Differential spatial distribution of arthropods under epiphytic lichens on trees

Abstract

Epiphytic lichen thalli on trees may protect arthropods - herbivores or their natural enemies. Although the relationships between lichens on the forest floor to arthropods have been widely studied in boreal regions, those between epiphytic lichens and the arboreal arthropod fauna in temperate and Mediterranean climates are poorly investigated. In particular it is unknown if the animals use lichens differently located on different part of the trees. Our results indicate that numerous arthropods, herbivores and predators, may live in epiphytic lichen cover, and that more of them are found on the trunk than on old or young branches: an average of 2000 individuals were found under each meter square of the thallus covering the trunk of 20 trees, but fewer on branches. In particular more insects from more Orders were detected on trunks than on branches. We propose that this issue should be investigated further to clarify the exact status of epiphytic lichens in arthropod biodiversity conservation.