As late May approached, the animals were growing restless. In little more than a day, the heat from the southerly desert winds had turned the grass dry, leaving Jesús Garzón's herd of 1,100 sheep and goats little to eat. Garzón knew – and the animals, nervous and bleating, knew as well – it was time to head north, where cool weather and fresh pastures awaited them.
Ahead lay an over 400km (250-mile) journey by foot across the Iberian Peninsula through heat, cold, wind and rain. Out of the winter lowlands west of Madrid, past crops of barley and wheat, through holm oak meadows speckled with juniper and rosemary, to forests of scots pines, where imperial eagles nest and black vultures breed. Continuing north through villages and cities into the territory of roe deer, wild boar and wolves, ascending plateaus and descending river valleys until, a month later, they would arrive at their summer destination: the mountain pastures in the Picos de Europa.
Every spring and autumn, Garzón and his herd make this seasonal migration, called transhumance – from the Latin trans for "across" and humus for "earth" – a form of pastoralism where animals typically move to and from summer highlands and winter lowlands to take advantage of seasonal peaks in pastures and avoid extreme temperatures.
After falling into steep decline in the latter half of the 20th Century, the recovery of transhumance in Spain demonstrates how pastoralism, a livelihood suited to coping with uncertainty and sustainable food systems, can help preserve biodiversity, while breathing life into depopulated rural areas.
Practiced by 200 to 500 million people across the world's rangelands – grasslands, savannahs, mountain pastures, tundra and steppe covering half the earth's land surface – pastoralism is significant socially, environmentally and economically. Yet misconceptions and an underappreciation of its benefits means it has been largely overlooked in international sustainability discussions and agendas.
As a herder who has also been at the forefront of efforts to revive this ancient practice and raise awareness of its importance, Garzón understands its potential, and its challenges, well.
Transhumant herds pass winters in lowlands where pasture and water are plentiful (Credit: TyN)
After thriving for hundreds of years, in the 20th Century modernity caught up with transhumance in Spain. Rail and eventually truck transport took its place, while many herders intensified production and settled. Long-distance transhumance up to 700km (435 miles) ceased to exist and the network of drove roads fell into disuse. For decades, only short journeys – transterminance – continued.
The end of transhumance in Spain had severe ecological impacts. Abandoned mountain pastures experienced biodiversity loss and heightened wildfire risk; lowlands suffered overgrazing and trees stopped regenerating.
It was the lack of new trees that brought Garzón, who previously worked in conservation, to transhumance. It was a turning point for him. At the time, he recalls, re-establishing transhumance was considered "totally impossible", but he persevered and in 1993 assisted Spain's first transhumance in more than half a century. Shortly after, Garzón founded the Association for Transhumance and Nature (TyN), which supports transhumant herders who face legal or logistical obstacles.
From the start, Garzón's objective was to recover Spain's drove roads, etched over centuries into the land, measuring 125,000km (78,000 miles) in length. Although pastoralism is practised in 75% of countries, Spain is the only country worldwide with a network of legally protected drove roads for the movement of herds. But Garzón's vision for transhumance extends well beyond the country's borders. "We're trying to transfer the Spanish example of a network of livestock trails, that herders can use freely, to the rest of the world," says Garzón.
Herds typically cover distances of 20km (12 miles) every day during the spring and autumn transhumance (Credit: TyN)
Leaving the lowland pastures west of Madrid behind, the high-rises of the city came into sight. But the state of the drove road Garzón travelled by deteriorated as it approached the city. In the years since herds had used it, cars and motorcycles had degraded the grassland and eroded the soil. With little pasture and water for the animals, it was not a place Garzón would normally linger in. The herd was here, however, with a specific mission: to help restore drove roads in the vicinity of Spain's capital.
While camping equipment, portable electric fences to corral animals overnight and vehicles to ferry supplies have made transhumance somewhat more comfortable, the journey remains difficult. Highways, crops and private land frequently encroach the roads. Finding places to overnight is tricky, and what shelters exist are often in disrepair, lacking water and sanitation facilities. Water sources for animals are few and far between, or broken; and herding hundreds or thousands of animals across highways requires coordination from authorities.
The poor state of the drove roads is a major obstacle challenging the viability of transhumance and preventing further revival. "If you don't have a way to get from point A to point B, no matter how much you want to do it, you're not going to be able to do it," says Maria Fernandez-Gimenez, professor of rangeland ecology and management at Colorado State University.
Recognising this, the Life Cañadas project was launched to recover the ecological role of drove roads in Madrid and the region of Castile-La Mancha, improve connectivity between landscapes and help herders with problems they face. With the collaboration of herders like Garzón, herds are being reintroduced to facilitate restoration.
Drove roads function as ecological corridors and provide a refuge for plants and animals, says Francisco Azcárate, project coordinator and professor at the Autonomous University of Madrid. As herds migrate, mimicking the role of natural grazers, they disperse seeds, connecting habitats and preserving biodiversity. In Spain, each sheep transports 5,000 seeds and fertilises the land with 3kg of manure daily. "In Europe, nature needs herbivores that don't exist nowadays [and] a way of grazing the landscape that is very similar to what transhumance does," Azcárate says. "You need to work with livestock, move the animals and plan on a seasonal basis the management of territory."
The project will also repair water points and shelters. "We have hope that if we can solve some of these main problems, people will continue to do the transhumance, or other[s] can join in the future," says Azcárate.
To monitor changes, the team will measure soil properties, conduct biodiversity surveys of flora and fauna and sample grassland communities in experimental and control plots. To Azcárate's knowledge, this is the first project in Spain to attempt to physically restore drove roads.
Drove roads around the country are in bad condition after decades of abandonment, encroachment and inappropriate vehicle use (Credit: Life Cañadas)
Through grazing, pastoralism provides further benefits to the ecosystem. So long as a threshold of overgrazing is not crossed – which seasonal migration helps avoid – grazing stimulates plant growth, increases productivity, reduces soil erosion and facilitates water retention.
Grazing also helps reduce wildfire risk and lessen the intensity of fires that do break out, says Elisa Oteros-Rozas, a researcher at the Open University of Catalonia. "When pastoralism disappears, biomass accumulates," she says. "And that makes ecosystems more vulnerable to large-scale wildfires." In areas prone to wildfires, like the Mediterranean, grazing could be a cost-effective prevention method – especially as more and bigger wildfires are predicted due to climate change.
More recently, grazing is being touted as a solution to climate change. However, the extent to which grazing contributes to climate mitigation is the subject of much debate. Some researchers argue grazing has significant potential to increase long-term carbon storage. Estimates of how much sequestration is possible vary widely. One study by the UN Food and Agricultural Organisation suggests improved grazing management of the world's grasslands could sequester 409 million tonnes of CO2 equivalent per year – equating to 1.1% of annual anthropogenic carbon emissions.
Other research argues ambitious climate mitigation claims about grazing are wrong. A 2017 report by the Food Climate Research Network writes that while better grazing management is worthwhile for reasons like soil health, biodiversity and erosion control, overall, it is not a significant solution for climate change. The report suggests grazing management offsets between 20-60% of annual average emissions from the grazing sector, which accounts for only a small fraction of all livestock, making an insignificant dent on total livestock emissions. The same report also suggests that the carbon benefits of grazing management will diminish over time, as the soil becomes less efficient at sequestering carbon.
Unlike industrial farming, which relies on fossil fuels, chemical inputs and fodder, pastoralism only relies on seasonally available pastures. "Grazing animals make use of the resources that are not good for cropping and for agriculture, and turn them into food we as humans can digest and can eat," says Oteros-Rozas.
Pasture-fed animal products have better nutritional profiles, too. Feeding on natural biodiverse pastures produces meat, milk and cheeses that contain more nutrients and healthy fats. The combination of minimal external inputs and high-quality food make pastoralism one of the most sustainable food production systems.
While many benefits of pastoralism are enjoyed by wider society, it has particular potential to bring vitality to rural areas that have long suffered from neglect. "Pastoralism helps to create employment in rural areas and fights against rural depopulation, and maintains culture and a valuable gastronomy," says Celsa Peiteado Morales, agricultural policy and rural development coordinator at WWF Spain.
Many of the ancient drove roads criss-crossing Spain pass through villages and city centres, including the capital of Madrid (Credit: David Rubio)
A lack of official data makes it difficult to know the state of transhumance in Spain. By the end of the 20th Century, the number of transhumant sheep was estimated at 1.3 million. The last survey, from 2011, recorded 270,000 transhumant sheep, only 10% of which moved between pastures by foot. Garzón estimates there are currently 600,000 transhumant livestock – sheep, cows and some goats – and 6,000 transhumant families, 20% of whom move by foot.
For Garzón, transhumance is undoubtedly gaining momentum as climate change creates more challenging conditions – droughts, rising fodder prices – for sedentary livestock in southern Spain.
Research suggests a revival has occurred in some corners of Spain. In the Aragonese Pyrenees, for example, Fernandez-Gimenez found several families have resumed transhumance over the past decade after abandoning it due to difficult living and working conditions. For herders, the increased availability of low-cost winter grazing lands made transhumance more profitable than sedentary livestock, but access to inexpensive, high-quality summer pastures, as well as technology, which helps families cope with time apart, were crucial, too. "There are many ecological, animal health and lifestyle benefits to being a transhumant. But bottom line, it's more profitable and that's why people are going back," says Fernandez-Gimenez.
People without experience in transhumance who are looking for a new way of life are also helping revive it. Since the 2000s, shepherd schools have popped up across Spain, teaching new generations the ins and outs of herding and helping to reverse low rates of younger generations taking up transhumance.
Jesús Garzón and the herd of the Mesta Council pass summers in mountain pastures of the Picos of Europe, where pastures are plentiful and weather is mild. (Credit: TyN)
Elsewhere in Spain, restoring drove roads could help more herders resume transhumance by foot – particularly in Castile and León, a major transhumance waypoint and destination. According to Garzón, the region has not complied with the 1995 Livestock Trail Act that protects, preserves and promotes the drove roads. Because of their condition, herders are hesitant to use them. "I'm concerned that…in almost 30 years of the law, practically nothing has been done – no signaling, no demarcation, no improvement of the livestock trails," he adds.
Differentiating extensive grazing – when livestock are raised on natural pastures – from industrial farming is also key, says Peiteado. Without this distinction, "policies cannot be properly oriented in support of pastoralism," she says. "This characterisation and differentiation…is the first step that has to be taken to guarantee the future of pastoralism in Spain."
On one hand, says Peiteado, this would allow tools such as public funds from the European Union's Common Agricultural Policy to ensure the socioeconomic viability of extensive grazing. On the other hand, differentiation would allow consumers to support pastoralism. "The problem we have in Spain…is that when we go to buy a product in the market, as consumers we can't differentiate," says Peiteado. "There should be clear labeling that allows us to see what comes from extensive livestock farming and what comes from industrial livestock farming, so that knowing the impacts of one model and the benefits of the other, we can choose."
Oteros-Rozas agrees that acknowledging the true value of the product is critical. "Shepherds say they want the product to be valued, and priced according to the value…the main point is to stop subsidising industrial farming and imports of meat and dairy products from other countries…that compete in an unfair way with our local pastoral systems," she says.
Advocates of pastoralism are hopeful it will continue carving out a place for itself in a world that has changed profoundly since the first transhumant herders began their journey.
"Pastoralism is this way of life attuned to making efficient use of the available resources and adapting to what's there in a way that doesn't harm the system and often enhances it," says Fernandez-Gimenez. "Rather than trying to get rid of it, we need to learn from it, because those lessons are going to be ever more important under a changing climate and changing environment."
In the mountain pastures of the Picos de Europa, Garzón and the herd pass the summer in ease, waking to crisp mornings and occasional showers while the rest of the country swelters through record-breaking heat. There they will remain until the first snowfall, signalling the time to retrace their steps south has arrived.
"The planet is facing a situation of real social and economic catastrophe," says Garzón. "But pastoralism is going to survive."
The emissions from travel it took to report this story were 0kg CO2. The digital emissions from this story are an estimated 1.2g to 3.6g CO2 per page view. Find out more about how we calculated this figure here.
Join one million Future fans by liking us on Facebook, or follow us on Twitter or Instagram.
If you liked this story, sign up for the weekly bbc.com features newsletter, called "The Essential List". A handpicked selection of stories from BBC Future, Culture, Worklife, Travel and Reel delivered to your inbox every Friday.