Back to Contents

Pak. J. Bot., 44: 171-176, Special Issue March 2012.

FREE FULL TEXT PDF

ENVIRONMENTAL INTERPOLATION MODEL OF VEGETATION DISTRIBUTION PATTERN AND ECOLOGICAL RESTORATION OF DEGRADED LANDS

AUDIL RASHID, SUNBAL SIDDIQUE AND TARIQ MAHMOOD

Abstract: The diversity of native plant species comprising of natural vegetation is closely related to patterns of soil processes controlled by environmental conditions. This study developed a logistic model integrating the relationship between spatially distributed vegetation patterns and ecological conditions of soil explicitly based along heavy metal contamination gradients. A quadrat size of 1 x 1 m was used to analyze herbaceous plant species in the vicinity of industrial area Islamabad that has been contaminated with wastewater effluents. We identified two dominant communities comprising of Desmostachya bipinnata and Trifolium alexandrinum as initial colonizers. The canonical correspondence analysis revealed that grass species were more tolerant to soil Pb concentration that ranged from 1.03 to 3.44 mg kg^–1 soil. The analysis of rhizosphere soil samples indicated that spots that were rich in Cd concentration were mainly occupied by Parthenium hysterophorus along with Malvastrum coromandelianum. We further interpolated the spatial patterns of soil properties in which pH and organic matter contents emerged as significant indicators. In areas where topography was uneven and natural depression created sinks for soil water, relatively higher soil heavy metal concentrations were observed. The vegetation-soil interaction (e.g. root proliferation and phytoextraction potential) has influenced the ability of plants to maintain cover on contaminated sites and thus ecological conditions were modified accordingly. We therefore stress upon considering topographic aspects and native plants of an ecosystem into one continuum system to address the restoration processes on degraded lands.

Department of Environmental Sciences, PMAS Arid Agriculture University, Rawalpindi, Pakistan

¹Corresponding author e-mail: audil@uaar.edu.pk