BIOMES

A biome is the largest ecological community. In Nigeria biomes can be divided into

1.       Forest

2.       Savanna

These biomes are determined by rainfall and temperature. The mean annual rainfall decreases from south to north.

Each of this biome is subdivided depending on the amount of rainfall, topography and soil factors.

Swamp (mangroove swamp)

The mangroove swamp is divided into salt water swamp and fresh water swamp.

v  They form a belt along the coast of nigeria.

v  The mean annual rainfall ranges from 2000mm and above.

v  Large sand and silt are deposited at the deltas and water is logged here. This makes the forest swampy.

v  In the rainy season, the swamp is filled with river water making it fresh

v  In the dry season, salt water percolates the forest giving it a salty swampy nature

v  Major plant communities here include: Red mangroove( Rhizophora racemose),White mangroove (Avicenna nitida)

ü  These plants have stilt roots, drop roots and breathing roots called pneumatophores

Animal community include: Crabs, oysters, mud skipper fish, birds .

Major states here are: Lagos, Ondo, Edo, Delta, Cross River, Rivers and Akwa Ibom

Tropical rain forest

The tropical rain forest has a mean annual rainfall of 1250mm to 2000mm of 8 – 10 months and relative humidity of 70%

Trees here are organized in layers of about 4005 they include

ü  upper layer or emergent layer. Grow above 40 meters, slender and straight.

ü  middle layer of about 16m to 34meters. They form continuous canopy

ü  lower layer of shrubs.

ü  ground layers of shed loving specie e.g. ferns, mosses etc.

·         The trees are evergreen, broad leaves and buttress root system.

·         Many climbers and epiphytes with parasitic plants are found here.

·         Wild animals like snake, chameleon, monkeys etc. are seen here

·         Common trees include obeche, mahogany, sapele, iroko, African walnut etc. are seen here

·         States here include Ogun, Lagos, all south-south states, all south-east state

Southern guinea savanna

·         This is a large grassland found just after the rain forest. It is the largest of the biomes in Nigeria.

·         Rainfall ranges between 1500mm- 1000mm. It has a luxuriant grassland that are tall. Many scattered trees with broad leaves. Most trees here are said to be deciduous i.e. Shedding their leaves in season.

Shear butter, locust bean, antelopes, lion, leopards, zebras are the common organisms found here

·         States here include Enugu, Ebonyi, Kogi, Benue, Kwara, Osun, Ekiti.

Northern guinea savanna/ sudan savanna

·         Has a low annual rainfall of 1000-500mm. Has scattered deciduous short trees and short grasses. Common plant species include date palm, baobab, silk cotton

·         Common animal species include snakes, lizard, antelope

·         States here are Kaduna, Bauchi, Jos, Niger, Adamawa, Kano.

Sahel savannah

·         This is found only at the extreme north such as Bornu, Kastina, Sokoto.

·         Mean annual rain fall is less than 500mm.

·         Short and scanty grasses, short and scanty tough shrubs. Drought resistant species here are gum Arabic, date palm. It translates into desert at the esteem Nigerian boarders.

DESERT

A desert has little or no rain fall in most of the year. It has high temperature and low humidity. Fewer grasses and shrubs with annual rain fall of 250-25 mm

Major world biomes

Throughout the globe, major biotic communities differentiate one region from another. These biomes include

Tropical rain forest, temperate rain forest, Savannah, desert, afro alpine, swamps, and tundra

Evaluation

Using a sketch map of Nigeria showing the major biomes of Nigeria. Locate 

I. Two states ii. Two animals iii. 2 plants that can be found in each biome shown

Assignment

Recently some states in America and London witnessed an unusual snow fall that resulted in the closure of schools and offices within those regions.1.  Research into the ecological issues that possibly may have led to these problems.2. What measures were taken by the government to relieve the situation 3. Outline any three problems that may result from this unusual snow fall.