This study was designed to evaluate the influence of microclimatic heterogeneity, associated with complex terrain, on phenology and to evaluate potential trophic responses to scenarios of climate change, disturbance and land use. We focus on a simplified model trophic system involving vascular plants, terrestrial and aquatic insects, and migratory neotropical and resident birds. The model trophic system is interesting because the phenologies of different components in the model system are independent (cued by various abiotic drivers) and dependent (due to trophic interactions), potentially leading to complex system behaviors.
Plant and poiklothermic animal (ex. invertebrates) phenologies are highly temperature dependent. Phenologies of terrestrial plants and invertebrates would therefore likely exhibit wide spatial and temporal variation across the landscape in response to temperature variation associated with elevational differences, cold air drainages patterns, and temperature inversions. Aquatic invertebrate phenologies are also tied to temperature, but stream temperatures are influenced by different factors than those driving air temperatures and they may be less sensitive to complex terrain.
For the invertebrate part of this study, we are examining spring-time (April through June) flying (terrestrial and adult aquatic) insect activity and adult aquatic insect emergence across a range of sites in the HJ Andrews Experimental Forest. Flying insect activity will be assessed using malaise traps deployed at 16 sites ranging from 450m to over 1300m in elevation, and with a variety of forest stand ages and slope aspects. Emerging aquatic insects will be collected with emergence traps in six 1st to 2nd order streams ranging from 450m to 1000m in elevation, and differing in water source (spring vs run-off) and surrounding forest age. Insects from malaise traps will be identified to varying levels from order to genus, depending on the group and available keys. Adult aquatic insects will be identified to varying levels from subfamily to species. We will be monitoring overall activity levels and emergence rates over time as well as the activity/emergence of selected key taxa.
Data collection began in 2009 and is ongoing.
Judith L. Li, Sherri L. Johnson, William J. Gerth
We will assess the activity level of flying insects and emergence rates of adults of aquatic insects across the range of microclimates provided by the complex terrain at the HJ Andrews experimental forest. Our goal is to look at spatial and temporal variation within the Spring season, and to assess the variability among years. Invertebrate data will be combined with plant and bird phenology data to look for interactions among trophic levels. Data collected will provide a baseline which will be used to assess possible effects of climate and/or land-use change.