The spectacular comeback of the Iberian lynx

This extensive news item is the English version of Louise Kelchtermans’ Dutch thesis. A mandatory but freely chosen assignment in terms of content to complete her studies in secondary education. This as preparation for university studies in terms of consulting and referring to official resources. In her thesis, Louise, the daughter of EB5 founder Jan, processes all available data on the Iberian lynx, once the most endangered feline in the world.

A European success story of recovery and survival

for the Iberian lynx.

What conservation measures and reintroduction programmes have helped the Iberian lynx avoid extinction?

: Nigeria, the well known local female arriving in her riverine core area near Encinarejo – Andujar, Spain March 2025 © Jan Kelchtermans

Preface

All my life I have accompanied my parents on family holidays. The focus is on spotting wildlife in the wild. From a young age I came face to face with wild carnivores and herbivores in their natural habitat. This was both at European (Spain, Finland, Poland, etc.) and global (RZA, Canada, etc.) level. In this way I became familiar with searching for tracks (paw prints, droppings, etc.) that indicate the presence of enigmatic animals in their natural habitat.

The immersion in nature, as well as the feeling of excitement when effectively observing a target species, made me think about a subject for my final thesis. Due to frequent travels in Europe, I eventually ended up in Spain. We spent the summer months there alternately in the north or the south in search of Cantabrian brown bears, Iberian wolves and Iberian lynxes.

I would also like to thank my parents for all those wonderful years full of adventures and encounters with wild animals, many of whom do not even know they exist. I would especially like to thank my father as a source of inspiration. After all, I owe my personal knowledge and interest in special predators to him. He is also the one who set me on the right track with source material for this thesis.

I would also like to thank Mr. Commers. He showed a great deal of interest in my thesis and communication was always smooth. I am grateful to him for the trust and space he gave me to choose a subject that really suits me.

Louise Kelchtermans – Mechelen, May 2025

Introduction: The Iberian Lynx

There are four species of lynx worldwide: the Canadian lynx, the bobcat (also known as the red lynx), the Eurasian lynx and the Iberian lynx or Pardel lynx. Of all the existing cat species worldwide, the Iberian lynx still has the smallest population. In other words: the European Iberian Peninsula (Spain and Portugal) is home to the rarest cat species in the world.

The Iberian lynx is a unique and very rare appearance. It makes the species one of Europe’s most characteristic animals. Its dense coat (from warm light brown to a yellow-grey colour) shows a pattern of dark spots that vary in size and shape. Morphological characteristics that camouflage it excellently in the scrub and open forests that are characteristic of its Mediterranean habitat. But it is especially the face that stands out. This is because of the long, black and white beard of hair around the cheeks. In addition, the pointed ears at the top are provided with characteristic black bristles, a striking detail that distinguishes lynxes from other cats. Furthermore, it has a short, stocky tail with a dark tip. The yellow-green eyes, which are sharp and alert, emphasize its status as an efficient hunter. Lynxes are generally shy, largely nocturnal and solitary.

At the beginning of the 21st century, the Iberian lynx was on the verge of extinction. The last wild individuals (less than 100) lived in two isolated relict populations in Andalusia, the southernmost province of Spain (European Climate, 2021). The decline in the wild rabbit population and habitat fragmentation were both the main causes that caused the threat to the survival of the species to increase rapidly. Due to the small numbers remaining in both isolated sub-areas, inbreeding also occurred. Non-natural causes (hunting, road casualties, etc.) also had a negative impact on the reproduction of Iberian lynxes. Cumulative threats that were not without consequences. The total number decreased rapidly. In 2002, the Iberian lynx, teetering on the brink of extinction, was given the status of a seriously endangered species. The loss of an endemic top predator on European territory is something that Europe could not afford. Alarm bells went off, funds were released to protect the remaining wild specimens and their habitat and measures were taken. The breeding of Iberian lynxes in captivity was of particular importance. This was to reintroduce the species to former habitats. It resulted in a steady increase in the total number on an annual basis. The combination of various aid factors, funds for local NGOs, European life projects and raising awareness among the local population ensured that the Iberian lynx was saved in terms of survival. By 2025, the global population of the Iberian lynx will no longer be threatened with extinction. With a current population of 2,000 individuals, currently roaming freely in Spain and Portugal, the population is once again viable. Today, the species can be found in several Spanish regions, including Extremadura, Castilla-La Mancha and Murcia, as well as near Alentejo in Portugal. The recovery of the Iberian lynx marks an important milestone in the protection of endangered species. It also shows how joint efforts can lead to sustainable conservation and biodiversity (European Climate, 2024). In this thesis, I investigate the causes, efforts and results of the recovery process of the Iberian lynx, with the central research question: “Iberian lynx from endangered to vulnerable: which conservation measures and reintroduction programs have contributed to the species not becoming extinct?”.

1 Causes

1.1 Lack of food

The Iberian lynx is known for its specific diet. This solitary animal spends most of its life alone and only comes together with conspecifics during the mating season to reproduce (Sarmento, 2019, p. 2). Outside of this short social period, the lynx is mainly focused on survival; a crucial aspect of this is its food. The diet of this feline is remarkably selective: it eats only fresh meat. The lynx obtains its food mainly from prey it has caught itself. This means that it is busy catching animals every day, using its sharp senses and agility to hunt successfully. For the lynx, the quality of the meat is essential. A carcass or meat that has been dead for a while is usually left untouched. However, recent research shows that carcasses of dead animals can also serve as a food source for Iberian lynxes. This is true both in areas where rabbits (80% of their staple food) are abundant or scarce (Tobajas et al., 2022).

Although the Iberian lynx occasionally eats other small mammals and birds, its diet is almost entirely dependent on the European rabbit. Rabbits are an ideal prey: they are relatively small, quick to kill and they provide the lynx with essential nutrients. In the Iberian lynx’s habitat, the Mediterranean scrub, rabbits have historically been abundant. However, in the recent past, in the late 20th century and early 21st century, rabbit populations have suffered from various diseases. Rabbit numbers have fallen by 90% at the beginning of the 21st century. The first notable crisis among rabbits was in the year 1950. Diseases such as myxomatosis and the Rabbit Hemorrhagic Disease Virus (RHDV) both caused mass mortality among rabbits (Delibes-Mateos et al., 2014, p. 2166). These diseases have had a serious impact on the food supply for the lynx, putting the lynx population under great pressure. This is and remains a problem today, especially where rabbit populations are unable to build up immunity to these diseases. Due to a shortage of prey, lynxes start to roam their territory in search of food. Animals that do not do this even die from famine in the worst case. In addition, territorial females do not reproduce in areas with few rabbits, as they are dependent on survival. Territorial males also display this behavior. In addition, they chase young animals out of their habitat, as they are direct competitors for the scarce food supply. Figures from research reveal that rabbits are always the main prey for this carnivore, constituting between 85 and 99.5% of the diet of lynxes or 84.7% to 98.7% of the total biomass consumed by lynxes. The predominance of rabbits in the diets of the Iberian lynx has not only been observed in Doñana National Park and Sierra Morena, the two main and remaining viable lynx populations at the time. In other areas where the lynx is present, the rabbit appears to be its staple food. It is also interesting that the Iberian lynx is basically dependent on rabbits, regardless of the abundance of this prey. For example, no differences were found in the diet of lynxes between two populations that settled in two different areas of Sierra Morena with high and low rabbit availability (Delibes-Mateos, Ferreira, 2010, p. 50). To date, there are locations where lynxes are dependent on rabbits released by local NGOs. This is especially the case in areas where females are known to be both food insecure and with young. It is also very clear that where rabbit numbers have declined significantly in the main lynx distribution areas, it is one of the main causes of the decline in the populations of this endangered carnivore. The Iberian lynx is considered a specialist and not an opportunist in predation. This is due to its specialisation in hunting rabbits.

1.2 Traffic

Traffic is an unavoidable factor in the modern landscape and plays a role in threatening the Iberian lynx. A mortality study based on radio and tracking data showed that the annual mortality due to road casualties between 2006 and 2011 was 6.6% in Sierra Morena (Andújar) and 8.6% in Doñana. These are two isolated relict populations of the Iberian lynx that were left worldwide (Garrote et al., 2018, p. 218).

The rate at which lynx are killed on the road cannot be easily compared between different areas. The study looks at the number of individuals detected per kilometre of road. Comparing these figures is complex due to variables such as the type of environment around the road or the number of carnivores in the area, which can influence the value of this rate. In areas where carnivore populations are low due to food shortages, the number of road casualties may also be low. This could give the wrong impression that the risk of collisions is low, while this is not necessarily true. An additional problem is the Mediterranean scrub. This scrubland has a high density of rabbits and sometimes comes so close to the road that animals that are hit go unnoticed. Roads that run through Mediterranean scrubland are often described as areas with a high risk of road casualties of the Iberian lynx. The individuals detected as road casualties are used to indicate risk areas. Areas with a high frequency of road casualties and road segments that run through scrubland should be identified and designated as ‘black spots’. These locations can be further investigated and appropriate measures can be taken to reduce the number of collisions (lifelynxconnect.eu, 2021e, p. 14).

1.3 Habitat fragmentation

Habitat fragmentation is the result of the interaction between roads, railways and other infrastructures, and the ability of animals to overcome these physical barriers. These physical barriers hinder the natural migration of animals and the ability to recognise their environment. They also cause habitats to split up, creating disconnections between different territories, cores or populations of a species. This can seriously weaken populations, as animals become isolated from other groups and lose vital connections between different populations.

For the Iberian lynx, this fragmentation makes it difficult or even impossible to move safely from one area to another. However, this problem is not always caused by fatal collisions with vehicles, but often by broader effects such as the construction of roads or railways (see 1.2). This causes the loss of suitable habitat and is accompanied by secondary effects such as light and noise pollution. The increase in human activity, pollution and uncontrolled urbanization discourages the Iberian lynx from approaching areas, making their survival and dispersal more difficult. This has a direct negative impact on population dynamics, as animals are no longer able to migrate effectively to new areas, search for food and suitable breeding sites, which is essential for their survival (lifelynxconnect.eu, 2021a, p. 4).

1.4 Semi-urbanized areas

Construction and urbanization have become an integral part of the landscape. Cities continue to expand and human presence is increasingly penetrating into natural habitats. Highways and roads are factors that influence the mortality of the Iberian lynx, but they do not limit the presence of the species. The same applies to the variable “distance to urban centers”. In recent years, a stable presence and reproduction of the Iberian Lynx has been observed in semi-urbanized areas, very close to urban centers. This behavior seems to be possibly linked to the degree of tolerance and the intensity of predator control exercised by the inhabitants of each area. In addition, urban areas can provide indirect benefits, such as increased availability of food sources or shelters. At the same time, these benefits bring new risks, such as traffic and human disturbance. The careful management of both natural and urban environments is therefore essential to ensure the survival of the species (lifelynxconnect.eu, 2021e, p. 9).

1.5 Depletion of genetic material

The historical low number of Iberian lynxes in 2002 resulted in low genetic diversity. Genetic diversity refers to the variation in genes within a population or species. The more lynxes, the higher the genetic diversity and the better its physical appearance. In addition, it helps the species adapt to changes in its environment. As the population decreases, genetic diversity will also decrease and encourage inbreeding, as closely related individuals mate with each other. Inbreeding produces offspring that are physically weaker. Animals often have a less general physical appearance and are more susceptible to diseases. This also sometimes results in morphological defects such as the absence of body parts (Saussard, 2022).

That is why genetic diversity of the Iberian lynx is essential. Antonio Rivas, coordinator of the Iberian lynx breeding center in Acebuche, informs us about the importance of studying genetic diversity. He is co-leading the process of building genetic reverse that will support the reproduction and health of this species in the future (Richards, 2024). The process begins by fragmenting the DNA into smaller pieces. These fragments are later assembled to reconstruct genetic patterns, demographic history, and the complete biological code of the species. Genetic variations can jeopardize the continuation of the species. By sequencing the genome, one can gain deep insight into the genetic variation within the species. This process is essential for the evolution of the Iberian lynx (CNAG, 2020).

Antonio Rivas and his team apply this information to their captive animals. They do this through a well-thought-out process. They select pairs of male and female lynxes based on their genetic profiles. Every year, when a young one is born, the animal’s genes are analyzed. Based on this genetic data, a careful decision is made on where best to release the young one, with the aim of increasing genetic diversity and optimizing the survival chances of the species. Information from the wild, collected by local people, is also added to this. This valuable data provides researchers with information about the locations of the adults and whether or not they are reproducing. This allows consideration of which genes are introduced into the wild populations (Richards, 2024).

2 Efforts and results

2.1 Monitoring of rabbit populations

2.1.1 Importance of the European rabbit

The Iberian lynx is almost completely dependent on the European rabbit as its primary food source. As mentioned earlier, rabbit populations have declined significantly in the late 20th century and early 21st century due to various diseases. The viability of newly reintroduced lynx populations through reintroduction can be seriously jeopardised if there are problems with the existing rabbit populations. The preservation and protection of rabbit populations is therefore crucial to guarantee the future of the Iberian lynx.

2.1.2 Protection of setts

The warrens of wild rabbit populations located in the reintroduction areas of the Iberian lynx will be actively protected, as will those of surrounding rabbit populations. The main objective is to prevent damage to the setts. To protect against predators such as foxes, badgers and wild boars, additional pruning waste will be added to strengthen the rabbits’ burrows. This pruning waste serves as a physical barrier on the one hand and as camouflage and additional shelter on the other. Both grazing cattle and digging are avoided in the vicinity of the burrows. Regular monitoring makes it possible to quickly repair and strengthen damaged burrows (lifelynxconnect.eu, 2021b, p. 5).

2.1.3 Artificial shelter

In areas where natural rabbit burrows are scarce, artificial shelters will be constructed. It is expected that at least 4 shelters per hectare will be provided. It is necessary to make a careful choice regarding the location. It must not be a flood area, and there must be water in the vicinity. In addition, the location must be suitable for digging rooms and tunnels, preferably between shrubs and grasslands. There are different types of possible constructions. The first preference goes to waste piles of eucalyptus stumps with a diameter of about 10 meters, in which the rabbits can build a burrow independently. As an alternative, artificial shelters can be provided, constructed from wooden pallets. A space must be created in the middle where at least one room and a corridor can be installed. The entrance must only be large enough for a rabbit to pass through. The construction is covered with pruning waste and, if necessary, reinforced with a thin layer of soil. Breeding burrows are also optional; they are modular burrows consisting of concrete parts. They are durable, well protected against predation and resistant to flooding during the rainy season. These breeding burrows can also be placed underground (lifelynxconnect.eu, 2021b, p. 5).

2.1.4 Food and water

In areas with dense undergrowth, small clearings will be created and sown with different types of grasses that contain a crude protein content of more than 15% during their entire growth cycle. On poor soils, a mixture of cereals such as oats, barley, wheat and clover will be used. Grasses with a protein content of around 15% will always be chosen. This is the minimum that a female rabbit needs to reproduce (lifelynxconnect.eu, 2021b, p. 5). Although planting grasses and seeds is a valuable measure, there is always a risk that growth will not match expectations. It may therefore be useful to provide seed feeders. The main objective of this measure is to extend the rabbit’s reproductive period as long as possible. Water is also essential during the rabbit’s reproductive cycle, especially in the Mediterranean climate. It is recommended to create and maintain a network of active water points, from late spring to early autumn. To avoid health problems, these water points must be well designed and maintained. In the case of artificial drinking troughs, it is advisable to install a protective mesh to prevent competition from ungulates (lifelynxconnect.eu, 2021b, p. 6).

2.1.5 Release

The transport and release of wild rabbits from other populations is specifically aimed at increasing rabbit density in Iberian lynx reintroduction areas. For this purpose, a fenced area with a minimum surface area of 4 hectares is created. In most cases, this area corresponds more or less to the Iberian lynx reintroduction area. Hunting wire mesh combined with chicken wire or single torsion wire is used for the fencing. This mesh is partly buried in the ground and partly placed above ground. The mesh must prevent the released rabbits from leaving the enclosure on the one hand, and opportunistic predators from entering the enclosure on the other. Artificial rabbit shelters are created inside the enclosure. The occupancy rate of one hectare is 20 to 30 rabbits with a sex ratio of three to five in favour of the females. The released rabbits are housed in the artificial shelters. Once reproduction has taken place and the enclosure becomes saturated, small openings are made in the side walls of the enclosure. In this way, the rabbits can gradually spread outside the enclosure (lifelynxconnect.eu, 2021b, p. 6).

2.1.6 Vaccination and quarantine

There is debate about vaccinating, deworming and quarantining released rabbits. Recent studies show that long-term quarantine is not necessary and that vaccinations are often ineffective or even harmful due to stress. During previous LIFE projects, there was no difference in survival between vaccinated and unvaccinated rabbits, while vaccination stress led to 20% mortality. In addition, it appears that administering deworming agents can also be accompanied by stress, which complicates recovery and adaptation to the new environment. Therefore, in practice, the choice is usually made to release rabbits without vaccination or quarantine (lifelynxconnect.eu, 2021b, p. 8). An important exception to this is the RHDV virus (Rabbit Hemorrhagic Disease Virus), which is highly contagious and often fatal (Delibes-Mateos et al., 2014, p. 2166). When releasing rabbits, it is essential to strictly monitor the absence of this virus. An infection can have disastrous consequences for both the released and the existing populations. Careful monitoring of donor populations and hygienic transport conditions therefore remain crucial.

2.2 Natural breeding areas

Today, there is an active search for areas that could serve as new breeding areas and reintroduction areas for potential new populations of the Iberian lynx. In 2021, Life Lynx Connect released a protocol to identify potential areas for long-term viable populations of the Iberian lynx. The size of the reintroduction areas will be the minimum necessary to maintain viable populations in the long term. The reintroduction area must have an area of at least 10,000 ha, in addition to many other factors and minimum requirements (lifelynxconnect.eu, 2021e, p. 5). The aim is to identify areas at a regional scale that meet the minimum general conditions for the establishment of the species. At a later stage, these proposed areas will be evaluated in as much detail as possible, examining the important ecological factors. A habitat suitability model for the Iberian lynx at the scale of the Iberian Peninsula has been developed. This model visualizes on a map the areas with suitable habitat conditions for the species. To construct it, existing data on the distribution of the species are mathematically or statistically linked to different environmental variables. The result of the analysis indicates with a certain probability value (and associated statistical error margin) which geographical area is suitable for the species (lifelynxconnect.eu, 2021e, p. 6).

: Habitat Suitability Model for the Iberian lynx at the Iberian Peninsula scale. Source: lifelynxconnect.eu, 2021e, p.8.

The resulting map was created using MaxEnt, with modelling performed using artificial intelligence. Since the finished model generates continuous favourable values, a threshold is established above which the habitat is considered suitable for the lynx. This threshold allows to evaluate the potential distribution while minimising omission errors. In addition, altitude is taken into account. All areas above 1300 metres altitude are eliminated, as this is the limit for the presence of the European rabbit. The model states that the minimum area for a viable population in the long term should be 10,000 ha of connected habitat. The map was used in the selection of reintroduction areas within the LIFE Iberlince project. In addition, this map has also been used as a basis for small-scale area selections in ongoing projects in the Autonomous Communities of Catalonia and the Autonomous Community of Valencia (lifelynxconnect.eu, 2021e, p. 8).

In the pre-selected large-scale areas, squares of 2.5 x 2.5 km are set as sampling units, the surface of which corresponds approximately to the average size of the vital domain of a breeding female lynx. Several variables are taken into account. In the assessment, variables such as rabbit population and habitat quality are considered as required. Other variables, such as social attitudes towards reintroductions, the number of road casualties, the length of high-risk highways and railways, the number of irrigation canals and ponds, the risk of interference by domestic animals and data on the health status of the fauna are also taken into account. It is difficult to establish objective thresholds for these variables. However, too much flexibility in the assessment can lead to the death of individuals of the species (lifelynxconnect.eu, 2021e, p. 10).

There is already a history of reintroduction projects that have been stopped due to incorrect assessment of these descriptor variables. Sierra Norte de Sevilla initially met the minimum conditions for rabbit population and habitat quality. However, the reintroduction process was stopped due to a social rejection of reintroductions. Local communities opposed the project. This aspect was addressed until a more favourable environment was reached. During that process, and thanks to the continuous monitoring of the established variables, it became possible to detect how the incidence of the new variant of the RHDV brought rabbit populations below the minimum levels to consider the area suitable for reintroduction. The area was eventually rejected. The Sierra Arana area in Granada is another example, where the release of specimens was planned for 2021. The high number of road casualties from predators, the high traffic intensity combined with the high average speed on the road, will continue to affect reintroductions until these problems are resolved (lifelynxconnect.eu, 2021e, p. 11).

The wild rabbit population plays a crucial role in the population dynamics of the Iberian lynx. It is therefore essential to know the rabbit population in the area to be assessed. The proposed method is the fixed transect-latrine count. It is a method to estimate the population of wild rabbits by counting feces along predetermined linear paths of at least 750 meters. This method helps to calculate the relative density of rabbits in a given area. At the same time, the shrub cover is visually estimated in circles of 25 meters every 500 meters. A shrub cover between 20% and 80% is considered suitable for lynx establishment, based on an average of 55% (lifelynxconnect.eu, 2021e, p. 12). On the other hand, standard surveys will be carried out so that the results are quantifiable and comparable. They will take place in the inhabited parts of the reintroduction areas targeting stakeholders involved in sectors such as agriculture, forestry and hunting. These people have an influence on decisions about the lynx areas. The evaluations will provide results that demonstrate public knowledge of the lynx biology and public attitudes towards reintroduction. Minimizing conflicts with humans and promoting local support are key (lifelynxconnect.eu, 2021, p. 13).

2.3 Breeding programmes

The first action plan for captive breeding of the Iberian lynx was approved by the Spanish National Commission for the Protection of Nature in 2001. The first breeding centre for the Iberian lynx, El Acebuche, is located in the south of Spain and was opened in 1992. However, the first real captive breeding attempt did not take place until 2004. This happened shortly after a census of the entire Iberian Peninsula had confirmed that there were no lynx left in Portugal and that there were less than 200 lynx left in Spain.

In 2003, there were only four female Iberian lynx in captivity at El Acebuche, of which only one was adult and suitable for reproduction. It was essential to transfer male lynx to the breeding centre. The Jerez Zoo made a vital contribution by capturing and transferring a wild male. For the 2004 breeding season, the centre had only one adult female and one recently captured male. The lack of successful reproduction during this first breeding attempt was therefore not unexpected. In the spring of 2005, the first litter of lynxes was born in captivity. In 2004, the captive population at El Acebuche increased to seven founder animals, of which 3 were male and 4 were female. In October of that year, the IUCN Reproduction Specialist Group presented its recommendations for the genetic and demographic management of the breeding programme. The chosen scenario aimed to maintain 85% of the available genetic diversity for 30 years. To achieve this, a total of 60 breeding animals (30 males and 30 females) would be kept in captivity, with four wild-born cubs added each year for five years, and one adult animal from a rehabilitation centre every two years (Serra et al., 2024, p. 24).

Subsequently, the creation of a network of exclusive breeding centres for the Iberian lynx began. In early 2007, the second breeding centre, La Olivilla, opened in the Spanish province of Jaén. The expansion of the breeding programme provides new opportunities and eventually leads to international expansion. As a result, the Iberian lynx could return to Portugal, where the species had disappeared since the early 1990s. In 2005, Portugal submitted its own national action plan, which was approved in 2008. In 2008, the first Portuguese breeding centre opened in the Algarve (CNRLI) in southern Portugal. Several agreements were signed between the Spanish and Portuguese governments, including an agreement in July 2009 on the exchange of lynx for breeding purposes. Portugal received its first animals in October 2009, leading to the first reintroduction of the Iberian lynx in 2015. The fourth breeding centre, Zarza de Granadilla, located in central Spain, received its first lynxes in March 2011, completing the current network of breeding centres: four exclusive breeding centres where only Iberian lynxes are bred (Serra et al., 2024, p. 25).

: Current breeding centers of the Iberian lynx. source: Serra et al., 2024, p. 25.

The close technical and scientific collaboration between these centers, led by different regional and national governments, has been essential to achieve common goals and milestones. Today, the breeding program offers more than 80 enclosures for breeding and reintroduction training, and houses approximately 150 animals during each breeding season (Serra et al., 2024, p. 25).

2.4 Reintroduction

2.4.1 Reintroduction programs

Reintroduced animals undergo a unique process in which they are transported from their natural habitat and placed in a completely unfamiliar landscape. Several reintroduction programs have been established over the years. Increasing the success rate of reintroduction programs requires efficient monitoring of reintroduced animals after their release. This monitoring provides the necessary information to assess the effectiveness of the entire reintroduction process. Monitoring of reintroduced animals is usually done using a GPS collar or radio collar. A radio collar is a simple type of transmitter that emits radio waves. This signal can be detected with an antenna and receiver, but the lynx must be present in the vicinity. It is a reliable system but less accurate and more labor-intensive. A GPS collar transmitter, on the other hand, uses satellites to determine the exact location of the lynx. The data is automatically transmitted via mobile phone or satellite (Wildlife ACT, 2021). Since the beginning of the release of Iberian lynxes in reintroduction areas in 2009, 302 individuals have been released up to 2020. In addition, eight individuals have been released in Doñana since 2007 for genetic reinforcement of the population. The analysis of the results of these releases has made it possible to evaluate important aspects in the development of the reintroduction processes (lifelynxconnect.eu, 2021d, p. 4).

: Reintroduced lynx with GPS collar (2025 – Toledo, Spain) © Jan Kelchtermans

2.4.2 Release protocol

There is currently an updated version of the original release protocol for the Iberian lynx, which was developed during the Life Iberlince project. This project, founded in 2006, coordinated the releases of lynx and was based on the first reintroductions in Guarrizas and Guadalmellato in 2009 and 2010 (iberlince.eu, 2011). The new version builds on experiences and includes important lessons learned since the beginning of the reintroduction process. The details and insights from this period have been incorporated into the current protocol. We discuss the origin of the individuals, the selection and preparation of the animals and the release criteria. In the early stages of a reintroduction, there is often little intraspecific competition, because population pressure is low. As a result, differences in survival chances and behaviour are less likely to play a role. However, as the reintroduction progresses and the population grows, competition for resources increases. These resources are considered in the ecological context and are things like food, water, territory and shelters. These are essential for the survival of each individual within the population. In the later stages, establishing new individuals in an already saturated population becomes much more difficult, and such differences become important. A good example of this can be seen in the Guadalmellato area. In the early stages of reintroduction (years 1-4), the survival rate of captive-bred animals in their first year after release was 55%. In the second phase (years 5-8), however, this figure dropped to only 20%. In the Guarrizas area, no difference was seen in first-year survival between the two stages, but there too a 20% drop was observed in phase 2. In addition, it appeared that far fewer lynx were able to establish themselves in the population in phase 2. In the third year after release, 35% of the released animals in phase 1 survived, while in phase 2 this had dropped to only 22%. These figures underline that the context of the population, and in particular the level of competition, can have a major impact on the success of reintroductions in the long term (lifelynxconnect.eu, 2021d, p. 4).

2.4.3 Selection and origin of individuals

Individuals selected for translocation can come from a captive breeding programme or can be wild-born. Individuals from the captive breeding programme must undergo a programme of adaptation to freedom in the breeding centres of origin, as well as a health check, before they are released. Using wild-born lynx to reinforce or establish new populations can have a number of advantages over using captive-bred animals. Firstly, the costs are significantly lower, as is the amount of work required, as no training or other interventions are required. On the other hand, wild-born Iberian lynxes have higher survival rates than captive-born lynxes. Another advantage may be that the number of lynxes available for translocation may be much higher than that of the breeding centres. In the wild, more than 300 cubs were born in 2019 and more than 400 cubs in 2020 (lifelynxconnect.eu, 2021d, p.4). It is important to take into account the characteristics of the donor population when translocating wild animals. The donor population must be sufficiently robust so that the removal of individuals does not have negative effects on the population. To assess this effect, it is necessary to obtain information on productivity, juvenile survival and juvenile mortality. In populations where juvenile mortality is high, translocation of young animals can be considered as a way to still benefit from individuals that would otherwise be lost. Mortality among juveniles can be a consequence of high densities and saturation of territories. From a genetic point of view it is important that these transferred animals contribute to increasing the genetic diversity within the receiving population. Based on demographic simulations an upper limit should be established for the number of animals that can be removed from each population each year (lifelynxconnect.eu, 2021d, p. 5).

Individuals between 9 and 12 months old that do not show dispersal behaviour are most suitable for translocation. Dispersal behaviour is the act of leaving the birth area to search for a territory of their own. Individuals between 1 and 4 years old can also be successfully translocated. Translocation of animals older than 4 years is discouraged. Elderly animals over 8 years old should not be used, as the chance of success in these cases is zero. In addition, it is important that the recipient population is located as far away from the donor population as possible. This helps to prevent philopatric behaviour, the tendency of animals to return to their birth area. A quarantine and adaptation period of at least 50 days must also be provided, so that the animals can recover sufficiently and get used to their new environment. Furthermore, strict guidelines apply regarding health and genetics. In addition, both the genetic characteristics of the animal and those of the recipient population must correspond to the guidelines in the genetic management protocol. Finally, all released animals must be fitted with a radio collar so that their behaviour and movements can be closely monitored after release (lifelynxconnect.eu, 2021d, p. 6).

2.4.4 Soft and hard releases

There are two basic methods for releasing individuals in reintroduction programmes: hard releases and soft releases. The first releases in a new reintroduction area must be carried out via soft releases. Here we are talking about a period of confinement to allow the individuals to adapt to the area. This release takes place in pre-adaptation enclosures to promote the survival of the individuals and ensure their establishment, thus avoiding dispersal and return behaviours.

The pre-adaptation enclosure must be built in a central area of the selected reintroduction area, with a high rabbit density, limited human access and support from the owners. The geological and physical characteristics of the area must be suitable for the construction of the infrastructure, as this is a factor that influences the costs. The area must provide sufficient shrubland for shelter and at the same time allow observation for monitoring. In this way, establishment is guaranteed and dispersal of released individuals is minimized. The number of enclosures depends on economic and logistical constraints and the number of lynxes to be introduced (lifelynxconnect.eu, 2021d, p. 6). The size of the enclosures has changed over time and depending on the initial objectives. The first enclosures were built in Guadalmellato. Three enclosures of between 4 and 5 hectares were built, in each of which a male and a female were introduced. These animals were born wild with reproductive potential and were placed in the enclosure during the breeding season so that the female could become pregnant and give birth in the enclosure. The lynxes could therefore remain in the enclosure for up to six months when breeding. This objective required large enclosure sizes. A similar process was replicated in Guarrizas. In the reintroductions outside Andalusia, one-year-old captive animals were released, without the possibility of breeding. The purpose of this enclosure was acclimatization and to minimize the chance of dispersal behavior (lifelynxconnect.eu, 2021d, p. 7).

Wild rabbits must be present within the enclosure at all times so that lynxes can develop their natural hunting behaviour. The rabbits placed in the enclosure must come from nearby areas or introduction programmes. In addition, the rabbits must have a high health guarantee to ensure that no external RHDV viruses are introduced. At the beginning of the soft release, we speak of an adaptation period and extra attention is paid to hunting and skill techniques, interactions between conspecifics and individual adaptation to the environment. This is done by means of visual checks from fixed observation points and camera traps. These close checks are essential for the survival chances of the individual and the final release. After the foreseen adaptation period, the lynxes leave the enclosure and can leave naturally (lifelynxconnect.eu, 2021d, p. 8).

Once the first introduced lynxes have been released and territorial individuals are present in the area, hard releases will take place in the following years. The presence of other animals in the area reduces the chance of dispersal behaviour. The individuals subjected to hard release skip the adaptation period. They only undergo a health check and are fitted with a radio transmitter (lifelynxconnect.eu, 2021d, p. 9).

3 Future challenges

3.1 Framework for future challenges

Although important progress has been made in recent years in the recovery process of the Iberian lynx, we must not lose sight of the challenges for the future. The continued expansion of urban areas, the impact of climate change and the preservation of suitable habitat are continuing obstacles to a stable and sustainable lynx population. In addition, there are other points of attention, such as the connection of dispersed populations and the promotion of a balanced relationship between humans and animals. Ecotourism also plays a role in this, provided that it is developed in a responsible and natural way.

3.2 Linking subpopulations

The careful selection of breeding areas, combined with breeding programmes and monitoring of the rabbit population, guarantees the development of a lynx population with a solid base within a reintroduction area.

However, to ensure that the numbers of the populations continue to increase, linking these populations together is a positive asset. This can be achieved by means of bridge areas, which serve as connection points between different populations. However, it is crucial to carefully determine the right location for these bridge areas. If a bridge area is not in a suitable location, it will not fulfill its function and cannot serve as a connecting link between the populations. In that case, it only forms an isolated island in a hostile environment with no possibilities for connection. When determining suitable locations, two populations are first chosen that need to be connected. Then, the path with the shortest effective distance between both populations is determined. Areas that are located on this path are optimally positioned as a bridge area. The further an area is from this path, the greater the effective distance becomes and the less suitable it is to serve as a functional bridge (lifelynxconnect.eu, 2021f, p.8).

: Visual representation of the connection of subpopulations using bridge areas. Source: lifelynxconnect.eu, 2021f, p. 8.

3.3 Conflicts with livestock

Since the beginning of the 21st century, attacks by the Iberian lynx on farm animals have been recorded. Such attacks occur in all areas where the species lives, both in historical populations and in new reintroduction areas. As with other felines worldwide, conflicts with farm animals can lead to retaliatory killings by farmers. In some regions, this has even prevented the lynx from establishing itself (lifelynxconnect.eu, 2021e, p. 15).

The historical lack of information on predation by the Iberian lynx on farm animals is probably due to the fact that for many years, studies on lynx ecology have mainly focused on the Doñana National Park, where there are hardly any livestock as potential prey. However, since the start of the reintroduction projects, the species’ distribution area has expanded considerably. The lynx habitat in Andújar-Cardeña has increased from 11,900 hectares in 2002 to 26,000 hectares in 2010. Within this increased area, there is a large amount of unprotected livestock, which increases the risk of lynx attacks and therefore conflict with humans. Although most attacks are on poultry, the economic losses are greatest when lambs are attacked. All known lynxes killed in revenge by owners have been involved in attacks on chicken coops. Two of these cases were confirmed by radio tracking in Sierra Morena. Since 2006, a compensation scheme for damage caused by lynx has been in place. Thanks to this scheme and the fact that 43 to 50% of the lynx population in semi-inhabited areas is monitored by transmitters, no new cases of revenge killing have been recorded. In recent years, lynxes have been regularly rescued alive from chicken coops, with the cooperation of the owners. This suggests that compensation is effective in the short term, although preventive measures such as reinforcing pens appear to be more effective and less expensive in the long term (Garrote et al., 2013, p. 289).

Research shows that male lynxes attack more often than females. Most attacks occur in extensive, unmonitored herds. The first attack on sheep in Andújar-Cardeña was recorded in 2011. Although the problem in Andújar-Cardeña remains limited for the time being, there are potential reintroduction areas that are particularly suitable for establishing new populations, but where there are also many herds of cattle. An example of this is in Guarrizas (Jaén). However, in such areas the presence of cattle can lead to increased conflict with local livestock farmers, which can arouse hostility towards the lynx and thus jeopardize the success of reintroduction. It is therefore essential to focus on extra protection of cattle in such areas. This can be achieved through measures such as electric fencing, guard dogs or keeping livestock indoors at night (Garrote et al., 2013, p. 290).

3.4 Ecotourism

As the recovery process of the Iberian lynx is a success story in development, it is receiving increasing international attention. This progress in conservation is attracting interest from both local communities and tourists from all over the world. More and more nature lovers are flocking to the Iberian Peninsula to observe this majestic animal in the wild. In this context, ecotourism plays an important role. Ecotourism differs from traditional tourism in its focus on sustainability, conservation and social involvement.

Ecotourism is a form of responsible travel to natural areas, which protects the environment, supports the well-being of local people and focuses on cultural education and mediation. This usually takes place in small groups and within small-scale structures in nature. Ecotourism aims to keep tourist pressure on sensitive ecosystems as low as possible, while at the same time contributing to the conservation of biodiversity (BeBiodiversity, 2017). In the case of the Iberian lynx, this form of tourism also creates economic opportunities for local communities, which in turn can strengthen their commitment to the conservation of the species. Farmers, guides and local entrepreneurs can generate alternative income through ecotourism, thus increasing support for the presence of the lynx. For example, some organisations offer guided observation trips led by a specialised guide. During this trip, visitors have the opportunity to observe the Iberian lynx from a viewpoint. Another option is to stay in a hide. These hides are usually located near waterholes or artificial rabbit warrens, locations where the chance of seeing the lynx is significantly greater. Visitors stay in these hides for three to four hours, usually in the early morning or at dusk. These are the times when the animal is most active. The hides are positioned in such a way that they are sufficiently distant from the lynx habitat, thus avoiding disturbance to the animal and biodiversity (Wild Watching Spain, 2025).

Conclusion

The central question of this thesis was: ‘How could the Iberian lynx, which was almost extinct, return to the wild?’. After extensive research it has become clear that this recovery is due to a combination of different factors and targeted efforts.

The main cause of the original decline was the drastic loss of habitat and prey. The large-scale mortality of the European rabbit due to disease has put the population under enormous pressure. Infrastructure, traffic, fragmentation of natural areas and human disturbance also played a key role. At the end of the 20th century, the Iberian lynx was on the brink of extinction. Alarm bells went off and around the beginning of the 21st century a turning point began. Large-scale nature restoration projects, funded by the European Union and national governments, formed the foundation of the resurrection of the Iberian lynx. The protection and expansion of suitable habitats were the first step. Factors such as the size of the area, the differences in altitude, the presence of food sources and suitable vegetation were consciously taken into account. A second major effort was the establishment of successful breeding programs in both Spain and Portugal. The bred lynxes are carefully raised and genetically monitored, so that they can later be introduced into the wild at strategic locations. Wild lynxes from the last remaining relict populations were also included and reintroduced to strengthen genetic diversity. Each reintroduction was preceded by thorough studies, in which it was investigated at which locations the chances of survival would be greatest. In addition, intensive efforts were made to protect the European rabbit population. By building artificial burrows and actively monitoring diseases, the lynx was given access to its primary food source again. Roads were also made safer with warning signs and different populations were connected to each other with bridge areas. Finally, there is the promotion of the relationship between humans and animals. By actively involving local communities in the recovery of the species, more understanding was created. Ecotourism became an important factor. People travel specifically to regions where the lynx lives, which provides new income and appreciation for nature conservation. The presence of the Iberian lynx not only strengthens the ecosystem, but also the bond between man and nature.

We can therefore conclude that the return of the Iberian lynx is a real success story for Europe. By thoroughly analyzing the causes, taking appropriate measures and making efforts, we have managed to give this top predator a future in the wild again.

Social relevance

The social relevance of the recovery of the Iberian lynx cannot be overstated. As this success story is not only a major victory for biodiversity, but also for the way society deals with the conservation of endangered species. The story of the Iberian lynx is in many ways an example of the broader problem of biodiversity loss. The species was on the Red List of Threatened Species at the beginning of the 21st century, with a population of less than 100 individuals in the wild. In 2025, the global population of the Iberian lynx is no longer threatened with extinction.

However, the recovery of the Iberian lynx shows that it is possible for critically endangered species to recover if the right measures are taken. At a time when humans are threatening biodiversity, ecosystems and species worldwide, this offers hope. This recovery project also has important social implications. It shows that the conservation of nature is not only the responsibility of scientists or conservation organisations, but that it also depends on the involvement of the wider community. The involvement of local pastoralists, farmers, nature lovers, guides and the local population has contributed to the success.

In addition, the project is also valuable on a socio-economic level. It promotes ecotourism, where the presence of the lynx acts as a major attraction. This offers new economic opportunities to local communities through the influx of tourists who want to observe the lynx in its natural habitat. The rise of ecotourism can in turn contribute to the conservation of the species by raising awareness of the value of biodiversity and the need for nature conservation.

This recovery project is proof that both nature and society are resilient. The recovery of the Iberian lynx is not only a triumph of conservation, but also of human cooperation and adaptability. It teaches us that the conservation of biodiversity is a responsibility that we all share. Europe can be proud of this achievement: it is an inspiring example of what is possible when people and nature work together to build a sustainable future.

Summary

In this thesis, I explore the spectacular return of the Iberian lynx, once the most endangered feline in the world. I highlight how this species, which was nearly extinct at the beginning of the 21st century, can now once again be found in parts of Spain and Portugal. The main cause of its original decline was the drastic loss of habitat and prey animals. The European rabbit is the primary food source and has suffered from a disease. Thanks to intensive conservation efforts such as breeding programs, habitat protection, reintroduction, and collaboration with local communities, the lynx population has increased significantly. As of 2025, the Iberian lynx is now classified as ‘vulnerable’ instead of ‘endangered’ on the global list.

The relationship between humans and animals is also addressed. Through preventive measures, compensation for farmers, and the promotion of ecotourism, steps are being taken toward a sustainable future. The return of the Iberian lynx is not only a biological success story, but it also reflects how society is evolving toward greater care and responsibility for nature.

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