In the first battle of what became known as the Emu War, in November 1932, the Australian army attempted to eliminate the plague of this bird, almost as large as an ostrich, with machine guns. It was damaging the country's cereal crops. But these birds dispersed very quickly and the operation failed. A few days later, according to chronicles, in a second campaign the soldiers adopted more mobile tactics and managed to shoot down hundreds of emus, but without sufficiently reducing the population. In fact, the Emu War is remembered as a symbolic victory of the emblematic emu over the Australian army.
And now, almost a hundred years later, faced with the advance of African swine fever (ASF) among the wild boars of Collserola and the risk of the disease reaching pig farms, we have maintained the same tactic, under a more elegant nomenclature: "zero density objective". If this is about battles, we are not approaching it correctly.
Before the arrival of this ASF outbreak, it was already evident that we had a problem with the expansion of wild boars. Year after year, their population continues to grow, as this ungulate lives very well alongside industrialized societies, where so-called progress has distanced us from nature. The mountain, a space with which our grandparents knew how to coexist very well – caring for it and utilizing it at the same time – has undergone a transformation very conducive to the life of wild boars.
And I see this when, from time to time, I go down to the beginning of Horta street to have breakfast at Bodega Massana. There they have old photographs of the town of Horta hanging, from shortly after it was annexed as a neighborhood of Barcelona. And you can see a Collserola completely different from today. It's not all forest, on the contrary, it's all crops or terraces, and rural paths where shepherds led their flocks. Firewood was used, and there were those who made a living making charcoal. An ecosystem of integration between human activity and nature in balance.
Hopefully, as the years go by, we will rediscover this holistic management of the mountains. Recovering a mosaic landscape, with crops, pastures, and herds, would not only make the territory less prone to the large forest fires that the country currently suffers. If we are truly concerned about the excess of wild boars and the diseases that stem from them, we need to make decisions along these lines, more reasonable and effective than just loading shotguns. And this means having a couple of dozen herds of goats and sheep grazing in Collserola again. It is easy to understand that, with their presence, the forests are cleared and the life of the wild boar, which likes the current "impenetrable" state, becomes much more difficult. Carles Conejero, a veterinarian with the soul of a shepherd, tells me: "Where a herd eats, the wild boar neither eats nor sleeps."
The presence of herds not only reduces the presence of wild boars, but, as a recent study published in the journal Journal of Environmental Management corroborates, this traditional extensive farming helps to slow down the circulation of pathogens. In fact, it is logical: it is the same as what happens when we analyze the vulnerability of a monoculture and the ease with which a plague can advance in a uniform landscape. Returning to Carles' simpler language: "The more diversity of species there is within the same ecosystem, the less prevalence diseases have."
This research adds a final virtue to the proposal to recover living and diverse ecosystems, instead of focusing on an obsessive fight against a single species. Using innovative health markers, such as the ADA enzyme, which indicates the level of immune system activation, researchers have found that wild boars coexisting with herds show less inflammation and a better general health status, which reduces the risks of disease transmission at the interface between wildlife, livestock, and humans.
The problem is not that there are too many wild boars, but that we have emptied the mountain of crops, shepherds, and herds. It is not a matter of nostalgia; it is a direct investment in the resilience of our territory, in the fight against devastating fires, and in the health security of us all.
