Ecology and Biology of Melaleuca quinquenervia

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Ecology and Biology of Melaleuca quinquenervia

• Cheryl McCormick-Rote
• Center for Aquatic and Invasive Plants
• UF-IFAS
• Gainesville, Florida 32653
• cheryl_at_ufl.edu

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Background

• Native range and introduction history
• Distribution in FL (and beyond)

Native Range NE Australia
Host Range South of Okeechobee
Regulatory status
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About Melaleuca
Related to tea tree oil species, M.
alternifolia Large, evergreen tree up to 100
tall Large tap root (similar to a carrot)
Success in FL attributed to climate matching
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Identifying Features
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Identifying Features
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Tolerant Resilient

• Soils
• Drought
• Flooding
• Nutrients
• Light
• Fire

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Seasonal Patterns

• Flowers produced w/in 1 yr of germination
• Year-round mostly fall-winter (Oct-March)
• Individual trees flower up to five times per
  year
• New Shoot growth
• Begins in mid winter extends into spring
• Plant Mating Systems Monecious
• Self-compatible out-crossing insect
  pollinated

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Seed Production

• Massive seed production
• 30-70 seed capsules/twig
• Average 264 seeds/capsule
• Over 500,000 seeds/twig/year!
• Why is this significant?
• 3x more than native range
• Contributes to rapid colonization
• High germination
• Release triggered by fire/girdling/stem
  damage

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Seed Dispersal

• No adaptations to facilitate seed
  dispersal
• High germination of seeds floating long
  distance
• Most fall close to parent tree short distance
• Wind Almost all disperse no farther than
  500
• Hurricane-force winds 11 miles
• No animal vectors (birds exception?)

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Seeds Everywhere

• Continuous, light seed rain
• Mature stand bi-weekly rain 2300
  seeds/m2
• Aerial seed bank estimates 100 million
  seeds!
• 15 embryos ? 62 viable ? 75
  germinate
• 7 million germinated lots of
  saplings!
• High percentage of dormant seeds
• Germination
• Saturated soil (w/in 3 days)
• Optimum in full sun, but not required
• Can germinate underwater on soil
• Favors Noisy hydroperiods wet
  conditions

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Habitat Requirements
Climate Warm, but tolerates infrequent
frost Survived severe freeze in Jan.
1977 Soils Flooded, saturated, and
well-drained also always or never
flooded soils Acid sand, organic soils,
alkaline marl, limestone Saline tolerant
Low nutrient soils deep tap root
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Invaded Communities
Virtually south FL upland/wetland communities
Undisturbed pine flatwoods, disturbed sites,
sawgrass marshes, cypress swamps,
savannahs, mangroves, and wet prairies.
Typically invades open-canopy forests,
sparse ecotones, wetlands, and fire-damaged
forests Xeric communities resistant, not
immune Dense hammock communities too shady
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Population Dynamics
MQ estab. in FL vigorous than in AUS No
co-evolved natural enemies to check
populations High-frequency FL fires and low
areas human disturbance ? explosive growth! MQ
infests wet marsh structure/richness PRE Low
structural diversity (grasses dominate) Initial
Savannah temp. increase in both S/R POST
Closed-canopy stand/sparse understory w/ low
structural diversity and community richness.
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Implications for Native Species
Competitive superiority for resources Light
Dense stands inhibit understory dev.
Nutrients Tap roots exploit nutrients at water
table Water Same as above Soil
Properties Decomposition rate change Soil
Fauna Soil micro- and macroarthropod shift
Fire Frequency and intensity changes
Wildlife Foliage/biomass not utilized birds
roost
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Thank You!