Understanding the effects of climate change on forest ecosystems requires exploration of the relationships of different components of the system, such as the response of biota to local hydrology, temperature, precipitation, and elevation. The Long-term Ecological Research Program at the H. J. Andrews Experimental Forest, located in the Western Cascades of Oregon, has been exploring these relationships since the late 1940s in the search for a sustainable method of harvesting lumber. This study in insect phenology utilizes terrestrial insect samples collected in malaise traps from early April until early July of 2011 at 16 core sites in the Andrews that differ in elevation, slope, aspect, and stage of forest growth. Each site was sampled multiple times during the sampling period. Insect life cycles and activity are highly regulated by temperature. It was predicted that greater insect abundance, where abundance is the amount of insects captured, would occur at higher temperatures and lower elevations. Results demonstrated that higher abundances occurred at mid-temperature sites, which were also mid-elevation sites. Additionally, high-temperature sites took more cumulative degree-days for insect activity to achieve maximum levels. Preliminary examinations indicate that old growth forests have higher levels of insect activity; however, sample size was skewed and future research looking at insect activity as a function of forest structure would best be explored utilizing data from multiple years.
Keywords: Long-term Ecological Research, H. J. Andrews Experimental Forest, insect abundance, phenological, climate change, invertebrate