Life history and secondary production of Cheumatopsyche spp. in a small Appalachian stream with two different land uses on its watershed

Ecological parameters of hydropsychid caddisflies are very important for production dynamics of stream ecosystems, due to the abundance and biomass of these collectorfilterers in many stream types. I studied life history and secondary production of Cheumatopsyche spp. (Trichoptera: Hydropsychidae) in Stroubles Creek, a 3rd order stream near Blacksburg, Virginia, in order to compare life histories and production dynamics in two reaches with different land-use in a watershed. The upstream section was influenced by urban and agricultural activities. The channel showed evidence of disturbance related to both geomorphological processes and agricultural activities. There was higher annual accumulated degree days, and stream substrate particles were mostly mid and coarse gravel. The downstream section was surrounded by forest, with little evidence of human activities and disturbance and with a more diverse distribution of particle size ranges in the streambed. Cheumatopsyche pettiti (Banks) was the only species of the genus that developed the whole life cycle in the upstream site, while C. pettiti and C. oxa Ross were both abundant downstream. There were three other Cheumatopsyche species collected with light traps in the area. Cheumatopsyche larvae and other aquatic insects were more abundant downstream, probably in relation to higher habitat availability. C. pettiti was determined to be bivoltine at the upstream site, perhaps related to high thermal input. However, only a fraction of the two Cheumatopsyche species could develop a 2nd generation downstream, overlapping with continuous emergence of the overwintering larvae during the summer. Cheumatopsyche production in Stroubles Creek was higher than in forested, low-order streams of North America but similar to some values obtained at streams in agricultural areas and large rivers. Production was less than from sites below food-enriched reservoir releases or from snag habitat in southeastern, coastal-plain rivers. Detritus was the greatest component of the diet of Cheumatopsyche at the two sites, but detritus and animal food had similar contribution to production downstream. The adjustment in life history and production dynamics in the two reaches showed the ecological plasticity of Cheumatopsyche and the importance of hydropsychids in the energy flow of moderately disturbed streams in mountainous regions.

Name thesis:degree_name

Ph. D.

Level thesis:degree_level

doctoral

Discipline thesis:degree_discipline

Biology

Department dc:contributor.department

Biology

Grantor dc:publisher

Virginia Tech

Year dc:date.issued

1996

Author dc:creator

• Sanchez R., Mario

Chair dc:contributor.committeechair

• Hendricks, Albert C.

Committee members dc:contributor.committeemember

• Benfield, Ernest F.
• Buikema, Arthur L. Jr.
• Voshell, Reese
• Webster, Jackson R.

Statement dc:rights

• In Copyright

Licence dc:rights.uri

• http://rightsstatements.org/vocab/InC/1.0/

Language dc:language.iso

en

Dc Identifier Other

etd-10262005-143539

OAI identifier oai:identifier

oai:vtechworks.lib.vt.edu:10919/40237