Seven Groups of Related Ecosystems. Biomes of the World Seven Groups of Related Ecosystems.

The Seven Major Biomes Biomes are distinguished by the presence of characteristic flora and fauna – but mostly by the flora. Climate plays an integral part in where a biome is found. Since climate changes gradually over a landscape, biomes do not have definite boundaries.

Where Biomes Are Found

The Tundra Cold and largely treeless biome. Forms continuous belt across northern Asia, Europe, and North America. Largest and northernmost biome. Permafrost, a permanently frozen layer of soil under the surface, is characteristic of the tundra. (Even soil above permafrost line stays frozen for all but 8 weeks per year.)

Tundra Climate The tundra receives little precipitation. The growing season in the tundra is very short. Cold temperatures slow decay therefore soil is low in nutrients. Plants include grasses and mosses. Animals include mosquitoes, caribou, snowy owls, and snowshoe hares.

The Taiga South of the tundra is the taiga. Taiga stretches across northern Europe, North America, and Asia. During long winters, snow covers and insulates the ground, protecting tree roots from freezing. Long and cold winters, short summers, and nutrient poor soil are typical of the taiga. Plants include pines, firs, and spruce. Animals include moose, bears, and wolves.

Taiga Locations

Temperate Deciduous Forests Characterized by trees that loose their leaves in the fall. Stretch across eastern North America, much of Europe, and parts of Asia, and the Southern Hemisphere. Compared to taiga, temperate forests have longer summers and milder winters with more precipitation.

Temperate Deciduous Forest Pronounced seasons, with precipitation spread out throughout the year. Common deciduous trees include maple, oak, sycamore, and hickory. Common critters include foxes, deer, squirrels, and raccoons.

Temperate Grasslands Dominated by grasses. Usually form interior of continents at same latitude as temperate forests. Rainfall patterns make these areas too dry to support trees. Covers much of North America, Asia, Europe, Australia, and South America.

Temperate Grassland Rich fertile soil. Can support large herds of grazing animals. Grass can survive constant grazing and even occasional fires because actively growing part of grass is at or below ground. Animals include bison, prairie dogs, and coyotes. Also called:prairies (US), steppes (Asia), pampas (S. America) , and veldt (S. Africa)

Temperate Grassland

Deserts Areas that receive an average of less than 25cm (9.9 inches) of rainfall per year. Deserts do not have to be hot all the time; come can be hot in summer but cold in winter. Temperatures can also drop by as much as 30°C (54°F) at night.

Deserts

Savannas Tropical or subtropical grasslands. Found in Africa, South America, and Australia. Alternating wet and dry seasons characterize savannas. (Periods of heavy rain followed by extended droughts. Receive more rainfall than deserts, but less than tropical rainforests.

Savanna Supports large numbers of grazing animals like zebra and gazelle as well as predators like lions and cheetah. Many plants loose leaves during dry season to conserve water.

Savanna Locations

Tropical Rainforests Characterized by tall trees. Most productive biome due to year-round growing season and abundant rainfall. Competition for sunlight is intense; trees grow up to 50-60m (164-197ft) and form continuous layer of treetops called the canopy, shading the forest floor.

Tropical Rainforests Small plants often grow on trees in order to reach sunlight. These plants are called epiphytes, including mosses and orchids. Much of forest floor is free of vegetation. Dense growth known as “jungle” is found along riverbanks and disturbed areas where sunlight can reach the forest floor. The rainforest is very rich in both flora and fauna diversity.

Rainforest Locations