Iberian Lynx Research Articles

Assessing the influence of ecological interaction patterns among habitat types on species distribution: studying the Iberian lynx (Lynx pardinus Temminck 1827) in central Spain

Species distribution models (SDMs) usually describe the landscape through single landcover types as explicative and independent variables. However, species distribution responds to ecological processes that are represented in spatial patterns of landcovers, which are not usually considered in SDMs. From the hypothesis that Iberian lynx occurrence will depend on landscape functioning and that spatial organisation of landcovers is a reliable indicator of landscape functionality, we built a SDM based on landscape structure, to: (i) assess the relevance that spatial organisation of landcovers has for SDMs; (ii) describe the suitable landscape for the presence/conservation of the Iberian lynx. Spatial organisation of landscape is identified by recognising landscape mosaics, which are sets of patches with a similar pattern of boundaries. We identified landscape mosaics within western area of the province of Madrid. Then, we used field-collected lynx scats to test if species’ preferences are related to landscape mosaics. The species shows its preference for two out of eight identified mosaics. It shows preference for mosaics with low human-modified holm oak forests, but it does not show rejection of traditional land-uses such as pasture or non-intensive agriculture. The relevance of watercourses was also shown, since two of four mosaics with characteristic riparian vegetation prove to be relevant in the model. As landscape includes spatial interactions (boundaries) among landcovers it is a more holistic descriptor than single landcovers. This contributes to increase SDMs performance and usefulness for designing more accurate conservation actions, compared to those based on single landcover composition.

Enabling conditions for the implementation and conservation outcomes of a private nature reserve

Abstract Expanding conservation efforts to private land is paramount to halt biodiversity loss and achieve global conservation targets. Individual landowners can play disproportionately important roles by establishing private parks and managing them with biodiversity‐focused objectives. However, several constraints hinder the expansion of such initiatives, and little is known about their extent, characteristics and keys for success. Here, we provide insights on the conditions that favoured the establishment and conservation outcomes of a private reserve in central Spain whose management has been fully conservation‐oriented for the past two decades. We report on the actions implemented to accomplish four key targets that aimed at protecting and enhancing wildlife populations, and on the landholder's motivations to devote his personal resources to pursue this goal. After acquiring the land, the landowner has made efforts to restore native wildlife populations after decades of poaching and intensive cattle raising. Key actions included re‐establishing degraded vegetation and fostering keystone rabbit populations to sustain carnivore populations. Water bodies are maintained to provide drinking points and foster aquatic animal populations; nest boxes target birds and bats. Many actions resulted from advice from multiple stakeholders, including public administration officers, academics, local residents and NGOs. The estate's formal conservation status has made it a partner in major conservation projects, including repeated releases of captively bred Iberian lynx. The landowner's determination for long‐term conservation was formalised through a legal protected‐area status. The condition that drove the creation of the reserve was the landowner's intrinsic motivation, which resulted from conservation ethic, personal identity and the desire to share and educate about the multiple values of nature. Additionally, several external conditions, such as accessibility and appropriate reserve size (biophysical conditions), the lack of need for economic activities (economic), a positive and pro‐active relationship with multiple stakeholders (social‐cultural), the protected‐area status and the capacity to make decisions independently (governance‐related), have helped sustain the project. The landholder suggests that public policy should reduce the bureaucratic burden to intrinsically motivated landowners and provide them technical advice, trust and financial incentives to expand conservation on private land.

Taphonomic criteria for identifying Iberian lynx dens in quaternary deposits

For decades, taphonomists have dedicated their efforts to assessing the nature of the massive leporid accumulations recovered at archaeological sites in the northwestern Mediterranean region. Their interest lying in the fact that the European rabbit constituted a critical part of human subsistence during the late Pleistocene and early Holocene. However, rabbits are also a key prey in the food webs of Mediterranean ecosystems and the base of the diet for several specialist predators, including the Iberian lynx (Lynx pardinus). For this reason, the origin of rabbit accumulations in northwestern Mediterranean sites has proved a veritable conundrum. Here, we present the zooarchaeological and taphonomic study of more than 3000 faunal and 140 coprolite remains recovered in layer IIIa of Cova del Gegant (Catalonia, Spain). Our analysis indicates that this layer served primarily as a den for the Iberian lynx. The lynxes modified and accumulated rabbit remains and also died at the site creating an accumulation dominated by the two taxa. However, other agents and processes, including human, intervened in the final configuration of the assemblage. Our study contributes to characterizing the Iberian lynx fossil accumulation differentiating between the faunal assemblages accumulated by lynxes and hominins.

The protection of the Iberian lynx under criminal law: case note on the judgement 150/2013 of June 6, pronounced by Jaén Provincial Court.

The Spanish legal system has sufficient tools to prevent indiscriminate acts against the Iberian lynx population at an administrative and criminal level. Through Judgment no. 150/2013 an analysis is carried out on practical aspects in the imputation of those criminal acts that aim to end the life of the lynxes, in which the evidence is taken as the main axis of prosecution.

Captivity-induced metabolic programming in an endangered felid: implications for species conservation

Reintroduction of captive-bred individuals into the wild is an important conservation activity. However, environmental conditions can influence developmental programming, potentially causing metabolic disorders in adults. These effects are investigated here for the first time in an endangered species. Using body weight and feed intake data for Iberian lynx (Lynx pardinus) (n = 22), we compared the growth of captive versus wild born and/or reared individuals. Captive-born individuals gained weight as a function of calorie intake, unlike wild-born individuals. When compared with females reared in the wild, captive-reared females achieved a larger body size, without evidence of obesity. Captivity-associated changes to metabolic programming may compromise survival in the wild if an increased body size incurs a greater energy requirement. Large body size may also confer a competitive advantage over smaller, wild-born individuals, disrupting the social organisation of existing wild populations, and inferring long-term implications for the phenotypic composition of wild populations.

Iberian Lynx Lynx pardinus Temminck, 1827 (Mammalia: Carnivora: Felidae) in central Spain: trophic niche of an isolated population

Understanding predator-prey relationships is fundamental to develop effective conservation plans. Between 2015 and 2018, we combed 21 transects, each 7km long, searching for Iberian Lynx Lynx pardinus scat within the province of Madrid in central Spain. In order to minimise inherent subjectivity of visual identification as much as possible, we performed a double specific nested polymerase chain reaction (PCR) followed by a primer extension assay addressed to two Iberian Lynx diagnostic single nucleotide polymorphisms. Forty-six scat samples were positively identified as belonging to Iberian Lynx through genetic analysis. From these, we extracted remains of consumed prey, which we determined to the lowest possible taxonomic level, mainly through hair identification. Identified prey was divided into four types: lagomorphs, small mammals, birds, and ungulates. The species’ diet composition was described based on the frequency of occurrence (FO) of each prey and niche breadth, and also compared with prior knowledge of the species using four prior studies as a comparative reference through the calculation of the niche overlap value. The FO of lagomorphs (39%) was the lowest, while the FO of small mammals (54%) was the highest recorded to date. The niche breath (0.36) was higher than recorded in prior studies, but still showing the specialist character of the Iberian Lynx. Niche overlap was low (C = 0.49), showing differences in trophic niche between the population in our study area and the one studied in southern Spain. This indicates that the Iberian Lynx is adept at switching its main prey, an ability that has previously been firmly rejected. It is, however, capable of adapting to alternative prey more often than recorded to date, which could be a behavioural response to the patchy distribution of European Rabbit Oryctolagus cuniculus in the study area.

Breaking barriers: Iberian Lynx Lynx pardinus Temminck, 1827 (Mammalia: Carnivora: Felidae) colonizing Olive groves

In recent years, the Andújar-Cardeña Iberian Lynx Lynx pardinus population has grown both in number and in occupied surface area. This feline has spread into areas surrounding existing population nuclei and occupied new habitats including human-dominated areas and tree crops. Here we describe this colonization process and the evolution of the Iberian Lynx populations in the Olive Olea europaea groves that surround typical Lynx scrub habitats in Andújar-Cardeña. Our findings were obtained through radio-tracking, camera trapping and European Rabbit Oryctolagus cuniculus monitoring. Two colonized areas—Zocueca and Marmolejo-Montoro—were identified in which Olive cultivation is predominant. Since 2011, a total of 45 and 50 different individuals have been detected in Zocueca and Marmolejo-Montoro, respectively. At present, 19 individuals are known to live in Zocueca and 29 in Marmolejo-Montoro. The main cause of mortality is road-kills. Our results suggest that the Iberian Lynx is capable of colonizing human-modified areas such as agricultural land provided that they can support high-density Rabbit populations and the causes of non-natural mortality are minimized.

Planning the peninsula-wide recovery of the Iberian lynx: identification of favourable habitat areas

Abstract The creation of new populations through reintroductions in their former range is still necessary for the long-term conservation of the Iberian lynx (Lynx pardinus). A large-scale assessment of habitat suitability is a necessary prerequisite for evaluating the possibility of carrying out lynx reintroductions. We modelled habitat suitability for the Iberian lynx in the Iberian Peninsula using MaxEnt. Lynx presence data for 2010–2013 from Andujar-Cardeña and Doñana populations were used. Habitat variables were quantified using the CORINE Land Cover. This habitat suitability model predicted an environmentally suitable area of 87,747 km2, which represents 14.08% of the whole Iberian Peninsula. Of the total suitable habitat identified, 45% is located in a large continuous area in the south-western quadrant coinciding with the historical range of the species in the mid-20th century. However, there are also relevant patches mainly in the north-eastern quadrant. About 55% of the potential area suitable for the lynx falls outside protected areas. If Iberian lynx populations are to attain levels that will facilitate their long-term survival, it will be necessary to consider potential habitat for the species throughout the whole of the Iberian Peninsula.

Sex steroids and glucocorticoid ratios in Iberian lynx hair.

Knowledge on species’ reproductive biology is a fundamental pre-requisite of every conservation effort, but is often lacking. Sex steroids can provide valuable information for the assessment of reproductive success, whereas glucocorticoids are used to assess adrenocortical activity and stress-related bodily adaption. However, due to their perilous condition, access to animals is often difficult, which makes hormone measurement in non-invasively collected hair samples an attractive option. We determined cortisol, cortisone, corticosterone, testosterone and progesterone in Iberian lynx hair using enzyme immunoassay (EIA). Cross-validation was performed with high-performance liquid chromatography (HPLC) and high-performance liquid chromatography coupled to tandem mass spectrometry (HPLC-MS/MS). Finally, we statistically evaluated the variations of sex steroids and glucocorticoids according to age, sex, origin, behavior and management. All steroids except corticosterone were detectable in Iberian lynx hair. Hair progesterone measured by EIA was overestimated by cross-reaction with 5α-dihydroprogesterone, a biologically active gestagene, and was highly correlated with HPLC-MS/MS results. Progesterone was higher in adult females compared to all other age-sex groups. Cortisol measured by EIA was overestimated due to antibody cross-reactivity with cortisone and was correlated to the sum of HPLC-MS/MS measurements for cortisol and cortisone. Cortisol was higher in females than in males measured by HPLC-MS/MS, but the EIA results were confounded by the lack of specificity. When using cortisol-cortisone and cortisol-dihydroepiandrosterone ratios, differences were noted between wild-caught and captive-bred lynxes. Additionally, longitudinal EIA measurements of an Iberian lynx after a wildfire showed an inversion of the cortisol-cortisone ratio that later subsided. These results validate the use of hair progesterone measurement for Iberian lynx reproductive monitoring and add to the growing evidence supporting the need for a more comprehensive approach to hair steroid measurement that accounts for local interconversion and co-regulation mechanisms.

Hair cortisol analyses in different mammal species: choosing the wrong assay may lead to erroneous results.

Wild animals are faced with a broad range of environmental stressors and research is needed to better understand their effect on populations. Hormone analysis based on enzyme immunoassays (EIAs) can provide valuable information on adrenocortical activity (stress), and assessment of cortisol in hair may allow the quantification of cortisol production. To validate hair hormone analysis, we compared two EIAs based on antibodies against cortisol-3-CMO-BSA and cortisol-21-HS-BSA for hair glucocorticoid (hGC) measurements in Egyptian mongoose, Iberian lynx, Alpine marmot, Asiatic black bear, spotted hyena and cheetah, with results obtained by liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS) measurements. Both EIAs were also characterized by HPLC immunograms. Our results revealed that the cortisol-21-HS EIA measured 2.3- to 12-fold higher hGC concentrations than the cortisol-3-CMO assay. In dependence of the species, high-performance liquid chromatography (HPLC) immunograms showed that up to 70% of immunoreactivities determined by the cortisol-21-HS constituted of unknown unpolar compounds leading to an overestimation of hGC. The cortisol-3-CMO EIA expressed a better specificity, with 32.1-67.4% of immunoreactivity represented by cortisol and cortisone. The LC-MS/MS analyses (gold standard) revealed that the cortisol-3-CMO EIA also resulted in an (up to 3-fold) overestimation of hGC, but EIA results were correlated with LC-MS/MS in the mongoose, the lynx, the spotted hyena and the marmot. No correlation was obtained for Asiatic black bears. As a result of our study, we strongly recommend to test any cortisol EIA for its specificity towards extracted hair components. In all analyzed species, except the Asiatic black bear, cortisone and cortisol were simultaneously present in hair extracts; consequently, an appropriate EIA should cross-react to these two glucocorticoid hormones and express negligible affinity towards substances with less polarity than corticosterone. Choosing the wrong EIA for hGC analyses may lead to overestimations of hGC or-in the worst case-to results that do not mirror real adrenocortical activity.

Improving the random encounter model method to estimate carnivore densities using data generated by conventional camera-trap design

AbstractThe random encounter model, a method for estimating animal density using camera traps without the need for individual recognition, has been developed over the past decade. A key assumption of this model is that cameras are placed randomly in relation to animal movements, requiring that cameras are not set only at sites thought to have high animal traffic. The aim of this study was to define a correction factor that allows the random encounter model to be applied in photo-trapping surveys in which cameras are placed along tracks to maximize capture probability. Our hypothesis was that applying such a correction factor would compensate for the different rates at which lynxes use tracks and the surrounding area, and should thus improve the estimates obtained with the random encounter model. We tested this using data from a well-known Iberian lynx Lynx pardinus population. Firstly, we estimated Iberian lynx densities using a traditional camera-trapping design followed by spatially explicit capture–recapture analyses. We estimated the differential use rate for tracks vs the surrounding area using data from a lynx equipped with a GPS collar, and subsequently calculated the correction factor. As expected, the random encounter model overestimated densities by 378%. However, the application of the correction factor improved the estimate and reduced the error to 16%. Although there are limitations to the application of the correction factor, the corrected random encounter model shows potential for density estimation of species for which individual identification is not possible.

Using MaxEnt algorithm to assess habitat suitability of a potential Iberian lynx population in central Iberian Peninsula

Iberian lynx distribution is currently restricted to the south of the Iberian Peninsula. Nevertheless, there is evidence of the presence of several small groups in the peninsular centre that have been forgotten by management and conservation actions. In this research, we gathered evidences of Iberian lynx presence along 21 transects located in the southwest of the Madrid province. In these transects lynx DNA was identified in 47 scats, which scientifically proves the presence of the species in that location. Using these locations (presence-only data) we built a maximum entropy model (MaxEnt) to estimate the suitability of the study area for the species. Our results show the existence of an almost continuous area that is approximately 744 km2 that is suitable for the Iberian lynx. Seventy-eight percent of this area is within the Natura 2000 network and, therefore, it falls under regulations to preserve and restore habitat types, flora and fauna. This study shows the suitability of this territory has for the Iberian lynx.

Benign juvenile focal epilepsy in a captive Iberian lynx (Lynx pardinus)

An 8-week-old intact male lynx cub (Lynx pardinus) from a captive breeding colony was presented with a 2-day history of cluster seizures. There was no history of intoxication. Physical and...

Spatial segregation between Iberian lynx and other carnivores

Rabbits represent the bulk of its diet as for many other Iberian predators. This study addresses how the presence of the Iberian lynx affects the spatial distribution of the mesocarnivore community at landscape scale in the Sierra de Andújar. We studied mesocarnivore presence by sampling at 230 camera trapping stations, located in areas with and without lynx. We used a x2–test to compare the proportion of stations in which each species of carnivore were recorded in the zones with and without lynx. The proportion of camera trapping stations in which red fox (Vulpes vulpes), Egyptian mongoose (Herpestes ichneumon), beech marten (Martes foina), wildcat (Felis sylvestris) and common genet (Genetta genetta) were detected was significantly lower in the area where lynx were present than in the area where it was absent. No significant differences between the two types of areas were found for badgers (Meles meles). Our results highlight the role of the lynx as apex predators and the benefits that the recovery of Iberian lynx populations would entail in terms of trophic interactions and restored disrupted ecosystems processes.Key words: Intraguild competition, Carnivores, Phototrapping, Apex preda

Restoring apex predators can reduce mesopredator abundances

The role that apex predators play in ecosystem functioning, disease regulation and biodiversity maintenance is increasingly debated. However, the positive impacts of their presence in terrestrial ecosystems, particularly in human-dominated landscapes, remain controversial. Limited experimental insights regarding the consequences of apex predator recoveries may be behind such controversy and may also impact on the social acceptability towards the recovery of these species. Using a quasi-experimental design and state-of-the-art density estimates, we show that mesopredator abundances were reduced after the restoration of an apex predator, with evidence of resonating positive impacts on lower trophic levels. Iberian lynx Lynx pardinus reintroduction was followed by the reduction of the abundance of mesocarnivores (red foxes Vulpes vulpes and Egyptian mongooses Herpestes ichneumon by ca. 80%) and the recovery of small game of high socio-economic value (European rabbits Oryctolagus cuniculus and red-legged partridges Alectoris rufa). The observed mesopredator reduction resulted in an estimated 55.6% less rabbit consumption for the entire carnivore guild. Our findings have important implications for the social acceptability of Iberian lynx reintroductions, which crucially depend on the perception of private land owners and managers. Under certain circumstances, restoring apex predators may provide a sustainable and ethically acceptable way to reduce mesopredator abundances.

The use of spatially explicit capture-recapture models for estimating Iberian lynx abundance in a newly reintroduced population

From 2015 till 2018, 33 lynxes were released in southeast Portugal (Guadiana valley) as a result of an Iberian reintroduction project. Since then, at least 45 lynxes were born in the wild during 3 breeding seasons. In 2018, a combination of sign search and camera trapping was applied to estimate lynx abundance in the Guadiana reintroduction area, using spatially explicit capture-recapture (SECR) models with the incorporation of sex-specific parameters. A total effort of 7210 trap-days led to 218 independent lynx captures (except for yearlings), which corresponded to 22 adults or sub-adults in 50 stations (28%). The estimated population size was 22–29 individuals (adults and sub-adults) in the 723 km2 study area, leading to a density of 3.4 lynxes (>1-year-old)/100 km2. Individuals were heterogeneously distributed, since most lynxes occurred in clusters with a few lynxes scattered among them. Use of space was sex-dependent and, as expected, males moved more distances than females. Apart from the estimated 22–29 over 1 year-old lynxes, the study detected the presence of 27 yearlings. The reintroduction project is still at an early stage, since the goal for a baseline population has not yet been reached (15 reproductive females) and it is therefore essential to improve organizational issues to implement a viable long-term system covering all critical areas, namely long-term replicable census for population monitoring.

Reintroduction of the Iberian lynx (Lynx pardinus): a preliminary case study in Extremadura, Spain

Iberian lynx (Lynx pardinus) reintroductions are part of this species’ conservation program to ensure its re-establishment and survival in areas of historical presence. Release protocols include hard-release, directly in the field, and soft-release, allowing reintroduced animals to acclimatize to the new environment site, which may lead to higher survival and reproductive rates. During soft-release reintroductions in Extremadura (Spain), we recorded individual and social behaviors of four released Iberian lynxes in a 1.5-ha enclosure, divided into three longitudinal strips to simplify behavioral data collection: zone 1, or releasing area, containing an additional feeding point; zone 2, or central zone, with rocks and natural rabbit refuges; and zone 3, or the farthest zone from the releasing area, of abundant arboreal vegetation. Our results showed that “pacing”, “lying” and “patrolling” were the most common behaviors observed in the four lynxes. Social interactions such as “approach”, and “lordosis” were the most common and indicated significant differences between individuals. Concerning sexes, males exhibited the behavior “showing indifference,” unlike females that never presented it. Data collected revealed that the lynx had a preference for zone 3 of the enclosure. Pre-release behavior monitoring is critical I n Iberian lynx soft-release reintroductions in order to ensure their acclimatization to the new site, identify their survival skills and allow their establishment in the reintroduction areas.

Molecular detection of Rickettsia rickettsii in ticks associated with the bobcat (Lynx rufus) in northeast Mexico

The study of rickettsial agents associated with ticks from wild felines is scarce. In Europe, three species of Rickettsia have been detected (Rickettsia helvetica, Rickettsia massiliae, and Rickettsia monacensis) in ticks collected from the Iberian lynx (Lynx pardinus). However, no studies have been conducted on another lynx species. For this reason, the aim of this study was to identify the diversity of Rickettsia species in ticks associated with bobcats (Lynx rufus) collected in the State of Tamaulipas, Mexico. During 1999 and 2004, nine bobcats from two municipalities of the state were trapped and visually inspected for the presence of ticks. A total of 95 ticks were collected from these lynxes. Ticks were preserved in 96% ethanol. Subsequently we identified the presence of Rickettsia DNA by the amplification of several fragments of genes 17 kDa, ompA and ompB. Recovered sequences were concatenated, aligned, and compared with those of reference deposited in GenBank. Additionally, a phylogenetic analysis was performed using the Maximum Likelihood method. The ticks were morphologically identified as belonging to the species Dermacentor variabilis. We selected a subset of 60 ticks which were examined, and 5% (3/60) were positive with an identity of 99% to sequences of R. rickettsii deposited in GenBank. The results obtained represent the first record of R. rickettsii in ticks associated with wild carnivores, and in particular with bobcats distributed in northeast of Mexico.

First description of sarcoptic mange in the endangered Iberian lynx (Lynx pardinus): clinical and epidemiological features.

A 6-month-old female Iberian lynx (Lynx pardinus) cub that was severely affected by mange died in September 2016 in the Montes de Toledo (Spain) with crusts and fissures on its face, outer ears, nipples and footpads. The body condition of the cub was very poor, and it also had a mandibular abscess and a severely ankylosed luxation on its left knee. After confirming that the origin of the deceased cub’s dermal lesions was Sarcoptes scabiei, the subsequent search for ectoparasites and a comparison of histopathological and immunohistochemical findings in all sympatric lynxes handled (n = 30) and submitted for necropsy (n = 4) during 2016 and 2017 revealed the presence of S. scabiei mites and/or milder mange compatible lesions in five members of her family group, which was treated against mange together with two exposed contiguous family groups. An ELISA developed by the authors showed the presence of antibodies against S. scabiei in the deceased female cub and one brother. The presence of concomitant immunosuppressive factors in the dead female cub and the results obtained for the other sympatric lynxes studied since 2016 suggest that S. scabiei had a limited effect on immune-competent Iberian lynxes in the local population of the Montes de Toledo. However, a different evolution and relevance of sarcoptic mange in different populations—or even in the same one in the presence of immunosuppressive factors—cannot be ruled out, thus confirming the need for further research in order to attain a complete comprehension of the epidemiology and the real threat that this ectoparasitic disease may imply for L. pardinus.

Lynx eats cat: disease risk assessment during an Iberian lynx intraguild predation.

Lethal interactions between members of the carnivore guild are well represented in literature. In the Iberian lynx, interspecific killing (without prey consumption) of some mesocarnivores, such as the Egyptian mongoose, genet, and red fox, has been reported. Although vaguely documented, evidence suggests feral cats fall victim to interactions with this apex predator. Here, we describe the first documented case of interspecific killing and partial consumption of a feral cat by an adult male Iberian lynx reintroduced in Southwestern Spain. Ulterior analyses demonstrated that the victim was viremic to feline leukemia virus. To prevent the dissemination of the virus and a potential outbreak in the Iberian lynx population, control measures, including the clinical evaluation of the male Iberian lynx, and intensive monitoring were implemented in order to detect intraspecific interactions. After 3 weeks, the lynx was evaluated, presented good condition and resulted negative to both ELISA and RT-PCR. Thanks to the long-term monitoring, this case could be detected and measures to prevent an outbreak could be implemented.