Organic carbon-rich sediments from the surface of fresh, intermediate, brackish and salt marshes of coastal Louisiana were sampled and analyzed for their C content. The average ∂C from all sites within each wetland type was-27.8‰,-22.1‰,-16.9‰, and-16.2‰, for fresh, intermediate, brackish and salt marshes, respectively. Means from the fresh, intermediate and brackish marshes were significantly different at the 0.01 level. A mixing model using measurements of standing crop and ∂C of plant carbon was applied to estimate the contribution of each species to the sedimentary carbon at four of the marsh sites. Sedimentary ∂C values generally reflected that of the dominant species present at each site. Brackish and salt marsh samples, however, showed a negative shift of ∂C with respect to whole plant carbon. We interpret these depeleted ∂C values to be the result of more extensive organic matter decomposition and selective preservation of C-depleted refractory components in sediments from saline sites. The results of this study suggest that ∂C composition of sedimentary carbon may offer a valuable tool for distinguishing subtle changes in paleohydrology of wetlands resulting from relative sea level changes.

Abstract. We studied the environmental conditions along 56 km of a backfilled pipeline canal four years after construction was completed. The canal traverses fresh, intermediate, brackish, and saline marshes in southeastern Louisiana, Over one-third of the sampling sections in the fresh intermediate marsh regained more than 60% vegetation cover; mean canal depth Was 44 cm, and submerged aquatic vegetation (SAV) covered 59% of the bottom. The brackish marsh sections revegetated only where the canal passed through the mineral soils of the Bayou Lafourche natural levee; mean canal depth was 67 cm, and SAV covered 23% of the bottom. The salt marsh revegetated poorly; the area remained 80% open water, as it was before canal construction. Mean canal depth was 59 crrt, and SAV covered 10% of the bottom. Backfilling did not return the marsh to its original condition, but the shallow ponds that formed along the canal resemble natural ponds in depth and vegetation.

Landscape-scale conservation initiatives have become more common in the past few decades. Many factors led to these increases including a broadening of conservation strategies, technology, and threats to many ecological systems; species' population declines; and a growing understanding of the need for cooperative conservation. Population and habitat threats and declines often occur on privately owned farms, ranches, and forests, sometimes referred to as 'working lands,' which presents a host of challenges and opportunities for conservation. A key challenge of emerging initiatives is funding for conservation. We explore 2 landscape-scale initiatives that have become loosely linked by the Working Lands for Wildlife partnership. Both have benefited from U.S. Department of Agriculture (USDA) funding that resulted from an agreement between the USDA Natural Resources Conservation Service and the U.S. Department of Interior Fish and Wildlife Service (USDA 2012). We describe a few national cooperative conservation developments to demonstrate their importance to our 2 case studies and the ecosystem of private lands wildlife conservation.

No abstract

No abstract