Threats to Grasslands

The grassland biome consists of land dominated by grasses instead of shrubs and trees. Grasslands go by various names in different parts of the world: In North America, grasslands are called prairies; in South Africa, they are velds; in Asia, they are called steppes; in Australia, rangeland; and in South America, the pampa. Two types of grasslands occur on Earth: temperate and tropical (also called the savanna). Temperate grasslands are found north of the tropic of Cancer and south of the tropic of Capricorn, while tropical grasslands occur near the equator.

Grasslands receive varied precipitation from season to season, ranging from deluges of rainfall to prolonged dry periods. The dry periods can be made worse for the ecosystem by overgrazing, the overuse of pesticides, invasive species, and the depletion of groundwater sources. The savanna’s shallow soil bakes in the hot dry seasons, and its porous consistency allows water to drain quickly, so even though savannas experience distinct dry and wet seasons, heavy downpours in a few concentrated regions must serve widespread ecosystems. Grazing, cutting, fires, and the trampling of the land by animals represent the greatest threats to grasslands, all of which lead to desertification. For example, elephants have been blamed for trampling large areas of African savanna that have turned into desert. Temperate grasslands have a wider temperature range than the savanna, but they receive slightly less rain. Savannas average 20–50 inches (51–127 cm) of rainfall per year; temperate grasslands receive 20–35 inches (51–89 cm).

China’s grasslands provide examples of the varied forces that conspire to bring a sensitive ecosystem to disaster. From the 1950s to the early 1980s, Chinese leaders encouraged the development of self-sufficiency within the population along with food security. Farmers and ranchers migrated to the steppes to cultivate the land and release cattle to graze. Without adequate knowledge of grassland conservation, the steppes became overgrazed and turned into barren land. Droughts and soil erosion had been increasing in the vast China plateau at the same time. Until 1998 China had no national plan for recovering the steppes or preventing further desertification, and even since then only two national laws focus on land loss from desertification. Currently, global warming has accelerated glacier melt on China’s Qinghai-Tibet plateau. The melting causes large amounts of runoff to erode the plateau’s soil, to be followed by desertification.

By the late 1990s, massive sandstorms swirled across China’s plateau, burying barns, vehicles, and sometimes animals. China Daily reported that between April 14 and 18, 2006, 330,000 tons (299,375 metric tons) of sand landed on the city of Beijing after the wind swept it across thousands of miles of steppes. Efforts have begun to recover the land from the desert by replanting it, but progress has been slow and frustrating. Farmer Zhang Minqing, a resident of Sichuan Province, was quoted in the New York Times as saying, “Last year [2003] our first crop failed because we didn’t know what we were doing. We didn’t provide enough water and they all died.” Still, once farming rebounds in China, the land will stabilize and offer more hope for improved conditions.

Each year in March through May, the sandstorms in China roll east. Yang Weixi, the chief engineer at the Desertification Control Center, lamented in 2006, “Given the millions of square kilometers of desert in China, they will continue to be a source of sandstorms in the future, and we cannot cherish unrealistic expectations this problem will vanish overnight.” Once desertification has taken hold, it is very difficult to reverse.

Source of Information : Green Technology Conservation Protecting Our Plant Resources