Эпизод 2

Chris travels to the savannah of Kenya, the grasslands of Australia and the Cerrado of Brazil to witness how one of our most important ecosystems work - grasslands. The secret of grasslands is not what they have, but what they don't have - and how they cope. Grasslands are lacking in one crucial nutrient. Nitrogen is the element necessary for all proteins, the building blocks of life. You can't grow without it, yet nitrogen-poor grasslands around the world support some of the world's largest animals. Something that's only possible, thanks to the ways that these ecosystems ‘manage' their nitrogen. Chris travels to Kenya to see the surprisingly important role that rhinos play in making the grasslands fit for antelope. In the Brazilian Cerrado, he sees how maned wolves get by on a low nitrogen diet by gardening their own fruit. And how anteaters hunt the world's richest source of nitrogen... not ants, but termites. In Australia, Chris encounters a weird cast of mini grassland characters, such as bandicoots and quols, driven to the edge of extinction by the introduction of alien species. Foxes and domestic cats have removed much of Australia's natural grassland fauna and, as a consequence, the whole ecosystem has suffered. Finally, Chris returns to East Africa to reveal how one extraordinary ecosystem works - that of the acacia tree. A gecko, a giraffe, an ant and a monkey all depend on this tree for their survival ... but what's really wonderful is how these individuals and the acacia also depend on the actions of each other.