STUDY AREA 
7/) 40265 Ha. 
  
  
E 
  
  
  
  
THE IMPACT OF FIRE FREQUENCY ON MARSH AREA SHRUB PATCHES 
Greg J. Arthaud and Rakesh Malhotra 
Daniel B. Warnell School of Forest Resources 
University of Georgia 
Athens, GA 30602-2152, USA 
ABSTRACT 
This study assesses the impact of prescribed burning on shrub invasion in selected fire units of 
the Merritt Island National Wildlife Refuge (MINWR). The refuge encompasses part of the John F. 
Kennedy Space Center (KSC) in east-central Florida. This area was studied due to the interest in the 
impacts of fire management on vegetation and wildlife in the refuge. Maintaining refuge marsh areas 
is important for preserving many of the threatened or endangered species present at MINWR. Aerial 
photography of the area was used to estimate shrub areal extent changes for 1982 to 1992. 
Vegetation was interpreted and digitized for both years. Error testing was also a critical portion of 
this study. In 1982, the seven fire units tested had shrub percentage range of 0.0% to 22.6% and an 
average of 4.1% of fire unit area. By 1992, five of the seven showed a significant increase. Shrub 
increased to 11.3% across the seven units with a range of 2.6% to 46.5% within units. The current 
level of burning seems inadequate to control the increase of shrub in most marsh areas. 
1. INTRODUCTION 
The study area lies on the northern 
part of Merritt Island and consist of 
approximately 57,000 ha of land and open 
water lagoons. KSC is a succession of swales 
and relict dunes with elevation ranging from 0 
to 3 m (Breininger ef al. 1994). The dunal 
areas on the eastern shore are dynamic, with 
initial colonization by succulent annuals 
followed by perennial grasses, vines and 
shrubs (Kurz 1942). On the backside of 
dunes, shrubby species such as saw palmetto 
(Serenoa repens) wax myrtle (Myrica 
cerifera), varnish-leaf (Dodonaea viscosa), 
and sand live oak (Quercus geminata) become 
common. As distance from the ocean 
increases, with its associated salt deposition, 
vegetation progresses from saw palmetto to 
hardwood shrubs. Areas of hammock support 
live oak (Quercus virginiana) and other sub- 
tropical species. On the lagoonal shores, 
black mangrove (Avicennia germinans) 
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become common. Forest vegetation 
dominates further in from the coast. 
The area has a history of manipulation 
by man. Preceding the acquisition of the by 
the U. S. National Aeronautics and Space 
Administration (NASA) in 1962, the area was 
used for grazing of free-ranging cattle, 
hunting, and wood production (Davidson and 
Bratton 1986). Areas not used for the space 
program are managed by the U. S. Fish and 
Wildlife Service (USFWS) and the U. S. 
National Park Service (Canaveral National 
Seashore). 
Extensive portions of marsh areas 
were impounded during the period of 1954 to 
1970. The impoundments were meant to 
serve two purposes: 1) to discourage 
mosquitoes during their spring through fall 
breeding season, and 2) to attract wintering 
waterfowl during winter months (Montiague 
et al. 1985, and Breininger and Smith 1990). 
According to Rey ef al. in 1991, 4500 ha of 
the refuge wetlands were flooded year-round