Dr. Robert C. Johnson

Dr. Johnson's research focuses on quantifying the role freshwater invertebrates play in the fundamental ecosystem processes of energy flow and nutrient cycling, and how anthropogenic disturbances affect the role these organisms play in ecosystems. To date, Dr. Johnson's research has focused on how urban development affects these fundamental ecosystem processes in freshwater invertebrate assemblages. While considerable research effort in the scientific community has been placed on quantifying the effects of urbanization on the composition of freshwater invertebrate assemblages (e.g. species richness, diversity, etc.), very little attention has been given to placing these assemblages within the ecosystem-level contexts of energy flow and the cycling of matter. However, understanding these relationships is imperative for the proper management and conservation of freshwater ecosystems in human-altered environments.

Current Research

Emergence production of adult aquatic insects from wetlands along a gradient of urban development with an emphasis on disease-transmitting species.

Aquatic insects have complex life cycles where the immature life stages are completed in the water, but these organisms emerge from the water to become terrestrial winged adults. The emergence of these insects from freshwater environments to become terrestrial adults represents the export of insect individuals and biomass from the freshwater ecosystem to the adjacent terrestrial ecosystem. The production of emerging adult insects is an important cross-system subsidy that links aquatic and terrestrial ecosystems, and represents an important source of potential prey for terrestrial predators. Many emerging aquatic insects also have other important societal and economic importance. For example, emerging mosquitos (Family: Culicidae) represent a group of insects that are typically described as nuisance species, and many mosquitos are also potential disease vectors. As a result, understanding the ecosystem properties that regulate the production of emerging adult mosquitos is important in controlling these species, particularly in human-dominated ecosystems such as cities.