
Gil Sánchez Jose MaríaHarmusch, Asociación de Estudio y Conservación de Fauna · no departament
Gil Sánchez Jose María
PhD
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Publications (113)
Body size rules the distribution and abundance of species, affecting the composition of animal communities. Body size distributions may explain niche partitioning and have been used to quantify the relative resilience of communities to perturbations. Five hypotheses have been put forward to explain observed body mass patterns in animal communities...
Modern humans widely shaped present ecosystems through intentional and unintentional geographical redistribution of wildlife, both in historical and pre‐historical times. However, the patterns of ancient human‐mediated indirect changes in wildlife range are largely unknown, and the mechanisms behind them remain obscure.
We used a multidisciplinary...
Sub-Saharan Africa is under-represented in global biodiversity datasets, particularly regarding the impact of land use on species’ population abundances. Drawing on recent advances in expert elicitation to ensure data consistency, 200 experts were convened using a modified-Delphi process to estimate ‘intactness scores’: the remaining proportion of...
Individual dietary variation has important ecological and evolutionary consequences. However, it has been overlooked in many taxa that are thought to have homogeneous diets. This is the case of vultures, considered merely as 'carrion eaters'. Given their high degree of sociality, vultures are an excellent model to investigate how inter-individual t...
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The Sahara desert is home to the greatest diversity of ungulates of all deserts. In this harsh environment, the endangered Cuvier’s gazelle finds at the southernmost limit of its distribution a key population for its survival. A better understanding of the feeding ecology of the species may improve our understanding of the biological...
Surveys based on indirect signs and camera trapping are two non-invasive methods extensively used for monitoring elusive mammals. Both approaches can be useful to obtain key information on wildlife in remote areas, since they may allow for the logistically viable design of optimal field frameworks. The sand cat (Felis margarita) is a feline that in...
Global warming and displacement of vectors and wild and domestic hosts by humans greatly change host-parasite interactions and parasite transmission rates. Thelazia callipaeda Railliet and Henry, 1910 (Spirurida: Thelaziidae) is a zoonotic parasite rapidly colonizing Europe from its Asian native range. This nematode is vectored by Phortica flies an...
The Earth's wildlife is facing a new, fast and huge extinction process due to the impact of humans. This scenario
not only affects the biodiversity itself but also the capacity of the ecosystems to retain their structure and
functions. The roles of megaherbivores and top predators are crucial for ecosystem ecological integrity and key in
many eco-e...
A reduction in adult survival in long-living species may compromise population growth rates. The spur-thighed tortoise (Testudo graeca) is a long-lived reptile that is threatened by habitat loss and fragmentation. Golden eagles (Aquila chrysaetos), whose breeding habitats overlap that of tortoises, may predate them by dropping them onto rocks and b...
In recent decades, intensive techniques of livestock raising have flourished, which has largely replaced traditional farming practices such as transhumance. These changes may have affected scavengers’ behaviour and ecology, as extensive livestock is a key source of carrion. This study evaluates the spatial responses of avian scavengers to the seaso...
Morphometric methods of sex differentiation may be cheap, simple, quick, and reliable alternatives to molecular approaches. However, there are still important uncertainties regarding the use of morphometric methods in birds, particularly regarding their applicability to different populations and environmental conditions. Between 2004 and 2019, we s...
Dieta de la nutria en ríos del sureste ibérico: papel de las presas invasoras y relación con contaminantes Las especies invasoras tienen un gran impacto en los ecosistemas dulceacuícolas y pueden influir en los hábitos alimentarios de los depredadores autóctonos. Los ríos mediterráneos, caracterizados por un caudal fuertemente inestable a lo largo...
Accurate estimations of adult mortality are essential for understanding population dynamics and achieving efficient management actions that are directed toward long-lived species. Several noninvasive methods may be used to monitor endangered long-lived birds like raptors, but their performance in real-world scenarios remains poorly studied. We used...
Humans have transformed most landscapes across the globe, forcing other species to adapt in order to persist in increasingly anthropogenic landscapes. Wide-ranging solitary species, such as wild felids, struggle particularly in such landscapes. Conservation planning and management for their long-term persistence critically depends on understanding...
Human activities are changing ecosystems and their trophic structures across the globe and tropical forests are one of the main affected. Large carnivores can have a key role in the maintenance of biodiversity through direct and indirect effects at lower trophic levels, which are the result of predation and competition. In this sense, it is expecte...
Transhumance is an extensive livestock technique that consist on the seasonal movement of herds to take advantage of natural high-quality pastures. Extensive pastoralism modulates the landscape, provide ecosystem services as well as feeding opportunities for scavengers. However, transhumance is in decline mainly due to socio-economic changes, so th...
In species that live in sympatry, some dimensions of their ecological niche can overlap, but coexistence is possible thanks to segregation strategies, being the differential use of space and time one of the most frequent. Through a pioneer study in North-West Africa based on a camera-trapping survey, we studied ecology features of a carnivores’ com...
Intentional poisoning is a global wildlife problem and an overlooked risk factor for public health. Managing poisoning requires unbiased and high-quality data through wildlife monitoring protocols, which are largely lacking. We herein evaluated the biases associated with current monitoring programmes of wildlife poisoning in Spain. We compared the...
Cryptic mammals with semi-aquatic habits, like otters, are notoriously difficult to study. Elusive behaviour, low population density, nocturnal habits and the type of continental habitat that characterize this group of species make the estimation of their population density an arduous task. Passive infrared-triggered camera devices are a non-invasi...
The study of the competitive interactions between predators has traditionally been approached within the context of predatory behavior. By using a quasi‐experimental, non‐intrusive approach, we go beyond the classical view that predators only compete for living prey and disentangle the mechanisms of exploitative and interference competition between...
An amendment to this paper has been published and can be accessed via a link at the top of the paper.
Monitoring populations and designing effective conservation actions for endangered species present significant challenges. An accurate understanding of current distribution, ecological traits and habitat requirements is imperative in formulating conservation strategies. Recent surveys on the southernmost Cuvier’s Gazelle (Gazella cuvieri) populatio...
: The honey badger (Mellivora capensis) is a medium-sized carnivore distributed throughout Africa to the Arabian Peninsula, Iran, Turkmenistan, and India. However, available information on its ecology is very scarce. We studied its feeding ecology in the remote north-western Sahara Desert, based on the contents of 125 fecal samples collected during...
Knowledge of population dynamics of threatened species in the wild is key to effective conservation actions. However, at present, there are many examples of endangered animals for which their current situation is unknown, and not just in remote areas and less developed countries. We have explored this topic by studying the paradigmatic case of the...
Studies that assess the conservation status of the megafauna of the Sahara desert are becoming more necessary given of the collapse of its populations have suffered in this last century. In this remote region of the planet, any work in situ poses severe challenges to logistic level and security, due to its remoteness, lack of infrastructure, extrem...
The interactions between animals and their environment vary across species, regions , but also with gender. Sex-specific relations between individuals and the ecosystem may entail different behavioral choices and be expressed through different patterns of habitat use. Regardless, only rarely sex-specific traits are addressed in ecological modeling...
Las interacciones entre los animales y su ambiente varían según las especies y regiones, pero también con el sexo. Las diferencias sexuales en estas relaciones pueden afectar a numerosos parámetros poblacionales y expresarse a través de los patrones de uso del hábitat. A pesar de ello, estas diferencias sexuales raramente se abordan en los enfoques...
How species use space and time is central in ecology and evolution as well as for the conservation and management of vulnerable species. Unfortunately, this information is scarce for elusive species such as the threatened European wildcat (Felis silvestris silvestris), especially in Mediterranean areas. Using radio-tracking and camera-trapping, we...
Lead is highly toxic for wildlife, with pernicious consequences especially in long-lived predators. The causes of lead ammunition ingestion in Bonelli's eagle (Aquila fasciata) and its effects on breeding success were studied in one of the most important populations of this endangered species in Europe. Regurgitated pellets belonging to different p...
The conservation status of the Saharan Barbary sheep is poorly known. We have initiated a series of expeditions with the aim of getting information on its current status and situation in the Atlantic Sahara, and collecting records of threatened and little-known wildlife. Here, we present the results of the expedition to Djebel Ouarkziz and Aydar mo...
The Endangered Cuvier's gazelle Gazella cuvieri is an endemic ungulate of northwestern Africa. Information on the species has been based primarily on non-systematic surveys, and the corresponding status estimates are of unknown quality. We evaluate the effectiveness and efficiency of two field methods for systematic surveys of populations of Cuvier...
En este estudio nos planteamos determinar de manera intensiva y extensiva la dieta reciente (1994-2014) del águila real en el sur de la Península Ibérica (Comunidad Autónoma de Andalucía y sector más occidental de la Región de Murcia), explorando diferencias a distintas escalas espaciales así como entre los territorios de reproducción y las áreas d...
The book is divided into two parts. The first part describes a series of expeditions carried out during 2011-2015 by the Harmusch Association to the Atlantic Sahara in order to search for little-known fauna. The second part summarises the preliminary results of the findings, giving an account of the species sighted and highlighting the status of Cu...
Hybridisation between domestic cats, Felis catus, and wildcats, Felis silvestris, could lead to the genetic extinction of the latter; therefore, checking hybridisation rates in wild populations is of vital conservation importance. However, detecting hybridisation in the field is particularly challenging. Here, we aim to test the success of morpholo...
La ecología de las grandes rapaces no deja de sorprendernos. En Andalucía, la recuperación del águila real, gracias entre otras causas a las acciones de conservación desarrolladas en los últimos años en favor de las aves de presa, ha tenido un fruto inesperado: una mayor competencia territorial con el águila perdicera, cuya población andaluza, la m...
Population viability analysis (PVA) has become a basic tool of current conservation practice. However, if not accounted for properly, the uncertainties inherent to PVA predictions can decrease the reliability of this type of analysis. In the present study, we performed a PVA of the whole western European population (France, Portugal and Spain) of t...
Most studies on felid depredation of livestock have focused on big cats, and little attention has been paid to this type of conflict in smaller species. The medium-sized Iberian lynx (Lynx pardinus) is not thought to be affected by conflict with humans. However, parallel to an increase in the range of the Iberian lynx in Andújar-Cardeña, an increas...
Population viability analysis (PVA) has become a basic tool of current conservation practice. However, if not accounted for properly, the uncertainties inherent to PVA predictions can decrease the reliability of this type of analysis. In the present study, we performed a PVA of the whole western European population (France, Portugal and Spain) of t...
1. A long-standing question in ecology is how natural populations respond to a changing environment. Emergent optimal foraging theory-based models for individual variation go beyond the population level and predict how its individuals would respond to disturbances that produce changes in resource availability.
2. Evaluating variations in resource u...
Capture–recapture analysis of camera trap data is a conventional method to estimate the abundance of free-ranging wild felids. Due to notorious low detection rates of felids, it is important to increase the detection probability during sampling. In this study, we report the effectiveness of attractants as a tool for improving the efficiency of came...
The critically endangered Iberian lynx (Lynx pardinus) is considered the most endangered cat in the world (IUCN 2002). During the Twentieth Century, its populations suffered a dramatic decrease, and by 2002 less than 100 individuals survived in two isolated populations in Andalusia (Southern Spain): Sierras de Andújar-Cardeña and Doñana National Pa...
Over the last 2 years surveys of the population of the Iberian lynx Lynx pardinus in Doñana National Park and its surroundings in Spain have produced estimates of a total population of 5–6 in fragmented patches. The population was estimated to be 26 adults in 22–23. Use of camera trapping and other field methods during 24–28 allowed us to determine...
With only about 350 individuals, the Iberian lynx Lynx pardinus continues to be the world’s most endangered felid. Ongoing conservation measures include both in-situ and ex-situ conservation programmes. As part of the first Iberian lynx reintroduction programme, two captive-born individuals were released in the wild in the 2010-2011 season for the...
A principios del siglo XXI la población de lince ibérico se había quedado reducida a menos de 160 individuos localizados únicamente en 2 poblaciones: Andújar-Cardeña y Doñana. Los principales factores limitantes de la especie eran la escasez de alimento y la elevada mortalidad no natural. En vista de esto, dentro del marco de los programas de conse...
The use of non-invasive long-term monitoring data to estimate home ranges of the critically endangered Iberian lynx has been
evaluated. This programme began in 2002 and consisting of both annual latrine and camera-trap surveys, with the aims of detecting
and individually identifying the maximum number of individuals and delineating female home rang...
The Iberian lynx (Lynx pardinus) is the most endangered wild feline species and the only feline listed as
critically endangered by the International Union for the Conservation of Nature. Successful conservation actions
rely on accurate knowledge of the species’ distribution and decline. Anecdotal unverified reports have
overestimated the distributi...
How predators impact on prey population dynamics is still an unsolved issue for most wild predator-prey communities. When considering vertebrates, important concerns constrain a comprehensive understanding of the functioning of predator-prey relationships worldwide; e.g. studies simultaneously quantifying 'functional' and 'numerical responses' (i.e...
Prey weighed to calculate the biomass ingested by eagles.
(DOC)
Results of the sensitivity evaluation of each parameter in the Lindén & Wikman (1983) equation.
(DOC)
Raptor predation rates on wild populations of adult game birds in Europe.
(DOC)
Spanish predators including >5% of rabbit (“rabbit consumers”) and red-legged partridge (“partridge consumers”) in their diet, together with their national and international conservation statuses.
(DOC)
Sensitivity analysis of the impact estimates.
(DOC)
Calculation of the biomass consumed and food requirements of Bonelli's eagles.
(DOC)
Biases in the impact estimates.
(DOC)
Predation may potentially lead to negative effects on both prey (directly via predators) and predators (indirectly via human persecution). Predation pressure studies are, therefore, of major interest in the fields of theoretical knowledge and conservation of prey or predator species, with wide ramifications and profound implications in human-wildli...
Based on both radio-tracking and photo-trapping data, we present in this paper the first evidence of a non-parental male infanticide in the Iberian lynx. This paper is focused on the behaviour of 3 Iberian lynxes [one resident male (RM); one resident female (RF), and one incoming male (IM)] of the Doñana population, recorded in the spring of 2007....
The distribution range of the largest Iberian lynx (Lynx pardinus) population of Eastern Sierra Morena was assessed between 1999 and 2006. The past distribution was evaluated using field interviews, the present range was determined by sign searching (scats) in 5x5 km and 1x1 km UTM quadrats, and the annual population size was estimated by camera-tr...
The dietary preference of badgers Meles meles (Linnaeus, 1758) for earthworms and other food resources has been widely discussed. In the Mediterranean area, rabbits Oryctolagus cuniculus, fruits (mainly olives Olea europaea) and arthropods are the most important foods. We describe badger dietary habits in a xeric Mediterranean area, comparing
use a...