Success criteria and adaptive management for a large-scale wetland restoration project

We are using a 20+ year photographic history of relatively undisturbed and formerly diked sites to predict the restoration trajectories and equilibrium size of a 4,050 ha salt marsh on Delaware Bay, New Jersey (USA). The project was initiated to offset the loss of finfishes from once-through cooling at a local power plant. We used a simple food chain model to estimate the required restoration size. This model assumed that annual macrophyte detritus production and benthic algal production resulted in production of finfishes, including certain species of local interest. Because the marsh surface and intertidal drainage system are used by many finfishes and are the focal points for exchange of detrital materials, the restoration planning focused on both vegetational and hydrogeomorphological parameters. Recolonization bySpartina spp. and other desirable taxa will be promoted by returning a natural hydroperiod and drainage configuration to two types of degraded salt marsh: diked salt hay (Spartina patens) farms and brackish marsh dominated byPhragmites australis. The criteria for success of the project address two questions: What is the “bound of expectation” for restoration success, and how long will it take to get there? Measurements to be made are macrophyte production, vegetation composition, benthic algal production, and drainage features including stream order, drainage density, channel length, bifurcation ratios and sinuosity. A method for combining these individual parameters into a single success index is also presented. Finally, we developed adaptive management thresholds and corrective measures to guide the restoration process.     

Salt marsh stabilization affects algal primary producers at the marsh edge

As sea level rise and human activities erode coastal wetlands, managers rebuild or preserve wetlands that can perform the ecosystem services of a natural system. One increasingly common mitigation activity is the construction of rock sills in the low marsh zone to stabilize marsh elevation. Sills dramatically alter the physical structure of marshes by changing elevation, adding hard substrate and potentially altering the spatial structure of benthic algal communities in and adjacent to the low marsh. We documented differences in benthic algal abundance at the seaward marsh edge in silled and unsilled marshes in North Carolina. We found that sills were associated with reduced standing stocks of benthic algal primary production and reduced macroalgal taxonomic richness, and this difference was driven primarily by differences in macroalgal abundance. We experimentally tested the effect of macroalgal abundance on cordgrass (Spartina alterniflora) growth in the low zone of an unmanipulated marsh, and found that macroalgal removal had no effect on final cordgrass abundance. Our study suggests that salt marsh management through the construction of sills in low marsh zones impacts benthic primary production in the low marsh zone, but that benthic algal production does not affect cordgrass growth over a growing season.     

Salt marsh harvest mouse demography and habitat use in the Suisun Marsh,California

We undertook a 2-year (2002–2004) mark–recapture study to investigate demographic performance and habitat use of salt marsh harvest mice (Reithrodontomys raviventris halicoetes) in the Suisun Marsh. We examined the effects of different wetland types and microhabitats on 3 demographic variables: density, reproductive potential, and persistence. Our results indicate that microhabitats dominated by mixed vegetation or pickleweed (Salicornia spp.) supported similar salt marsh harvest mouse densities, reproductive potential, and persistence throughout much of the year, whereas few salt marsh harvest mice inhabited upland grass-dominated microhabitats. We found that densities were higher in diked wetlands, whereas post-winter persistence was higher in tidal wetlands, and reproductive potential did not differ statistically between wetland types. Our results emphasize the importance of mixed vegetation for providing adequate salt marsh harvest mouse habitat and suggest that, despite their physiognomic and hydrological differences, both diked and tidal wetlands support salt marsh harvest mouse populations by promoting different demographic attributes. We recommend that habitat management, restoration, and enhancement efforts include areas containing mixed vegetation in addition to pickleweed in both diked and tidal wetlands. © 2011 The Wildlife Society.     

Restoration principles emerging from one of the world's largest tidal marsh restoration projects

One of the world's largest tidal wetland restorationprojects was conceived to offset the loss of nekton toonce-through cooling at a power plant on Delaware Bay,USA. An aggregated food chain model was employed toestimate the area of tidal salt marsh required toreplace these losses. The 5040 ha was comprised of twodegraded marsh types – Phragmites- dominatedmarshes and diked salt hay farms – at elevenlocations in oligo-mesohaline and polyhaline reachesof the estuary. At a series of summits convened withnoted experts in the field, it was decided to apply anecological engineering approach (i.e., self design,and minimal intrusion) in a landscape ecologyframework to the restoration designs while at the sametime monitoring long-term success of the project inthe context of a bound of expectation. The latterencompassed a range of reference marsh planforms andacceptable end-points established interactively withtwo advisory committees, numerous resource agencies,the permitting agency and multiple-stakeholder groups.In addition to the technical recommendations providedby the project's advisors, public health and safety,property protection and public access to the restoredsites were a constant part of the dialogue between theutility, its consulting scientists and theresource/permitting agencies. Adaptive management wasused to maintain the restoration trajectories, ensurethat success criteria were met in a timely fashion,and to protect the public against potential effects ofsalt intrusion into wells and septic systems, andagainst upland flooding. Herbicide spray, followed byprescribed burns and altered microtopography were usedat Phragmites-dominated sites, and excavation ofhigher order channels and dike breaching were themethods used to initiate the restorations at the dikedsalt hay farms. Monitoring consisted of evaluating therate of re-vegetation and redevelopment of naturaldrainage networks, nekton response to therestorations, and focused research on nutrient flux,nekton movements, condition factors, trophic linkages,and other specific topics. Because of its size anduniqueness, the Estuary Enhancement Program as thisproject is known, has become an important case studyfor scientists engaged in restoration ecology and theapplication of ecological engineering principles. Thehistory of this project, and ultimately theRestoration Principles that emerged from it, are thesubjects of this paper. By documenting the pathways tosuccess, it is hoped that other restoration ecologistsand practitioners will benefit from the experiences wehave gained.     

Long-term response of fishes and other fauna to restoration of former salt hay farms: multiple measures of restoration success

This synthesis brings together published and unpublished data in an evaluation of restoration of former salt hay farms to functioning salt marshes. We compared nine years of field measurements between three restored marshes (Dennis, Commercial, and Maurice River Townships) and a reference marsh (Moores Beach) in the mesohaline portion of Delaware Bay. In the process, we compared channel morphology, geomorphology, vegetation, sediment organic matter, fish assemblages, blue crabs, horseshoe crabs, benthic infauna, and diamondback terrapins. For fishes we compared structural (distribution, abundance) and functional (feeding, growth, survival, reproduction, production) aspects to evaluate the restored marshes in an Essential Fish Habitat context. Marsh vegetation and drainage density responded gradually and positively with restored marshes approximating the state of the reference marsh within the nine-year study period. The fauna responded more quickly and dramatically with most measures equal or greater in the restored marshes within the first one or two years after restoration. Differences in response time between the vegetation and the fauna imply that the faunal response was more dependent on access to the shallow intertidal marsh surface and intertidal and subtidal creeks than on characteristics of the vegetated marsh. The fishes in created subtidal creeks in restored marshes responded immediately and maintained fish assemblages similar to the reference marsh over the study period. The intertidal creek fish assemblages tended to become more like the reference marsh in the last years of the comparison. Overall, these results document the success of the restoration and how marshes function for both resident and transient fauna, especially fishes.     

Tidal Marsh Restoration: Trends in Vegetation Change Using a Geographical Information System (GIS)

Adequately evaluating the success of coastal tidal marsh restoration has lagged behind the actual practice of restoring tidally restricted salt marshes. A Spartina-dominated valley marsh at Barn Island Wildlife Management Area, Stonington, Connecticut, was tidally restricted in 1946 and consequently converted mostly to Typha angustifolia. With the re-introduction of tidal flooding in 1978, much of the marsh has reverted to Spartina alterniflora. Using a geographical information system (GIS), this study measures restoration success by the extent of geographical similarity between the vegetation of the restored marsh and the pre-impounded marsh. Based on geographical comparisons among different hydrologic states, pre-impounded (1946), impounded (1976), and restored (1988) tidal marsh restoration is a convergent process. Although salt marsh species currently dominate the restored system, the magnitude of actual agreement between the pre-impounded vegetation and that of the restored marsh is only moderate. Further restoration of the salt marsh vegetation may be limited by continued tidal restriction, marsh surface subsidence, and reduced accretion rates. General trends of recovery are identified using a gradient approach and the geographic pattern’ of vegetation change. In the strictest sense, if restoration refers only to vegetation types that geographically replicate preexisting types, then only 28% of the marsh has been restored. Restoration in a broader sense, however, representing the original salt marsh vegetation regardless of spatial position, amounts to 63% restored. Unrestored marsh, dominated by Typha angustifolia and Phragmites australis, remains at 37%. By emphasizing trends during vegetation recovery, this evaluation technique aims to understand the restoration process, direct future research goals, and ultimately aid in future restoration projects.     

Effects of historic tidal restrictions on salt marsh sediment chemistry

The effects of tidalrestrictions by diking on salt marshbiogeochemistry were interpreted by comparingthe hydrology, porewater chemistry and solidphase composition of both seasonally floodedand drained diked marshes with adjacentnatural salt marshes on Cape Cod,Massachusetts. Flooding periods weregreatest in natural and least in drainedmarshes.Differences between the chemistry of thenatural and diked marshes depended upon thedepth of the water table and the supply ofsulfate for anaerobic metabolism. Drainedmarsh sediments were highly acidic (pH <4)with porewaters rich in dissolved Fe; thenatural and diked flooded marshes had pH 6–7.5and Fe orders of magnitude lower. Porewater nutrients, sulfides and alkalinitywere much lower in both flooded and draineddiked marshes than in the natural marsh.Sediments of the drained marsh had subsided90 cm relative to the natural site due toorganic matter decomposition and compaction. However, despite the loss of organic matter,much of the P and N was retained, withNH₄ likely protected from nitrificationby low pH and PO₄ adsorbed on Fe and Aloxides. Iron, and to a lesser degree sulfur,had also been well retained by the sediment. Despite eight decades of diking, substantialamounts of reduced S, representing potentialacidity, persisted near the top of the watertable.In contrast, the surface of the seasonallyflooded marsh was only 15 cm below thenatural marsh. Accretion since dikingamounted to 25 cm and involved proportionallyless mineral matter.The restoration of seawater flow to bothseasonally flooded and drained diked marsheswill likely extend flooding depth andduration, lower redox, increase cationexchange, and thereby increase NH₄,Fe(II), and PO₄ mobilization. Increasedporewater nutrients could benefitrecolonizing halophytes but may also degradesurface water quality.     

Ecological responses to tidal restorations of two northern New England salt marshes

Efforts are underway to restore tidal flow in New England salt marshes that were negatively impacted by tidal restrictions. We evaluated a planned tidal restoration at Mill Brook Marsh (New Hampshire) and at Drakes Island Marsh (Maine) where partial tidal restoration inadvertently occurred. Salt marsh functions were evaluated in both marshes to determine the impacts from tidal restriction and the responses following restoration. Physical and biological indicators of salt marsh functions (tidal range, surface elevations, soil water levels and salinities, plant cover, and fish use) were measured and compared to those from nonimpounded reference sites. Common impacts from tidal restrictions at both sites were: loss of tidal flooding, declines in surface elevation, reduced soil salinity, replacement of salt marsh vegetation by fresh and brackish plants, and loss of fish use of the marsh.Water levels, soil salinities and fish use increased immediately following tidal restoration. Salt-intolerant vegetation was killed within months. After two years, mildly salt-tolerant vegetation had been largely replaced in Mill Brook Marsh by several species characteristic of both high and low salt marshes. Eight years after the unplanned, partial tidal restoration at Drakes Island Marsh, the vegetation was dominated bySpartina alterniflora, a characteristic species of low marsh habitat.Hydrologic restoration that allowed for unrestricted saltwater exchange at Mill Brook restored salt marsh functions relatively quickly in comparison to the partial tidal restoration at Drakes Island, where full tidal exchange was not achieved. The irregular tidal regime at Drakes Island resulted in vegetation cover and patterns dissimilar to those of the high marsh used as a reference. The proper hydrologic regime (flooding height, duration and frequency) is essential to promote the rapid recovery of salt marsh functions. We predict that functional recovery will be relatively quick at Mill Brook, but believe that the habitat at Drakes Island will not become equivalent to that of the reference marsh unless the hydrology is further modified.Corresponding Editor: R.E. Turner Manuseript     

Transport of particulate organic material between salt marsh and estuary

Summary The macrophyte production and the transport of particulate organic matter between march and adjacent estuary have been investigated for a 30 ha salt marsh along the Oosterschelde estuary, The Netherlands.The primary production of macrophytes, measured with Smalley's method, was 837–1030 g dry organic matter.m^–2.year^–1. Measurements of amounts of particulate organic matter transported through one of the main tidal creeks in the salt march resulted in a net import. On average 31% of the material brought in by the flood settled in the marsh. The majority of this material is smaller than 63 m. On the other hand large floating material is exported during storm tides, although the quantity seems to be smaller than that of the suspended material imported.The differences between various marshes with regard to export and import of organic matter are explained in terms of marsh level, primary production, turbulent diffusion, sinking and resuspension of particulate matter and biotic transformations.     

基于胁迫梯度假说和互惠理论的海三棱藨草种群恢复技术

滨海湿地生态修复已成为阻止海岸带生态系统退化、保护生物多样性以及提供生态服务的关键措施。以长江口原生盐沼植物海三棱藨草(Scirpus mariqueter)为研究对象,选取崇明东滩新生滩涂湿地为研究区域,通过沿潮滩高程梯度的海三棱藨草植株斑块的移植实验,探究胁迫梯度假说和互惠理论(即种内的正相互作用)对长江口海三棱藨草种群恢复的指导意义。研究结果显示:(1)在一定的胁迫梯度范围内(潮滩高程2.0 m以上),增大种植斑块可以促进海三棱藨草的种内正相互作用,显著提高种植斑块的存活率和植株密度(P0.05);(2)潮滩水文动力沉积条件与潮滩高程梯度密切相关(P0.05),水文动力沉积作用对海三棱藨草定居和生长的胁迫随高程梯度下降而增强。潮滩高程2.0 m以下处强烈的水文动力条件干扰限制了生物-物理因素的正反馈作用。滨海湿地盐沼植被修复工作的成功率可以通过改进种植方式,增强种内的正相互作用得到极大的提高。研究可为开展大规模滨海湿地盐沼植被修复工程和提高生态修复效率提供科学依据和技术支持。     

Effects of Natural and Anthropogenic Change on Habitat Use and Movement of Endangered Salt Marsh Harvest Mice

The northern salt marsh harvest mouse (Reithrodontomys raviventris halicoetes) is an endangered species endemic to the San Francisco Bay Estuary. Using a conservation behavior perspective, we examined how salt marsh harvest mice cope with both natural (daily tidal fluctuations) and anthropogenic (modification of tidal regime) changes in natural tidal wetlands and human-created diked wetlands, and investigated the role of behavioral flexibility in utilizing a human-created environment in the Suisun Marsh. We used radio telemetry to determine refuge use at high tide, space use, and movement rates to investigate possible differences in movement behavior in tidal versus diked wetlands. We found that the vast majority of the time salt marsh harvest mice remain in vegetation above the water during high tides. We also found no difference in space used by mice during high tide as compared to before or after high tide in either tidal or diked wetlands. We found no detectable difference in diurnal or nocturnal movement rates in tidal wetlands. However, we did find that diurnal movement rates for mice in diked wetlands were lower than nocturnal movement rates, especially during the new moon. This change in movement behavior in a relatively novel human-created habitat indicates that behavioral flexibility may facilitate the use of human-created environments by salt marsh harvest mice.     

Increased Benthic Algal Primary Production in Response to the Invasive Zebra Mussel (Dreissena polymorpha) in a Productive Ecosystem, Oneida Lake, New York

Increased water clarity associated with zebra mussel (Dreissena polymorpha) populations may favor benthic algal primary production in freshwater systems previously dominated by pelagic phytoplankton production. While zebra mussel-mediated water clarity effects on benthic primary production have been implicated in published reports, few production estimates are available. This study estimates benthic primary production in Oneida Lake, NY before and after zebra mussel invasion (1992), using measured photosynthetic parameters ( , α^B and β) from sampled benthic algal communities. In the summers of 2003 and 2004, primary production was measured as O₂ evolution from algal communities on hard (cobble) and soft (sediment) substrate from several depths. We also backcast estimates of benthic primary production from measurements of light penetration since 1975. Estimates of whole-lake epipelic and epilithic algal primary production showed a significant (4%) increase and exhibited significantly less interannual variability subsequent to the establishment of zebra mussels. We applied our model to two lakes of differing trophic status; the model significantly overestimated benthic primary production in a hypereutrophic lake, but there was no significant difference between the actual and predicted primary production values in the oligotrophic lake. The hypereutrophic lake had higher zebra mussel densities than Oneida (224 vs. 41 per sample respectively). Though total community respiration (measured in total darkness) was factored into our model predictions of production, our model may need modification when heterotrophic respiration is a large portion of total community metabolism.     

Drainage and Elevation as Factors in the Restoration of Salt Marsh in Britain

Intertidal restoration through realignment of flood defenses has become an important component of the U.K. coastal and estuarine management strategy. Although experimentation with recent deliberate breaches is in progress, the long‐term prognosis for salt marsh restoration can be investigated at a number of sites around Essex, southeast England where salt marshes have been reactivated (unmanaged restoration) by storm events over past centuries. These historically reactivated marshes possess higher creek densities than their natural marsh counterparts. Both geomorphology and sedimentology determine the hydrology of natural and restored salt marshes. Elevation relative to the tidal frame is known to be the primary determinant of vegetation colonization and succession. Yet vegetation surveys and geotechnical analysis at a natural marsh, where areas with good drainage exist in close proximity to areas of locally hindered drainage at the same elevation, revealed a significant inverse relationship between water saturation in the root zone and the abundance of Atriplex portulacoides, normally the physiognomic dominant on upper salt marsh in the region. Elsewhere in Essex natural and restored marshes are typified by very high sediment water contents, and this is reflected in low abundance of A. portulacoides. After a century of reestablishment no significant difference could be discerned between the vegetation composition of the storm‐reactivated marshes and their natural marsh counterparts. We conclude that vegetation composition may be restored within a century of dike breaching, but this vegetation does not provide a reliable indicator of ecological functions related to creek structure.     

Denitrification in salt marsh sediments: Evidence for seasonal temperature selection among populations of denitrifiers

Direct measurements of bacterial denitrification in salt marsh sediments near Woods Hole, Massachusetts were made over a 10-month period using a simple and precise gas-chromatographic technique. Based on laboratory experiments at 5°, 10°, and 20°C, it is shown that seasonal temperature variations select for at least two distinct populations of denitrifiers.In situ incubations suggest that resident populations of denitrifying bacteria are cold-sensitive. Salt marsh denitrifying bacteria are not optimally adapted to their thermal environment, but to temperatures 5°–10°C higher. In these water-logged muds, rates of bacterial denitrification (0.3–1.5g N₂/gm sediment-hr) are up to three orders of magnitude greater than maximum potential rates of insitu bacterial and algal nitrogen fixation.Supported by the Victoria Foundation and NSF grants GA 28365, GA 28272, and GA 41506. This is Contribution No. 3730 from the Woods Hole Oceanographic Institution.     

Interrelation between plankton and benthos in the littoral algal community of Lake Yunoko,Central Japan

To ascertain the floristic interaction between phytoplankton and benthos in the littoral, the composition of each community was investigated and the effect of the substrata on the benthic communities was also examined.The main component of the benthic algal population wasFragilaria pinnata followed byF. pinnata var.lancettula. Although the dominant species of the plankton in the upper layers were similar to those in the limnetic, and those immediately above the bottom contained species of benthic origin, the similarity index of C implied high similarity between these two plankton layers. This index was developed by Morishita (1959) to measure the degree of overlap of component species between two communities. The value of C distributes from 0 to 1. The closer the value approaches 1, the more the communities are similar.For the dominant species, a significant difference was observed between the phytoplankton and benthic communities and in addition, C values indicated low overall similarity in the composition of the communities. These results suggest that there is little interrelation between phytoplankton and benthos even in the shallow littoral zone.     

Development of filamentous green algae in the benthic algal community in a littoral sand-beach zone of Lake Biwa

Temporal changes of biomass and dominant species in benthic algal communities were investigated in a littoral sand-beach zone in the north basin of Lake Biwa from December 1999 to September 2000. Chlorophyll-a amounts of benthic algal communities per unit area of the sandy sediments rapidly increased from late April to June. Increases in biomass of the benthic algal communities are considered to result from the propagation of filamentous green algae Oedogonium sp. and Spirogyra sp. The cell numbers of filamentous green algae and chlorophyll-a amounts of benthic algal communities at depths of 30 and 50cm at a station protected by a breakwater in May were significantly higher than those of a station exposed directly to wave activity. Thus, the biomass accumulation of the benthic algal communities seems to be regulated strongly by wave disturbance. The development of filamentous green algae may contribute to the increase in biomass of the benthic algal community and to the changes in seasonal patterns of biomass in the sand-beach zone of Lake Biwa. We consider that the development of the filamentous green algal community in the littoral zone of Lake Biwa is the result of eutrophication.     

Evaluating tidal marsh sustainability in the face of sea-level rise: a hybrid modeling approach applied to San Francisco Bay

Background

Tidal marshes will be threatened by increasing rates of sea-level rise (SLR) over the next century. Managers seek guidance on whether existing and restored marshes will be resilient under a range of potential future conditions, and on prioritizing marsh restoration and conservation activities.

Methodology

Building upon established models, we developed a hybrid approach that involves a mechanistic treatment of marsh accretion dynamics and incorporates spatial variation at a scale relevant for conservation and restoration decision-making. We applied this model to San Francisco Bay, using best-available elevation data and estimates of sediment supply and organic matter accumulation developed for 15 Bay subregions. Accretion models were run over 100 years for 70 combinations of starting elevation, mineral sediment, organic matter, and SLR assumptions. Results were applied spatially to evaluate eight Bay-wide climate change scenarios.

Principal Findings

Model results indicated that under a high rate of SLR (1.65 m/century), short-term restoration of diked subtidal baylands to mid marsh elevations (−0.2 m MHHW) could be achieved over the next century with sediment concentrations greater than 200 mg/L. However, suspended sediment concentrations greater than 300 mg/L would be required for 100-year mid marsh sustainability (i.e., no elevation loss). Organic matter accumulation had minimal impacts on this threshold. Bay-wide projections of marsh habitat area varied substantially, depending primarily on SLR and sediment assumptions. Across all scenarios, however, the model projected a shift in the mix of intertidal habitats, with a loss of high marsh and gains in low marsh and mudflats.

Conclusions/Significance

Results suggest a bleak prognosis for long-term natural tidal marsh sustainability under a high-SLR scenario. To minimize marsh loss, we recommend conserving adjacent uplands for marsh migration, redistributing dredged sediment to raise elevations, and concentrating restoration efforts in sediment-rich areas. To assist land managers, we developed a web-based decision support tool (www.prbo.org/sfbayslr).     

Impact of black bullhead (Ameiurus melas) on turbidity in a diked wetland

Benthivorous fish in shallow, aquatic systems have been correlated with increased turbidity and declines in macrophyte production and wildlife use. Bullheads have been credited with increasing turbidity, but this has been seldom tested and has not been studied in a diked marsh. To assess the relationships of black bullhead (Ameiurus melas) and turbidity, we assembled mesocosmsin the Show Pool Management Unit of The Ottawa National Wildlife Refuge, OH, U.S.A. We stocked treatment enclosures with different biomasses of black bullhead at weekly intervals. Mean turbidity within treatment enclosures was significantly higher than within controls but remained lower than that of the open marsh. Both surface and bottom turbidity increased with adult and juvenile black bullhead biomass. Turbidity increased with fine sand concentration only in the presence of juvenile fish. Wind speed and direction were significant influences on the turbidity of the open marsh, but not within control enclosures. That treatment turbidity – even at extreme biomasses – remained significantly lower than the turbidity of the open marsh implicates fetch in having a greater influence on a marsh's turbidity than the presence of black bullhead. The greater impact of benthivorous fish on turbidity within shallow systems may be an indirect one through the destruction of macrophytes and subsequent destabilization of unconsolidated substrates.     

Tracking marsh restoration using macrobenthic metrics: implementing a functional approach

Attempts to understand ecological processes within restored saltmarsh ecosystems have increased dramatically in recent years; and it is now generally agreed that marsh restoration success should be gauged relative to the recovery of ecosystem function. Studies of macroinfaunal recovery in created marshes typically employ faunistic metrics to examine colonization and succession. Few studies employ macrobenthic functional metrics. Here, we present an evaluative approach employing macrobenthic functional metrics for use in marsh restoration studies in the context of a comparative study. To illustrate the approach, a four-way comparison of functional and faunistic metrics is made between intertidal Spartina and adjacent subtidal habitats and between a set of created marsh islands that have been established for 27 years and a set of nearby natural marsh islands within Davis Bay, Mississippi. The suite of functional metrics used in this study characterizes the macroinfauna in terms of biological production based and community maturity based attributes. Several production-based attributes (e.g., production potential, normalized biomass size spectrum (NBSS) intercept residuals, total abundance) differed between habitats and between created and natural sites; and community maturity based attributes (e.g., mean size, NBSS slope, faunal turnover rate) differed between habitats. Of the functional metrics, NBSS intercept residuals were most effective for discerning created and natural sites, followed by production potential and total abundance. Of the faunistic metrics, faunal diversity and dominance did not differ between created and natural sites; however evenness was higher at the created site. Diversity and evenness differed significantly between habitats; and dominance almost differed between habitats. Community structure (Bray–Curtis similarity) differed between habitats and between created and natural marshes. This study illustrates how macrobenthic functional metrics can be practical and informative for tracking marsh restoration success. Functional metrics deliver additional insights and appear to be more effective than faunistic metrics. Not only do these functional metrics fulfill the need to understand the role of benthic processes within the context of marsh restoration; they can be related appropriately to other aspects of ecosystem function.     

Sources of organic carbon in the littoral of Lake Gooimeer as indicated by stable carbon isotope and carbohydrate compositions

The relative importance of potential carbon sources in the littoral of Lake Gooimeer, a lake in the centre of the Netherlands, was studied using a combination of ¹³C/¹²C-ratio analysis and carbohydrate composition analysis. The littoral is covered on the land side by a 80 m wide Phragmites australis bed. Potential carbon sources were macrophyte litter, seston and benthic algae. Samples of potential carbon sources, sediments and benthic macrofauna from inside and outside the bed were analyzed for their¹³C/¹²C-ratio and some for their carbohydrate composition. Results indicate that inside the bed, macrophyte litter was the main source of carbon for both the sediment organic matter and the benthic macrofauna, and that algal material was of minor importance. Outside the bed, production by benthic algae was the main carbon source, with seston as a second source. No macrophyte derived material could be detected outside the reed bed.Abbreviations DOC (Dissolved Organic Carbon) - SOM (Sediment Organic Matter)