Comparative Evaluation Of Tree Species Populations Under Different Land Use Types Within The University Of Port Harcourt Environs

Ud Chima,C Uwaegbulem

doi:10.4038/tare.v15i1.5236

Ud Chima, C Uwaegbulem

Open Access

https://doi.org/10.4038/tare.v15i1.5236

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Abstract

Impact of land use changes and varying levels of habitat disturbance on tree populations was evaluated using the spatial analogue technique of studying ecosystem dynamics. Three sites with low, moderate, and high levels of disturbance were purposively chosen from the Biodiversity Conservation Area (BCA), an Unprotected Secondary Regrowth (USR), and an Arable Farmland (AF) respectively, for the study. Tree density and alpha diversity were evaluated in each site. The level of tree species compositional similarity/variation was also ascertained for each pair of the sites, and the extent of change in populations of individual tree species measured for the unprotected sites – USR and AF. Total tree density was highest in BCA (466 trees/hectare) followed by USR (317 trees/hectare) and AF (73 trees/hectare). Tree diversity was highest and lowest in BCA and AF respectively. Tree species compositional variation was higher between BCA and each of USR & AF (66.7%), than between USR and AF (57.1). Harungana madagascariensis, Berlinia grandiflora, and Eleais guineensis were the most abundant tree species in BCA, USR, and AF, respectively. Although, populations of many tree species were found to be drastically reduced or completely lost in the unprotected sites, improvement was observed in populations of few species with Spondias mombin having the highest improvement index (314.29%) in USR while E. guineensis had the highest improvement index (72.7%) in AF. S. mombin is highly valued in the study area because of its edible fruits and diverse medicinal attributes while palm oil and palm kernel oil from E. guineensis contribute immensely to rural livelihoods. Hence, the rural dwellers tend to favour and encourage their growth. Tropical Agricultural Research and Extension 15(1): 2012: page 1-7 DOI: http://dx.doi.org/10.4038/tare.v15i1.5236

Highlights

Tree species composition/density at the various land use types The density of tree species is shown in Tables 1, 2, and 3 for the Biodiversity Conservation Area (BCA), Unprotected Secondary Regrowth (USR) and Arable Farmland (AF), respectively
Total tree density was highest in BCA (466 trees/ha), followed by USR (317 trees/hectare), while the Arable farmland had the lowest tree density (73 trees/ha)
The highest and lowest tree diversity recorded for the BCA and AF respectively reflects the level of protection enjoyed by the two sites and the consequent level of exploitation and resource utilization

Summary

Introduction

These include farming, fuel, shelter, damming, industrial purposes, mining and others. In the process of achieving these purposes, man changes the terrestrial habitats and affects the life forms - animals, plants and microorganisms, which live in or on them. The continuous clearing of the forest for shifting cultivation, cattle ranching, timber, fuel wood, road construction, pipe-laying, shelter, mining and industrial purposes have caused the loss and degradation of forests. Loss of tree species could occur through other causes, the most important single factor affecting the fate of tree species populations on Earth is the accelerated rate of habitat destruction (Harris 1984).

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