Plant community structure and function in natural and restored Platte River slough wetlands.
Meyer, C*,1, Whiles, M1, Baer, S1, 1 Southern Illinois University Carbondale, Carbondale, IL, USA
ABSTRACT- Wetland slough restoration is an increasingly common practice in the Platte River Basin of central Nebraska, but little information exists on the recovery of ecosystem characteristics following restoration. To assess similarity of restorations to native sloughs, we examined plant community structure and function along transects located in the middle (channel) and margins of recently restored (1-2 years), older restored (4-7 years), and natural sloughs. Plant cover and species diversity were estimated in summer 2003 and aboveground net primary production (ANPP) and root biomass were estimated in fall 2002 and 2003. No differences were found in slough channels. In slough margins, total plant cover was lowest in newly restored sloughs, higher in older restored sloughs, and significantly higher in natural sloughs compared to new restorations (P=0.017). The same pattern was found in both years for ANPP and root biomass. In 2002, ANPP was lower in newly restored sites (218 g/m2) than older restorations (378 g/m2), and ANPP was significantly higher in native sloughs (522 g/m2) compared to new restorations (P=0.046). Root biomass was significantly different between all treatment groups in 2002, and was lowest in newly restored sloughs (349 g/m2), intermediate in longer restored sites (914 g/m2), and highest in natural systems (2372 g/m2)(P=0.035). Shannon diversity was highest in old restorations (5.6), intermediate in natural sites (4.1), and lowest in new restorations (2.4)(P=0.0009), suggesting that seeding may enhance dispersal of species over time relative to natural sloughs. Our results suggest that plant community structure and function in slough restorations increases through time, that recovery occurs at different rates in slough channels and margins, and that seeding may enhance species richness.
Key words: restoration, diversity, wetland, recovery
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