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Fire and

Biodiversity

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Species - a naturally occurring population or a group of interbreeding populations that is reproductively isolated (cannot exchange genetic material) from other such populations or groups.

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Niche - an organism’s physical location and function within an ecosystem.
A niche includes:

Habitat
Trophic category (e.g., producer, tertiary consumer, decomposer)
Impact on ecosystem

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Habitat - the place where an animal or plant normally lives or grows, usually characterized either by physical features or by dominant plants.

Examples:

Post oak tree - usually on xeric sites, dry gravelly and sandy ridges and uplands, dry clays, prairies and limestone hills, woodlands and deciduous forests

White-tailed deer - includes areas along streams and rivers, mixed woodlands, farms, forests, and burned shrub fields

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Population - group of individuals of a single species.

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Population Ecology - the study of factors that cause populations to increase or decrease.

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Community - all the populations of organisms living together in the same area, usually interacting or depending on each other for existence.

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Community Ecology - the study of interactions among species and the stability of a community’s species composition.

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Fire tolerant species - organisms that have a lower probability of being injured or killed by fire due to morphological or physiological characteristics.

Such species are also referred to as “fire-resistant.”

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Fire intolerant species - organisms with a relatively high probability of being injured or killed by fire.

Fire-sensitive
Eastern Redcedar (example)
Protected Areas

Fire shadow
Fire refuge

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Fire and Biodiversity

What would happen to a species/community if a fire passed through the area where it is found?

Short-term?
Long-term?

What would happen to a species/community if fire never occurred in the area where it is found?

Short-term?
Long-term?

Why is fire important for species and communities?

Click What would happen to a species/community if a fire passed through the area where it is found? Click Obviously, there could be dramatic short-term impacts, Click but how will the species/community respond in the following months or years? Give students an opportunity to respond. Fire can have direct and indirect impacts on plants and animals found in the Cross Timbers. Direct impacts include burns, heat stress, and predation as animals flee a fire. Indirect impacts include changes in food availability, loss of nesting sites, and increased predation pressure due to a loss of cover. On the community level, a disturbance usually “resets” succession which provides a variety of niche opportunities in a system. Such variety helps to promote biodiversity. Click Next, what would happen to a species/community if fire never occurred in the area where it is found? Click Once again, keep short-term and Click long-term impacts in mind. Give students an opportunity…. The biggest long-term problem with a lack of fire in the Cross Timbers would be the transition from one ecosystem to another (e.g., prairie to savanna to woodland to forest). This would cause the biodiversity in an area to decline. Click The main question that you will address in this lesson is “Why is fire important for species and communities?” Click Any possible reasons why elk populations are struggling in the Cross Timbers? Give students an opportunity…. Plausible explanations include overhunting, disease outbreaks, loss of habitat (lack of fire or land use conversions), etc. Click

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Fire and Biodiversity