SPECIES RICHNESS AND ABUNDANCE OF LOW-TRUNK HERB EPIPHYTES IN RELATION TO HOST TREE SIZE AND BARK TYPE, EASTERN AMAZONIA

The composition and structure of the low-trunk epiphytic herb assembly as well as its vertical distribution were studied. DBH of host tree and bark type influence species richness and abundance in a non-flooded lowland tropical rainforest in Eastern Amazonia (1 degrees 57' 36"S 51 degrees 36' 55"W). A total of 37 epiphytic herb species were identified, among which 60% were Araceae. Species richness and abundance of epiphytic herbs showed tendency of positive correlation with host tree size and no relationships with bark type. Low positive correlation may be a by-product of the predominance of trees with smaller diameter in our sample rather than a reflection of neutral relationship. The absence of relationships with bark type may be partially explained by the large number of secondary, generalist, hemi-epiphytes and also may reflect the absence of suitable substrate in trees with smaller diameter.