Urbanization minimizes the effects of plant traits on soil provisioned ecosystem services across climatic regions.

An increasingly urbanized world is one of the most prominent examples of global environmental change. Across the globe, urban parks are designed and managed in a similar way, resulting in visually pleasing expansions of lawn interspersed with individually planted trees of varying appearances and functional traits. These large urban greenspaces have the capacity to provide various ecosystem services, including those associated with soil physicochemical properties.

Metagenomics Reveals Bacterial and Archaeal Adaptation to Urban Land-Use: N Catabolism, Methanogenesis, and Nutrient Acquisition.

Urbanization results in the systemic conversion of land-use, driving habitat and biodiversity loss. The "urban convergence hypothesis" posits that urbanization represents a merging of habitat characteristics, in turn driving physiological and functional responses within the biotic community. To test this hypothesis, we sampled five cities (Baltimore, MD, United States; Helsinki and Lahti, Finland; Budapest, Hungary; Potchefstroom, South Africa) across four different biomes.

The capacity of urban forest patches to infiltrate stormwater is influenced by soil physical properties and soil moisture.

Forest patches in developed landscapes perform ecohydrological functions that can reduce urban stormwater flows. However, urban forest patch contributions to runoff mitigation are not well understood due to a lack of performance data. In this study, we focus on the potential of urban forest patch soils to infiltrate rainfall by characterizing rates of unsaturated hydraulic conductivity (K) in 21 forest patches in Baltimore, Maryland.

Litter quality, dispersal and invasion drive earthworm community dynamics and forest soil development.

In temperate deciduous forests of eastern USA, most earthworm communities are dominated by invasive species. Their structure and functional group composition have critical impacts on ecological properties and processes. However, the factors determining their community structure are still poorly understood, and little is known regarding their dynamics during forest succession and the mechanisms leading to these changes.

Urbanization erodes ectomycorrhizal fungal diversity and may cause microbial communities to converge.

Urbanization alters the physicochemical environment, introduces non-native species and causes ecosystem characteristics to converge. It has been speculated that these alterations contribute to loss of regional and global biodiversity, but so far most urban studies have assessed macro-organisms and reported mixed evidence for biodiversity loss. We studied five cities on three continents to assess the global convergence of urban soil microbial communities.

Legacies of Lead in Charm City's Soil: Lessons from the Baltimore Ecosystem Study.

Understanding the spatial distribution of soil lead has been a focus of the Baltimore Ecosystem Study since its inception in 1997. Through multiple research projects that span spatial scales and use different methodologies, three overarching patterns have been identified: (1) soil lead concentrations often exceed state and federal regulatory limits; (2) the variability of soil lead concentrations is high; and (3) despite multiple sources and the highly heterogeneous and patchy nature of soil lead, discernable patterns do exist. Specifically, housing age, the distance to built structures, and the distance to a major roadway are strong predictors of soil lead concentrations.

Nitrate leaching and nitrous oxide flux in urban forests and grasslands.

Urban landscapes contain a mix of land-use types with different patterns of nitrogen (N) cycling and export. We measured nitrate (NO(3)(-)) leaching and soil:atmosphere nitrous oxide (N(2)O) flux in four urban grassland and eight forested long-term study plots in the Baltimore, Maryland metropolitan area. We evaluated ancillary controls on these fluxes by measuring soil temperature, moisture, and soil:atmosphere fluxes of carbon dioxide on these plots and by sampling a larger group of forest, grass, and agricultural sites once to evaluate soil organic matter, microbial biomass, and potential net N mineralization and nitrification.

Lead forms in urban turfgrass and forest soils as related to organic matter content and pH.

Soil pH may influence speciation and extractability of Pb, depending on type of vegetation in urban soil environments. We investigated the relationship between soil pH and Pb extractability at forest and turf grass sites in Baltimore, Maryland. Our two hypotheses were: (1) due to lower pH values in forest soils, more Pb will be in exchangeable forms in forested than in turfgrass soils and (2) due to the greater lability of exchangeable Pb in equilibrium with soil solution in forest soils, concentrations of this form will increase with depth more so than in the turfgrass soils, as related to organic matter content and pH.

Carbon storage by urban soils in the United States.

We used data available from the literature and measurements from Baltimore, Maryland, to (i) assess inter-city variability of soil organic carbon (SOC) pools (1-m depth) of six cities (Atlanta, Baltimore, Boston, Chicago, Oakland, and Syracuse); (ii) calculate the net effect of urban land-use conversion on SOC pools for the same cities; (iii) use the National Land Cover Database to extrapolate total SOC pools for each of the lower 48 U.S. states; and (iv) compare these totals with aboveground totals of carbon storage by trees.