FIRE DISTURBANCE IN THE EVERGLADES

ECOSYSTEM

Lisa Melanson December 13, 2006

Disturbance

• Disturbance: Any relatively discrete event in space and time that disrupts ecosystem, community, or population structure and changes resources, substrate, or the physical environment. Disturbances typically cause a significant change in the system.

• Landscape processes transfer energy and matter across a landscape.

Ming Xu, Lecture notes

Disturbance RegimeA summary description of a repeating disturbance type for a given landscape, for a given period of time

Described using empirical data and statistical summaries

Described by spatial, temporal and magnitude measurements

Ming Xu, Lecture notes

Disturbance and Landscape Interactions

Landscape pattern may affect the spread of disturbances

Existing landscape pattern may inhibit or facilitate the spread of a disturbance

Ming Xu, Lecture notes

Located in southwestern Florida, north and west of Everglades National Park.Wetland communities, especially those dominated by bald cypress (Taxodium distichum), make up much of the preserve’s landscapeTopographic relief in the preserve is minimal, with a gradual slope (about 1 foot per mile) toward the coast, most of the preserve is under at least few inches of water during the summer rainy season The flat nature of the land supports large areas of shortgrass prairies and sawgrass marshes Graminoid communities naturally burn every few years Fire is a common and significant ecological factor

Big Cypress National Preserve

FACTS

In terms of the amount of burning accomplished, the Big Cypress prescribed fire management program is the largest in the National Park Service (NPS) Approx. 40,000 acres burned annually to reduce accumulated fuels in plant communities

IMPORTANT ENDANGERED WILDLIFE CONSIDERATIONSFlorida panther (Felis concolor coryi) habitat and prey Red-cockaded woodpecker (Picoides borealis) nesting colony sitesCape Sable seaside sparrow (Ammodramus maritimus mirabilis) nest site availabilityFlorida tree snail (Liguus fasciatus) hardwood hammock habitats

Florida tree snail (Liguus fasciatus)

Why is fire important in the Everglades Ecosystem?

Fire is an essential component of South Florida wetlands and pineland uplands and has been an important ecological process in shaping Everglades vegetation patterns • can determine inland expansion of mangroves• tree-island growth • plays an important role in preventing cypress

trees from extending into marshes

70% of plants endemic to southern Florida occur in pyroclimactic (fire climax) communities, Wade et al. (1980)

FIRE DISTURBANCE BENEFITS

Exotic plant removal•Melaleuca (Melaleuca

quinquenervia)Stand health and maintenanceReduction of Hazardous FuelsNew growth provides food for wildlife (i.e. deer)Controls pest problems

“Moderate fires influence nutrient cycling, stimulate net primary production, and may even be the evolutionary process that selects for sawgrass and slough environments” (Wade et al. 1980).

FIRE DISTURBANCE BENEFITS

WITHOUT FIRE…

Cypress domes can be replaced by mixed hardwoods

Flammable leaf litter builds up, increasing the fuel loads = higher risk for more severe fires

“Lack of fire has allowed succession to proceed in many areas, so that herbaceous communities are being invaded by dense shrub thickets and pine on more upland sites, and cypress forests are being invaded by shrubs and hardwoods” (Hofstetter 1984).

ALTERED FIRE REGIMES

Altered timing, frequency, and intensity of fires Drainage of Everglades attributed to change in regimeCan result in peat or muck fires, which may burn over extensive time periodDisrupt entire everglades ecosystem health

Exotic Species Effects on Natural Fire Regimes

• Old World climbing fern (Lygodium microphyllum (Cav.) R. Br.) promotes the spread of wildfires, due to kiting of burning mats into adjacent habitats that would otherwise be protected by fire breaks, and due to its tendency to act as a flame ladder carrying fire high into native tree canopies (Roberts 1996).

FIRE SEASON

Late spring is likely season for firesEcological observations: • (1) late spring is usually the driest season• (2) dry conditions occur through much of

this season• (3) afternoon lightning becomes common

SEASONALITY OF FLOWERING PLANTS IN VARIOUS COMMUNITIES

Prescribed Burns and Fire Season

Therefore, prescribed burn plans should take into account the natural fire regimes that occurs in the preserve. Avoid burning in communities at times when fires would not naturally occurDoing so might alter the ecological effects of the natural fire regime

Fire DisturbanceSimulation Models

Useful for land managers to model fire regimes to estimate the ecological effects of fire disturbance

Hierarchical Fire Frequency Model Yang et al.

Hierarchical fire frequency model Accounts for the separation of fire ignition from fire occurrence Complicated non-stationary temporal patterns of fire can be simulatedImplemented as an improved fire module in LANDIS

Hierarchical Fire Frequency Model Yang et al.

Can simulate a wide range of fire regimes across heterogeneous landscapes with a few parameters and a moderate amount of input data

The model possesses great flexibility for simulating temporal variations in fire frequency for various forest ecosystems and can serve as a theoretical framework for future statistical modeling of fire regimes

Swamp Buggy Fire Truck

Prescribed Burn

Hot palmetto fire

Forest fire in the Everglades

Forest fire in the Everglades

Forest fire in the Everglades

CONCLUSIONS

A disturbance is any relatively discrete event in space and time that disrupts ecosystem, community, or population structure and changes resources, substrate, or the physical environment. Typically cause a significant change in the system.

The ecology of biological communities should be considered in planning fires

CONCLUSIONS

Recovery of natural fire regimes is critical for the overall Everglades restoration effort

Fire disturbance simulation models can be used as a valuable management tool to predict ecological fire disturbance effects.

SOURCESIMAGES

http://www.georgewright.org/0365burch.pdf

LITERATURE SOURCES

http://images.fws.gov

http://fcit.usf.edu/FLORIDA/photos/envirmnt/ffires/1674.htmhttp://www.bigcypressswamp.com

Melanson- personal digital photo collection

James N. Burch PhD, Big Cypress National Preserve, “Fire Management and Resource Management at Big Cypress National Preserve”

SOURCESXu, Ming. 2006. Lecture Notes. Rutgers University.Wade, D., J. Ewel, and R. Hofstetter. 1980. Fire in South Florida Ecosystems. General Technical Report SE-17. Asheville, N.C.: U.S. Department of Agriculture–Forest Service, Southeast Forest Experiment Station.Duever, Michael J. “Big Cypress Regional Ecosystem Conceptual Ecological Model”Robertson 1955, White 1970, Cohen 1974, Duever et al. 1976, Wade et al. 1980, Wu et al. 1996.Davis 1943, Egler 1952Long, Alan J. 1999. “Benefits of Prescribed Burning” University of Florida.Jian Yang, Hong S. He and Eric J. Gustafson. 2003. “A hierarchical fire frequency model to simulate temporal patterns of fire regimes in LANDIS”