Liana habitat and host preferences in northern temperate forests

Abstract

Lianas and other climbers are important ecological and structural components of forest communities. Like other plants, their abundance in a given habitat depends on a variety of factors, such as light, soil moisture and nutrients. However, since lianas require external support, host tree characteristics also influence their distribution. Lianas are conspicuous life forms in tropical regions, but in temperate areas, where they are less prominent, little is known about factors that control their distributions in these forests. We surveyed the climbing plant species in 20 mature (100 years and greater) forested habitats in the Midwest USA at a variety of levels from simple presence/absence, to ground layer abundances, to those species that had ascended trees. We also examined attributes of the tree species with climbers attached to them. Using cluster analysis, we distinguished five different tree communities in our survey locations. We determined that 25% of the trees we surveyed had one or more lianas attached to it, with Parthenocissus quinquefolia (Virginia creeper) the most common climbing species encountered. Canopy cover and soil attributes both influenced climber species presence/absence and ground layer climber abundance. The proportion of liana species of a given climbing type (roots, stem twiner, tendril climber) was significantly related to the DBH of the host tree, with more root climbers and fewer stem and tendril climbers on large trees. In general, the DBH of climbing lianas had a significant positive relationship to the DBH of the host tree; however this varied by the identity of the liana and the tree species. The greater the DBH of the host tree, the higher the probability that it was colonized by one or more lianas, with tree species such as Pinus banksiana (jack pine) and Quercus alba (white oak) being more susceptible to liana colonization than others. Finally, some liana species such as Celastrus scandens (American bittersweet) showed a preference for certain tree species (i.e., P. banksiana) as hosts. The information obtained about the relationship between the tree and climber community in this study provides insight into some of the factors that influence liana distributions in understudied temperate forest habitats and how lianas contribute to the structure of these mature forests. In addition, these data can provide a point of comparison to other liana communities in both temperate and tropical regions.