PARENT SESSION
Poster Session # 17: Aquatic Systems.
Thursday, August 7 Presentation from 5:00 PM to 6:30 PM. SITCC Exhibit Hall B.
Changes in benthic algal attributes during salt marshes restoration and use in bioassessment.
Zheng, Lei*,1, Stevenson, R. 1, Craft, Christopher2, 1 Department of Zoology, East Lansing, MI2 School of Public & Environmental Affairs, Bloomington, IN
ABSTRACT- Although salt marsh restoration has been used to mitigate loss of habitat and ecosystem function, few effective rules and indicators have been developed to determine success of ecological restoration in salt marshes. To assess attributes of algal assemblages as indicators of salt marsh restoration, we chose 8 pairs of salt marshes in North Carolina, each pair with one restored marsh (from 1 to 28 year old) and a nearby existing salt marsh. Algae on both macrophytes and sediments were collected in each marsh during spring and summer 1998 for assaying algal biomass (dry mass (DM), ash free dry mass (AFDM), chl a content, algal biovolume), algal species composition and diversity, and gross primary production. An attribute restoration ratio was calculated by dividing attribute values from each restored marsh by values from a paired reference marsh. The organic matter restoration ratio of sediments increased with age of restored marshes in both spring and summer. The algal biomass restoration ratios of epiphytes, calculated with algal biovolume and chl a, increased with restored marsh age in summer but not during spring. Biomass of sediment algae was not related to marsh age. The species diversity of sediment algae in summer showed an asymptotic relationship with sediment nutrient concentration. The similarity of diatom species composition between paired restored and reference sites increased with age of restored marshes during spring and summer. Primary production by epiphytic and sediment algae in summer showed site-specific changes and did not change consistently with marsh age. Algal biomass, algal diversity, and diatom species assemblages during summer were positively correlated with sediment nitrogen and phosphorus concentration. We concluded that overall structural and functional development of restored wetlands, especially nutrient storage in sediments, regulates algal community structure and function, which can be used to evaluate marsh restoration.
Key words: restoration, diatom, salt marsh, algae