Insect community associated with black cherry (Prunus serotina) in the Allegheny National Forest

Abstract

Black cherry (Prunus serotina Ehrh.) is valuable species managed for its economic and ecologic benefits. This species grows best in the environment of the Allegheny Plateau region in northwestern Pennsylvania. Land managers on the Allegheny National Forest (ANF) have been managing black cherry for a variety of goals and purposes. Over the last few decades, the land managers have noticed a decline in the natural regeneration of black cherry in the forest. Because the black cherry flowers are self-incompatible and require animal pollinators to transfer the pollen from one tree to another one hypothesis for this decline could be a deficiency of insect pollinators. There are little published studies documenting pollinators in the forest canopy ecosystem. Even less literature is available regarding the pollinators of black cherry flowers. My research presented in this thesis is intended to answer these questions about the insect pollinators of black cherry. First, we conducted a survey in the canopies of black cherry in two mixed upland hardwood stands in the ANF. We surveyed for seven days before, during and after peak flowering of black cherry using color pan traps. We found that Diptera was significantly more abundant (P Next, we surveyed insects during the peak flowering of black cherry in three different harvesting treatment types in the ANF. These stands were defined by the foresters in the ANF as shelterwood seed tree, shelterwood removal stand treatments, and unmanaged. The shelterwood seed tree treatment is the first stage of a harvest cycle which involves removing approximately one-third of the overstory canopy trees, leaving mature black cherry to seed in the next generation. The shelterwood removal cut is the final stage of harvest and removes all the merchantable tree species in the stand. The overstory is almost completely removed, favoring the understory vegetation. The mixed-age upland hardwood stands have no recent history of management and were used as the control stand. We found the order Diptera to be most abundant in all stand types, with the highest trap captures in the shelterwood seed tree treatment. The lowest species diversity and richness was found in the canopy of the removal stand. The top ten most prevalent insects composed ~69% of the total trap captures and many of these species showed a preference toward the canopy in each of the stand types. The results of my studies elucidate which insects are associated with the canopies of black cherry