By the early 2000s, the scrublands of southern Spain had lost a critical part of their ecological structure. Two viral outbreaks, spread largely through human activity, had nearly eliminated the European rabbit from the Iberian Peninsula. That loss had severe consequences for the region’s wildlife, particularly for the Iberian lynx, a predator that depends almost entirely on rabbits for food.

The Iberian lynx is a compact animal, weighing between 8 and 16 kilograms, with a spotted coat and distinctive black ear tufts. Its skull and jaw muscles are adapted for hunting a single type of prey: the European rabbit. However, its role in the ecosystem extended beyond eating. A territorial lynx would also hunt and kill foxes, mongooses, genets, and feral cats, not to consume them, but to remove competitors from its territory. This behavior exerted a regulatory pressure on the scrubland, keeping mid-sized predators in check and preventing them from over-consuming the rabbit population.

When the rabbit populations collapsed, the system broke down. The lynx lost its food source, and the mid-sized predators, no longer suppressed, multiplied and further depleted the remaining rabbits. The lynx population fell sharply. By 2001, only 62 mature adults remained in the wild, split between two fragmented areas of Andalusia. They were separated by highways and plantations, and their small numbers raised concerns about genetic diversity. The situation was set for the lynx to become the first feline species to go extinct since the saber-toothed cat.

In response, the Spanish government and the European Union funded a major conservation program. The initial goal was straightforward: breed the remaining lynx in captivity, release them back into the wild, and prevent extinction. The effort, which would eventually cost over 100 million euros over two decades, involved a coordinated approach that extended beyond breeding the cats themselves.

The captive breeding program was established in the early 2000s, but success did not come quickly. The first births occurred in 2004. Managing the breeding required careful genetic planning to preserve as much diversity as possible from the 56 founding animals. It also required handling behavioral issues. Around 44 days old, when kittens begin eating solid food, a dominant sibling would sometimes attack and kill its littermates. Staff had to monitor the litters constantly to intervene when these conflicts occurred.

While the breeding program worked on increasing the lynx population, the landscape needed to be prepared for their return. Early attempts to release rabbits into the scrubland failed because foxes and other predators quickly consumed them. To address this, conservationists built artificial warrens using wooden pallets and earth to shelter the rabbits. They also used a non-lethal method to suppress predators: meat baits laced with a nausea-inducing compound and scented with vanilla were placed in the release areas. Foxes that ate the bait became ill and learned to avoid the vanilla scent. When rabbits with a vanilla scent appeared, the foxes were less likely to hunt them. Over 100,000 rabbits were eventually restocked into these engineered shelters.

The release sites also required infrastructure changes. Road collisions were a major cause of death for dispersing lynx. Underpasses and wildlife corridors were built beneath major highways, along with tall fencing designed to steer the animals toward safe crossing points.

The first captive-bred lynx were released at scale in 2010. They spread across the landscape, establishing territories that had not hosted lynx in decades. Within two years of lynx establishment in these zones, populations of red foxes and Egyptian mongooses had dropped by 80%. The lynx were again fulfilling their role as regulators of the ecosystem.

The data from these reintroduction zones produced a notable finding. Even though a lynx consumes roughly one rabbit per day, the total pressure on rabbit populations in areas with lynx was lower than in areas without them. By removing the numerous mid-sized predators that also eat rabbits, the lynx effectively reduced overall predation on the rabbit population by 55.6%. One specialist predator had replaced the collective pressure of many generalist ones.

This result had a significant impact on public opinion in rural Spain. Landowners and gamekeepers had traditionally viewed the lynx as a competitor for rabbits and partridges, and illegal traps and poisons had killed lynx in the past. The new data, however, showed that valleys with lynx produced more rabbits and partridges. Over 200 private landowners signed conservation agreements covering more than 150,000 hectares.

The lynx population grew steadily. By 2015, the species was reclassified from critically endangered to endangered. By 2020, the total population exceeded 1,000, and the captive breeding program was no longer needed to sustain the population. Lynx began to expand into new regions, including areas with working agricultural landscapes, such as olive plantations. In some areas, the presence of lynx supported a growing wildlife tourism economy.

The broader system remains fragile in some respects. New mutations of rabbit hemorrhagic disease continue to threaten the rabbit population, and the Iberian climate is gradually drying. The European rabbit itself is now considered more threatened than the lynx that depends on it.

By 2024, the population had grown to roughly 2,401 individuals, including 470 breeding females. Occupied territory had expanded from 449 square kilometers to over 3,300. In June of that year, the IUCN reclassified the species from endangered to vulnerable.

Researchers have also documented an unexpected behavior change. In 2020, a camera trap recorded a female lynx holding a freshly killed rabbit underwater near a trough. Similar behavior was observed several more times over subsequent years. Researchers suggested that the females may have adopted this technique to provide water to their cubs during the dry season. The behavior was documented in a study published in the journal Ecology in 2026.

The recovery of the Iberian lynx required the reinstallation of a regulatory mechanism that had been missing from the landscape for decades. The project demonstrates how a single species can affect the balance of an entire ecosystem. The lynx, driven by instincts developed over a million years, continues to enforce territorial rules that the scrubland was built to respond to.