A Comparative Assessment of Genetic Diversity among Differently‐Aged Populations ofSpartina alternif loraon Restored Versus Natural Wetlands

Abstract

We collected naturally recolonizing Spartina alterniflora (smooth cord grass) from each of three restored sites and one undisturbed reference site in southwestern Louisiana to assess the impact of wetland restoration on genetic diversity. We used amplified fragment length polymorphisms (AFLPs) to produce 94 polymorphic genetic markers, which were used to characterize genetic diversity as average heterozygosity Ͻ H Ͼ and the proportion of polymorphic loci Ͻ P Ͼ . Overall our findings indicate that restored populations of S. alterniflora maintain levels of genetic diversity comparable to natural populations, which should provide some measure of resistance against environmental disturbances. Diversity estimates were lowest for the natural reference site ( Ͻ H Ͼ ϭ 0.1059; Ͻ P Ͼ ϭ 0.2763), whereas estimates for the three restored sites ranged from < H > ϭ 0.1148 to 0.1256 and Ͻ P Ͼ ϭ 0.3114 to 0.3202. All sites maintained sufficiently high diversity levels to suggest significant rates of outcrossing. Overall, genetic differentiation among populations was small (Weir and Cockerham's ⌰ ϭ 0.0645), with the values from each pairwise comparison among the populations increasing with the geographic distance between sites (range ϭ 0.0490-0.1101). These values indicate an average migration rate of 3.6 migrants, either pollen or seeds, per generation.

Reforming Watershed Restoration: Science in Need of Application and Applications in Need of Science

“…But aside from valued fisheries or threatened species, there has been only scant research on the role of genetics in restoration success and this is mostly on plants. Travis et al (2002) found that Spartina alterniflora that naturally colonized restored marshes had levels of genetic diversity as high or higher than reference sites. However, when plants are collected elsewhere and brought to a site, genetic diversity is not always as desired as was the case for eelgrass (Williams 2001).…”

Local-scale characteristics of high-marsh communities next to developed and undeveloped shorelines in an ocean-dominated estuary, Murrells Inlet, SC

“…Significant high-marsh changes may not have had time to take place along newly altered shorelines depending on the variable being measured. Based on salt marsh restoration studies, plant biomass (Broome et al 1986;Roman et al 2002), genetic diversity (Travis et al 2002), fish utilization (Roman et al 2002;Able et al 2004), and sediment salinities (Walters 2009) can change rapidly within newly planted marshes, while changes in sediment organic content (Craft et al 1999), nutrient cycling (Thompson et al 1995;Craft et al 1999), infauna (Sacco et al 1994;Levin et al 1996), and plant canopy (Zedler 1993) tend to require significant time if not decades. Ecological changes in Narragansett Bay salt marshes only were detected after two decades of urbanization (Wigand et al 2010).…”

Genetic structure of natural and restored shoalgrass Halodule wrightii populations in the NW Gulf of Mexico

“…Genetic analyses. We extracted DNA from seagrass rhizomes using a standard CTAB (hexadecyltrimethyl-ammonium bromide)-based method (Saghai-Maroof et al 1984, Rogers & Bendich 1985, Doyle & Doyle 1987, as described in Travis et al (2002). Leaf tissue was omitted from the extractions in order to avoid contamination of seagrass DNA with that of epiphytic algae.…”