Vacant lot plant establishment techniques alter urban soil ecosystem services

Abstract

Abstract Vacant residential lots are ubiquitous in cities. While there is increasing interest in enhancing the aboveground habitat and biodiversity of vacant lots via restoration, vacant lot restoration may also affect the properties of and ecosystem services provided by soil. We assessed the effects of four vacant lot plant community establishment techniques (seed bombing, broadcast seeding, plug planting, and intensive gardening) and unaltered lawn on three critical ecosystem services provided by urban soils: carbon sequestration, nutrient retention, and water infiltration. We found that aboveground-focused treatments had belowground consequences. Consistent with other “urban grassland” studies, lawns exhibited the highest carbon storage among our treatments. However, soil carbon may increase in our other treatments over time – a common phenomenon in disturbed urban soils. We also found that nutrient retention – particularly nitrogen retention – increased with treatment intensity, likely due to increased plant uptake and microbial immobilization in our plots with prairie plantings. Finally, our most investment-intensive treatment, intensive gardening, resulted in decreased water infiltration, likely due to soil disturbance and increased bare soil resulting from frequent watering and weeding. Thus, treatments did not have consistent positive or negative effects on soil ecosystem services, emphasizing the multifunctionality and trade-offs associated with urban soil ecosystem processes. However, assuming low soil carbon and organic matter pools in our broadcast seeding and plug planting treatments recover over time, these two treatments may optimize aboveground plant community establishment and belowground ecosystem service provision in urban vacant lots.