Wildlife managers should watch the growing population closely in case of negative ecological effects in the future
Thousands of years after wild horses last roamed the Italian Peninsula, a growing population is now grazing—and potentially maintaining—grassland near Florence.
“The horses might be an asset for the preservation of these grasslands,” said Ilaria Greco, a research fellow in ecology at the University of Florence.
During the Pleistocene and perhaps the Early Holocene, horses distantly related to the domesticated species found all around the world and in some reintroduced wild populations used to roam the grasslands of Europe.
The questions of exactly which species these may have been and where they roamed are complicated by years of interbreeding with domesticated horses. The Przewalski’s horse (E. f. przewalskii), which lives in Mongolia, is the only subspecies of wild horses that has survived in some form to the present day. But horses in Italy were likely related to the now extinct tarpan (Equus ferus ferus). The genes of all domestic horses today are made up of these horses and potentially other wild subspecies.
Wild horse release
Around 40 years ago, a breeder released some domesticated horses into La Calvana, a protected area in central Italy. The population did quite well, expanding in the mountainous area until it reached a number of around 83 individuals in 2024, according to census data carried out by Associazione Salvaguardia e Sviluppo Calvana, an association focused on preserving La Calvana.
Researchers have studied little about the impact of this feral population, though. In a study published recently in the Journal of Wildlife Management, Greco and her colleagues sought to understand more about the ways that the horses used the landscape in La Calvana and how they interacted with other ungulates in the area.
“It was an accidental rewilding project—we are just studying the consequences of it,” Greco said.
From May to July 2022, the team placed 40 trail cameras in La Calvana—one for every 2 square kilometers in an area spanning 45 square kilometers. Each camera was active in the field for at least 30 days during this period.
Analysis of the photos revealed that the horses tended to use the upper-ridge grasslands in the area more often than other regions.
Forest encroachment has been increasing in this area over the years, leading to a decrease in grasslands home to various endemic and rare plants. But Greco said that the horses’ grazing is likely stopping the encroachment of forests in these areas.
“This is a demonstration of the utility of the horses actually taking care of the grassland,” she said.
In some ways, this might be coming at the expense of other ungulates, though. The trail cameras caught native ungulates like roe deer (Capreolus capreolus), common fallow deer (Dama dama), red deer (Cervus elaphus) and wild boar (Sus scrofa) showing up in some of the same areas as the horses, but not at the same time. The trail cameras revealed that the horses were taking up prime areas for keeping cool, such as shaded grassland during hot days. “Other ungulates, they avoid these places,” Greco said.
This may be due to the size of horses, but it also may be due to their tendency to move in larger herds than these other ungulates.
The trail cameras also revealed that humans using the area for recreation didn’t bother the horses much.
Growing population
Census records revealed that the horse population in La Calvana has grown by about 12% each year from 2018 to 2024. This translates to a density of roughly 1.8 horses per square kilometer, Greco said.
While the density doesn’t seem to be a problem as of now, she said that wildlife managers should continue to monitor the situation so the population doesn’t grow out of control, like it has in western states in the U.S.
Wolves (Canis lupus) occasionally prey on horses in the area—records show they kill about three per year, Greco said. But there aren’t many other predators there, and most horses there die from other causes.
Currently, horses are still considered domestic animals, so the Italian government doesn’t regulate the population. Just before 2018, when the census began on the population, unknown people removed some 30 horses from the area, potentially with the goal of domesticating them or potentially killing and eating them, Greco said.
In other parts of Europe, stakeholders involved in rewilding efforts are attempting to create a new label for domestic species reintroduced into the wild, such as these, but there are currently no laws to regulate them one way or another.
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