Establishing baselines for trophic rewilding: mammal density, occupancy, and activity patterns in two Italian sites

Imagine the natural world as a giant, bustling city where every animal has a specific job, a favorite neighborhood, and a strict daily schedule. Some are the early risers, some are the night owls, and some are the quiet neighbors who only come out when the streetlights are off. For decades, humans have been the landlords of this city, often kicking out the original tenants or changing the rules so much that the ecosystem gets out of balance. Now, a movement called "rewilding" is trying to fix this. Think of rewilding as a massive renovation project where conservationists want to bring back the original, wild tenants—like big herbivores—to restore the city's natural rhythm and make it run on its own again. But before you can renovate a house, you need to know exactly what's already inside: how many people live there, where they hang out, and what time they wake up. If you don't have a solid "before" picture, you can't tell if your new furniture is actually helping or making things worse. This is the challenge scientists face: they need a clear, data-driven snapshot of the wild city before they start moving in the new residents.

This paper is that snapshot. Researchers Niccolò Ceci and his team from Sapienza University of Rome went to two very different Italian neighborhoods—the Alfina Plateau in Umbria and the Diaccialone estate in Tuscany—to take a census of the local mammal population. They weren't just counting heads; they were acting like detectives with high-tech cameras, trying to figure out three big things: how many animals were living there (density), exactly where they were hanging out (occupancy), and what their daily schedules looked like (activity patterns). They focused on six key characters: the badger, the marten (a clever cat-like creature), the porcupine, the red fox, the roe deer, and the wild boar. Using a grid of camera traps that snapped photos whenever an animal walked by, they built a detailed profile of these wild communities. Their goal was to set a "baseline"—a scientific starting line—so that when the planned rewilding projects (which involve bringing back large, free-roaming herbivores) begin, we can compare the "after" pictures to these "before" pictures to see if the ecosystem is actually healing.

Here is what the camera traps revealed about the two neighborhoods. First, the population counts were quite different. In the Alfina Plateau, which is a mix of open fields and woodlands, there was a huge number of porcupines and martens. In contrast, the Diaccialone estate, which is a private, hunting-free reserve with dense woods and some semi-free-ranging cattle, was packed with wild boars. The wild boar density there was so high it was likely inflated because a few cameras happened to be placed right in the middle of their favorite hangout spots. Roe deer, however, were equally common in both places, suggesting they are happy in either environment. The badgers and foxes were present in both, but their numbers varied slightly.

The researchers also looked at where these animals preferred to live. They found that almost all the animals were present across both sites, but the "detectability"—how easy it was to spot them—was higher in Alfina. This is likely because Alfina has more open spaces, making it easier for the camera lenses to see the animals, whereas the thick, complex woods of Diaccialone act like a camouflage net, hiding the animals from the cameras. Interestingly, the martens seemed to avoid the grazing areas in Diaccialone, perhaps because the livestock disturbed them, while in Alfina, they seemed to like being near human buildings, possibly because the beech marten (a type that likes living near people) was the main one there.

Finally, the study uncovered some fascinating daily schedules. The badgers and porcupines were strict night-shift workers in both places. The martens, however, were the ultimate night owls who also worked day shifts, staying active all 24 hours. The red foxes showed the biggest difference between the two sites: in Alfina, they were active for a long time during the day and night, but in Diaccialone, they were much more strictly nocturnal, hiding during the day. The scientists suspect this is because Diaccialone has a stable pack of wolves and daily livestock, forcing the foxes to be more cautious and hide until dark. The wild boars were also more active at night in Diaccialone, likely because the dense woods there concentrate their food, so they don't need to wander as far, whereas in Alfina's open fields, they had to spend more time foraging.

The paper concludes that these two sites are already home to diverse and active wildlife communities, but they are shaped by different pressures like hunting, livestock, and habitat type. The authors suggest that when the rewilding projects introduce large herbivores, these changes could ripple through the community. For instance, more grazing might reduce the undergrowth, which could make life harder for the porcupines but easier for the foxes. They also warn that the presence of wolves in both areas, especially the stable pack in Diaccialone, means the new herbivores could be at risk of predation. The study doesn't claim to have solved the puzzle of how rewilding will play out; instead, it provides the essential "before" data. By having these precise numbers on density, location, and daily habits, conservationists can now watch closely to see if the ecosystem changes in the ways they hope, or if they need to adjust their plans to keep the balance right.