 24 h vocal behavior of the Guianan red howler monkey (Alouatta macconnelli) and to compare the acoustic structures of howling bou...

Abstract: Climatic conditions represent one of the main constraints that influence avian calling behavior. Here, we monitored the daily calling activity of the Undulated Tinamou (Crypturellus undulatus) and the Chaco Chachalaca (Ortalis canicollis) during the dry and wet seasons in the Brazilian Pantanal. We aimed to assess the effects of climate p...

Wind farm implementation is a rapidly growing source of landscape transformation that may alter ecological processes such as predator–prey interactions. We tested the hypothesis that wind farms increase the activity of nest predators and, ultimately, increment ground-nest predation rates. We placed 18 plots in Iberian shrub-steppes (11 at control a...

Cue counting is a method developed for estimating vocally active wildlife density by dividing the density of cues (number of cues per unit area surveyed per unit time) by the average cue rate (ACR) at which individuals vocalize. It has been used successfully to estimate whale density using passive acoustic monitoring, but its efficacy has had limit...

Monitoring the vocal behavior of owls is challenging because of their nocturnal habits and limited vocal activity. Here, we evaluated the use of passive acoustic monitoring coupled with automated signal recognition software to monitor the spontaneous vocal activity of the Ferruginous Pygmy-Owl (Glaucidium brasilianum) over a complete annual cycle a...

Understanding patterns of dispersal behaviour of threatened species is important in conservation biology and population ecology, especially in fragmented landscapes. Dupont's Lark Chersophilus duponti is a threatened passerine whose European population has declined by around 40% in the last decade. To study natal and breeding dispersal of the speci...

Conservation research is less often applied in practice than is desirable for the optimization of conservation outcomes. We evaluated this conservation research-practice gap for a threatened passerine, Dupont's lark Chersophilus duponti. We reviewed the literature and classified the conservation interventions proposed by scientists as regulation an...

Passive acoustic monitoring is a non‐invasive tool for automated wildlife monitoring. This technique has several advantages and addresses many of the biases related to traditional field surveys. However, locating animal sounds using Autonomous Recording Units (ARUs) can be technically challenging, and therefore ARUs have traditionally been little e...

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...

Passive acoustic monitoring, when coupled with automated signal recognition software, allows researchers to perform simultaneous monitoring at large spatial and temporal scales. This technique has been widely used to monitor cetaceans, bats, birds, and anurans but rarely applied to monitor primates. Here, we evaluated the effectiveness of passive a...

The moon phase affects the ecology and vocal activity of nightjars (Caprimulgidae). However, some studies have found contradictory results regarding the impact of the moon phase on the vocal activity of nightjars. To increase our knowledge on this topic, we monitored the vocal behavior of two Neotropical nigthjars, the Little nightjar (Setopagis pa...

Access here: https://onlinelibrary.wiley.com/share/author/QM7CYNCAPXNW4FXBPNQZ?target=10.1111/ibi.12909 Some diurnal birds vocalize at night, but the reason for this has seldom been studied. We monitored the nocturnal vocal activity of the Undulated Tinamou Crypturellus undulatus from June 2015 to May 2016 at three recording stations in the Brazil...

Current knowledge regarding the vocal behavior in tropical non-passerines is very limited. Here, we employed passive acoustic monitoring to study the vocal activity of the white-tipped dove (Leptotila verreauxi) at three sites over a year in the Brazilian Pantanal. The diel pattern of vocal activity showed a bimodal pattern, with significantly high...

The use of Autonomous Recording Units (ARUs) for wildlife monitoring has increased in recent years. Acoustic monitoring has been used for a wide range of research topics, but it has rarely been used for monitoring wildlife migrations. In this work we evaluate the use of acoustic monitoring to characterise the diurnal migration pattern of a bird spe...

Moult is a vital and endogenously controlled process in the avian life. However, birds may modulate their feather renovation properties, such as the extent of moult, based on exogenous factors. Despite the large body of knowledge about moult patterns, numerous questions remain unclear. In this study, we aimed to improve our knowledge about the fact...

Bird vocal activity is affected by endogenous and exogenous factors. Owl surveys are mainly based on the detection of nocturnal calls, and therefore, the impact of exogen-ous factors on owls' vocal activity may have consequences in conservation planning and behavioural studies. However, our current knowledge about the impact of climatic factors and...

Our current knowledge of the vocal behaviour of Palaeognathae is limited, although it may increase our understanding of the evolution of avian vocal behaviour. The Greater Rhea (Rhea americana) has a complex syrinx, and males produce guttural sounds during the courtship display, which makes this species an interesting model to study vocal behaviour...

Potoos (Nyctibius spp.) are nocturnal Neotropical canopy-dwelling birds, making them one of the most enigmatic and least known avian families. The Common Potoo (Nyctibius griseus) and the Great Potoo (Nyctibius grandis) are the most widespread species, but little information on their life histories is available. We evaluated the utility of autonomo...

Data Sets Audios of Common Potoo (Nyctibius griseus) and the Great Potoo (Nyctibius grandis) in the Brazilian Pantanal

Anuran advertisement calls are life history traits associated with sexual selection and reproduction, and they play an important role in premating isolation mechanisms between species. Comparative bioacoustical analyses of these calls can be useful for taxonomic purposes. Phylogenetic relationships within the genera Pseudis are controversial, espec...

The ecology of tropical wildlife remains unknown for most nocturnal species owing to difficulties in performing night surveys. To improve our understanding of the ecology of nocturnal tropical birds, we monitored the calling activity of two Neotropical nightjars, the Little nightjar (Setopagis parvula) and the Common pauraque (Nyctidromus albicolli...

Despite increasing interest in moult in birds, there are still clear gaps in our knowledge of this topic. For example, many aspects of the moult of several European passerines remain unknown. Here, I describe the extent of the postjuvenile and the post-breeding moult of Black Wheatears Oenanthe leucura in south-eastern Spain and analyse the possibl...

Moon phase affects the ecology and behaviour of animals and may thus affect both circadian and circannual rhythms. Its influence on nocturnal and dawn bird behaviour is known, but fewer studies have examined its effect on passerines' singing activity, some of which have yielded contradictory findings. With the aim of elucidating whether moon phase...

Acoustic monitoring provides the opportunity to study ecological pro-cesses that are difficult to assess with traditional surveys. Elachistocleis matogrosso is an anuran species, described in 2010, for which limited biological information is available. This study investigated the calling activity of the species in the north-eastern portion of the Pan...

Tinamous (Tinamidae) are a group of Neotropical birds for which little information is available. The Undulated Tinamou ( Crypturellus undulatus ) is one of the most widespread species but also declining. Due to its secretive habits, ecological knowledge regarding the species relies on few anecdotal descriptions. We used automated recorders to monit...

Anuran calling behaviour is determined by environmental, endogenous, and social factors. The effect of these factors usually differs among and within species. We used acoustic monitoring to evaluate the effects of environmental predictors on the daily occurrence and call production of Elachistocleis matogrosso (Microhylidae) in the northeastern Bra...

The interactions between ecosystem components and their implications on birds have been poorly studied, especially in shrub-steppes. In this work, we evaluate the interactions between vegetation structure, arthropods availability and the use of space by the Dupont´s lark (Chersophilus duponti) in important areas for the species in the Iberian Penin...

Some birds use social cues, such as the presence of conspecifics, when selecting breeding habitat. This phenomenon, known as conspecific attraction, has been well‐documented in migratory species, but has not been assessed for resident species of birds. We used Dupont's Larks (Chersophilus duponti) as a model species to determine if conspecific attr...

https://bioone.org/journals/Ardeola/volume-66/issue-2/arla.66.2.2019.ra4/Cost-Effectiveness-Assessment-of-Five-Audio-Recording-Systems-for-Wildlife/10.13157/arla.66.2.2019.ra4.short Audio recording systems coupled with automated song recognition are commonly being used for monitoring wildlife. Recorders usually differ in cost and effectiveness, an...

La pérdida y transformación de los paisajes esteparios es considerada la principal causa del declive que han sufrido las poblaciones ibéricas de alondra ricotí (Chersophilus duponti) en las últimas décadas. Entre otros, los procesos de matorralización, originados en su mayoría por el abandono del pastoreo extensivo tradicional, han reducido la cant...

Autonomous Recording Units have been widely used in a large number of bird studies in recent years, but challenges remain in estimating abundance based on acoustic monitoring. We tested whether or not Vocal Activity Rate index (the number of songs per unit time for a species), recorded using Autonomous Recording Units, was related to population abu...

Los efectos del fuego sobre la fauna terrestre son devastadores. Pero algunas especies pueden verse beneficiadas. Una de ellas es la alondra ricotí, amante de las parameras y del matorral ralo, una estructura vegetal que antaño se encargaba de mantener a raya el ganado extensivo.

Este volumen contiene siete artículos sobre la avifauna madrileña. Algunos se basan en estudios de larga duración, como el dedicado al papamoscas cerrojillo, que abarca cuarenta años de seguimiento; el realizado a partir de diez años de anillamiento de paseriformes; y el basado en la observación de gaviotas argénteas en vertederos durante doce años...

Biology and conservation of Dupont's Lark Chersophilus duponti Dupont's Lark is one of the most emblematic steppe bird species in Spain. Here, we review advances in knowledge of its basic biology and ecology during the past decade, with special emphasis placed on studies carried out in a peripheral population located in Rincón de Ade-muz (Valencia)...

Monitoring programmes are needed to assess the conservation status of species and to quantify the effectiveness of conservation effort. Rare species are usually poorly studied due to dif