Author: Joe S Girgente,  Student (Virginia Tech)

Description:
Anthropogenic salinization of freshwater streams is a growing global stressor due to activities including mining, urbanization, and road salting. While salinization generally predicts decreased taxa richness and density and local extirpations of salt-sensitive taxa, the stonefly genus, Leuctra, increases in abundance, suggesting favorable conditions in spite of this stressor. While they appear beneficial, the effects of salinization on Leuctra sp. remain unknown. Our objective is to understand how salinization alters the growth and development of Leuctra sp. by modeling length-mass regressions. We measured specimen lengths and masses collected from nine Appalachian headwater streams with varying salinity (25–1460 µs/cm). We predict Leuctra sp. experience lower individual fitness measurable through a decline in mass accrual rates. However, preliminary data suggest that Leuctra in medium-salinity (402-594 µs/cm) conditions accrued mass at a faster rate (4.7-6.0 mg/mm) than Leuctra at lower (3.4 mg/mm)- and higher (3.1 mg/mm)-salinity conditions. We can use these mass accrual rates as a method of impact assessment to identify possible individual and population-level stress.  Freshwater salinization can also reduce aquatic biodiversity and redistribute macroinvertebrate community benthic biomass creating cascading, yet currently unknown effects on stream food webs.

Category: Scientific Program Abstract > Special Session > CS43 Undergraduate Research Projects