Spatial Ecology And Host Diversity Of Three Arboreal Plants From Lord Howe Island

In canopy ecology, it has long been understood that different guilds of arboreal plants have different spatial distributions and degrees of host specificity. Here, we present a case study looking at how within-crown spatial niche and host specificity vary between three very different morphologies of arboreal plant on Lord Howe Island, interpreting these in terms of different water acquisition strategies. We quantify within-crown spatial niche and created a null model to test host specificity in three species with very different water acquisition strategies (a mistletoe, an orchid and a detritus-collecting fern). The mistletoe had greater host specificity than the two epiphyte species, and was restricted to thinner branches. The fern occurred further from the outer crown than the other species including on the trunks of host trees, and was the only species to show no indication of host specificity. Differences in distribution are consistent with differences in water acquisition strategy, providing an initial link between traits and spatial distribution, a potentially fruitful avenue of future research.