Vulnerability of Soil Carbon Regulating Ecosystem Services due to Land Cover Change in the State of New Hampshire, USA

Valuation of soil carbon (C) regulating ecosystem services (ES) at the state level is important for sustainable C management. The objective of this study was to assess the value of regulating ES from soil organic carbon (SOC), soil inorganic carbon (SIC), and total soil carbon (TSC) stocks, based on the concept of the avoided social cost of carbon dioxide (CO2) emissions for the state of New Hampshire (NH) in the United States of America (USA) by soil order and county using information from the State Soil Geographic (STATSGO) database. The total estimated monetary mid-point value for TSC stocks in the state of New Hampshire was USD 73.0 B (i.e., 73.0 billion U.S. dollars, where B = billion = 109), USD 64.8 B for SOC stocks, and USD 8.1 B for SIC stocks. Soil orders with the highest midpoint value for SOC were Histosols (USD 33.2 B), Spodosols (USD 20.2 B), and Inceptisols (USD 10.1 B). Soil orders with the highest midpoint value for SIC were Inceptisols (USD 5.8 B), Spodosols (USD 1.0 B), and Entisols (USD 770 M, where M = million = 106). Soil orders with the highest midpoint value for TSC were Histosols (USD 33.8 B), Spodosols (USD 21.2 B), and Inceptisols (USD 15.9 B). The counties with the highest midpoint SOC values were Rockingham (USD 15.4 B), Hillsborough (USD 9.8 B), and Coos (USD 9.2 B). The counties with the highest midpoint SIC values were Merrimack (USD 1.2 B), Coos (USD 1.1 B), and Rockingham (USD 1.0 B). The counties with the highest midpoint TSC values were Rockingham (USD 16.5 B), Hillsborough (USD 10.8 B), and Coos (USD 10.3 B). New Hampshire has experienced land use/land cover (LULC) changes between 2001 and 2016. The changes in LULC across the state have not been uniform, but rather have varied by county, soil order, and pre-existing land cover. The counties that have exhibited the most development (e.g., Rockingham, Hillsborough, Merrimack) are those nearest the urban center of Boston, MA. Most soil orders have experienced losses in “low disturbance” land covers (e.g., evergreen forest, hay/pasture) and gains in “high disturbance” land covers (e.g., low-, medium-, and high-intensity developed land). In particular, Histosols are a high-risk carbon “hotspot” that contributes over 50% of the total estimated sequestration of SOC in New Hampshire while covering only 7% of the total land area. Integration of pedodiversity concepts with administrative units can be useful to design soil- and land-cover specific, cost-efficient policies to manage soil C regulating ES in New Hampshire at various administrative levels.