Abstract
Bioswales and other forms of green infrastructure can be effective means to reduce environmental stresses in urban ecosystems; however, few studies have evaluated the ecology of these systems, or the role that plant selection and microbial assembly play in their function. For the current study, we examined the relationship between plant transpiration rates for five commonly planted herbaceous species in three bioswales in New York City, as well as bioswale soil microbial composition and soil chemistry. Soils were sampled near individual plants, with distinction made between upper (bioswale inlet) and lower slopes (bioswale outlet). We found high variation in transpiration rates across species, and that Nepeta × faassenii was the highest conductor (13.65 mmol H2O m–2s–1), while Panicum virgatum was the lowest conductor (2.67 mmol H2O m–2s–1) (p < 0.001). There was significant variation in percent N of leaves and soil, which did not relate to the higher water conductance in bioswales. Significantly higher C, N, and water content on the high end of bioswale slopes suggest storm water run-off is mostly absorbed on the inlet side. Bacterial and fungal communities were significantly clustered by bioswale and by plant species within each bioswale implying there are micro-environmental controls on the soil microbial composition, and that plant composition matters for microbial assemblages within bioswales. Plants with higher transpiration rates were associated with greater fungal and bacterial diversity at the level of the bioswale and at scale of the individual plant, suggesting a possible link between plant physiological traits and soil microbial communities. These data suggest that the specific plant palette selected for planting bioswales can have deterministic effects on the surrounding microbial communities which may further influence functions such as transpiration and nutrient cycling. These results may have implications for bioswale management to improve urban water quality and reduce stress on sewage systems after storm events by revising plant species palette selection based on the functional consequences of plant-microbial associations in engineered green infrastructure.
Highlights
Cities with older infrastructure that combine both sanitary, industrial, and storm sewers are at risk of overwhelming the capacity of these sewer systems during wet weather events, which trigger combined sewer overflows (CSOs) into nearby waterways (Burian et al, 2000)
Bioswales play an integral role in mitigating the incidences of storm water overflow events, and this study is among the first of its kind to detect relationships between the physiological traits of plants, the abiotic properties of soils, and the community composition of soil microbes that occupy these engineered ecosystems
We found strong separation of microbes across bioswales that was related to soil physical and chemical properties, and possible microclimatic effects that were not measured in the current study
Summary
Cities with older infrastructure that combine both sanitary, industrial, and storm sewers are at risk of overwhelming the capacity of these sewer systems during wet weather events, which trigger combined sewer overflows (CSOs) into nearby waterways (Burian et al, 2000). These CSOs can be triggered by a single precipitation event, and are related to significant economic, human health, and environmental problems (Lee and Bang, 2000; Marsalek and Rochfort, 2004; Gasperi et al, 2010). Few studies have evaluated the ecology of these systems, so whether or not particular plant palettes are more or less effective for the multi-functionality of their benefits remains uncertain
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
