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Urban soil carbon and nitrogen converge at a continental scale
Author(s) -
Trammell Tara L. E.,
Pataki Diane E.,
Pouyat Richard V.,
Groffman Peter M.,
Rosier Carl,
Bettez Neil,
CavenderBares Jeannine,
Grove Morgan J.,
Hall Sharon J.,
Heffernan James,
Hobbie Sarah E.,
Morse Jennifer L.,
Neill Christopher,
Steele Meredith
Publication year - 2020
Publication title -
ecological monographs
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 4.254
H-Index - 156
eISSN - 1557-7015
pISSN - 0012-9615
DOI - 10.1002/ecm.1401
Subject(s) - yard , environmental science , urban ecosystem , soil water , soil carbon , phoenix , ecosystem , geography , miami , ecology , urbanization , soil science , biology , metropolitan area , archaeology , physics , quantum mechanics
In urban areas, anthropogenic drivers of ecosystem structure and function are thought to predominate over larger‐scale biophysical drivers. Residential yards are influenced by individual homeowner preferences and actions, and these factors are hypothesized to converge yard structure across broad scales. We examined soil total C and total δ 13 C, organic C and organic δ 13 C, total N, and δ 15 N in residential yards and corresponding reference ecosystems in six cities across the United States that span major climates and ecological biomes (Baltimore, Maryland; Boston, Massachusetts; Los Angeles, California; Miami, Florida; Minneapolis‐St. Paul, Minnesota; and Phoenix, Arizona). Across the cities, we found soil C and N concentrations and soil δ 15 N were less variable in residential yards compared to reference sites supporting the hypothesis that soil C, N, and δ 15 N converge across these cities. Increases in organic soil C, soil N, and soil δ 15 N across urban, suburban, and rural residential yards in several cities supported the hypothesis that soils responded similarly to altered resource inputs across cities, contributing to convergence of soil C and N in yards compared to natural systems. Soil C and N dynamics in residential yards showed evidence of increasing C and N inputs to urban soils or dampened decomposition rates over time that are influenced by climate and/or housing age across the cities. In the warmest cities ( Los Angeles , Miami, Phoenix), greater organic soil C and higher soil δ 13 C in yards compared to reference sites reflected the greater proportion of C 4 plants in these yards. In the two warm arid cities ( Los Angeles , Phoenix), total soil δ 13 C increased and organic soil δ 13 C decreased with increasing home age indicating greater inorganic C in the yards around newer homes. In general, soil organic C and δ 13 C, soil N, and soil δ 15 N increased with increasing home age suggesting increased soil C and N cycling rates and associated 12 C and 14 N losses over time control yard soil C and N dynamics. This study provides evidence that conversion of native reference ecosystems to residential areas results in convergence of soil C and N at a continental scale. The mechanisms underlying these effects are complex and vary spatially and temporally.