Life History Strategies of Florida Scrub Plants in Relation to Fire

Menges, Eric; Kohfeldt, Nancy

To characterize life history strategies of Florida scrub plants in relation to fire, we classified 98 species into guilds based on recovery mechanisms and post-fire abundance patterns. Two types of scrub were analyzed: xeric, infrequently-burned rosemary scrub and more productive, more-frequently burned scrubby flatwoods. Based on recovery mechanisms, most (92%) species are in four guilds: resprouters (mainly woody shrubs), resprouters and seeders (small-statured shrubs, palms, and herbaceous perennials), obligate seeders (mainly herbs), and resprouters and clonal spreaders. The last category contains most of the dominant shrubs of scrubby flatwoods. Two pine species each comprised a unique guild based on recovery mechanisms. Most species of scrubby flatwoods (59%) and rosemary scrub (53%) had no significant trend in post-fire abundance. About twice as many scrubby flatwoods species increased as decreased in frequency with time since fire; increasers included ground lichens and two of the three dominant oaks. Similar numbers of species increased and decreased in rosemary scrub. Most increasers were ground lichens and most decreasers were herbaceous perennials. In scrubby flatwoods, most plants with vegetative recovery modes tended to increase in frequency with time since fire, mixed recovery mode plants usually had no trend, and obligate seeders decreased. In rosemary scrub, mixed recovery modes were associated with decreasing post-fire trends, while seeders tended to increase in post-fire abundance. Infrequently-burned rosemary scrub provides opportunities for seedling recovery from fire, evident in both in its dominant species and in the many endemic and open-space specialist herbs. In contrast, recovery from fire by resprouting and clonal growth is common in the more-frequently burned scrubby flatwoods, promoting rapid post-fire recovery and long-term competitive superiority in this more productive habitat. To promote life history and species diversity, fire management in Florida scrub should avoid overly regular fire regimes, fire suppression or too-frequent burning. Modal intervals will differ between scrubby flatwoods (5- 20 years) and rosemary scrub (15-40 years). When to reburn rosemary scrub may depend on the specific responses of its many endemic plant species to fire.

Life History Strategies of Florida Scrub Plants in Relation to Fire

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