Twenty-Five Years of Ecosystem Development of Constructed Spartina alterniflora (Loisel) Marshes

Abstract

See, stats, and : http : / / www . researchgate . net / publication / 250077291 Twenty - Five Constructed (Loisel) Marshes ARTICLE Impact : 4 . 13 : 10 . 2307 / 2641405 CITATIONS 139 DOWNLOADS 73 VIEWS 40 4 , INCLUDING : Stephen North 42 , 067 SEE Available : Stephen Retrieved : 05 Abstract . Wetland creation and restoration are frequently used to replace ecological functions and values lost when natural wetlands are degraded or destroyed . On many sites , restoration of ecological attributes such as secondary production , habitat / species diversity , and wetland soil characteristics do not occur within the first decade , and no long - term studies exist to document the length of time required to achieve complete restoration of wetland dependent functions and values . Characteristics of community structure (macro - phyte aboveground biomass , macro - organic matter [ MOM ] , benthic invertebrates) and eco - system processes (soil development , organic C , N , and P accumulation) of two constructed Spartina alterniflora (Loisel) marshes (established 1971 and 1974) and paired natural S . alterniflora marshes in North Carolina were periodically measured during the past 25 yr . On constructed marshes , the macrophyte community developed quickly , and within 5 to 10 yr , aboveground biomass and MOM were equivalent to or exceeded corresponding values in natural marshes . After 15 – 25 yr , benthic infauna density and species richness were greater than in the natural marshes . Soil bulk density decreased , and organic C and total N increased over time in constructed marshes , but after 25 yr , soil organic C and N reservoirs were much smaller than in a 2000 - yr - old natural marsh . Organic C accumulation was similar in constructed and natural marshes with 12 – 24% of the net primary production buried annually . Nitrogen accumulation was much higher in constructed marshes (7 – 12 g · m Ϫ2 · yr Ϫ1) than in natural marshes (2 – 5 g · m Ϫ2 · yr Ϫ1) , reflecting the open biogeochemical cycles and paucity of N in these young ecosystems . Different ecological attributes develop at different rates , with primary producers achieving equivalence during the first 5 yr , followed by the benthic infauna community 5 – 10 yr later . Accumulation of soil nutrients to levels similar to those of reference marshes may require more time .