Suchergebnisse

Executive Summary -- Overview and Purposes -- Key Message -- Chapter 1. State Of Forest And Rangeland Soils Research In The United States (Dan Binkley, Daniel D. Richter, Richard V. Pouyat, and Linda Geiser) -- Chapter 2. Soil Carbon (Erin Berryman, Jeff Hatten, Deborah S. Page-Dumroese, Kate Heckman, David D'Amore, Jennifer Puttere, Michael SanClements, Stephanie Connolly, Charles H. (Hobie) Perry, and Grant Domke) -- Chapter 3. Soils And Water (Mary Beth Adams, Vince Archer, Scott Bailey, Kevin McGuire, Chelcy Miniat, Dan Neary, Toby O'Geen, Pete Robichaud, and Mike Strobel) -- Chapter 4. Biogeochemical Cycling In Forest And Rangeland Soils Of The United States (Lindsey E. Rustad, Jennifer Knoepp, Daniel D. Richter, and Andrew Scott) -- Chapter 5. Forest And Rangeland Soil Biodiversity (Stephanie A. Yarwood, Elizabeth Bach, Matt Busse, Jane E. Smith, Mac A. Callaham, Jr., Chih-Han Chang, Taniya Roy Chowdhury, and Steven D. Warren) -- Chapter 6. Wetland And Hydric Soils (Carl Trettin, Randall Kolka, Anne Marsh, Sheel Bansal, Eric Lilleskov, Patrick Megonigal, Marla Stelk, Graeme Lockaby, David D'Amore, Richard MacKenzie, Brian Tangen, Rodney Chimner, and James Gries) -- Chapter 7. Urban Soils (Richard Pouyat, Susan Day, Sally Brown, Kirsten Schwarz, Richard Shaw, Katalin Szlavecz, Tara Trammell, and Ian Yesilonis) -- Chapter 8. Soil Management And Restoration (Mary Williams, Cara Farr, Deborah Page-Dumroese, Stephanie Connolly, and Eunice Padley) -- Chapter 9. Soil Mapping, Monitoring, And Assessment (Mark J. Kimsey, Larry E. Laing, Sarah Anderson, Jeff Bruggink, Steve Campbell, David Diamond, Grant Domke, James Gries, Scott Holub, Greg Nowacki, Deborah Page-Dumroese, Charles H. (Hobie) Perry, Lindsey Rustad, Kyle Stephens, and Robert Vaughan) -- Chapter 10. Challenges And Opportunities (Linda Geiser, Toral Patel-Weynand, Anne Marsh, Korena Mafune, and Daniel Vogt) -- Appendix A: Regional Summaries -- Appendix B: Soils Networks And Resources -- Appendix C: Summary Of Research Questions.

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 delta C-13, organic C and organic delta C-13, total N, and delta N-15 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 delta N-15 were less variable in residential yards compared to reference sites supporting the hypothesis that soil C, N, and delta N-15 converge across these cities. Increases in organic soil C, soil N, and soil delta N-15 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 delta C-13 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 delta C-13 increased and organic soil delta C-13 decreased with increasing home age indicating greater inorganic C in the yards around newer homes. In general, soil organic C and delta C-13, soil N, and soil delta N-15 increased with increasing home age suggesting increased soil C and N cycling rates and associated C-12 and N-14 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. ; U.S. National Science FoundationNational Science Foundation (NSF) [EF-1065548, 1065737, 1065740, 1065741, 1065772, 1065785, 1065831, 121238320] ; The authors thank La'Shaye Ervin, William Borrowman, Moumita Kundu, and Barbara Uhl for field and laboratory assistance. This research was funded by a series of collaborative grants from the U.S. National Science Foundation (EF-1065548, 1065737, 1065740, 1065741, 1065772, 1065785, 1065831, 121238320). The authors appreciate valuable comments by anonymous reviewers on a previous version of the manuscript. ; Public domain authored by a U.S. government employee