Fire Dependent Ecosystems

 

As development continues to grow around natural areas, understanding the role of fire becomes increasingly important. Residents may occasionally see smoke near preserves or parks, but these signs often indicate proactive land management. To mimic natural fire cycles and prevent uncontrolled wildfires, land managers in Hillsborough County use prescribed fire as a carefully planned land management tool. Burns are conducted only under specific weather conditions and follow strict safety guidelines to protect nearby neighborhoods, roadways, and air quality. By continuing to use prescribed fire as a land management tool, we are protecting native ecosystems, supporting wildlife, and preserving the natural character of the Tampa Bay region.

Fire and Ecosystems

Many of the Earth's ecosystems are adapted to naturally occurring fire cycles. Some even largely depend on fire for survival! Key fire-dependent ecosystems found in and around Hillsborough County include:

Pine Flatwoods - One of the most common natural communities in Hillsborough County, pine flatwoods are dominated by slash pine or longleaf pine with an understory of saw palmetto, wiregrass, and native wildflowers. Regular fire keeps these areas open and prevents hardwoods, like oaks, from taking over.

Sandhill Communities - Sandhills occur on well-drained, sandy soils and are characterized by longleaf pine, turkey oak, and wiregrass. These ecosystems require frequent fire to maintain their open, grassy ground layer and support wildlife such as gopher tortoises.

Florida Scrub - Although less widespread, scrub habitat can still be found in parts of Hillsborough County. Scrub ecosystems need occasional, higher-intensity fires to regenerate. Many scrub plants, such as scrub oaks and rosemary, depend on fire to stimulate new growth.

Dry Prairie and Native Grasslands - Dry prairies and grasslands once covered large portions of Hillsborough County. Fire prevents shrubs and trees from encroaching while allowing grasses and wildflowers to thrive.

Natural Fire Cycle

Fire is an inherent and fundamental process of the Earth's system and has been for millions of years. The occurrence of fire has been one of the most influential evolutionary factors in shaping the ecology of flora all over the world. The cause of natural fires differs based on geography, but the most common cause is due to lightning strikes. It is estimated that lightning strikes the Earth's surface between 1.4 to 2 billion times annually, responsible for 10% of the world's wildland fires. With increased development, prescribed burning is an essential mitigation technique to allow the land to experience its natural cycles while also protecting human investments such as houses, roads, schools, office buildings, hospitals, etc.  

 

Ecology of Fire Dependent Ecosystems

Fire ecology is a branch of ecology that concentrates on wildland fire history and its relationship to the environment. It recognizes fire as a natural process operating as an important component of an ecosystem. Most of the US forest and grasslands are adapted to fire. The role of fire in an ecosystem is vital for promoting biodiversity, enhancing the nutrient cycle, and maintaining the vegetation dynamic. Other ways that fire shapes an ecosystem include: 

• Keeping ecosystems open: Many native plants need sunlight at ground level, which fire helps provide.
• Supporting native wildlife: Open habitats created by fire benefit species such as gopher tortoises, white-tailed deer, and grassland birds.
• Encouraging native plant growth: Some plants, including wiregrass, flower and produce seed primarily after a fire.
• Reducing wildfire risk: Regular prescribed burns reduce the buildup of dry vegetation that can fuel dangerous wildfires.

Pyrophytic Plants 

A pyrophytic plant is a plant that has adapted to survive and thrive in fire-prone environments. Some plants rely on fire for their survival, germination, and propagation. Species such as longleaf pine rely on fire to reduce competition and expose bare soil so their seeds can germinate, and plants like wiregrass often flower and produce seeds only after a fire. Pyrophytic plant species have been categorized into two types: active and passive. 

Active pyrophytic plants are actively promoting fire. They do this with adaptations that produce flammable oils or resin and leaf litter that help spread fire. This helps clear any invasive plant species that may be invading their habitat. Active pyrophytic seeds can have a thick coating or resin-sealed cones that require heat or smoke from the fire to break open, using fire as a reproductive trigger. 

Passive pyrophytic plants do not promote fire but they have evolved to resist the effects of fire, giving them a competitive advantage over surrounding plants that have been damaged fire. They use structural and physiological defenses in order to survive. These adaptations include thick, insulating bark that protects the inner cambium layer from heat damage, high-moisture tissue, and underground buds that can sprout through newly exposed soil from the fire.

Fire Dependent Wildlife 

Restoring fire regimes that are meant to mimic natural occurrences is vital for the survival of many ecosystems. Several well-known Florida species rely on fire-maintained habitats around Tampa Bay. The gopher tortoise, a keystone species, depends on open sandy areas maintained by frequent burns. Its burrow also provides shelter for more than 300 other species including the Eastern Indigo snake. Eastern Indigo snakes depend on Gopher Tortoise burrows for shelter. Much like the gopher tortoises and indigo snakes, Florida scrub jays rely on open space, low lying trees and scattered shrubs in order for them to forage for food. Fire is also a crucial element for vegetation thinning and cavity construction for the red-cockaded woodpecker.

With increased development, habitat loss, and fire suppression, these fire dependent species are federally listed as threatened and protected under the Endangered Species Act. By continuing to use prescribed fire as a land management tool, Hillsborough County is protecting native ecosystems, supporting wildlife, and preserving the natural character of the Tampa Bay region.