Liane Distribution within Native Forest Remnants in Two Regions of the South Island, New Zealand

New Zealand Journal of Ecology (1998) 22(1): 71-85 ©New Zealand Ecological Society Availability of suitably-sized support is a major factor limiting liane access to the canopy because lianes are not self-supporting (Putz and Holbrook, 1991). In the Knysna Forest, South Africa, aspects of forest architecture which affect support availability, rather than abiotic factors such as light levels and soil nutrients, were the primary determinants of liane distribution (Balfour and Bond, 1993). Climber abundance was negatively associated with canopy height. In high canopies there were fewer low supports available; support availability is greatest where there is regeneration of young vegetation following disturbance in a forest. As the tree canopy becomes taller and more continuous, lianes must climb higher to reach the light. Some climbing mechanisms (such as twining) seem to be more effective at reaching high canopies than others (e.g. tendril climbing; see Discussion). Lianes are generally not distributed at random on their potential host trees (Campbell and Newberry, 1993), suggesting that trees are not equally likely to host lianes (Putz, 1984b; Hegarty, 1991). The susceptibility of individual trees to invasion by lianes is determined by the habitat of the host and by host architecture. Early-successional trees of disturbed habitats in the tropics often have Introduction