TP8 Biomonitoring
A105 & A106
1:20 PM - 4:40 PM, Tuesday
() Artificial substrate colonization and recolonization a tool to detect differences in macroinvertebrate composition in relation to water quality.
Mahato, M1, 2, Kennedy, J.H.1, 1 Department of Biological Sciences, University of North Texas, Denton, TX, USA2 URS Corporation, Dallas, TX, USA
ABSTRACT- Reference sites for risk assessment of perturbations on water quality are frequently not available in semi-arid regions because flow in impacted urban streams is often greatly enhanced due to discharge from wastewater treatment plants. This study evaluated the potential of using artificial substrates colonized by macroinvertebrates in a minimally impacted stream (Clear Creek) and then transferred to an urban impacted stream from waster water treatment plant (Lower Pecan Creek) to detect impact on colonized macroinvertebrates. This experiment carried out in the spring and summer of 2003 also assessed how seasonal changes in macroinvertebrate community structure influenced the ability of the technique to detect differences. Hester-Dendy samplers were anchored to racks for invertebrate colonization. After 6 weeks, colonized some artificial substrates were transported from the reference site to the urban sites. Artificial substrates were retrieved one week after the transfer event, and collected invertebrates were identified to genus or practical taxonomic level. Statistically significant differences (ANOVA 
= >0.05) were recorded for taxa composition and abundance between minimally impacted and impacted sites. A significant increase in the number of local taxa colonized on the transfer substrates at the impacted site were recorded within a week. Statistically significant changes in macroinvertebrate communities consistent with changes in water quality were found between sites. Reduction of flow during the summer results in reduced taxa richness in the reference stream. This study concludes that in semi-arid regions, spring monitoring is the appropriate time for biomonitoring and is sufficient to detect a difference in macroinvertebrate distribution in relation to water quality.
Key words: Macroinvertebrates, Artificial Substrate, Biomonitoring