title: Indirect human impacts reverse centuries of carbon sequestration and salt marsh accretion.
abstract: Direct and indirect human impacts on coastal ecosystems have increased over the last several centuries, leading to unprecedented degradation of coastal habitats and loss of ecological services. Here we document a two-century temporal disparity between salt marsh accretion and subsequent loss to indirect human impacts. Field surveys, manipulative experiments and GIS analyses reveal that crab burrowing weakens the marsh peat base and facilitates further burrowing, leading to bank calving, disruption of marsh accretion, and a loss of over two centuries of sequestered carbon from the marsh edge in only three decades. Analogous temporal disparities exist in other systems and are a largely unrecognized obstacle in attaining sustainable ecosystem services in an increasingly human impacted world. In light of the growing threat of indirect impacts worldwide and despite uncertainties in the fate of lost carbon, we suggest that estimates of carbon emissions based only on direct human impacts may significantly underestimate total anthropogenic carbon emissions.
authors.affiliation: Department of Ecology and Evolutionary Biology, Brown University, Providence, Rhode Island, United States of America.
authors.forename: Tyler C
authors.initials: TC
authors.lastname: Coverdale
authors.affiliation: Department of Ecology and Evolutionary Biology, Brown University, Providence, Rhode Island, United States of America.
authors.forename: Caitlin P
authors.initials: CP
authors.lastname: Brisson
authors.affiliation: Department of Ecology and Evolutionary Biology, Brown University, Providence, Rhode Island, United States of America.
authors.forename: Eric W
authors.initials: EW
authors.lastname: Young
authors.affiliation: Department of Ecology and Evolutionary Biology, Brown University, Providence, Rhode Island, United States of America.
authors.forename: Stephanie F
authors.initials: SF
authors.lastname: Yin
authors.affiliation: Woods Hole Oceanographic Institution, Woods Hole, Massachusetts, United States of America.
authors.forename: Jeffrey P
authors.initials: JP
authors.lastname: Donnelly
authors.affiliation: Department of Ecology and Evolutionary Biology, Brown University, Providence, Rhode Island, United States of America.
authors.forename: Mark D
authors.initials: MD
authors.lastname: Bertness
mesh_terms: D000818:Animals; D003386:Brachyura / Q000502:physiology; D002244:Carbon / Q000737:chemistry*; D057965:Carbon Sequestration / Q000502:physiology*; D003247:Conservation of Natural Resources; D040362:Geographic Information Systems; D006801:Humans; D054712:Salinity; D012492:Salts; D012987:Soil; D014481:United States; D014872:Water Movements; D053833:Wetlands
chemical_list: D012492:Salts; D012987:Soil; D002244:Carbon