SOURCE:

Faculty: Biosences
Department: Botany

CONTRIBUTORS:

Danladi Y. Papi
Mbaekwe E. I.
Izundu A. I.

ABSTRACT:

Ecological studies were carried out to ascertain the niche of latex-producing plants considering soil, climate, vegetation and anthropogenic interrelationships. Global Positioning System (GPS) and Stratified random sampling were used to locate towns for data collection. Twenty (20) plots of 15 m x 20 m (300 m2) in quadrat size were considered, 5 plots from each study area of Southern Guinea Savanna (SGS), Northern Guinea Savanna (NGS), Sudan Savanna (SDS) and Montane Vegetation (MNV). Also a quadrat size of 1 m x 1 m was placed 4 times in each of the 20 plots to enable the counting of forbs and grasses. Soil and vegetation analyses were carried out to determine some parameters. Ordination by Principal Components Analysis (PCA) was used to analyse the data. The results showed that over all, 142 plant species were encountered in all the 20 plots samples. Ten (10) families were noted to exude latex namely, Aloeceae, Sapotaceae, Cohlospermaceae, Euphorbiaceae, Moraceae, Convolvulaceae, Meliaceae, Asclepiaceae, Cactaceae and Apotaceae. Thirty three
(33) of the plants collected were latex-producing plants, while 109 were non-latex producing plants. Vegetation attributes such as total number of species and total number of woody individuals have higher mean values for MNV and SGS (36.20 and 27.80; 65.20 and 42.40 per 300 m2) while lower mean values were recorded for NGS and SDS (24.20 and 11.60; 35.80 and 23.00 per 300 m2) respectively. Total number of individuals was higher in MNV and SGS with mean values of 85.20 and 73.60 per 300 m2, while it was lower for NGS and SDS with mean values of 68.60 and 30.00 per 300 m2 respectively. The abundance of latex-producing plants, girth size of woody plants above 1 metre high and girth size of woody latex-producing plants were higher in SGS and MNV with mean values of (4.60 and 17.60; 473.80 and 471.80; 111.40 and 72.20 per 300 m2) respectively. Constancy values were calculated as percentages of occurrence of plant species in a plot and mean total number of latex producing plants gave 20.14%, 9.33%, 6.57% and 3.76% for the MNV, SDS, SGS and NGS respectively. Soil samples from the study areas gave a pH range of 5.39–6.83 indicating weak acidic soil. The percentage of soil content was over 96% referred to as sandy texture for all the study areas. The percentage organic matter and percentage nitrogen content showed lower values for SDS and MNV as 0.96% and 1.62%; 0.36% and 0.46% respectively. The ordinations showed clusters representing the four study areas with Lokoja to the north and Jos to the south in a vertical line gradient, while, Katsina study area to the west and Minna to the east in a horizontal gradient. The measured vegetation attributes, namely; total number of species, total number of woody species, species diversities, and basal area of woody species reflected the general south-north decreasing trend in all the parameters. The Montane vegetation of Jos recorded high value for the latex-producing plants, suggesting that the environmental conditions in the area favoured their greater abundance. Since the Montane vegetation was found to be substantially different in the physiographic, climatic and biotic factors, the higher abundance of latex-producing plants in these areas can be attributed to them. The ordination analysis brought out these relations more succinctly, suggesting a good correlation between them. Ten (10) responses on questionnaire administered on natives of the study area, it seems that some people especially in the savanna vegetation do not know these latex-producing plants. This study will elicit greater interest in the study of all aspects of the biology and ecology of latex-producing plants. Specifically, there is need to explore more of their responses and adaptations to their environment, their life histories and phenological characteristics, their diversity and genetic attributes, as well as their ethno-medicinal values.