Urban soil carbon and nitrogen converge at a continental scale
Urban soil carbon and nitrogen converge at a continental scale
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DOI：
10.1002/ecm.1401
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发表时间：
2020-05
影响因子：
6.1
通讯作者：
T. Trammell;D. Pataki;R. Pouyat;P. Groffman;C. Rosier;N. Bettez;J. Cavender-Bares;M. Grove;S. Hall;J. Heffernan;S. Hobbie;J. Morse;C. Neill;M. Steele
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文献类型：
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作者：
T. Trammell;D. Pataki;R. Pouyat;P. Groffman;C. Rosier;N. Bettez;J. Cavender-Bares;M. Grove;S. Hall;J. Heffernan;S. Hobbie;J. Morse;C. Neill;M. Steele
在城市地区，生态系统结构和功能的人为驱动因素被认为比更大规模的生物物理驱动因素占主导地位。住宅庭院受到个体房主偏好和行为的影响，这些因素被假设为在大尺度上收敛庭院结构。我们研究了美国六个城市（马里兰州巴尔的摩、马萨诸塞州波士顿、加利福尼亚州洛杉矶、佛罗里达州迈阿密、明尼阿波利斯-圣路易斯市）的住宅庭院和相应参考生态系统中的土壤总C和总δ¹³C、有机C和有机δ¹³C、总N和δ¹5 N。保罗,明尼苏达;以及亚利桑那州凤凰城)。在各个城市，我们发现与参考地点相比，住宅院子的土壤C、N浓度和土壤δ 1 5 N的变化较小，支持土壤C、N和δ 1 5 N在这些城市收敛的假设。在几个城市的城市、郊区和农村住宅院落中，有机土壤C、土壤N和土壤δ 1 5 N的增加支持了这样的假设，即土壤对城市资源投入的变化做出了类似的反应，与自然系统相比，土壤C和N在院落中趋同。住宅院落土壤C和N动态表明，随着时间的推移，城市土壤的C和N输入增加，或受城市气候和/或房屋年龄的影响，分解率受到抑制。在最温暖的城市（洛杉矶、迈阿密、凤凰城），与参考地点相比，院子里更高的有机土壤C和更高的土壤δ¹³C反映了这些院子里更大比例的氯化碳植物。在两个温暖的干旱城市（洛杉矶和凤凰城），随着房屋年龄的增加，土壤总δ¹³C增加，有机土壤δ¹³C减少，这表明新房屋周围院子里的无机碳含量更高。总体而言，土壤有机C和δ¹³C、土壤N和土壤δ¹5 N随家庭年龄的增加而增加，表明土壤C和N循环速率的增加以及相关的¹²C和¹⁴N随时间的损失控制了土壤C和N的动态。本研究提供了证据，证明本地参考生态系统向居民区的转化导致了大陆尺度上土壤C和N的收敛。这些影响背后的机制是复杂的，并且在空间和时间上存在差异。
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 δ¹³C, organic C and organic δ¹³C, total N, and δ¹⁵N 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 δ¹⁵N were less variable in residential yards compared to reference sites supporting the hypothesis that soil C, N, and δ¹⁵N converge across these cities. Increases in organic soil C, soil N, and soil δ¹⁵N 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 δ¹³C in yards compared to reference sites reflected the greater proportion of C₄ plants in these yards. In the two warm arid cities (Los Angeles, Phoenix), total soil δ¹³C increased and organic soil δ¹³C decreased with increasing home age indicating greater inorganic C in the yards around newer homes. In general, soil organic C and δ¹³C, soil N, and soil δ¹⁵N increased with increasing home age suggesting increased soil C and N cycling rates and associated ¹²C and ¹⁴N 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.