Temperate grasslands and savannas are two types of grassland biomes. Like savannas, temperate grasslands are areas of open grassland with very few trees. Temperate grasslands, however, are located in colder climate regions and receive less precipitation on average than savannas.
Temperatures in temperate grasslands vary according to the season. In winter, temperatures can plummet to well below 0 degrees Fahrenheit in some areas. In summer, temperatures can reach above 90 degrees Fahrenheit. Temperate grasslands receive low to moderate precipitation on average per year (20-35 inches). Most of this precipitation is in the form of snow in temperate grasslands of the northern hemisphere.
It is the soil that makes the temperate grasslands such an integral part of human society. It is unusually rich and fertile, it is also deep. The world’s most fertile soil is found in the eastern prairies of the U.S., the pampas of South America, and the steppes of Ukraine and Russia.
The seasons deliver patterns of rainfall that never hit the extremes of a monsoon which could wash soil and vegetation away.
For man, the grassland waterways and soil patterns also provided ideal points to establish transportation hubs too.
The wide expanses and rich plant growth, plus adequate rainfall features of the temperate grasses make it ideal for herd based animals, such as the following, to exist.
- Prairie dogs
- Swift foxes
- Pocket gophers
There is a delicate balance of predator and prey on this kind of grassland. It is most common that the prey-herbivore types such as Bison exist in large herds. Predators, such as wolves, operate in small packs. There is abundant ground life here with hares and other burrowing animals heavily represented. The avian life features flocks drawn to the seeds of the plants and the small groups of predator birds who hunt them as well.
Regions of Mediterranean-type climate occur roughly between 30° and 40° latitude on the west coasts of continents, where offshore there are cold ocean currents. Each region in which the Mediterranean shrublands and woodlands occur is island-like in character and thus there is frequently a high degree of endemism. Comparative studies of the several regional expressions of this biome reveal interesting examples of convergent evolution in plant families and birds (but not among reptiles or small mammals) on the different continents.
The Mediterranean Climate (Cs) is unique in that the wet season coincides with the low sun or winter period. Summers are dry. Total annual precipitation ranges between 15 and 40 inches per year. Temperatures are those of the subtropics moderated by maritime influence and fogs associated with the cold ocean currents. The result is a very limited, but predictable, growing season when there is both sufficient soil moisture and adequately warm temperatures
Throughout the world, the Mediterranean biome is characterized by shrubs. In most regions these shrubs are evergreen and have small, leathery (sclerophyllous) leaves with thick cuticles. Sometimes the leaves are so reduced as to appear needle-like. Many typical members of the shrub flora are aromatic (for example, sage, rosemary, thyme, and oregano) and contain highly flammable oils.
Mediterranean regions have long been impacted by humans especially through the use of fire and the grazing of livestock. The Mediterranean proper, we know from classical Greek literature, was formerly forested with live oaks, pines, cedars, wild carob and wild olive. The shrublands of California, likewise, are believed much more extensive today than before aboriginal burning and Spanish livestock grazing.
Deserts cover about one fifth of the Earth’s surface and occur where rainfall is less than 50 cm/year. Although most deserts, such as the Sahara of North Africa and the deserts of the southwestern U.S., Mexico, and Australia, occur at low latitudes, another kind of desert, cold deserts, occur in the basin and range area of Utah and Nevada and in parts of western Asia. Most deserts have a considerable amount of specialized vegetation, as well as specialized vertebrate and invertebrate animals. Soils often have abundant nutrients because they need only water to become very productive and have little or no organic matter. Disturbances are common in the form of occasional fires or cold weather, and sudden, infrequent, but intense rains that cause flooding.
There are relatively few large mammals in deserts because most are not capable of storing sufficient water and withstanding the heat. Deserts often provide little shelter from the sun for large animals. The dominant animals of warm deserts are nonmammalian vertebrates, such as reptiles. Mammals are usually small, like the kangaroo mice of North American deserts.
Desert biomes can be classified according to several characteristics. There are four major types of deserts:
- Hot and dry
Adaptations in Desert Biome
Two characteristics of the desert i.e., high temperature and scarcity of rainfall determine the occurrence, distribution and adaptations of desert animals. In addition to these the highly characteristic “spaced distribution” of the desert vegetation also affects the desert fauna.
The characteristic animals of the desert are insects, small rodents, and reptiles. Birds and mammals are comparatively rare or absent. Poikilothermic animals, which match their internal temperature to the external, are adapted to live easily in the desert.
Extreme desert is without any vegetation and rainfall. However, some deserts receive less than 5 cm of rain per year. Deserts include arid regions, which contain considerable vegetation, commonly called xerophytes, in the form of desert bushes and shrubs, succulents such as cacti which store water, and other small plants which avoid drought by growing only when there is adequate moisture. In some deserts, plants survive as seeds for several years until a little rainfall provides conditions suitable for growth and flowering.
Cold deserts are found in the Antarctic, Greenland, Northern and Western China, Turkestan, Iran and the Nearctic area. Many nomads have settled on farms in the Gobi Desert and it was crossed as early as the 13th century by Genghis Khan. Cold deserts can also be found in certain mountainous areas, such as the Great Basin area of western United States.
Deserts in this category have the following characteristics:
Large amount of snowfall in winter (and sometimes in summer), plus a high average of rainfall (15-26 cm.) occurring mainly in April and May or autumn, depending upon the area
- Short, wet moderately warm summers
- Mean average winter temperature -2 to 4ºC
- Mean average summer temperature 21-26º
- Heavy, relatively porous soil with a lot of silt and salt
- Good drainage to leach out most of the salt