EXAM_2_REVIEW_Fire_ecology

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University of Florida *

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Biology

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Jan 9, 2024

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Dadadadada .... It’s the mothafucking S-N-Double-0-P D-0-Double-G!!!! Who’s coming to this exam high on confidence bitch!!!? EXAM 2 REVIEW Student-Provided Questions. Study questions submitted on Canvas as extra credit. Some of the guestions will appear on the exam (possibly with a little modification). Compare & Contrast A. Define the following terms, B. Indicate how they are similar and how they are different, and C. Give an example of each. 1. First order fire effects vs. second order fire effects First Order Fire Effects- Occur during or immediately after a fire and are localized to the burn area. Ex. burned foliage. consumed litter, smoke effects on air, release of carbon. Second Order Fire Effects- Effects that occur after the fire is completed. Ex. Erosion, altered competition, increased tree growth, gap creation. Comparison- First order fire effects occur while the fire is active and are often a direct result of contact with fire. Second order fire effects come later and can be additional effects caused by the first order effects.

2. Mastication/mulching vs. prescribed fire (Part C not applicable) Mastication/Mulching- reduces small trees and shrubs, reduces fire intensity, ROS, and flame height. Increases severity by placing more heat on the ground possibly damaging roots. Prescribed Fire- management tool used to decrease competition, allocate nutrients to targeted species, and promote regeneration of fire adapted species. (Ex. backing, head, strip, flank, etc.) Comparison- Prescribed fire consumes fuels while mastication just chops them and places them on the forest floor. 3. Communities vs. populations Community- Fire regimes and interspecies/interpopulation competition for resources. Fire- related population traits dictate success and survival over others. Ex. Understory oaks vs. overstory pines. Population- Fire regimes interspecies and intraspecies competition for resources. Can vary in age, size distribution, density, and health. Ex. A group of high-density monotypic Rocky Mountain lodgepole pine are adapted to high-severity fires when the population is mature. Comparison- Populations are focused to the intra and interspecies level while communities Include interactions between populations. A community is a group of populations. Typically a population would be intraspecific (one species), while a community consists of groups of populations (interspecific, meaning multiple species) 4. Fire-related trait vs. fire adaptation Fire-related trait- traits which help species survive and compete in fire adapted ecosystems. Adaptation- species or ecosystem traits that evolved because of a relationship with some feature (such as a disturbance). Some environmental pressure (like fire) culled the population, and only members of the population with a mutation that allows them to survive the environmental pressure continue to reproduce. Comparison- fire-related traits do not suggest that fire was the primary selective feature for a particular trait. Fire-related traits are traits that aid a species in dealing with fire but may not have evolved because of fires effect on the plant (some fire related traits could develop because of another disturbance, before fire was a factor) 5. Fire invaders vs. fire evaders Fire invaders- well-dispersed weedy species with short-lived seeds. Ex. cogongrass high flammability and rhizomes. Fire evaders- species with long-lived seeds stored in the soil or in the canopy. Ex. sand pine serotinous cones. Comparison- Invaders ability to disperse and establish rapidly allow it to invade areas with the appropriate conditions. Invaders such as cogongrass use their high flammability and underground rhizomes to kill other species and immediately re-establish themselves. Evaders store seeds in their canopy or in the soil or have serotinous cones which aid them in reestablishing. The main difference is evaders do not survive the fire but set their offspring up for regeneration.

6. Fire avoiders vs. fire resisters Fire Avoiders- shade-tolerant species with slow recolonization rates (usually killed by fire). Ex._ chinese tallow which suppresses fire with its litter. Fire Resisters- Adults can withstand fire, otherwise intolerant of fire. Ex. longleaf pine with thick corky insulative bark and high foliar moisture. Comparison- Avoiders have no resistance to fire and either avoid or suppress it. Resisters can withstand fire to a certain extent and often encourage fire. 7. Fire ecology vs. disturbance ecology Fire Ecology- Study of fire as a natural disturbance. Impacts living organisms, physical environment and the nature of subsequent fires. Examines feedback loops (ecology of fire can be described for these feedbacks at multiple organizational areas) Disturbance Ecology- Study of relatively discrete events in time and space that alter organisms, communities, and ecosystems and/or a change in resource availability or the physical environment. Comparison- The main difference between the two is that fire influences subsequent fires (feedbacks) and affects both biotic and abiotic factors. These characteristics are unique to fire ecology. 8. Fire independent ecosystem vs. fire sensitive ecosystem Fire Independent Ecosystem- Fire is not a recurring process, plant mortality is high when/if fire occurs. Ex. Tropical Forest. Fire Sensitive Ecosystem- Fire plays little or no role in the ecosystem. Conditions are too wet or dry to burn. Ex. Desert or Tundra. Comparison- Fire independent ecosystems do not have naturally occuring fire regimes but will burn if a fire starts. Sensitive ecosystems have no fire and are generally incapable of having large fires. 9. Alternative stable states vs. succession Alternative Stable States- when an ecosystem is considered stable over time despite disturbance and becomes resistant to disturbances unless they are large enough. Ecosystems can have multiple alternative stable states. Succession- The different stages of growth that move into an ecosystem after a type of disturbance. Major disturbance starts at primary succession, lichens, grasses, forbs. Followed by secondary, more grasses, and shrubby species then followed by trees and woody species. Comparison- Alternative stable states are usually a loop of similar vegetation that tends to resist disturbances such as fire. Alternative stable states do not move through stages, but remain stable and become difficult to return to original state. Short Answer Questions. Answer the following questions with 1-2 declarative sentences.

10. List and explain the four general effects of fire on wildlife habitat and give an example for Each. (COVER, NUTRITION, EDGE EFFECTS, SNAGS/LOGS) 1. Snags and logs- cavity nesting birds and food availability for wood-boring insects. 2. Cover- increased edge habitat and decreased forest cover for ground-foraging birds such as quail. 3. Microsite availability- embers immediately post fire for beetles, and downed logs for herps and invertebrates. 4. Forage- increases for large herbivores such as deer. 12. Describe TWO traits of individual plants that allow them to survive and perpetuate their species in fire’s presence? 1. Serotinous cones (sand pine): serotinous cones are an evasion strategy which allows plants to regenerate after fire. The cones are stimulated by high heat and open after fire which provides bare soil and low competition, optimal conditions for new growth. 2. Fire-resistant bark and self pruning (longleaf pine): Thick bark allows mature species to survive fire and self pruning prohibits fire from reaching the crown. 3. Grass stage longleaf seedling: Thick needles in the grass stage of longleaf protect the terminal bud from being damaged. 13. How do plant species regenerate or recolonize following fires that kill/remove aerial foliage? Which of the methods indicated confers an advantage in fire-frequented ecosystems? Why? e Some species will resprout from rhizomatous stems. Aerial and above ground foliage is killed every burn, but the underground material lives and resprouts afterwards. e Some species like sand pine have serotenous cones that require fire or high heat to open cones and disperse seeds. This allows new growth to take over from trees killed in a recent fire. e Longleaf pine in a young plant has protective needles that cover the bud and protect it from fire. The needles will burn and die, but the bud remains protected and alive. 14. Are plant communities “fire dependent”? Why or why not? e Some plant communities can be fire dependent because in the absence of fire the structure, function, and composition of the community changes. Additionally if the fire perpetuates the survival and sustenance of multiple populations then the community could be considered fire dependent. Eire dependent communities are typically dependent on particular fire regimes. 15. The R-A-M model, which describes the evolution of ecosystem engineers, describes a vegetation-fire feedback. Describe each of the three components of the R-A-M model using 1-2 sentences for each component. Describe the feedback developed in the model and indicate how you would apply this model to restoration of southeastern pine savannas. 1. Resistance- plants that in early life cycle stages can survive fires and respond to post- fire conditions. Resistors are able to survive and have higher fitness to fire, leaving more offspring.

2. Adaptation- Selection shifts toward effects of post-fire environmental conditions on survival, growth, and reproduction. Offspring benefit from post-fire environment (increased mineral nutrients, high light conditions, dry open enviroQnment). 3. Modification- modify fire regimes by their effects on fuels which generate positive feedback loops producing conditions for which they are adapted. Pine needles are an example of a modification due to their high flammability when dry and their ability to carry higher intensity fires across a landscape. 16. What steps can land managers take to decrease fire-caused tree mortality? Land managers can burn during the summer when moisture in tissues are high. Rake away or remove thick duff from around trees. Burn more frequently to maintain low fuel levels Use headfires with low residence time. 17. How does wildfire help restore soil nutrients? e High temperatures combust soil organic matter releasing nutrients. e Nutrients from dead matter returns to soil after burn, but can sometimes release too much carbon into soil 18. When tree mortality does result from a fire, how and why does it happen? e Tree mortality is most often caused by a fire burning too hot on the surface of the forest. Duff fires around roots are the leading cause of mortality! 19. Describe the trend represented in the graph below. What fire-diversity hypothesis is represented in the graph? Why do we see this trend in nature? In other words, why does diversity decline at high AND at low levels of disturbance? Speces Divarsiy . —— Leavel of Dasturbance e Species diversity is highest when at intermediate disturbance levels (not too little/often or weak/intense). Intermediate Disturbance Hypothesis. Because species have developed adaptations and traits which allow them to succeed under natural fire conditions. If a disturbance is extremely weak or too strong it won't provide adequate conditions for diversity and growth. Some species need lots of time

between disturbances while some need very little time and a balance leads to the highest diversity. 20. Use the diagram below to describe the relationship between fire frequency, productivity, and aridity. Explain why this pattern is observed. ! % l Productivty ——————> < Auidity Limited by Limited by blomass fire condilions e Fire frequency is greatest at intermediate levels of productivity because at low levels fire cannot spread or start and at high productivity levels fire has a hard time burning dense and moist vegetation. 21. Use the diagram to the right to answer the following questions: Adapted from Nowack! a. With fire and Abrams (2008) Conditions a. Explain the pattern in the diagram. e Without fire the ecosystem state is altered (troughs) and eventually through the process of mesophication will enter an alternative stable state (pit). b. What do the troughs represent? e The troughs represent alterations in areas in regards to structure and composition. The ecosystem can be restored to its natural state without too much struggle. c. Define mesophication. e Environmental conditions continually improve for shade-tolerant species and deteriorate for shade-intolerant, fire-adapted species. d. How does mesophication change the role fire plays in eastern forests?

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