HUMA N IMPA C T O N BIO MES A RO UN D THE W O RLD

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Charla Carter
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1 HUMA N IMPA C T O N BIO MES A RO UN D THE W O RLD HOMEWORK DIRECTIONS (due Wed/Thurs): For EACH of these biomes (yes, go through all), look for evidence of HIPPCO in the article (these are the main ways humans impact biomes). If you find evidence that humans have been impacting the biome in that way, UNDERLINE OR HIGHLIGHT THE EVIDENCE IN THE TEXT (you must do this for ANY HW credit) and then check off the appropriate box. Human impact on the TUNDRA The tundra may seem tough, but it is a very sensitive environment. More people have recently been moving to the tundra to work in the mines and oil industry. New towns and roads are being built to support the increased population. Developments have interrupted many of the animals migrations and feeding patterns, as well as caused damage to the permafrost. It takes so long for the tundra to recover that tire tracks and footprints remain on the ground for decades after they were made. In areas of the tundra there are also many natural resources, such as oil. People worry that pollution from these mines and rigs may ruin the fragile ecosystem. A caribou migration route was interrupted by construction of the Alaskan oil pipeline. In some places the pipeline has been raised high enough above the ground for caribou to pass under it. Insects bombard the tundra in the summer and birds flock there to eat them. Pesticides used to control insects may work their way up through the food chain and affect many of the animals that live on the tundra. We need to be careful with the delicate tundra environment. There is also much we can learn from the tundra. Permafrost has the ability to preserve plants and animals in the cold ice for long periods of time. Scientists can use the permafrost as a record of the past to learn about climate. These records are a tool to compare past climates with the current climate to see how much the earth may be warming. As we learn more about this unique biome, it is important that we continue to care for it.

2 Human impact on the TROPICAL RAIN FOREST Tropical rainforests are important because they provide oxygen, take in carbon dioxide, and are a huge source of biodiversity and cultural diversity. However, people also rely on tropical rainforests for food, medicine, timber, travel, and more. Rainforests around the world provide people with food and spices, for example, allspice, vanilla, cacao, cassava, ginger, bananas, black pepper, sugar cane, nutmeg and more. Many people are also moving from crowded cities where they cannot find jobs into the rainforest where they are becoming smallscale farmers. With all of this use, we need to be concerned about the stress we are putting on rainforests. Thirty acres of trees are cut in tropical rainforests every minute! Some scientists estimate that rainforests the size of Pennsylvania are lost each year. There are many reasons people cut down trees. People are logging for firewood, charcoal, building materials and other uses. Trees are being removed for commercial agriculture, which may cause permanent damage. Converting rainforests to pasture land for cattle ranching has destroyed many rainforests. Mining for gold, bauxite, and other minerals can destroy the land, and make it vulnerable to erosion.

3 Human impact on the SAVANNAH Some environmental concerns with savannas include poaching or hunting, overgrazing, and destruction of land to grow commercial plant crops. There are over 800 species of trees and shrubs in certain Brazilian Savannas but much of these biomes are being cleared so crops such as beans, corn and rice can be grown and for other such agricultural uses. Many animals in the savanna, such as the rhinoceros and zebra, are endangered and threatened with extinction due to hunting, poaching, and habitat loss. Humans are also disrupting the natural flow of the Savanna by releasing foreign species into the wild. These are referred to as introduced species or exotic species. One example of this is when rabbits were introduced into Australian Savanna and they quickly multiplied and spread across the entire country. There are many types of grassland plants which are now extinct because of the introduction of these pests. The savanna is often damaged when it is used as pastureland for non-native domestic cattle. Cattle grazing also limits the amount of food available for wildlife.

4 Human impact on the TAIGA/BOREAL FOREST There are a few large cities in the southernparts of the taiga, such as Moscow and Toronto, but most of it is relatively unpopulated. There are also a few native communities of people who still live indigenously in the taiga. The major industries of the taiga include logging, mining, and hydroelectric development. These activities have had negative impacts on areas of this biome and may continue to negatively affect it in the future. A majority of the logging in the taiga is done by clear-cutting, using heavy machinery to remove much of the surrounding forest. Hydroelectric development may seem beneficial because it uses water to generate power, but it has damaged the taiga by changing stream habitats and flow patterns, and flooding large areas and changing the landscape. Mining is a concern because it may result in pollution of surrounding soils and water, specifically acid rain. Regrowth of mature forests takes a long time because of the climate and soil conditions of the taiga. Many large vertebrates who live in the taiga are sensitive to human presence, habitat alteration, and pollution. Two simple things you can do to help the taiga are learn more about this biome, and use paper wisely making sure to recycle. This will help reduce the need for logging of trees for pulp used to make paper.

5 Human impact on the TEMPERATE DECIDUOUS FOREST Temperate forests are very important to people as they provide enjoyment as well as many resources including food, timber, and oxygen for us to breathe. However, we are also the cause of some major threats to this biome, one of which is acid rain. Acid rain caused by industrial and vehicle emissions damages the leaves of trees, and causes them to produce smaller and fewer seeds. It also reduces the trees' resistance to disease, pests, and frost. Clear cutting of forests is also a threat to this biome. Trees are cut for timber and land cleared for agriculture. Another problem associated with deciduous forests is the introduction of non-native plant and animal species because it upsets the balance of the forest ecosystem. Non-natives may compete for food and habitat space, possibly threatening the native species. An example is the red imported fire ant. Over the last 60 years, this species of ants has increased dramatically in North America. However, this has come at a cost, as the presence of fire ants has led to a decreased diversity of other species of ants. Moreover, in the presence of the fire ants, the co-occurrence of many ant species has been random. This is because the invasive ants, foreign to their new habitat, fail to acknowledge the domains of other ant species. Instead, they inhabit land randomly, leading to aggressive behavior between ants that would otherwise not have occurred.

6 Human impact on the GRASSLANDS One of the main environmental concerns regarding temperate grasslands is the conversion of grassland to farmland. The rich soil is ideal for farming and grazing. With continual agricultural development and progress we have lost many of our natural grasslands. Instead of native grasses, now grasslands supply corn, wheat, and other grains, as well as grazing areas for domestic ungulates, such as sheep and cattle. The food supplied by farmlands is important, but so is this unique biome, and the plants and animals that live in the temperate grassland. When grasslands are converted into farmland, it reduces the food source for many wild animals. In this case, the animals are considered pests by the farmers when they feed on the crops. This can lead to migration or possibly the starvation of the animals. Not only does the conversion of land into crops change the ecosystem, but so does the farming of livestock. If livestock are allowed to graze in areas where wild animals live, they compete over the food source and can deplete it. This overgrazing is a problem especially in the drier grassland regions, where the grasses resources can be depleted. The land can also be plowed too much, stripping the nutrients from the soil. Hunting has had and continues to have a serious impact on the biome. The American bison population was devastated by the European settlers and almost became extinct due to overhunting for the fur and meat. Poachers are likewise killing rhinoceroses for their tusks and elephants for their ivory in Africa.

7 Human impact on the CHAPARRAL Humans have a large impact on the chaparral biome. Chaparral biomes are very dry and can result in large fires, but a lot of these fires are caused by human activity in the area. In Santa Barbra there are endangered species due to them being killed by fires caused by humans. Chaparral biomes all over the world have been heavily affected by grazing, logging, damns being built, agriculture and urbanization, All of these are human activity have a major effect of chaparral biomes. Population growth and its attendant activities threaten the very existence of the chaparral. Humans destroy chaparral to build home sites, suppress fires, and plant grass in burned areas to stabilize the soil and to mitigate future fires. The grasses compete with chaparral plants, which slows down chaparral recovery. The impact of these and other activities on the native chaparral ecosystem is not well understood but is almost certainly negative. Some plant species, like the Coastal Sage Scrub, have been nearly wiped out by agriculture and urbanization. Grazed areas of chaparral can contribute to flooding. Wellvegetated areas will normally hold back rainfall and release it slowly after the plants and their root systems soak up a good portion of the water. Grazed areas will not do this since they don t have the benefit of plant roots, and the runoff from a typical storm could cause flooding.

8 Human impact on the DESERT Human activities, such as off-roading, farming, ranching, cattle grazing and collection of firewood, destroy the natural vegetation found in desert areas. This damage, due to the sensitivity of the desert, takes a long time to repair. The saguaro cactus, for example, takes over 200 years to grow. Tracks from off-road vehicles scar the land, which causes the inability for vegetation to grow in the area. As a result, many plant species are becoming extinct, and the soil is eroding faster without sufficient plant roots to hold it in place. Animals that live in the desert such as the sand viper have experienced declining numbers as a consequence of human activity. Not only can they be trampled under the tires of vehicles or the hooves of cattle, but many of them struggle with the loss of habitat due to humans. The presence of humans reduces the availability of the native vegetation that animals rely on to survive and seek shelter. The destruction of plant populations is generally followed by a decrease in local animal species. Off-road riding (riding 4x4 and dirt bikes) can damage desert plants and pollute the soil, as well as disrupting the activities of wildlife. Finally, diverting the desert s few water supplies, which are already likely scarce, can prevent infrequent rainfall from reaching the native plants.

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