N-Control
Seagrass Restoration Monitoring Report
Monitoring Events 2003-2008
Florida Keys National Marine Sanctuary, Monroe County, Florida
Author:
Alicia A. Farrer, Environmental Specialist II
Florida Keys National Marine Sanctuary
This document presents the results of the monitoring of a repaired seagrass area injured
by the N-Control vessel grounding incident of May 29, 2001. This grounding occurred in
State of Florida waters within the boundaries of the Florida Keys National Marine
Sanctuary (FKNMS) and impacted a total of 96.87 m2 of seagrass habitat, predominantly
Turtle grass (Thalassia testudinum). Restoration of this site was completed on March 25,
2003 and consisted of forty-four seagrass planting units (Halodule wrightii and
Syringodium filiforme) and 39 bird stakes. The monitoring program of the N-Control site
was designed to determine whether the restoration effort provided services in a manner
consistent with restoration goals, and to monitor the potential need for mid-course
corrections. Monitoring consisted of both quantitative and qualitative methods adapted
from Fonseca et al "Guidelines for the Conservation and Restoration of Seagrasses in the
United States and Adjacent Waters". A total of six monitoring events were conducted
over five and a half years. After 64 months (5.5 years) post-restoration, the percent cover
of total seagrass in the restored injury increased from 5.6% to 17%. The target species, T.
testudinum, increased from 0.5% to 12.1% in the restoration area by the 5.5 year
monitoring event. In comparison, the percent cover of T. testudinum was 28.5% in the
reference area adjacent to the injury during the 5.5 year monitoring event. This
restoration effort accelerated the recovery of the injured area but the injury has yet to
reach pre-grounding baseline levels. Research on restoration techniques and natural
recovery continues, and will provide valuable information on the practicality and
effectiveness of seagrass restoration of vessel grounding injuries.
Keywords: N-Control, Florida Keys National Marine Sanctuary, seagrass, vessel grounding,
restoration, monitoring, planting units, bird stakes
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