Soil-vegetation interrelationships of the tree species in lowland forest in the Puerto Princesa Subterranean River National Park.

Abstract

Several studies have tried to examine the variations in soil conditions and relate it to variations in patterns of plant distribution. In this study, we tried to determine the association between the ten most important tree species and different soil parameters in the jungle trail of Puerto Princesa Subterranean River National Park (PPSRNP). Soil and vegetation data were collected from 30 sampling sites along a 3-kilometer transect divided into three sites - Beach, Hill 1, and Hill 2. The ten most important tree species out of the 106 species sampled were chosen based on their importance values. Using Canonical Correspondence Analysis (CCA), soil parameters were tested against data on vegetation producing two axes. The first axis was an axis of pH while the second axis denoted soil fertility. Tree species which preferred more basic soils included Hernandia ovigera and Intsia bijuga. On the other hand, Durio sp., Casearia grewiifolia, Dimorphocalyx murinus, and Intsia bijuga, preferred areas with relatively lower soil fertility. It was also observed that majority of the sites possessed relatively acidic soil. In addition, most portions of the lowland forest (Hill 1 and 2) possess low soil fertility. Using the data obtained from CCA, we can predict areas where growth of certain species would be optimal thus enabling forest managers to select which species are better suited for reforestation activities based on their adaptability to different environmental gradients.