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European swallowwort [Vincetoxicum rossicum(Kleopow) Barbarich] is found in the northeastern United States and southeastern Canada. It forms dense growth patterns that reduce plant and insect biodiversity, and lab assays show that it produces allelopathic compounds that affect microbial activity. Consequently, we hypothesized thatV. rossicumalters soil microbiome composition and activity in invaded habitats, which may impact ecosystem properties and processes. We sampled soil from a similar time point within a growing season at each of five sites in New York State whereV. rossicumwas both present and absent. We measured bacterial and fungal microbiome composition, available soil nitrogen (N), soil respiration (CO2flux), and soil extracellular enzyme activities. Microbial composition varied across field sites, but only fungal composition was affected by invasion. No significant differences were found between the invaded and uninvaded plots at any of the sites for available soil ammonium, nitrate, or respiration, though extractable N varied greatly between sites. Microbial hydrolytic extracellular enzyme activities suggest decreased protein degradation and increased oxidative enzyme activity withV. rossicuminvasion, which is relevant to soil N and carbon cycling processes. AlthoughV. rossicumimpacted rhizosphere microbial composition and activity, it was not associated with large perturbations in ecosystem function when examined across multiple invasion sites during this short-term study.

Urban forests are valuable assets to a community from multiple perspectives. Diversifying urban forests is a common and important management goal to increase resilience in the face of biotic pests and diseases, climate change, and to increase ecosystem services. Multiple design and engineering consultants develop site plans and specify trees for public and private projects, and consultant disciplines differ in their training plant material selection and diversity. Publicly available site plans from Des Moines (79) and Iowa City, Iowa, USA (70) between 2015–2018 that passed planning and zoning review were analyzed to determine the associations between practitioner disciplinary training and the diversity of specified trees at site, city, and landscape scales. We found that consultant discipline was not related to the alpha diversity of a site until site size was greater than 2.42 ha, then civil engineers were associated with lower tree diversity than other consultants. Landscape architects completed a majority of the project plans (43 %), specified the most trees (62 %), and utilized the most diverse plant palette, including 30 species not used by other consultants. However, landscape architects also frequently specified clonally produced cultivars (62 % of all selections) which may limit genetic diversity at a landscape scale, thus potentially undermining diversification efforts by repeating genotypes. Findings from this study suggest that messages pertaining diversification efforts, plant selection, and reduction of genetic diversity resulting from cultivar specification are important for all consultants, but especially for landscape architects who were responsible for specifying a majority of trees and sites. This case study of two Iowa (USA) communities provides evidence of landscape-scale diversity outcomes associated with consultant discipline and the potential for use of public site plan documents to assess such relationships. Further research is needed to determine if these findings are generalizable to other municipalities or states.

Urban grasslands are turfgrass dominated landscapes of varying functions and uses that are ubiquitous in areas associated with human population growth and urbanization. While these landscapes are perceived to serve a primarily aesthetic function, they provide a multitude of beneficial ecosystem functions that impervious surfaces do not provide. Urban grassland soils have been shown to accumulate carbon (C) and nitrogen (N) for decades, matching native grasslands and eastern hardwood forest soils in terms of C and N densities. The establishment and maintenance of urban grasslands alters many microbially-mediated biogeochemical processes in soils, including soil organic matter (SOM) dynamics. Despite strong evidence of alterations to soil C and N cycling, the impacts of maintaining urban grasslands on soil microbiomes and their functions remain understudied compared to other ecosystems. Typical management practices can directly and indirectly affect edaphic factors in urban grasslands, which in turn, could impact soil processes mediated by microorganisms. We reviewed the existing literature on urban grassland management, focusing on how mowing, fertilization, irrigation, grass species composition, and soil cultivation could impact the composition and function of soil microorganisms. Although sparse, the literature indicates that the techniques used to maintain urban grassland habitats broadly select for copiotrophic microorganisms adapted to higher resource availability. Additionally, the studies indicate that greater soil fertility and plant productivity found in urban grasslands facilitate the accumulation of soil C and N, as well as SOM as compared to other land-use types. However, effects on soil biology and biogeochemistry depend on specific management practices, which are quite variable. Future research on soil C and N dynamics in urban grasslands should focus on the dominant component of this ecosystem—residential lawns—however, much of the existing scientific literature featuring turfgrass systems focus heavily on golf courses, athletic fields, and major tourist parks.

In the United States, there is a growing need for turfgrass management practices that protect community and environmental health. The proportion of the developed landscape in the United States covered by turfgrass is significant and, at present, covers at least 1.9% of the total land area and comprises 60% in parts of the country. As urbanization progresses, there is a critical need to re-examine turf management practices that reduce reliance on pesticide and fertilizer inputs while contributing additional beneficial ecosystem services. In this review, we discuss the functional role of turfgrass in urban ecosystems. We identify key urban ecosystem processes associated with turfgrass and evaluate the potential to integrate biodiversity into their design and management. Specifically, we summarize research on the Biodiversity and Ecosystem Function theory that shows enhanced C storage, N retention, and weed suppression in natural and managed ecosystems, which are traits that are relevant to turfgrass systems. Enhancing biodiversity in turfgrass systems could increase ecosystem services in urban landscapes and should be considered a component of sustainable management practices.

Urban grasslands, landscapes dominated by turfgrasses for aesthetic or recreational groundcovers, are rapidly expanding in the United States and globally. These managed ecosystems are often less diverse than the natural or agricultural lands they replace, leading to potential losses in ecosystem functioning. Research in non-urban systems has provided evidence for increases in multiple ecosystem functions associated with greater plant diversity. To test if biodiversity-ecosystem function findings are applicable to urban grasslands, we examined the effect of plant species and genotypic diversity on three ecosystem functions, using grassland assemblages of increasing diversity that were grown within a controlled environment facility. We found positive effects of plant diversity on reduced nitrate leaching and plant productivity. Soil microbial diversity (Mean Shannon Diversity, H') of bacteria and fungi were also enhanced in multi-species plantings, suggesting that moderate increments in plant diversity influence the composition of soil biota. The results from this study indicate that plant diversity impacts multiple functions that are important in urban ecosystems; therefore, further tests of urban grassland biodiversity should be examined in situ to determine the feasibility of manipulating plant diversity as an explicit landscape design and function trait.