Grantee Research Project Results
Final Report: Applying Ecological Succession Theory to Evaluate Wetland Restoration in Urbanizing Coastal Watersheds
EPA Grant Number: R826111Title: Applying Ecological Succession Theory to Evaluate Wetland Restoration in Urbanizing Coastal Watersheds
Investigators: Craft, C. B. , Stevenson, R. Jan , Megonigal, J. P. , Broome, S. W.
Institution: Indiana University - Bloomington
EPA Project Officer: Hahn, Intaek
Project Period: June 1, 1998 through May 31, 2001 (Extended to May 30, 2002)
Project Amount: $534,239
RFA: Ecosystem Restoration (1997) RFA Text | Recipients Lists
Research Category: Ecological Indicators/Assessment/Restoration , Hazardous Waste/Remediation , Land and Waste Management , Aquatic Ecosystems
Objective:
The objective of this research project was to assess the degree of full or complete restoration of wetland structure and function on restored salt marshes and other ecologically similar restored wetlands.
Summary/Accomplishments (Outputs/Outcomes):
Ecological attributes were measured along a chronosequence of 1 year-old to 28 years-old constructed Spartina alterniflora marshes to identify trajectories and rates of ecosystem development of wetland structure and function. Attributes related to biological productivity and diversity (Spartina, epiphytic and sediment algae, benthic invertebrates), soil development (sediment deposition, organic carbon (C), nitrogen, (N), phosphorus (P), organic matter quality) and microbial processes (C mineralization, denitrification) were compared among seven constructed marshes and seven paired natural reference marshes.
Most of the ecological attributes developed in a predictable manner over time, and most attributes achieved equivalence to natural marshes 5 to 15 years after marsh construction (see Table 1). An exception was soil organic C and N pools (0-30 cm) that, after 28 years, significantly were less in constructed versus natural marshes. Development of habitat structure (Spartina stem height and density) and biodiversity (algae and invertebrates) developed concurrently with functional characteristics like biomass, chlorophyll a, and invertebrate density, achieving equivalence within 5 to 15 years. Processes related to hydrology, sediment deposition, and soil C and N accumulation, developed almost instantaneously with the establishment of Spartina and young (1 to 3 years-old) constructed marshes, trapped sediment, and sequestered N at higher rates than comparable reference marshes. Most other ecological attributes increased gradually before converging to equivalence. Development of heterotrophic microbial activity (C mineralization, potential denitrification) strongly was linked to surface (0-10 cm) soil organic C content.
Ecological Attribute | Time Required to Achieve Equivalence |
Indicator Status |
||
Producers and Consumers | Predictable (R2)3 |
Easy to Use |
Inexpensive |
|
Spartina aboveground biomass | 5-10 yr |
Yes (0.53-0.87) | Yes | Yes |
Spartina MOM | 15 yr |
Yes (0.88) | No | Yes |
Spartina stem density | 5-15 yr |
No | Yes | Yes |
Spartina stem height | 10-15 yr |
Yes (0.50-0.70) | Yes | Yes |
Algae chlorophyll a – epiphytic4 | 15 yr |
Yes (0.81) | No | No |
Algae chlorophyll a – sediment4 | -- |
No | No | No |
Diatom similarity – epiphytic4 | >30 yr |
Yes (0.66) | No | No |
Diatom similarity – sediment4 | >30 yr |
Yes (0.71) | No | No |
Benthic invertebrate density | 5-10 yr |
Yes (0.89) | No | No |
Benthic invertebrate diversity | 5-10 yr |
Yes (0.90) | No | No |
Wetland Soils | ||||
Sediment deposition | Instantaneous |
-- | No | No |
Element sequestration | ||||
Soil organic C pools (0-30 cm) | >30 yr |
Yes (0.80) | Yes | Yes |
Soil N pools (0-30 cm) | >30 yr |
Yes (0.69) | Yes | Yes |
Organic C and N accumulation | Instantaneous |
-- | No | No |
Organic Matter quality (lignin) | 5-15 yr |
Yes (0.75) | No | No |
Microbial processes | ||||
Carbon mineralization | 5-15 yr |
Yes (0.71) | No | No |
Denitrification | 5-10 yr |
Yes (0.84) | No | No |
1 Attributes were evaluated based on the amount of time required for achieving equivalence to natural marshes, their predictability, ease of use and cost. | ||||
2 Attributes in italics perform at a higher level in young constructed marshes as compared to older constructed marshes and natural marshes. | ||||
3 "Goodness of fit" of the regression between the ecological attribute and constructed marsh age. | ||||
4 Ratio of constructed marsh to reference marsh. |
Ecological attributes related to soils and vegetation were practical and effectual indicators of marsh structural and functional equivalence (see Table 2). Soil organic C and macro-organic matter are ideal indices describing the development of ecological attributes following marsh construction. They are predictable, easy to use, inexpensive, and they accurately describe the development of other ecological attributes. Attributes describing Spartina structure and function (e.g., aboveground biomass, stem height) were not as useful for describing ecosystem development as macroorganic matter (MOM) and soil organic C and N (see Table 2).
Above. biomass |
MOM |
Stem ht. |
Organic C |
Nitrogen |
|||
(g/m2) |
(g/m2)1 |
(cm) |
(g/m2)2 |
(%)3 |
(g/m2)2 |
(%)3 |
|
Producers and Consumers | |||||||
Above. biomass | -- | -- | -- | -- | -- | -- | -- |
MOM | 0.64 | -- | -- | -- | -- | -- | -- |
Stem height | 0.82 | 0.68 | -- | -- | -- | -- | -- |
Stem density | 0.04 | -0.08 | -0.07 | -0.24 | -0.21 | -0.20 | -0.19 |
Chl a (epiphytes) | 0.12 | -0.38 | -0.01 | -0.41 | -0.48 | -0.35 | -0.47 |
Chl a (sediment) | -0.10 | 0.34 | -0.20 | 0.22 | 0.16 | 0.25 | 0.11 |
Similarity (epiphyte) | 0.55 | 0.62 | 0.35 | 0.82 | 0.82 | 0.74 | 0.73 |
Similarity (sediment) | 0.56 | 0.71 | 0.29 | 0.82 | 0.63 | 0.77 | 0.63 |
Invertebrate density | 0.64 | 0.71 | 0.55 | 0.80 | 0.68 | 0.74 | 0.61 |
Invertebrate richness | 0.82 | 0.57 | 0.53 | 0.63 | 0.47 | 0.61 | 0.42 |
Wetland Soils | |||||||
Silt+clay | 0.54 | 0.58 | 0.37 | 0.93 | 0.91 | 0.94 | 0.89 |
Organic C (g/m2) | 0.67 | 0.89 | 0.65 | -- | -- | -- | -- |
Organic C (%) | 0.60 | 0.91 | 0.70 | 0.97 | -- | -- | -- |
Nitrogen (g/m2) | 0.63 | 0.82 | 0.58 | 0.98 | 0.94 | -- | -- |
Nitrogen (%) | 0.57 | 0.85 | 0.65 | 0.96 | 0.99 | 0.96 | -- |
OM quality (lignin) | 0.72 | 0.70 | 0.50 | 0.70 | 0.60 | 0.62 | 0.51 |
C mineralization | 0.58 | 0.87 | 0.61 | 0.99 | 0.98 | 0.97 | 0.96 |
Denitrification | 0.91 | 0.97 | 0.90 | 0.87 | 0.95 | 0.82 | 0.94 |
1 Coefficients are derived from mean (n = 6-8) values from the constructed marshes. Coefficients in bold are significant at p < 0.05. n = 8 except for n = 6 (diatom similarity, denitrification) or n = 7 (Chl a, silt+clay, invertebrates). | |||||||
2 0-30 cm depth. | |||||||
3 0-10 cm depth. |
Most ecological attributes achieved equivalence to natural marshes within 5 to 15 years following marsh construction, the amount of time required to accumulate 1000 g organic C/m2 (0.5-1 percent C) and 100 g N/m2 (0.05-0.1 percent) in the soil. Once these levels were achieved, constructed marshes provided sustainable ecosystem services comparable to services provided by natural marshes.
The results of this study are useful for:
(1) Setting realistic expectations for the amount of time required for complete restoration of wetland dependent functions of created and restored salt marshes and other wetland creation and restoration projects. For example, achieving structural and functional equivalence does not occur immediately following construction or restoration. For constructed salt marshes, 5 to 15 years is needed for these ecosystems to achieve full or complete equivalence to natural marshes. Thus, performance of wetland creation and restoration projects may need to be monitored longer than the 5 year period required by most permits.
(2) Predicting rates of development of specific wetland functions, like water quality improvement and biological productivity. For example, wetland functions related to hydrology, such as sediment deposition, develop almost instantaneously with the establishment of Spartina, whereas development of heterotrophic-based salt marsh food web, dependant on accumulation of soil organic matter, requires more time.
(3) Identifying predictable, reliable, inexpensive, and easy-to-use performance criteria used to assess structural and functional development of other created and restored salt marshes and other wetland creation and restoration projects. For example, soil organic C content may be useful for assessing the development of heterotrophic activity (e.g. decomposition, methanogenesis, dentirification) and food webs (benthic invertebrates) of wetlands and other heterophic-based ecosystems.
Journal Articles on this Report : 1 Displayed | Download in RIS Format
Other project views: | All 9 publications | 6 publications in selected types | All 5 journal articles |
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Type | Citation | ||
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|
Loomis MJ, Craft CB. Carbon sequestration and nutrient (nitrogen, phosphorus) accumulation in river-dominated tidal marshes, Georgia, USA. Soil Science Society of America Journal 2010;74(3):1028-1036. |
R826111 (Final) R832220 (Final) |
Exit Exit |
Supplemental Keywords:
estuary, sustainable development, public policy, decision making, monitoring., RFA, Scientific Discipline, Geographic Area, Water, Ecosystem Protection/Environmental Exposure & Risk, Water & Watershed, Restoration, State, Southeast, Mid-Atlantic, Ecological Risk Assessment, Aquatic Ecosystem Restoration, Watersheds, wetlands, ecological succession theory, biodiversity, watershed, Virginia (VA), tourism, regional economies, sustainable development, decision making, coastal environments, conservation, ecological recovery, marshes, aquatic ecosystems, urbanizing coastal watershed, North Carolina (NC), water quality, watershed restorationRelevant Websites:
http://www.spea.indiana.edu/craft Exit
Progress and Final Reports:
Original AbstractThe perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Conclusions drawn by the principal investigators have not been reviewed by the Agency.