Jennifer Milligan

Ph.D. Candidate, Cleveland State University

Field Travel Grant Type 1

Utility of Fluctuating Asymmetry in Caddisflies (Trichoptera) as an Indicator of Coastal Wetland Health in Lake Erie

“My interests are in the overlap of organismal biology, ecology, and biomonitoring. Human impacts on freshwater lakes, streams, and wetlands are an urgent and major environmental concern worldwide. This has led to broad interest in the development of methods that allow us to quickly obtain information on the natural environment and assess habitat quality.

Human impacts on freshwater lakes, streams, and wetlands are of great environmental concern in the Great Lakes region. Past and present land use patterns are reflected in the physical, biological, and chemical conditions of these valuable ecosystems. Prior to 1850, wetlands covered nearly 4000 km2 of the watersheds within the western basin of Lake Erie. However, by 1900 the majority of these wetlands were drained and converted for agriculture and development. Urban and agricultural runoff and increased municipal and industrial waste resulted in poor water quality problems for Lake Erie by the mid 1900’s.

Developing methods that allow us to quickly obtain information on the natural environment and assess habitat quality is of utmost importance. Standard habitat quality monitoring techniques rely on the use of ecosystem-wide characters such as changes in biomass and loss of species diversity of focal taxa. A drawback of these techniques results from the fact that by the time it takes an ecosystem to respond in a measurable way it may be too late for remedial actions to save threatened or highly affected species. A good alternative is the use of a relatively inexpensive and rapid monitoring tool such as fluctuating asymmetry (FA).

Caddisflies (Trichoptera) are often used in biomonitoring studies because they are an abundant, taxonomically rich, and diverse group that can be found in nearly every aquatic habitat. Their sensitivity to pollution makes them ideal in studies of habitat and water quality. A number of factors may stress populations of Trichoptera. Water chemistry and atmospheric CO2 may not only directly affect populations but also indirectly affect them through changes in the biochemical makeup, and defensive chemicals of the algal food sources. However, few studies have explored FA in Trichoptera found in wetland habitats and none have been conducted in Ohio and Michigan coastal wetlands.

The aims of the present study are to: 1) apply measurements of FA to assess wetland quality; 2) determine the relationship of caddisfly FA to water chemistry; 3) assess whether habitat generalist species (Hydroptila waubesiana) exhibit less asymmetry than habitat specialist species (Agraylea multipunctata).“