Habitat Monitoring

Seagrass - Salt Marsh - Anadromous Fish Habitat

Seagrass

Researcher surveying restored eelgrass bed using line-intercept/quadrat method. F. Short, courtesy of NOAA

Monitoring of eelgrass transplant or seeding projects focuses on quantitatively estimating the degree of transplant success (Moore and Orth 1982; Phillips and Lewis 1983; Orth et al. 1994; Fonseca 1994; Fonseca et al. 1987a, 1998). A secondary objective of an eelgrass transplant monitoring program is to ascertain the recovery of ecosystem function and community structure that has been achieved, in comparison to natural eelgrass beds. This typically involves collecting data on water quality and nutrient exchanges within the beds, colonization of the bed by epiphytic and benthic organisms, and use of the bed by fishery species (Thayer et al. 1975; Homziak et al. 1982; Hoffman 1988; Smith et al. 1989; Fonseca et al. 1990, 1998). Recommendations for monitoring frequency, and data interpretation techniques are provided by Fonseca (1994), and Fonseca et al. (1998).

Suggested parameters to be monitored at eelgrass restoration and reference sites include:

• Surface water quality
• Light attenuation
• Soil organic matter content
• Sediment accretion rates
• Transplant survival, areal coverage, number of shoots per area
• Epiphyte community composition and biomass
• Incidence of disease (e.g., Labryinthula zosterae infection)
• Benthic invertebrate communities
• Utilization of the beds by fishery species

As a local example, basic monitoring costs for the eelgrass restoration component of the U.S. Army Corps of Engineers New England District (USACE-NED) South Shore Habitat Restoration study (presumably just percent coverage per recolonization surveys) are estimated at $45,000 for the first year, and $15,000 per year for the next two years.

Duration of Monitoring
Availability of funds and resources often limits the duration for which seagrass restoration projects can be monitored, however the duration and frequency of monitoring must be sufficient for a determination of functional equivalency with reference or donor beds. Three to five years of annual monitoring is considered a minimum level of effort (USACE-NED 2002). Considerably longer monitoring periods are likely to be necessary to document complete coalescence and succession of transplanted areas. Some transplanted areas may never achieve levels of coalescence comparable to that of natural beds (Fonseca 1994).

The principles of Adaptive Management have been incorporated into the administration of habitat restoration projects within a variety of governmental funding authorities and programs (Thom 1997). Comprehensive, long-term monitoring is a component of adaptive management, which relies on the accumulation of evidence (via long-term monitoring) to support a decision that demands action. If established early in the project-planning phase and implemented during successive monitoring and management phases, adaptive management can be a powerful method to systematically assess and improve the performance of restored ecosystems (Thom 2000).

A well-designed restoration monitoring program will allow project managers to detect deviation from projected results months, years, or decades following construction. For example, monitoring of a transplanted eelgrass bed might reveal the presence of seasonal algal blooms which reduce available light, or evidence of grazing or disturbance. Corrective measures such as supplemental transplants or the installation of cages to exclude grazers might be necessary to maintain the integrity of the transplant site.

Monitoring data can be used by project managers to demonstrate the ability of the project to meet stated goals and objectives. This is especially important in promoting the benefits of eelgrass restoration to funding agencies, potential partners or sponsors for future restoration projects, and the general public. Finally, long-term monitoring data allows managers to learn from early projects, and avoid potential pitfalls in successive restoration efforts (Thom and Wellman 1997).

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References

Fonseca, M.S. 1994. A guide to transplanting seagrasses in the Gulf of Mexico. Texas A&M University Sea Grant College Program, TAMU-SG-94-601, College Station, Texas.

Fonseca, M.S., W.J. Kenworthy, D.R. Colby, K.A. Rittmaster, and G.W. Thayer. 1990. Comparisons of fauna among natural and transplanted eelgrass Zostera marina meadows: criteria for mitigation. Marine Ecology Progress Series 65:251-264.

Fonseca, M.S., W.J. Kenworthy, and G.W. Thayer. 1987a. Transplanting of the seagrasses Halodule wrightii, Syringodium filiforme, and Thalassia testudinum for sediment stabilization and habitat development in the southeast region of the United States. Technical Report EL-87-8, U.S. Army Engineer Waterways Experiment Station, Vicksburg, Mississippi.

Fonseca, M.S., W.J. Kenworthy, and G.W. Thayer. 1998. Guidelines for the conservation and restoration of seagrasses in the United States and adjacent waters. NOAA Coastal Ocean Program Decision Analysis Series No. 12. NOAA Coastal Ocean Office, Silver Spring, Maryland.

Hoffman, R.S. 1988. Fishery utilization of natural versus transplanted eelgrass beds in Mission Bay, San Diego, California, pp. 58-64. In: Proceedings of the California Eelgrass Symposium. Chula Vista, California.

Homziak, J., M.S. Fonseca, and W.J. Kenworthy. 1982. Macrobenthic community structure in a transplanted eelgrass meadow. Marine Ecology Progress Series 9:211-21.

Moore, K.A. and R. J. Orth. 1982. Transplantation of Zostera marina L. into recently denuded areas, pp. 92-148. In: R.J. Orth and K.A. Moore, (eds.), The Biology and Propogation of Zostera marina, eelgrass, in the Chesapeake Bay, Virginia. Special Report No. 265 in Applied Marine Science and Ocean Engineering, Virginia Institute of Marine Sciences, Gloucester Point, Virginia.

Orth, R.J., M. Luckenbach, and K.A. Moore. 1994. Seed dispersal in a marine macrophyte: implications for colonization and restoration. Ecology 75:1927-39.

Phillips, R.C. and R.R. Lewis, III. 1983. Influence of environmental gradients on variations in leaf widths and transplant success in North American seagrasses. Marine Technology Society Journal 17:59-68.

Smith, I., M.S. Fonseca, J.A. Rivera, and K.A. Rittmaster. 1989. Habitat value of natural versus recently transplanted eelgrass, Zostera marina, for the bay scallop, Argopecten irradians. Fishery Bulletin 87:189-96.

Thayer, G.W., S.M. Adams, and M.W. LaCroix. 1975. Structural and functional aspects of a recently established Zostera marina community. pp. 518-540 in: L.E. Cronin (Ed.) Estuarine Research. Academic Press, New York, New York.

Thom, R.M. 1997. System-development matrix for adaptive management of coastal ecosystem restoration projects. Ecological Engineering 8:219-232.

Thom, R.M. 2000. Adaptive management of coastal ecosystem restoration projects. Ecological Engineering 15:365-372.

Thom, R.M. and K.F. Wellman. 1997. Planning aquatic ecosystem restoration monitoring programs. Evaluation of Environmental Investments Research Program, U.S. Army Corps of Engineers Institute for Water Resources, IWR Report 96-R-23, Alexandria Virginia.

U.S. Army Corps of Engineers New England District (USACE-NED). 2002. Rhode Island South Shore Habitat Restoration Feasibility Report and Environmental Assessment (Draft). U.S. Army Corps of Engineers, New England District, concord, Massachusetts.

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