Transcript Pine Systems

Pine Grasslands and Flatwoods
Chapters 3 & 4
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 (Pinus palustris) and slash pine
(Pinus elliotti)
Pine Grasslands
• Technically a “forest,” but trees are scattered
and plenty of sunlight reaches the ground
• Huge diversity of grasses and forbs (lowgrowing non-grasses)
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
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.
What Makes Pine Ecosystems so
Diverse?
FIRE!
Fire and Pine Ecosystems
Types of Fire:
•
surface or ground fire
•
crown fire
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
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
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
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
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
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
The Longleaf Pine
Growth Stages:
Seedling (grass stage)
Sapling
Mature tree
Wiregrass (Aristida stricta)
- The dominant ground cover in longleaf pine systems
- Other species live within & among the bunches of
grass
- Can live for hundreds of years
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
Legumes
Short herbaceous plants that benefit from fire and
which can then benefit the soil by adding nitrogen:
milkpea
lespedeza
native mimosas
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
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
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
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:
http://www.youtube.com/watch?v=FKOo7NwPiQ
The Gopher Tortoise
A keystone species
- hundreds of other species rely on the gopher
tortoise burrow for shelter
- the community’s most significant grazer
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
The Gopher Tortoise
Species that rely on gopher tortoise burrows:
The Gopher Tortoise
Threats to gopher tortoises:
Cars
Development (habitat loss)
Fire suppression
They are listed as a threatened species in Florida.
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
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.
The Fox Squirrel
The squirrel:
Scatters pine
seeds while
eating
Distributes
fungal spores in
its feces
The pine:
Provides food
and shelter for
the squirrel
Provides sugar
to the fungi
through its
roots
The fungi:
Provide
minerals to the
pine
Provides food
for the squirrel
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
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
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’s must have old growth pinelands
(trees older than 70 years)
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
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
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
http://www.youtube.com/watch?v=4lNizh5Rc
Ck&feature=related
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
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