Subsequently, slower flows of gas and rock destroyed trees and living organisms in the soil. Mature forests were turned into ash covered wasteland. Since then, hardy plants have reappeared in the ash field. The plants attract herbivores that drop seeds from other plants in their dung. About three decades after the eruption, the forest began to regrow. The steady progression of species change and replacement in an ecosystem over time, as occurred after the eruption of Mount St.
Helens, is called ecological succession. Humans impact the natural world more than any other species. Without limits on human activity, humans can damage the environment in many ways. As the human population grows, it requires more resources to keep its members healthy and comfortable. Each new family needs a place to live, food, water, clothing, medicine, and tools. Habitat destruction occurs when a habitat is removed and replaced with some other type of habitat.
No matter how careful the plan, land used to grow crops or build houses is no longer suitable for some of the organisms that once lived there. As a result, the organisms living at the site must move or be destroyed. Habitat destruction is the most important reason species are threatened with extinction today.
Habitat destruction can have harmful effects on humans, too. Scientists believe that some of the destruction caused by Hurricane Katrina in resulted from the removal of wetlands that would normally take up much of the regional floodwaters. Natural coastal ecosystems, including thick vegetation, may be able to buffer the coastline from hurricanes and other storms.
Wherever humans go, they take animals, plants, and microorganisms with them. Tulips-as well as most crop plants and many other highly-valued garden plants-are not native to the United States but rather are introduced species. Introduced species are an important part of the economy and of society.
Some introduced species, however, can be disruptive to an ecosystem. An introduced species that has negative effects in its new ecosystem is called an invasive species. Invasive species can have serious effects on an ecosystem and on the human population. For example, a vine called kudzu was introduced to the southern United States as a way to control soil erosion. However, the kudzu spread rapidly, choking the roots of some plants and blocking light for other plants, effectively killing them and changing the ecosystem.
Throughout history, humans have hunted or killed animals for several reasons. They obtained food and necessary materials from animals and eliminated competition for crops and prey.
They protected livestock by trapping or hunting animals such as wolves. The Effects of Mining on the Ecosystem. The Effects of Human Intervention on the Environment. Human Influences on the Temperate Rainforest. Summary of an Ecosystem. Types of Pollutants. How Does Pollution Affect Photosynthesis? What Damages an Ecosystem? Depletion of the Ecosystem. Human Uses of the Tundra. Human Impact on New Zealand Ecosystem. What Factors Influence the Biodiversity of an Ecosystem?
Define Chemical Pollution. For several reasons, groups such as the poor, women, and indigenous communities have tended to be harmed by these changes. Poor people have historically lost access to ecosystem services disproportionately as demand for those services has grown. Coastal habitats are often converted to other uses, frequently for aquaculture ponds or cage culturing of highly valued species such as shrimp and salmon. Despite the fact that the area is still used for food production , local residents are often displaced, and the food produced is usually not for local consumption but for export C Many areas where overfishing is a concern are also low-income, food-deficit countries.
For example, significant quantities of fish are caught by large distant water fleets in the exclusive economic zones of Mauritania, Senegal, Gambia, Guinea Bissau, and Sierra Leone. Much of the catch is exported or shipped directly to Europe, while compensation for access is often low compared with the value of the product landed overseas. These countries do not necessarily benefit through increased fish supplies or higher government revenues when foreign distant water fleets ply their waters C Diminished human well-being tends to increase immediate dependence on ecosystem services , and the resultant additional pressure can damage the capacity of those ecosystems to deliver services SG2ES.
As human well-being declines, the options available to people that allow them to regulate their use of natural resources at sustainable levels decline as well.
This in turn increases pressure on ecosystem services and can create a downward spiral of increasing poverty and further degradation of ecosystem services. Dryland ecosystems tend to have the lowest levels of human well-being C5. Drylands have the lowest per capita GDP and the highest infant mortality rates of all of the MA systems Nearly million people live in rural areas in dry and semiarid lands, mostly in Asia and Africa but also in regions of Mexico and northern Brazil C5 Box 5.
The small amount of precipitation and its high variability limit the productive potential of drylands for settled farming and nomadic pastoralism, and many ways of expanding production such as reducing fallow periods, overgrazing pasture areas, and cutting trees for fuelwood result in environmental degradation.
The combination of high variability in environmental conditions and relatively high levels of poverty leads to situations where human populations can be extremely sensitive to changes in the ecosystem although the presence of these conditions has led to the development of very resilient land management strategies. Once rainfall in the Sahel reverted to normal low levels after , following favorable rainfall from the s to the mids that had attracted people to the region, an estimated , people died, along with nearly all their cattle, sheep, and goats C5 Box 5.
Although population growth has historically been higher in high- productivity ecosystems or urban areas, during the s it was highest in less productive ecosystems C5. ES, C5. In that decade dryland systems encompassing both rural and urban regions of drylands experienced the highest, and mountain systems the second highest, population growth rate of any of the systems examined in the MA.
This summary is free and ad-free, as is all of our content. You can help us remain free and independant as well as to develop new ways to communicate science by becoming a Patron!
Languages: English [en]. Home » Ecosystem Change » Level 3 » Question 3. Previous Question. Next Question. How have ecosystem changes affected human well-being and poverty alleviation? The source document for this Digest states: Relationships between Ecosystem Services and Human Well-being Changes in ecosystem services influence all components of human well-being , including the basic material needs for a good life, health , good social relations, security, and freedom of choice and action CF3.
The source document for this Digest states: Ecosystem services contribute significantly to global employment and economic activity. Figure 3. The source document for this Digest states: Ecosystem Services , Millennium Development Goals, and Poverty Reduction The degradation of ecosystem services poses a significant barrier to the achievement of the Millennium Development Goals and to the MDG targets for In , some 1.
Inequality in income and other measures of human well-being has increased over the past decade C5. A child born in sub-Saharan Africa is 20 times more likely to die before age five than a child born in an industrial country, and this ratio is higher than it was a decade ago. During the s, only four countries experienced declines in their rankings in the Human Development Index an aggregate measure of economic well-being, health , and education ; during the s, 21 countries showed declines, and 14 of them were in sub-Saharan Africa.
Despite the growth in per capita food production in the past four decades, an estimated million people were undernourished in —03, up 37 million from — South Asia and sub-Saharan Africa, the regions with the largest numbers of undernourished people, are also the regions where growth in per capita food production has been the slowest. Most notably, per capita food production has declined in sub-Saharan Africa C Some 1. Water scarcity affects roughly 1—2 billion people worldwide. ES, C7. Examples of these impacts include: Half of the urban population in Africa, Asia, Latin America, and the Caribbean suffers from one or more diseases associated with inadequate water and sanitation C.
Approximately 1. The declining state of capture fisheries is reducing a cheap source of protein in developing countries. Per capita fish consumption in developing countries, excluding China, declined between and C
0コメント