The Ecology of Mayflies (Ephemeroptera) in the Guadalupe River Basin, Texas

Distribution, life histories, and production were considered for mayflies in the Guadalupe River basin, Texas. Distribution patterns and species richness were dictated by the stream source; springbrooks had fewer species and were dominated by a single species of South American origin. Streams fed by surface runoff had more species and numerical dominance was more evenly distributed among the taxa. Life histories for all species were asynchronous and multivoltine in Honey Creek, a springbrook, and the Blanco River, a surface runoff stream. This seems to be due mainly to high temperatures. Body size of mature nymphs of Baetis quilleri were largest in the winter in the Blanco River and decreased during the summer months. Patterns for Honey Creek were less distinct, but body weight tended to be more constant throughout the year. In both winter and summer, body size was greater in Honey Creek than in the Blanco. Differences in individual body size, population biomass, and asynchronous multivoltine life cycles did not coincide well with predictions of the thermal equilibrium hypothesis. Secondary production for all mayflies in Honey Creek was 4,332 mg/m2/yr and 53,929 mg/m2/yr in the Blanco. These estimates did not take the cohort production interval (CPI) into consideration and must therefore be considered minimal estimates. Nonetheless, values for the Blanco River were extremely high, mostly due to Traverella presidiana, which had a production value of 33,676 mg/m2/yr. Such values are very high, and if properly corrected, may be among the highest rates of secondary production yet reported. This indicates that mayflies in the Blanco River may be very important in ecosystem structure and function.

Name thesis:degree_name

Master of Science

Level thesis:degree_level

Masters

Discipline thesis:degree_discipline

Biology

Grantor

Southwest Texas State University

Year dc:date.issued

1986

Author dc:creator

• Stanley, Emily H.

Advisor dc:contributor.advisor

• Short, Robert A.

Committee members dc:contributor.committeemember

• Hannan, Herbert H.
• Tomasso, Joseph R.

• mayflies
• Guadalupe River Basin

Language dc:language.iso

en

Handle dc:identifier.uri

https://hdl.handle.net/10877/21709

OAI identifier oai:identifier

oai:digital.library.txst.edu:10877/21709