People around the world acknowledge the importance of forests and trees to humankind and the survival of our planet. But grasslands; the wind-torn steppe of South America or rolling prairies of Northern America; surely these do not score highly in the global index of priority conservation habitats? 

Wrong. 

This diminutive habitat is in fact an important agent for carbon sequestration and provides crucial habitat to large herbivores, top predators and a plethora of species; many of whose populations are threatened. 

For nearly twenty years, Kristine McDivitt Tompkins and her husband Douglas Tomkins have been battling to conserve this and other globally exploited and degraded habitats in Chile and Argentina; restoring vast tracts of grassland in southern Patagonia and raising consciousness of the forgotten and misunderstood grassland ecosystem. 

When Katharine and David Lowrie ran into McDivitt Tompkins in her Patagonian home, along the route of their 5000 mile year-long run of South America, they took the opportunity to quiz her on the significance of this under-celebrated landscape.

8 November 2012, Patagonia.

Miraculously, after three months and over 1,200 miles of running from the southernmost tip of continental South America, we're on time for one of the most important interviews of our expedition. We are meeting with Kristine McDivitt Tompkins and her husband Douglas Tompkins, who have protected more land than any other private individuals in the world – over 2.2 millions acres.

We settle deep into the cushioned sofas in her home in the fjords of southern Chile, as plump raindrops burst against the windows and the verdant gardens beyond receive their daily inundation. Kris curls by the fire instantly setting us at ease. She's just returned home from a six week intensive fundraising trip and is clearly tired from the long flight, but still offers us tea and chocolates and begins answering our abundant questions on her work in Patagonia restoring and conserving grassland ecosystems.

Kris has always been passionate about grasslands after a childhood spent exploring the ranch-land of her home in southern California. The loss of the great grassland ecosystems of North America - once home to tens of millions of bison - which shaped the vast floral and wildlife-rich prairies, resonated deeply with her. The biodiversity-rich habitat had been replaced by intensively grazed, biodiversity moribund pasture and croplands, leaving an estimated 1% of the former prairies “unimproved”.

This trend, she told us, has been repeated throughout the world's major grassland biomes of Australia, southern Africa, Asia and South America. But it is in the last of these regions, the Patagonian steppe of Chile and Argentina; where the mighty Andean condor still flies and the long-necked guanaco gallops, that Kris has chosen to focus her conservation work.

In 2000 she formed Conservacion Patagonica (CP) and in 2004 the conservation charity bought a 200,000 acre Estancia in Valle Chacabuco, in the Aysen Region of southern Chile. Here, gradually, CP is restoring this highly over-grazed area of Patagonian steppe into functioning grasslands. 

First the 30,000 sheep and 3,800 cattle were sold, removing the relentless grazing pressure on the impoverished land. Next began the task of removing hundreds of miles of fencing; an on-going job, but crucial for allowing wildlife movement and access. The fences additionally caused the gory death of hundreds of guanacos, which were found hanged up in the wire after failed jumping attempts. Countless other projects have been launched including; gathering native grass seeds to reseed denuded areas and wildlife-recovery programmes.

On our way to our interview with Kris we ran to the Chacabuco Valley. We wanted to meet the team who are restoring the area and catch a glimpse of some of the fabled wildlife. The view was extraordinary. Ochre grasslands swept over a rolling plain. The winter-purple outline of the southern beech lenga forests clutched the hillsides and soared up to the jagged snow-capped Andean peaks. 

When we asked Kris about her greatest wildlife moments, it was this view which she christened as one of the 'big moments'; “Sitting on a hill, looking over the Chacabuco Valley and watching guanacos from up on high. It was like a whole story in a snap shot; how the grasslands had never been in better shape (since modern man arrived) and that there, at that moment: guanacos, armadillos, birds, mountain vizcachas... were all thriving”.

The vivid contrast to the neighbouring Patagonian steppe through which we have been running was starkly clear. There, dust storms and tumble-weed danced across the road, a few unpalatable spiky shrub species pock-marked the terrain, hundreds of cloven hooves compacted the soil, a handful of guanaco fled at the merest sniff of us. The soil, vegetation and species appeared to be crumbling before our eyes in the deadly march of desertification. 

Del Valle (1998) confirmed this devastation, stating that an estimated 65% of Patagonia's grassland was seriously degraded; only 9% was lightly affected and in no area was grazing negligible.

It is not only the sheer number of domesticated animals that have destroyed the steppe grasslands, it also the manner in which they use it. The native guanaco in comparison has grazed the habitat for millennia, adapting to its hydrological, vegetative, edaphic and climatic variables; functioning within the ecosystem of the steppe rather than imposing upon and transforming it.

In addition, an oft quoted reference to wildlife from the ranch-land owners we have spoken to in Argentina elucidates the predicament, “Todo son bichos”, translated as, “They're all insects”. This has led to hunting of pumas, guanaco, Darwin's rhea, Patagonian Humbolt skunk, Patagonian armadillo, in fact virtually everything that moves; producing an unbalanced, unhealthy ecosystem.

Kris and her CP team are leading the way in restoring threatened wildlife such as the endangered huemul deer. A little known species endemic to Chile and Argentina, yet with less than 2000 individuals remaining in the wild, is in similar peril to the rather better known giant panda. CP is also studying the much maligned puma, to find solutions to prevent its relentlessly hunting by ranchers who kill the animal to prevent attacks on their sheep and livelihood. For the puma, sheep replace its natural diet of guanaco; a species that has been extirpated from 60% of its former range (IUCN, 2013), chiefly due to competition with livestock for pasture and water. 

Kris, who proclaims she identifies more with animals than humans, beams when she discusses one of her favourite projects, the Livestock Guardian Dog Programme. This initiative draws from European shepherding history and employs Great Pyrenees dogs to guard livestock against attacks from predators such as pumas and culpeo foxes. “The key to the dogs' work, Kris explains, is that they believe they're sheep!” 

CP bought five dogs as puppies and ever since they have lived with the sheep; feeding and sleeping amongst the flocks. Their smell, bark and very presence dissuades the predators from attacking. There has been no history of using dogs to deter predators in Patagonia and so CP is demonstrating the effectiveness of this model to ranchers throughout the region. Kris elaborates, “It's a relatively simple solution with a reduction in flock predation of 60 -80% or more”.

Whether pumas in Chile, tigers in India, jaguars in Central America or lions in Africa, the relationship between farming and large cat predators is lethal - with the cats constantly on the losing side. The importance of CP's model is huge and great news for both pumas and farmers.

But for Kris the puma is an enigma, “It's like boyfriends, when you look, you just can't find them! So I stopped looking, stopped concentrating on seeing them, but still I haven't see one!”

Whether pumas, flamingos, Darwin's rheas, upland geese or guanacos; a fantastic diversity of wildlife can be thankful to Kris and her team as it flourishes in the oasis that is now Chacabuco Valley. Kris intends to donate this wildland to the Chilean State, which in combination with the neighbouring Jeinimeni and Tamango National Reserves will form a 650,000 acre National Park. This will form a vital stepping stone in global grassland conservation; with only 4% of the world's grasslands currently protected. 

The Chacabuco Valley has been crowned by Thomas Lovejoy (the man who coined the term 'biodiversity') as, “The world's largest grassland restoration project”. Kris McDivitt Tompkins is certainly fulfilling her dream of waking the world up to the importance of grasslands and her vision to, “leave behind a lasting legacy of new parklands and restored landscapes”. As she puts it, “To help pay our rent for living on this planet”.

Ecologist husband and wife team, Katharine and David Lowrie, are currently 2,500 miles into their world first expedition to run the length of South America, over 5000 miles, in a year, unsupported, for the continent’s wild lands and wildlife.

They pull a trailer they made from recycled materials containing all they need to survive, including: food, water, camping equipment, laptop and binoculars. As well as their daily 20 mile run, they undertake wildlife surveys, present to schools and interest groups and write articles about the environment they’re running through.

Their goal is to connect people from the UK and the world to South America’s remaining wildernesses; showing how our actions impact upon them and how with small steps we can help to conserve them.

To follow Katharine and David’s expedition click www.5000mileproject.org and www.facebook.com/5000mileproject