Research Gaps in Florida Scrub Fire Ecology and Management

Little is known about the ecosystem ecology of Florida scrub. With respect to fire, research gaps include the effect of fire on nutrient cycling, the potential effects of frequent fires on nutrient stores, the effects of fire on soil water dynamics, and atmospheric-vegetation interactions during fire.

Fire behavior in Florida scrub is extreme, but little documented. Fuel models for scrub systems are in development, but not tested for Florida scrub. Most land managers have used fuel model 4, which was developed for California chaparral (e.g., Custer and Thorson 1996). This fuel model can underestimate fire behavior in Florida scrub (Menges, personal observation). Fire managers feel that there is sometimes a narrow ledge between being unable to get fire to carry and conditions that are dangerous to burn. However, this judgment is based on intuition and experience. The role of live fuels in carrying fire and their variation over seasons and with weather conditions is not well known and could help predict fire behavior. Although something is known of fire intensity variation (Wally et al. submitted), there needs to be more work on fire intensity effects on vegetation and rare species recovery. Smoke management is another applied issue that would benefit from research into predictive models.

Fire recovery strategies are known for many plant and animal species although some species still need direct studies. Fire return intervals are only guessed at for many types of scrub, and there is a tendency of land managers to use narrow ranges. We need to understand the full range of fire return intervals that provide variation and support biodiversity in Florida scrub. Some information is known on effects of fire season (e.g. Robbins and Myers, 1992) but more information is needed.

Because of the difficulty of applying and controlling fire, and smoke management issues, many land managers are using mechanical treatments such as roller chopping, mowing, logging, and chain-sawing as surrogates or pretreatments for fire. Ongoing studies on the effects of these treatments on wildlife, vegetation, and rare species show varying results (Schmalzer and Boyle 1998, Roberts and Cox 1999, Menges et al. 2001, Berish et al. 2002, Schmalzer et al. 2003). One study in the Ocala National Forest found that wildfire followed by salvage logging had similar effects to clearcutting, but this study was hampered by the lack of an unsalvaged burn treatment (Greenberg et al. 1994, 1995). The widespread use of mechanical surrogates and pretreatments for fire needs to be looked at more critically. The standards for evaluating the use of mechanical treatments should go beyond their effects on a single species (usually the Florida scrub jay) to multi-species responses and include effects on soil properties and invasive species. The standard to which mechanical treatments should be compared is periodic fire.