Epiphytes & Arthropods

(Miller, Wagner, and Woods) - Epiphytes and arthropods play important roles in forest ecosystems and are important sources of biodiversity. However, their life history characteristics, habitat requirements, and response to forest management are poorly understood. This study investigated associations between epiphytes and arthropods, and assessed the effect of gap harvesting using AFERP research areas.

Arboreal arthropods and epiphytes on the bark of red maple (Acer rubrum) trees located in undisturbed forest and harvest gaps were compared at three height intervals (0-2, 2-4, and 4-6 m). A strong vertical gradient was observed for both epiphytes and arthropods. Bryophytes, Cladonia spp., and cyanolichens were most abundant near the base of the tree, while foliose and fruticose lichens were most abundant at 4-6 m. Acari (mites), Araneae (spiders) and Collembola (springtails) were most abundant near the base of the tree, whereas Diptera (flies) were most abundant above 2 m.

Gap harvesting reduced the abundance of bryophytes, Collembola, and Araneae on the bark of trees. A positive correlation in the abundance of bryophytes, Collembola, and Araneae suggested that there may be a trophic interaction among the three. During their early developmental stages, arboreal spiders appeared to be dependent upon availability of Collembola prey, which in turn were dependant upon bryophytes. This relationship appeared to be sensitive to a decline in bryophyte abundance that occurred following gap harvesting.

This study was the first to identify Diptera as a major component of the arboreal community. Fifteen Diptera families were identified, eight of which were common. The eight common families utilized the arboreal habitat differently depending on height along the bole and abundance of crustose and "other" lichen. A potential interaction was identified between Diptera and a Collembola morphospecies in the family Entomobryidae. These findings suggest a diverse arthropod community that exploits different characteristics of the arboreal habitat and exhibits varied responses to harvest gaps.