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Pine Grasslands and Flatwoods

Pine Grasslands and Flatwoods

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Pine Grasslands and Flatwoods

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  1. Pine Grasslands and Flatwoods Chapters 3 & 4

  2. Pine Grasslands • Pine ecosystems in uplands • Once the dominant ecosystem in North and Central Florida (as well as much of the southestern U.S. • Logged out during the 1800’s • Mostly longleaf (Pinuspalustris) and slash pine (Pinuselliotti)

  3. Pine Grasslands • Technically a “forest,” but trees are scattered and plenty of sunlight reaches the ground • Huge diversity of grasses and forbs (low-growing non-grasses)

  4. Pine Flatwoods • Pine ecosystems in lowlands • Also called savannas or prairies • Flat, fine sandy soils, low in nutrients, slow rates of runoff (often quite moist) • Often there is seasonal standing water • Trees are not as common as in uplands

  5. Pine Flatwoods • Often alternate with pine grasslands, depending on elevation • Diversity is high in both communities; a combination increases diversity still more • Not unusual to have more than 100 plant species per acre.

  6. What Makes Pine Ecosystems so Diverse? FIRE!

  7. Fire and Pine Ecosystems • Types of Fire: • surface or ground fire • crown fire

  8. Fire and Pine Ecosystems • Lightning strikes trees and starts them smouldering • Wind fans the flames and they move quickly through the ground cover • Roots survive, trees are only scorched on the outside

  9. Fire and Pine Ecosystems • Benefits: • Nutrients are returned to the soil • Hardwood trees that could choke out the smaller plants are eliminated • A mosaic is created: some patches burn more than others, increasing diversity • Some plants are stimulated to release seeds – open ground is available for germination • Diseased trees are eliminated

  10. Fire and Pine Ecosystems • Timing of fire is important • If fires are not frequent, litter will build up and the next fire will be too hot • Winter fires aren’t as effective at killing hardwoods • If soil is exposed during the wrong season, plants may not be ready to release seeds • Florida fires should be in late spring/early summer

  11. The Longleaf Pine • Well-adapted to conditions in the southeast • Can withstand fire even as a seedling • Tolerates poor soil • Deep taproot for withstanding hurricanes • Competes against neighboring plants

  12. The Longleaf Pine • Strongly fire-adapted • Widely spaced so crown fires can’t spread • Mature trees host a fungus that makes heartwood more flammable • Needles are highly flammable • Drop seeds in fall, after fire season

  13. The Longleaf Pine • More fire adaptations: • Silver scales on growing tip reflect heat of fire • Long, moist needles protect growing tip from scorching • No low branches • Thick corky bark that flakes off when it burns

  14. The Longleaf Pine Growth Stages: Seedling (grass stage) Mature tree Sapling

  15. Wiregrass (Aristidastricta) - The dominant ground cover in longleaf pine systems - Other species live within & among the bunches of grass - Can live for hundreds of years

  16. Wiregrass • Fire adaptations: • roots are deep enough to escape fire • evenly spaced across the landscape • leaves die but stay on plant • without fire, does not make enough seeds

  17. Legumes Short herbaceous plants that benefit from fire and which can then benefit the soil by adding nitrogen: milkpea lespedeza native mimosas

  18. Species Relationships Longleaf pine and wiregrass form the backbone of an ecosystem that supports hundreds if not thousands of other species fungi insects and other arthropods worms other plants algae mosses reptiles amphibians birds and mammals

  19. Species Relationships When conditions are right for some species, then they can become prey for others - herbivores eat plants, seeds, or berries; insectivores eat insects; carnivores eat the insectivores or herbivores Or, they can provide shelter or some other service - woodpecker holes, gopher tortoise burrows

  20. Species Relationships • Contributions of the Longleaf Pine alone: • straw prevents erosion and conserves moisture • tip-up mounds expose bare soil • snags provide shade and habitat • ash fertilizes • root holes make tunnel systems for shelter

  21. Species Relationships Flatwoods are wetter and have less trees, but still a huge diversity of plants, hundreds of species of insects, and diverse arrays of amphibians Also cranes, burrowing owls, and caracaras Huge quantities of earthworms:

  22. The Gopher Tortoise A keystone species - hundreds of other species rely on the gopher tortoise burrow for shelter - the community’s most significant grazer

  23. The Gopher Tortoise • Natural History: • mates in April and May • lays about 6 eggs, most of which are eaten before they hatch • hatch in August after fires, so plants are short • can live 50+ years; don’t mature until age 18-25 • have 8-10 burrows; burrow may be decades old • burrows may be 40+ feet long

  24. The Gopher Tortoise Species that rely on gopher tortoise burrows:

  25. The Gopher Tortoise Threats to gopher tortoises: Cars Development (habitat loss) Fire suppression They are listed as a threatened species in Florida.

  26. The Fox Squirrel Not your average squirrel – those are grey squirrels Large (~1000g), dark on top with a rusty or yellow underside, white ears, and a long tail

  27. The Fox Squirrel Fox squirrels live in pine ecosystems up and down the east coast. Three-way relationship between the squirrels, pines, and fungi in the soil.

  28. The Fox Squirrel The squirrel: Scatters pine seeds while eating Distributes fungal spores in its feces The fungi: Provide minerals to the pine Provides food for the squirrel The pine: Provides food and shelter for the squirrel Provides sugar to the fungi through its roots

  29. The Fox Squirrel • Only fox squirrels are large enough to open green longleaf pine cones (gray squirrels can’t cut it) • They need a mix of pine ecosystems and hardwoods for nesting • Species of special concern in Florida

  30. The Red-Cockaded Woodpecker • Named for a very small red “cockade” towards the back of the head in the male (very hard to see) • about 8.5” long

  31. The Red-Cockaded Woodpecker • Only woodpecker in Florida that makes a nest cavity in a living pine • The pine must be old enough to heart rot: otherwise it is too hard to drill • Therefore, rcw’smust have old growth pinelands (trees older than 70 years)

  32. The Red-Cockaded Woodpecker • Family members stick around to raise the young of that year – sometimes males will stay for several years before going off to breed • One family needs at least 125 undisturbed acres to hunt various insects (especially ants) and fruits • One nest cavity may take several months to years to complete

  33. The Red-Cockaded Woodpecker • Since they need such large tracts of undisturbed land, rcw’s are threatened by habitat fragmentation • Even if a family group is thriving, there may be no mates for the offspring • Biggest populations are in Apalachicola National Forest

  34. The Red-Cockaded Woodpecker • Unoccupied nest cavities are used by many other species, including snakes, bees, flying squirrels, and eleven species of birds • Federally endangered, listed as threatened in Florida

  35. Values of Pine Ecosystems • Moderate climate, capture runoff, capture or break down toxins, allow for nutrient cycling • Harbor many species that exist nowhere else • Help to spread fire to less flammable communities – increases diversity • Spiritual inspiration

  36. Values of Pine Ecosystems • 30 million hectares (ha) when Europeans arrived; 1.2 million ha remain (96% loss) • Fire suppression, development, and logging are to blame • Needs management, but can still support timber harvests