The History and Evolution of Grasslands:
Geologically speaking, grasslands are one of the youngest ecosystems of the planet, second only to the modern deserts (Raven, 1986). Grasslands, and grass plants themselves, first made an appearance only 54.9 million years ago, whereas the first plants appeared over 505 million years ago (Raven, 1986). This phase is called the Eocene epoch, close to the beginning of the Tertiary period. Climatically, this was a tropical time in the evolutionary development of the planet; Australia had newly separated from Antarctica and India had collided with Asia producing the Himalayas. In comparison, forests gained domination as early as 360 million years ago during the Carboniferous period.
It has been argued that early humans moved with the savannas and grasslands as they hunted the grazing animals. It is certain that since the first agrarian society, human settlements have depended on grasses. Ecologically speaking, the wild cereal grains grow readily on open or disturbed areas. It is thought that the first people to gather this grain may have scattered seeds at their campsites, either on purpose or accidentally. They may have noticed that the cereals grew well, thus leading to the beginning of the cultivation of cereal crops. So, a more dependable food source was secured, the campsites grew into villages, and commercial trading began.
The Agrarian Revolution:
With the development of cultivation, the characteristics of the cultivated crops would have changed gradually as people selected more seeds from plants with certain desirable characteristics, such as an ease of harvest, good storage potential, and most importantly, good eating. This domestication of grasses (along with other plants and animals) began about 1 1,000 years ago in the "Fertile rescent" of the eastern Mediterranean region, in lands that extended through the modern countries of Lebanon, Syria, Turkey, Iraq and Iran. This cultivation began about 10,000 years ago with the cultivation of rice in Asia, around the areas of modern Thailand (Raven, 1986).
The cultivation of grasses became more and more organized as time went by. Spedialized implements were designed for planting and harvesting, pots and other containers were devised for improved storage, and grinding implements were created and refined. With the cultivation of plants came the domestication of animals. As humans increased in numbers, there were larger and larger herds of grazing animals, which began to over graze this amazingly fertile region. In addition to the damage caused by overgrazing, soil erosion caused by the sharp hooves of these animals eventually turned rich grasslands to deserts. Destruction of vegetation, along with soil erosion and climate change, has devastated vast regions of this planet.
Overgrazing destroys the plant communities because it does not give them enough time to grow between grazings, so they have a lesser chance of seeding for the next generation of plants. This destruction of vegetation leads to high rates of soil erosion and eventually to the creation of deserts; a process known as desertification. Once an area has been overused and becomes desertified, the possibilities of recovery become slim.
The ecological destruction caused by domesticated animals seems to be a basic characteristic of human population growth and development, as our herds are still overgrazing grasslands and the world's and regions are still increasing. Desertification has become a major problem throughout the world, including North America.