Temperate+Grasslands+Human+Impact

Previous Temperate Grassland Home Next = = =//**__Human Impact on Grasslands__**//= Human impact is defined as occurrence/change attributed to the activity of humans.

=//__**Negative Impacts**__//=

**Climate Change**
A major threat to grasslands is global warming. This ecosystem is relatively dry with strong seasonal climate. They are very sensitive to climate changes and shifts in climatic regime. The primary source of human contribution to climate change is burning fossil fuels. Things like burning gas, coal, oil, and clearcutting greatly increase the CO2 concentration in the world.

A regional drought, shown in model simulations, caused a loss of valuable habitat for breeding waterfowl in an area that historically has produced 50-80% of the continent's ducks. Hot and dry conditions may also lead to the encroachment of new species and a greater risk of wildfires. (I13)

Wildfires, like prescribed burns, help maintain healthy ecosystems and reducing the amount of fuel sources for large-scale wildfires and providing ecological benefits through its returning of nutrients into soil. However, like all good things, in excess, it can harm the environment, ecosystem, as well as local community and public health. (I12) Increasing temperatures, reduced rainfall, and drought are already being observed in regions with this ecosystem, especially in the Southwest, where it is projected to become even drier, causing desertification.

Drought is a major driver of impacts to grasslands and prairie ecosystems. Many habitats -- such as prairie potholes that are critical for migratory birds-- are lost. Grasslands in the US are dominated by a few highly productive C4 species (low-latitude crops such as maize, sugar cane, millet etc.) as well as numerous C3 (mid latitude food staples, wheat, rice, soybean). Vegetation shifts from C3 to C4 grassland communities and phenological shifts impact ecosystems and species. Change in species composition as well as plant productivity also impact this ecosystem.

Any slight change in temperature and precipitation can greatly alter the composition, distribution, and abundance of species in the grasslands.

For example, predicted and occurring decreases in the frequency of freezing temperatures, lengthening of the season without frost, and increased minimum temperatures can alter plant species ranges and shift the geographic and elevational boundaries of many grasslands. The extent of these changes are also dependent on changes in precipitation and fire. Increased drought frequency could also cause major changes in vegetation cover. Losses of vegetative cover coupled with increases in precipitation intensity and climate-induced reductions in soil aggregate stability will dramatically increase potential erosion rates. Transport of eroded sediment to streams coupled with changes in the timing and magnitude of minimum and maximum flows can affect water quality, riparian vegetation, and aquatic fauna. Land trusts and conservation agencies are already observing these changes and are working to identify risks, reduce vulnerabilities, and manage grassland systems for shifting conditions. (I13)

Industrialization and Urbanization
Since grasslands are flat and devoid of trees, they are prime areas for urbanization and industrialization. Each year, acres of grassland are cleared away to build parking lots, buildings, and factories. In fact, only 5% of the original prairies in America remain(I1). Such massive destruction of natural habitats results in a steep decline in biodiversity. This fragmentation of grasslands also accelerates the extinction of native species (I5).

Besides the obvious effect of habitat destruction, industrialization in temperate grasslands also pollutes the surrounding ecosystems. More specifically, wastes from drainage pipes can end up in bodies of water. Animals that drink from these contaminated bodies of water can become very sick. In addition, organisms like fish and tadpoles that live in these waters can become poisoned and die (I11). If these poisoned animals are consumed by another, the consumer also gets poisoned I2 I3

__Agricultural Impacts__
In addition, the soil of temperate grasslands is often rich in minerals and nutrients, making them suitable for croplands and agricultural development. Demand for this fertile land leads to many problems to the surrounding ecosystem. The fertile topsoil of grasslands is very delicate and must be treated with care. Plants typically act as the soil's anchor, securing it to the ground. When livestock is introduced to temperate grasslands, overgrazing may occur. When this happens, the soil loses its anchor and gets blown away by the wind. Erosion of this precious resource is a root cause of desertification - the degradation and drying of previously fertile land(I8). Desertification is accompanied by a drop in both the gross and net primary product of an ecosystem.

Often times, the native plants are removed and replaced with new species. Some of these new species are inedible to the native wildlife and quickly takes over, damaging the natural order of the surrounding communities.

Cultivating too many crops depletes the soil's nutrient supply, causing fragmentation and deterioration of this biome, rendering it useless and unproductive. Habitat fragmentation also accelerates the extinction of a species(I5). With the cultivation of crops comes the use of pesticides and herbicides. According to the American Bird Conservatory, the cause of the recent decline in bird populations was due to the use of toxic pesticides(I4).

The native inhabitants of grasslands are often driven out to raise livestock. Predators of the livestock, like wolves and coyotes, are hunted until there are very few left. Native herbivores are also hunted because they compete with livestock for food. For example, the American Bison was almost hunted to extinction, with only 400 remaining in 1893(I6). The killing of native species upsets the balance of the ecosystem and in an extreme case, the elimination of a keystone species may result in the collapse of the ecosystem.



I7

I9

=__Positive Impacts__=

Humans are starting to realize how important grasslands are, and more effort has been taken recently to protect this fundamental biome. Such examples include:

- Bans and restrictions in the hunting of endangered animals - Creation of reserves to help protect the habitats of endangered animals - Educating people about the importance of grasslands and its topsoil - More and more farmers are using grassland-friendly methods such as crop rotation to prevent the sapping of nutrients - Rows of trees called windbreaks are planted to prevent wind from blowing topsoil away - Climate change policies address industrial and developmental habits that have caused harm to grasslands

I10

Though efforts to protect temperate grasslands are laudable, more needs to be done. For example, stricter laws and larger fines must be put in place to deter farmers and ranchers from damaging grasslands. The previously mentioned idea of educating farmers on how to properly treat grasslands will prevent large-scale degradation in the first place. The declining state of grasslands is a matter of exigency that will cause a severe blow to both humans and mother nature if not addressed.

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