Abstract
Ketak (Lygodium circinatum (Burm.) Sw. is a fern plant and its growth requires other plants as a host plant for climbing of tendrils to get light. Information of vegetation association of host plant is needed, due to it is considered to have an influence on growth and productivity. This data and information is important to develop a strategy of ketak for cultivation and conservation. This research was aimed to determine vegetation association of ketak host plant in its habitat. The study applied purposive systematic sampling by survey technique based on altitude i.e. 0-249, 250-499 and 500-750 m asl. There are 10 of observation plot with dimension of 20 m x 20 m. In each plot, an analysis of vegetation association of ketak host plant to determine association between species, type of interaction and index of association between species of ketak host plant. The results showed that vegetation association of ketak host plants in each altitude classification which had a positive and strong association were 14 pairs species in altitude of 0-249 m asl, and 8 pairs species in altitude 250 – 499 m asl, and also in altitude 500 – 750 m asl had 15 pairs species. Altitude 500 - 750 m asl, shows the association of vegetation with the highest combination of species pairs.