Leaf Damage in Island Buttonwood, Conocarpus Erectus: Correlations with Pubescence, Island Area, Isolation and the Distribution of Major Carnivores

Abstract

Buttonwood (Conocarpus erectus) is a widespread species of terrestrial mangrove that occurs on islands of a variety of sizes, down to the smallest island having any vegetation. It exists as and morphs (with some intermediates), having highly pubescent and nearly glabrous leaves, respectively. Buttonwood leaf damage was measured on 74 small islands in the central Bahamas, and various multifactorial analyses were performed. Results were 1) leaves on lizard-inhabited islands were less damaged than those on lizardless islands; 2) silver leaves were less damaged than green leaves, and this effect was about equal to the first; 3) island area was positively correlated with leaf damage in some cases; 4) island distance was seldomly strongly correlated with leaf damage, but both near and far islands showed significantly more damage in a few respective cases; 5) orb-spider density and total numbers of orb-spider individuals were seldom correlated with leaf damage; the single significant coefficient was positive. Results strongly support pubescence as an effective deterrent against herbivory and lizards as a major protective carnivore for the plant. The reasoning of Hairston et al. is consistent with results for lizards but not spiders.