Measuring soil fauna in stormwater green infrastructure
Citation:
OConnor, T. Measuring soil fauna in stormwater green infrastructure. Low Impact Development (LID) Conference, Oklahoma City, OK, August 06 - 09, 2023.
Impact/Purpose:
EPA has been developing techniques to monitor the water quality and water volume of stormwater runoff diverted from the receiving system through plant-based stormwater control measures (SCM) more commonly known as green infrastructure (GI). EPA is involved in ongoing investigatory research to monitor SCMs at the Edison Environmental Center (EEC) in Edison, NJ and off-site. Research includes completing equipment calibrations, verifications, fabrication and maintenance; data collection and management; and sample collection and analyses or transfer to specified laboratories. This research on soil fauna in green ifrastructure is to ascertain whether stormwater controls are providing habitat for nearby soil fauna or whether the conditions of the green infrastructure stormwater controls are selecting soil fauna that are adaptable to frequent inundation, other conditions such as low organic matter content or proprietary media mixes that could be harmful to soil fauna.
Description:
Stormwater controls in urban environments that use plants are being promoted as green infrastructure. To better understand these controls and relationship to the environment, soil fauna extraction was performed on a variety of stormwater controls from various urban locations including rain gardens, basins and curb cuts. Urban wooded areas were used for background comparisons, Additional metrics, including bulk density, loss on ignition (LOI) and soil moisture were also performed on samples. A variety of ecological indices were calculated and statistically tested. Three groupings were identified for the 23 samples collected over a two-year period: urban trees (7), rain gardens (10) and combination of basins (4) or curb cuts (2) which had the lowest number and variety of organisms. Statistical testing of these groupings by the Shapiro-Wilk W test indicated several indices were considered parametric. A One-way ANOVA of the Shannon diversity index was considered significant (p< 0.05) and both the Shannon diversity index and Simpson index of diversity had Fisher LSD multiple comparison tests that indicated rain gardens and urban trees were statistically different from the basin or curb cut grouping. Comparisons of sample enumerations and indices to other metrics were not linear though plotting potentially indicated maximum relationship for certain metrics. One example is that <5% or >15% LOI was associated with lower numbers and variety of fauna. A One-way ANOVA of the sun of taxa was significant (p< 0.05) with the larger mean (>5) sum of taxa associated between 5-15% LOI versus the lower mean (<3.5) sum of Taxa (<3.5). Further sampling and analysis is planned.