An ecosystem consists of the plants and animals of an area, and all the things which make up their surroundings – like soil, water and air. It can be a small area such as a pond; a medium sized area such as a forest; or a large area such as the earth itself.

Ecosystem is any geographic area that includes all of the organisms and nonliving parts of their physical environment.

• Abiotic – the non living factors of an ecosystem – geology, water and soils

• Producers or Autotrophs – organisms which manufacture their own food eg green plants make their own food using the sun’s energy

• Consumers or Heterotrophs - organisms that cannot make their own food – they must obtain energy from other animals and organisms

• Decomposers – organisms that break down other organisms (eg Bacteria)

An ecosystem is formed by the interactions between all living and non-living things. How do living and non-living things interact in an environment?

Arid deserts generally occur at low latitudes, and can be found in North-America, South-America, Africa, and Southern Asia. Seasons in the arid desert are generally dry and hot, with few occurrences of rain during the winter. The heat peaks to extremes during the daytime because there are no clouds to shield the earth from the sun's rays.

Forest Biomes represent the largest and most ecologically complex systems. They contain a wide assortment of trees, plants, mammals, reptiles, amphibians, invertebrates, insects and micro-organisms which vary depending on the zone's climates. Sadly, rainforest biomes are being cut down at an alarming rate, with hundreds of species of plants and animals disappearing from the planet on a daily basis.

Grassland biomes are unaltered areas of land where grass is the dominant plant life, as opposed to other terrestrial biomes where trees occupy most of the land surface. Grassland are found around the globe and have served as grazing areas for a large number of animals, and have been exploited as farming grounds or plantations by humans.

Tundra, the "ice desert", "frozen prairie", the cold plains of the Far North get their name from the Finnish word "tunturia", which means treeless land. The tundra biome is the coldest of all terrestrial eco-systems, and also the most chaotic. Still, the tundra is host to a surprising number of plants and animals, and represents a fascinating testament to nature's adaptability, and cruel beauty.

The chaparral biome has flat plains, rocky hills and mountain slopes.

Chaparral is characterized as being very hot and dry.

Droughts are very common Most of the plants have small, hard leaves which hold moisture( Yucca and other shrubs, trees and cacti)

The animals are all mainly grassland and desert types adapted to hot, dry weather (coyotes, jack rabbits, mule deer, alligator lizards, horned toads, praying mantis, honey bee and ladybugs).

Taiga, also known as coniferous or boreal forest, is the largest terrestrial biome on earth. It extends in a broad band across North America, Europe, and Asia to the southern border of the arctic tundra. It is also found at cool, high elevations in the more temperate latitudes, for example, in much of the mountainous western region of North America. Much of the taiga in North America was once covered with glaciers. As the glaciers receded, cuts and depressions were left in the landscape that have since filled with rain creating lakes and bogs.

The ocean holds the largest of Earth’s biomes. It covers 70% of the planet’s surface. Life in the ocean is diverse.

The smallest creatures that call the ocean home are so tiny that they can only be seen with a microscope.

The largest creatures are blue whales, which can be as much as 34 meters (110 feet) long.

The temperate deciduous forest is a biome that is always changing. It has four distinct seasons: winter, spring, summer and fall. Winters are cold and summers are warm. Temperate deciduous forests get between 30 and 60 inches of precipitation a year. Precipitation in this biome happens year round. Because the soil is very fertile and hardwood trees are good for building, this biome has some of the world's largest population centers in it.

Ecosystem services are the goods and services derived from natural and managed ecosystems upon which human welfare depends. Because of the global intensification of land use, these services are declining, especially in agricultural ecosystems.

Ecosystem services are essential in maintaining human welfare as well as ecological integrity, yet these services can be affected by natural changes and management actions.

Lands used for agricultural purposes are significantly reduced due to rapid conversion of these lands from traditional farming use, to alternate farming practices, to urban development, and to non-agricultural use.

Natural Capital Ecological Goods and Services Provided

Forests

Carbon sequestration, soil formation, waste treatment, biological control, cultural, air quality, flood control, recreation, raw material (timber), genetic resources

Grasslands, rangelands

Carbon sequestration, water regulation, erosion control, soil formation, waste treatment, pollination, biological control, food production

Wetlands Disturbance regulation, water supply and treatment, carbon sequestration, food production, recreation, cultural habitat/refuge

Lakes, rivers, riparian (river banks) zones

Water supply, waste treatment, food production, recreation

Croplands Food production, habitat/refuge, scenic

Undeveloped lands Tourism

Source: The Value of Natural Capital in Settled Areas of Canada (Olewiler, 2004)

• Aims of Agriculture – To obtain higher crop yield

and increased animal production to feed the growing population

– To achieve sustainable production

• However, natural resources are limited!

• Ecosystems are NOT stationary – Climate changes

– Nutrient depletion

– Other: diseases, pests, predators, etc

Crops Cereal (grain): rice, wheat, corn, barley, millet Vegetables: leafy vegetables, fruit vegetables , etc. Root crops: sweet potato, cassava, potato Legumes: soybean, mungbean, peanut Fruit: many kinds (trees) Fiber: cotton, hemp

Livestock Grazing: cattle, sheep, goats and wool, leather, dairy animals, swine, chicken

Aquaculture: farming of fish (milkfish,tilapia, etc) Harvesting of natural ecosystems

Fisheries Fish Shellfish Seaweeds

Forests: timber, paper, natural products (resin, rubber)

2006 自然科学の英語-ENS-L6

‘A given area of land can produce up to a certain limit’

• Limiting factors – Land availability

– Physiological constraints

– Environmental factors • Light

• Temperature

• Water

• Soil nutrients

– Pests and diseases

Productivity of agriculture

Green Revolution

Genetic improvement Irrigation Fertilizers Chemical control

Climate change will affect negatively affect agriculture and will threaten the food security of millions of people especially the small-scale crop and animal producers and fishermen. Climate change will affect availability of land, water and biodiversity. Changes in temperature and rainfall, as well as more frequent extreme weather patterns, are expected to result in agriculture production shortfalls with negative impact on access to food.

2006

• Exhaustion of nutrients – Intensive cropping nutrient depletion

– Solutions • Letting the land rest: land put aside to recover fertility

• Crop rotation using legumes (N2 fixation) = biofertilizers

• Add organic fertilizers

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• Erosion = loss of soil – Agents: wind and water

– Causes • Excessive Tillages

– too much plowing unprotected land after cultivation (bare soil)

• Overgrazing by livestock – animals/area > grassland

carrying capacity

Excessive tillage + Overgrazing erosion desertification

2006

soil loss > soil formation – Land fertility decreases – overgrazing – deforestation – Wind erosion – Abandonment of the land

A majority of farmers depend upon rains for irrigation of their crops. Therefore, farmers have to use ground water for irrigation.

Population pressure on agriculture forces increasing use of ground water day by day. This results in depletion of water table.

URBANIZATION consumes FORESTS: In the past, forest loss was caused by logging and agriculture. Today, urbanization and industrialization are key factors. As cities and industrial areas expand, they consume land that is occupied by trees and natural vegetation. Sources: World Bank, Lincoln Institute of Land Policy (2011).

Unabated population growth continues to pose a formidable challenge to the loss in land productivity: as population pressure on land intensifies.

Annual losses in agricultural land translate into a rather persistent decline in the country’s capacity to feed its ever growing population. Such losses adversely affect both the economy and the environment.