For many years, parts of northern and western China have become increasingly dry and desert-like. This does not always mean that the land is covered with sand. In some areas, there is very little rainfall, and the surface of the ground has become extremely hard. When rain finally falls, much of the water runs across the hard surface instead of entering the soil. China has tried many ways to stop desertification, including planting millions of young trees. However, trees alone cannot always repair a damaged grassland ecosystem.

Scientists began to consider another solution: bringing back large wild horses that had once lived in these grasslands. Przewalski's horses are strong, heavy animals with powerful hooves. As groups of horses walk and run across hard ground, their hooves can break parts of the hard surface and create small spaces and depressions. Rainwater can collect in these places instead of immediately running away. The horses also leave manure, which returns nutrients to the soil. In this way, the animals may help create better conditions for plants to grow.

An especially surprising result is what can happen underground. Seeds from grasses and other native plants may remain in the soil for many years without growing because conditions are too dry. When more water remains in the soil and nutrients are added by the horses, some seeds can begin to grow again. The horses can also carry and spread seeds as they move across the land. Gradually, grasses and other plants can return, creating food and shelter for insects, birds, and other animals. The project shows an important idea behind rewilding: sometimes protecting nature is not only about planting something new. It can also mean bringing back an animal that once played an important role in keeping an ecosystem healthy.

 

Vocabulary

desertification, the process in which healthy land becomes increasingly dry and unable to support many plants

terrain, the physical type and surface of an area of land

rainfall, the amount of rain that falls in a place

surface, the outside or top layer of something

runoff, rainwater that flows across the ground instead of entering the soil

soil, the top layer of earth in which plants grow

rewilding, returning animals or plants to an area where they once lived

hoof, the hard foot of an animal such as a horse

nutrient, a substance that helps a plant or animal grow

manure, animal waste that can make soil more fertile

fertilize, to add nutrients to soil so that plants grow better

dormant, alive but temporarily not growing or developing

native, naturally belonging to a particular place

ecosystem, the plants, animals, and environment that live and work together in an area

restore, to bring something back to a healthier or earlier condition

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Discussion Questions

1. What is desertification?

2. How is this type of desert different from a sandy desert?

3. Why does rainwater sometimes run off very hard ground?

4. Why did China plant large numbers of trees in dry areas?

5. Why might planting trees alone not solve the whole problem?

6. Why are large wild horses useful in this restoration project?

7. How can the horses' hooves change the ground?

8. How can hoofprints help rainwater remain on the land?

9. Why is horse manure useful for the soil?

10. What does it mean when a seed is dormant?

11. How can seeds survive for many years without growing?

12. What might cause old seeds in the soil to begin growing again?

13. How can horses spread seeds from one place to another?

14. What other animals could benefit when grasses and plants return?

15. Why might bringing back an animal improve an entire ecosystem?

16. Which do you think is more effective in this situation: planting trees or reintroducing animals? Why?

17. What problems could occur if too many horses lived in one area?

18. Do you think people sometimes try to solve environmental problems without fully understanding how nature worked in the past?

19. Can you think of another animal that changes its environment in an important way?

20. What is the most surprising part of this rewilding project for you?