(a) Give a brief description of the characteristics of the Northern Guinea Savanna.
(b) Describe how you can estimate the density of a plant species using a quadrat.
Explanation
(a). The characteristics of Northern Guinea Savanna are:
(i) It has bare soil with scanty trees.
(ii) Has long twisted roots to facilitate the absorption of water and mineral salts.
(iii) Possesses thick barks which enable it to withstand harsh weather, e.g. fire and intensive sunlight.
(iv) Has twisted and gnarled trunks, which enable it to resist fire and excessive transpiration.
(v) Availability of herbivorous animals such as zebra, squirrel, antelope, grasscutter etc.
(vi).Availability of perennial grasses that grow in tufts and resist fire.
(vii) Presence of underground stems, e.g. spear grass which make the plants to be able to survive, after long period of dry season or fire out break.
(viii) Temperature is usually above 18°C throughout the year.
(ix) Trees shed their leaves during the dry season and this enables them to conserve water.
(b) Aim: To estimate the density of a plant species using quadrat sampling technique (a method of studying plant species).
Method: A quadrat is a rectangular frame which is constructed from wire or wood of known dimension. Before usage, mark the area where the species to be measured occurs. Then throw the quadrat to land randomly on any part of the marked off area. Note the area covered at each landing of the quadrat. In the process, each species of plant is counted and recorded. To determine the density, calculate the average frequency of the plant species as the number of times the plant species occurs divided by the total number of quadrat throws made.
Formula= Number of times plant species occurs
Total number of quadrat throws made
Finally, divide the average frequency by the area of the quadrat =
Average Frequency
Area of quadrat .