Colonization, succession, and nutrition of macrobenthic assemblages in a restored wetland at Tijuana Estuary, California Serena M. Moseman a, ) , Lisa A. Levin a , Carolyn Currin b , Charlotte Forder a,c a Integrative Oceanography Division, Scripps Institution of Oceanography, 9500 Gilman Drive, La Jolla, CA 92093-0218, USA b Center for Coastal Fisheries and Habitat Research, National Ocean Service NOAA, Beaufort, NC, USA c 101 Onley Street, Norwich, Norfolk NR2 2EA, UK Received 6 November 2003; accepted 22 March 2004 Abstract Modes of colonization, the successional trajectory, and trophic recovery of a macrofaunal community were analyzed over 19 months in the Friendship marsh, a 20-acre restored wetland in Tijuana Estuary, California. Traditional techniques for quantifying macrofaunal communities were combined with emerging stable isotopic approaches for evaluation of trophic recovery, making comparisons with a nearby natural Spartina foliosa habitat. Life history-based predictions successfully identified major colonization modes, although most taxa employed a variety of tactics for colonizing the restored marsh. The presence of S. foliosa did not seem to affect macrofaunal colonization or succession at the scale of this study. However, soil organic matter content in the restored marsh was positively correlated with insect densities, and high initial salinities may have limited the success of early colonists. Total macrofaunal densities recovered to natural marsh levels after 14 months and diversity, measured as species richness and the Shannon index (H#), was comparable to the natural marsh by 19 months. Some compositional disparities between the natural and created communities persisted after 19 months, including lower percentages of surface-feeding polychaetes (Polydora spp.) and higher percentages of dipteran insects and turbellarians in the Friendship marsh. As surficial structural similarity of infaunal communities between the Friendship and natural habitat was achieved, isotopic analyses revealed a simultaneous trajectory towards recovery of trophic structure. Enriched d 13 C signatures of benthic microalgae and infauna, observed in the restored marsh shortly after establishment compared to natural Spartina habitat, recovered after 19 months. However, the depletion in d 15 N signatures of macrofauna in the Friendship marsh indicated consumption of microalgae, particularly nitrogen-fixing cyanobacteria, while macroalgae and Spartina made a larger contribution to macrofaunal diets in the natural habitat. Future successional studies must continue to develop and employ novel combinations of techniques for evaluating structural and functional recovery of disturbed and created habitats. Ó 2004 Elsevier Ltd. All rights reserved. Keywords: infauna; salt marsh; succession; colonization; isotope ratio; California coast; Insecta; Polychaeta 1. Introduction Attempts to counter wetland losses due to coastal development commonly include salt marsh restoration and creation. In southern California, more than 75% of historic wetlands have been lost to development, and a number of endangered bird and plant species rely on the heavily disturbed remnants of coastal habitats (Zedler, 1991). Marsh restoration sites serve conserva- tion goals while simultaneously providing the valuable opportunity to manipulate biotic and abiotic features and to evaluate factors that facilitate community re- covery (Ewel et al., 2001; Craft and Sacco, 2003). While the attempt to construct salt marsh habitats is not new, the key ecological parameters vital to optimal ecosystem function continue to evade ecologists. Scientific studies of salt marsh recovery initially tar- geted vascular plants and fishery organisms (Mathews and Minello, 1994). However, there has been increasing ) Corresponding author. E-mail address: smoseman@ucsd.edu (S.M. Moseman). Estuarine, Coastal and Shelf Science 60 (2004) 755e770 www.elsevier.com/locate/ECSS 0272-7714/$ - see front matter Ó 2004 Elsevier Ltd. All rights reserved. doi:10.1016/j.ecss.2004.03.013