title: Coastal regime shifts: rapid responses of coastal wetlands to changes in mangrove cover.
abstract: Global changes are causing broad-scale shifts in vegetation communities worldwide, including coastal habitats where the borders between mangroves and salt marsh are in flux. Coastal habitats provide numerous ecosystem services of high economic value, but the consequences of variation in mangrove cover are poorly known. We experimentally manipulated mangrove cover in large plots to test a set of linked hypotheses regarding the effects of changes in mangrove cover. We found that changes in mangrove cover had strong effects on microclimate, plant community, sediment accretion, soil organic content, and bird abundance within 2 yr. At higher mangrove cover, wind speed declined and light interception by vegetation increased. Air and soil temperatures had hump-shaped relationships with mangrove cover. The cover of salt marsh plants decreased at higher mangrove cover. Wrack cover, the distance that wrack was distributed from the water's edge, and sediment accretion decreased at higher mangrove cover. Soil organic content increased with mangrove cover. Wading bird abundance decreased at higher mangrove cover. Many of these relationships were non-linear, with the greatest effects when mangrove cover varied from zero to intermediate values, and lesser effects when mangrove cover varied from intermediate to high values. Temporal and spatial variation in measured variables often peaked at intermediate mangrove cover, with ecological consequences that are largely unexplored. Because different processes varied in different ways with mangrove cover, the "optimum" cover of mangroves from a societal point of view will depend on which ecosystem services are most desired.
authors.affiliation: Tianjin Key Laboratory of Animal and Plant Resistance, College of Life Sciences, Tianjin Normal University, Tianjin, 300387, China.|Department of Biology and Biochemistry, University of Houston, Houston, Texas, 77204, USA.
authors.forename: Hongyu
authors.initials: H
authors.lastname: Guo
authors.affiliation: Department of Ecosystem Science and Management, Texas A&M University, College Station, Texas, 77843, USA.
authors.forename: Carolyn
authors.initials: C
authors.lastname: Weaver
authors.affiliation: Department of Biological Sciences, Florida International University, Miami, Florida, 33199, USA.
authors.forename: Sean P
authors.initials: SP
authors.lastname: Charles
authors.affiliation: Department of Marine Biology, Texas A&M University at Galveston, P.O. Box 1675, Galveston, Texas, 77553, USA.
authors.forename: Ashley
authors.initials: A
authors.lastname: Whitt
authors.affiliation: Department of Biology and Biochemistry, University of Houston, Houston, Texas, 77204, USA.
authors.forename: Sayantani
authors.initials: S
authors.lastname: Dastidar
authors.affiliation: Department of Environmental Sciences, University of Virginia, Charlottesville, Virginia, 22904, USA.
authors.forename: Paolo
authors.initials: P
authors.lastname: D'Odorico
authors.affiliation: Department of Meteorology, The Pennsylvania State University, 503 Walker Building, University Park, Pennsylvania, 16802, USA.
authors.forename: Jose D
authors.initials: JD
authors.lastname: Fuentes
authors.affiliation: Department of Biological Sciences, Florida International University, Miami, Florida, 33199, USA.
authors.forename: John S
authors.initials: JS
authors.lastname: Kominoski
authors.affiliation: Department of Marine Biology, Texas A&M University at Galveston, P.O. Box 1675, Galveston, Texas, 77553, USA.
authors.forename: Anna R
authors.identifier: http://orcid.org/0000-0003-1563-8026
authors.initials: AR
authors.lastname: Armitage
authors.affiliation: Department of Biology and Biochemistry, University of Houston, Houston, Texas, 77204, USA.
authors.forename: Steven C
authors.identifier: http://orcid.org/0000-0003-4757-7125
authors.initials: SC
authors.lastname: Pennings
mesh_terms: D057231:Climate Change; D017753:Ecosystem; D012987:Soil; D013696:Temperature; D053833:Wetlands
chemical_list: D012987:Soil
keywords: coastal ecosystem; ecosystem function; foundation species; mangrove; regime shift; salt marsh